CN101762829A - Analog measurement method and device of oil saturation in strata - Google Patents

Abstract

The invention provides an analog measurement method and a device of oil saturation in strata, which belong to a geophysical exploration testing method and an analog device. The analog measurement method of the oil saturation in the strata comprises the steps of simulating an actual stratum (manufacturing an artificial cemented rock core model), arranging an analog well, arranging an oil-water saturation monitoring system in the artificial cemented rock core model, constructing an electric field at the periphery of the wall of the well, obtaining the oil saturation illustrative charts of different pervious courses by measuring the change of the resistivity of the rock core model and the like. The method not only can well simulate and measure the underground geological condition but also can further learn the position of the residual oil of a reservoir and the change rule of the saturation, thereby learning and determining the oil accumulation reserves and the grade in the simulated stratum.

Description

The analog measurement method of oil saturation and device in the stratum

Technical field

The present invention relates to the geophysical survey method of testing, be specially the analog measurement method and the device of oil saturation in the stratum (rock), relate in the geophysical survey analog measurement method and analogue means based on the oil saturation of oil water front.

Background technology

In seismic prospecting and exploitation, because underground existence or residual a large amount of remaining oil need further exploration and exploitation, so the exploratory development researchist just utilizes multiple means exploitation.Before exploitation, the reserves and the grade of necessary evaluation of subterranean oil reservoir are with the expense and the profit of further assessment exploitation.Accurate mensuration for the subsurface deposit grade is a world-class difficult problem, and now the method that generally adopts is to be the measurement of oil saturation to every bit profit content in the underground rock, promptly to the measurement of oil saturation.The main method of measuring about saturation degree has at present: X ray CT method, X ray absorption process, nuclear magnetic resonance method, microwave absorbing method and gamma-ray decay saturation degree detection method, above-mentioned each method all is variations of measurement model section average staturation, the method and the instrument that do not have the measurement point saturation degree, more not method and the instrument that the dynamic change of oil saturation is measured in real time.

Therefore, numerous earth exploration research institution actively develops the research of this measurement stratum mid point profit saturation degree.For example disclose a kind of formation fluid saturation degree evaluating method in No. the 200610112745.2nd, the Chinese patent application, this method utilization is constructed a kind of rock electricity relational model and is estimated formation fluid saturation degree.But in disclosed text only a kind of rock of structure electricity relational model, and do not provide actual formation (rock stratum) model of concrete structure, promptly do not provide the basis of carrying out the rock physics experiment.

U.S. Western Atlas International, Inc. discloses the method for the oily saturation degree in a kind of definite rock stratum in the CN1190741A patented claim of China's application, wherein determine the method for the oily saturation degree in the big formation according to the measurement result of the relative quantity of carbon in the described rock stratum and oxygen, described measurement result is by in separate position, the neutron-induced inelastic gamma ray that detects from described big formation is carried out spectral analysis and is obtained, this method comprises the relative quantity according to described carbon and oxygen, calculates in the described wellhole apparent oil hold-up in each described separate position; According to the difference between the described apparent hold-up of each described separate position, calculate the oily hold-up of the correction in the described wellhole; According to the relative quantity and the described correction hold-up of described carbon and oxygen, calculate in the described rock stratum apparent oil saturation degree in each described separate position; According to the difference between the described apparent saturation degree of each described separate position, calculate the oily saturation degree of the correction in the described rock stratum.

But the oily saturation intent in above-mentioned definite rock stratum lacks physical simulation, can not accurately descend physical state well definitely, so accuracy is not high.And along with the oilfield chemistry displacement of reservoir oil round Realization industrialization, binary and ternary composite driving test site are also in progressively expansion, and the part second class reservoir also will be carried out the chemical displacement of reservoir oil in succession at present, and the chemical displacement of reservoir oil has progressively become the main means of oil field sustainable development.But result of study shows the poly-underground still remaining a large amount of remaining oils in back that drive, therefore, further deepen the exploratory development technology, thereby accurately discern the position of underground remaining oil, all significant to oil-field development production planning, formulation exploitation adjustment measure and raising comprehensive benefit.In addition, develop better profit desaturate monitor simulation means, can further enrich the understanding of water drive, chemical flooding oil-displacement mechanism, for output operation is arranged, output is taken over and performance history in different times carry out and follow the tracks of the adjustment measure targetedly theoretical foundation is provided.

Summary of the invention

In order to solve the problem that exists in the top background technology, the present invention proposes the analog measurement method and the device of oil saturation in a kind of stratum (rock), relate in the geophysical survey analog measurement method and analogue means based on oil saturation, this method not only can have been simulated the subsurface geology situation well, can also further know the position of reservoir remaining oil.

According to first aspect present invention, the analog measurement method of oil saturation in a kind of stratum is provided, this method may further comprise the steps:

(1) simulation actual formation, make the artificial consolidated core model of silica sand and epoxy gluing: at each permeability, select the silica sand of reasonable size-grade distribution meansquaredeviation, by adjusting quartz sand size distribution intermediate value Φ, determine the consumption and the content of epoxy resin of various particle diameter sands, after sand stirred, put into the mould extrusion forming;

(2) at four jiaos of artificial consolidated core model, the mid point and the foursquare center in sideline, each installs a bite well, is furnished with nine mouthfuls of simulation wells altogether, utilizes these nine mouthfuls of wells to come various injection-production methods in the imitation oil displacement experiment process; The electronics Closing Switch is installed in every mouthful of well,, realizes Five-point method pattern, 9 method well patterns or seven-spat pattern injection-production method by switch to each well;

(3) profit desaturate monitor system is set in artificial consolidated core model: this profit desaturate monitor system is made up of transmitting electrode, potential electrode, transmission cable, A/D transfer interface board, digital quantity output board and computing machine, potential electrode is made up of two copper enameled wires of diameter 1mm, potential electrode is before the compacting model, be inserted in the model, equidistantly distribute on the plane; After potential electrode cloth is good, potential electrode and flat cable is welded, and link to each other with computing machine with the A/D change-over panel;

(4) set up electric field around the borehole wall: supplying with intensity by electrodes of A, B two electrodes is the electric current of I, sets up electric field around the borehole wall, promptly sets up electric field in the stratum, measures the potential difference (PD) Δ U of potential electrode M, N point-to-point transmission (between A, B two electrodes) then _MNΔ U _MNVariation promptly reflected the variation of formation resistivity;

(5) return according to Archie equation, the resistivity of being measured is carried out inverse, determine diverse location on the artificial consolidated core model, different oil saturation constantly;

(6) utilize diverse location on the artificial consolidated core model, different oil saturation results constantly to obtain the oil saturation collection of illustrative plates of different pervious courses;

(7) according to the oil saturation collection of illustrative plates of the different pervious courses that obtain, determine reservoir reserve and grade in the simulated formation.

Preferably, the resistivity of setting the consolidated core model is R, is the centre of sphere with the point source in resistivity measurement, is that radius is made a ball with r, and current density is on ball:

$j=\frac{1}{4\mathrm{\π}{r}^2}---\left(1.1\right)$

According to Ohm law differential form,

$E=\frac{\mathrm{<figure-callout\; id="4"\; label="RI"\; filenames="H2010100008081E00011.png,H2010100008081E00012.png"\; state="\{\{state\}\}">RI</figure-callout>}}{4\mathrm{\&pi;}{r}^2}---\left(1.2\right)$

The E integration is got

$U=\frac{\mathrm{<figure-callout\; id="4"\; label="RI"\; filenames="H2010100008081E00011.png,H2010100008081E00012.png"\; state="\{\{state\}\}">RI</figure-callout>}}{4\mathrm{\&pi;r}}---\left(1.3\right)$

If electrode system is made up of A, M, N, then

$U_M=\frac{\mathrm{<figure-callout\; id="4"\; label="RI"\; filenames="H2010100008081E00011.png,H2010100008081E00012.png"\; state="\{\{state\}\}">RI</figure-callout>}}{4\mathrm{\&pi;}\stackrel{\&OverBar;}{\mathrm{AM}}},U_N=\frac{\mathrm{<figure-callout\; id="4"\; label="RI"\; filenames="H2010100008081E00011.png,H2010100008081E00012.png"\; state="\{\{state\}\}">RI</figure-callout>}}{4\mathrm{\&pi;}\stackrel{\&OverBar;}{\mathrm{AN}}}---\left(1.4\right)$

$\mathrm{\&Delta;}{U}_{\mathrm{MN}}=U_M-U_N=\frac{\mathrm{<figure-callout\; id="4"\; label="RI"\; filenames="H2010100008081E00011.png,H2010100008081E00012.png"\; state="\{\{state\}\}">RI</figure-callout>}}{4\mathrm{\&pi;}}(\frac{1}{\stackrel{\&OverBar;}{\mathrm{AM}}}-\frac{1}{\stackrel{\&OverBar;}{\mathrm{AN}}})=\frac{\stackrel{\&OverBar;}{\mathrm{MN}}}{4\mathrm{\&pi;}\stackrel{\&OverBar;}{\mathrm{AM}}\&CenterDot;\stackrel{\&OverBar;}{\mathrm{AN}}}\mathrm{RI}---\left(1.5\right)$

Then

$R=\frac{4\mathrm{\&pi;}\stackrel{\&OverBar;}{\mathrm{AM}}\&CenterDot;\stackrel{\&OverBar;}{\mathrm{AN}}}{\stackrel{\&OverBar;}{\mathrm{MN}}}\&CenterDot;\frac{\mathrm{\&Delta;}{U}_{\mathrm{MN}}}{I}---\left(1.6\right)$

K factor is:

$K=\frac{4\mathrm{\&pi;}\stackrel{\&OverBar;}{\mathrm{AM}}\&CenterDot;\stackrel{\&OverBar;}{\mathrm{AN}}}{\stackrel{\&OverBar;}{\mathrm{MN}}}---\left(1.7\right)$

Low frequency (the frequency stepping is adjustable) square wave ac is supplied with in resistivity measurement, measures the potential difference (PD) Δ U between M and the N _MN, and be calculated as follows resistivity:

$R=K\frac{\mathrm{\&Delta;}{U}_{\mathrm{MN}}}{I}---\left(1.8\right)$

R＝KR _L????????????????????????????????????????????????(1.9)

K is a K factor, and it is only relevant with electric system size, type; R _LBe two resistance values between electrode M, the N, so only need record R _LJust can get resistivity by calculating.

Further, water drive to moisture 98% back implantation concentration is the super high molecular weight polymer solution 0.25PV of 1000mg/L, the concentration of reinjecting is the middle heavy polymer 0.32PV of 1000mg/L, and polymer solution is surveyed each electrode resistance by the preparation of 1000mg/LKCl solution every half an hour;

Measured the resistivity on stratum, calculated water saturation by the Archie formula:

$I=\frac{\mathrm{Rt}}{\mathrm{Ro}}=\frac{b}{S{w}^n}---\left(1\right)$

$S_w={\left(\frac{b}{\left(\frac{R_t}{R_0}\right)}\right)}^{\frac{1}{n}}---\left(2\right)$

In the formula: Rt-rock oil-containing resistivity (resistivity of actual measurement);

The complete moisture resistivity of Ro-rock;

The Sw-water saturation;

The b-coefficient;

The n-saturation exponent.

The method of determining coefficient b and n has two kinds of rock core displacement test method and empirical coefficient methods, and clean sandstone is generally got b=1, n=2;

By the Archie formula resistivity that records is converted into water saturation, only contains You Heshui in the pore media because of the artificial model set up, because of S _w+ S _o=1, so just can obtain oil saturation S _o

Preferably, a bite well is respectively opened at cornerwise two ends in artificial consolidated core model, adopts notes one to adopt pattern shape, can be used for simulating 1/4th element patterns of five-spot network unit.

According to a second aspect of the present invention, the analogue measurement device of oil saturation in a kind of stratum is provided, it is characterized in that making and the akin artificial consolidated core of formation physical property, wherein make artificial consolidated core and carry out according to following requirement:

(1) adopted pressure experiment machine pressurization manufacture craft, be that jointing compound is made artificial consolidated core with epoxy resin;

(2 reservoir physical properties according to the oil field of being simulated are selected the reasonable size-grade distribution variances sigma of silica sand, are controlling under the constant situation of manufacture craft condition, by adjusting quartz sand size distribution intermediate value Φ, control core permeability;

(3) core porosity control: pressurization intensity be respectively 3,5,7.5,10 and 15MPa under make a series of rock cores, drill through rock core behind the isothermal curing, analyze the Changing Pattern of factor of porosity with pressure;

(4) core wettability control:

1) the slightly oil-wet rock core is made: 1/3rd of silica sand consumption is carried out silicone oil handle, make the rock core of producing be slightly oil-wet;

Part 40～60,60～100 and 100～200 order silica sands are handled with silicone oil, be prepared into silicon oil sand.From coarse to fine selecting for use always (at first carried out the silicone oil processing to coarse sand 40～60 orders with 1/3rd of sand weight when making rock core, if the sand amount of handling does not reach 1/3rd of total sand amount, handle 60～100 order sand again, up to total sand amount of handling account for whole sand amounts 1/3rd till;

The silicon oil sand preparation process is as follows: sand is weighed 1% silicone oil and dilute with 20 times of sherwood oils, stir with silica sand, volatilization was put into electric drying oven with forced convection and is heated to 180 ℃, constant temperature 8 hours after 20 hours under the room temperature;

2) the wet rock core of neutrality and water is made: with unprocessed silica sand and epoxy resin, adopt 20% dibutyl phthalate (DBP) to make hardening agent as toughner, 7% ethylenediamine, the artificial consolidated core of made has the neutral wetting property of oleophylic partially;

(5) rock core pore texture control: get the low-permeability natural core, be crushed to 20-40 order particle, behind the artificial consolidated core sand cutting, evenly add 30% natural core chip before the moulding, the artificial consolidated core hole of made is shouted to distribute and is approached natural core after the extrusion forming.

Preferably, in the stratum in the analogue measurement device of oil saturation, described core permeability is controlled to be under pressurization intensity 3MPa and σ=0.8 condition, selects for use Φ to be respectively 2.1,2.4,2.7,3.0,3.3,3.6,3.9 and 4.2 size composition and has made a series of artificial consolidated cores.

According to a third aspect of the present invention, a kind of method of making the analogue measurement device of oil saturation in the above-mentioned stratum is provided, it comprises makes artificial consolidated core according to the following steps:

1. by permeability, factor of porosity and sand using amount, select Φ value and pressurization intensity, and calculate each the grade silica sand consumption and the jointing compound that comprise silicon oil sand and form proportioning;

2. take by weighing each grade silica sand by prescription, mix and cross 20 mesh sieves thoroughly;

3. prepare the epoxy gluing agent in proportion;

4. sand cutting is also crossed 10 mesh sieves;

5. pack into mould and pressurizeing constant 10 minutes;

6. take apart a die, 120 ℃ of constant temperature are more than six hours;

7. as required, cut, drill through, shaping;

8. perm-plug method obtains needed artificial consolidated core.

Use said method and device, further deepen the exploratory development technology, thereby accurately discern the position of underground remaining oil and the Changing Pattern of profit saturation degree, all significant to oil-field development production planning, formulation exploitation adjustment measure and raising comprehensive benefit.And, in non-homogeneous pay different layers position, by profit saturation degree migration rule, oil content cloth and the sweep efficiency of measuring, quantized to enlarge swept volume and improved oil displacement efficiency in of the contribution of each stage of displacement different pervious course recovery ratio, all have outstanding effect.

Brief Description Of Drawings

Fig. 1 is artificial consolidated core model permeability and quartz sand size distribution intermediate value relation curve;

Fig. 2 is that the core permeability of artificial consolidated core model is with pressure history;

Fig. 3 is the core porosity and making pressure dependence curve of artificial consolidated core model;

Fig. 4 is natural core and untreated artificial consolidated core pore throat size distribution contrast;

Fig. 5 is the artificial consolidated core pore throat size distribution contrast after natural core and the processing;

Fig. 6 is an interlayer non-homogeneous model synoptic diagram;

Fig. 7 is the photo figure in kind of profit desaturate monitor system;

Fig. 8 is that the rectangular model leading edge of one dimension homogeneous detects synoptic diagram;

Fig. 9 is different electrodes monitoring point oil saturation and a resistivity relation curve on the steady state method one dimension core;

Figure 10 is the normal sonde synoptic diagram in the analogue measurement device of oil saturation of the present invention;

Figure 11 is that profit saturation degree measuring system signal flow in the analogue measurement device of oil saturation of the present invention is to graph of a relation.

Embodiment

According to technical scheme of the present invention, the analog measurement method and the measurement mechanism of oil saturation in a kind of stratum is provided, wherein the design philosophy of this method is:

(1) physical model of research and making monitoring chemical displacement of reservoir oil water saturation;

(2) in the model displacement process, utilize data acquisition system (DAS), monitor the variation of each layer, each point resistivity;

(3) gather out each situation of change of resistivity constantly of different pervious courses by data acquisition system (DAS);

(4) return according to Archie equation, the resistivity of being measured is carried out inverse, finally determine diverse location on the model, different oil saturation constantly;

(5) utilize diverse location on the model, different oil saturation results constantly to obtain the oil saturation collection of illustrative plates of different pervious courses;

(6) determine reservoir reserve and grade in the simulated formation according to the oil saturation collection of illustrative plates of the different pervious courses that obtain.

Particularly, the analog measurement method of oil saturation may further comprise the steps in the stratum:

(1) simulation actual formation, make the artificial consolidated core model of silica sand and epoxy gluing: at each permeability, select the silica sand of reasonable size-grade distribution meansquaredeviation, by adjusting quartz sand size distribution intermediate value Φ, determine the consumption and the content of epoxy resin of various particle diameter sands, after sand stirred, put into the mould extrusion forming, at 120 ℃ of following isothermal curings of temperature; The different layers position in common different oil fields, its oil reservoir size-grade distribution variances sigma difference, size-grade distribution variances sigma as the Daqing oil field Putaohua reservoir is 1.0, concern by finding out between quartz sand size distribution intermediate value Φ and the different permeabilities, can determine the typical curve of permeability and intermediate value Φ in the Putaohua reservoir.

(2) at four jiaos of artificial consolidated core model, the mid point and the foursquare center in sideline, each installs a bite well, is furnished with nine mouthfuls of simulation wells altogether, utilizes these nine mouthfuls of wells to come various injection-production methods in the imitation oil displacement experiment process; The electronics Closing Switch is installed in every mouthful of well,, realizes Five-point method pattern, 9 method well patterns or seven-spat pattern injection-production method by switch to each well;

(3) profit desaturate monitor system is set in artificial consolidated core model: this profit desaturate monitor system is made up of transmitting electrode, potential electrode, transmission cable, A/D transfer interface board, digital quantity output board and computing machine, potential electrode is made up of two copper enameled wires of diameter 1mm, potential electrode is before the compacting model, be inserted in the model, equidistantly distribute on the plane; After potential electrode cloth is good, potential electrode and flat cable is welded, and link to each other with computing machine with the A/D change-over panel;

(4) set up electric field around the borehole wall: by electrodes of A, B two electrode supplying electric current intensity is the electric current of I, around the borehole wall, set up electric field, promptly in the stratum of artificial consolidated core model, set up electric field, measure the potential difference (PD) Δ U of potential electrode M, N point-to-point transmission (between A, B two electrodes) then _MNΔ U _MNVariation promptly reflected the variation of formation resistivity;

(5) return according to Archie equation, the resistivity of being measured is carried out inverse, determine diverse location on the artificial consolidated core model, different oil saturation constantly;

(6) utilize diverse location on the artificial consolidated core model, different oil saturation results constantly to obtain the oil saturation collection of illustrative plates of different pervious courses;

(7) according to the oil saturation collection of illustrative plates of the different pervious courses that obtain, determine reservoir reserve and grade in the simulated formation.

Wherein, the resistivity of setting the consolidated core model is R, is the centre of sphere with the point source in resistivity measurement, is that radius is made a ball with r, and current density is on ball:

$j=\frac{1}{4\mathrm{\&pi;}{r}^2}---\left(1.1\right)$

According to Ohm law differential form,

$E=\frac{\mathrm{<figure-callout\; id="4"\; label="RI"\; filenames="H2010100008081E00011.png,H2010100008081E00012.png"\; state="\{\{state\}\}">RI</figure-callout>}}{4\mathrm{\&pi;}{r}^2}---\left(1.2\right)$

The E integration is got

$U=\frac{\mathrm{<figure-callout\; id="4"\; label="RI"\; filenames="H2010100008081E00011.png,H2010100008081E00012.png"\; state="\{\{state\}\}">RI</figure-callout>}}{4\mathrm{\&pi;r}}---\left(1.3\right)$

If electrode system is made up of A, M, N, then

$U_M=\frac{\mathrm{<figure-callout\; id="4"\; label="RI"\; filenames="H2010100008081E00011.png,H2010100008081E00012.png"\; state="\{\{state\}\}">RI</figure-callout>}}{4\mathrm{\&pi;}\stackrel{\&OverBar;}{\mathrm{AM}}},U_N=\frac{\mathrm{<figure-callout\; id="4"\; label="RI"\; filenames="H2010100008081E00011.png,H2010100008081E00012.png"\; state="\{\{state\}\}">RI</figure-callout>}}{4\mathrm{\&pi;}\stackrel{\&OverBar;}{\mathrm{AN}}}---\left(1.4\right)$

$\mathrm{\&Delta;}{U}_{\mathrm{MN}}=U_M-U_N=\frac{\mathrm{<figure-callout\; id="4"\; label="RI"\; filenames="H2010100008081E00011.png,H2010100008081E00012.png"\; state="\{\{state\}\}">RI</figure-callout>}}{4\mathrm{\&pi;}}(\frac{1}{\stackrel{\&OverBar;}{\mathrm{AM}}}-\frac{1}{\stackrel{\&OverBar;}{\mathrm{AN}}})=\frac{\stackrel{\&OverBar;}{\mathrm{MN}}}{4\mathrm{\&pi;}\stackrel{\&OverBar;}{\mathrm{AM}}\&CenterDot;\stackrel{\&OverBar;}{\mathrm{AN}}}\mathrm{RI}---\left(1.5\right)$

Then

$R=\frac{4\mathrm{\&pi;}\stackrel{\&OverBar;}{\mathrm{AM}}\&CenterDot;\stackrel{\&OverBar;}{\mathrm{AN}}}{\stackrel{\&OverBar;}{\mathrm{MN}}}\&CenterDot;\frac{\mathrm{\&Delta;}{U}_{\mathrm{MN}}}{I}---\left(1.6\right)$

K factor is:

$K=\frac{4\mathrm{\&pi;}\stackrel{\&OverBar;}{\mathrm{AM}}\&CenterDot;\stackrel{\&OverBar;}{\mathrm{AN}}}{\stackrel{\&OverBar;}{\mathrm{MN}}}---\left(1.7\right)$

Low frequency (the frequency stepping is adjustable) square wave ac is supplied with in resistivity measurement, measures the potential difference (PD) Δ Umn between M and the N and is calculated as follows resistivity:

$R=K\frac{\mathrm{\&Delta;}{U}_{\mathrm{MN}}}{I}---\left(1.8\right)$

R＝KR _L????????????????????????????(1.9)

K is a K factor, and it is only relevant with electric system size, type; R _LBe two resistance values between electrode M, the N, so only need record R _LJust can get resistivity by calculating.

Preferably, by adding accurate voltage for two sections at electrodes of A, B, form a loop through the measuring resistance and the resistance between electrode value of precision again, magnitude of voltage between potential electrode can obtain two interelectrode resistance values by converting, thereby by calculating saturation degree.The saturation degree measuring probe adopts four electrode systems: A, B to be the power supply utmost point, and M, N are potential electrode, and three electrodes are arranged on electrode bar, and loop electrode B is at a distance.Will be in finite medium accurate measured resistivity, electrode system should be too not big, could satisfy the condition of point source as far as possible, but owing to be subjected to the restriction of probe manufacturing technology, that can not do is very little.The potential electrode diameter is 1.2mm at present, and two distance between electrodes are 10mm.

In the stratum, in the analog measurement method of oil saturation, at first measure the resistivity on stratum, calculate water saturation by following formula:

$I=\frac{\mathrm{Rt}}{\mathrm{Ro}}=\frac{b}{S{w}^n}---\left(1\right)$

$S_w={\left(\frac{b}{\left(\frac{R_t}{R_0}\right)}\right)}^{\frac{1}{n}}---\left(2\right)$

In the formula: Rt-rock oil-containing resistivity (resistivity of actual measurement),

The complete moisture resistivity of Ro-rock,

The Sw-water saturation,

The b-coefficient,

The n-saturation exponent;

For clean sandstone, b=1, n=2;

By the Archie formula resistivity that records is converted into water saturation, only contains You Heshui in the pore media because of the artificial model set up, because of S _w+ S _o=1, so just can obtain oil saturation S _o

In addition, also can respectively open a bite well in cornerwise two ends in artificial consolidated core model, adopt notes one to adopt pattern shape, can be used for simulating 1/4th element patterns of five-spot network unit.

The analogue measurement device of making oil saturation in the stratum in the present invention also is the very gordian technique that the inventor invents, it requires to make and the akin artificial consolidated core of formation physical property, wherein makes artificial consolidated core and requires to carry out according to following technical matters:

(1) adopted pressure experiment machine pressurization manufacture craft, be that jointing compound is made artificial consolidated core with epoxy resin;

(2 reservoir physical properties according to the oil field of being simulated are selected the reasonable size-grade distribution variances sigma of silica sand, are controlling under the constant situation of manufacture craft condition, by adjusting quartz sand size distribution intermediate value Φ, control core permeability;

(3) core porosity control: pressurization intensity be respectively 3,5,7.5,10 and 15MPa under make a series of rock cores, drill through rock core behind the isothermal curing, analyze the Changing Pattern of factor of porosity with pressure;

(4) core wettability control:

1) the slightly oil-wet rock core is made: 1/3rd of silica sand consumption is carried out silicone oil handle, make the rock core of producing be slightly oil-wet;

Part 40～60,60～100 and 100～200 order silica sands are handled with silicone oil, be prepared into silicon oil sand.From coarse to fine selecting for use always (at first carried out the silicone oil processing to coarse sand 40～60 orders with 1/3rd of sand weight when making rock core, if the sand amount of handling does not reach 1/3rd of total sand amount, handle 60～100 order sand again, up to total sand amount of handling account for whole sand amounts 1/3rd till;

The silicon oil sand preparation process is as follows: sand is weighed 1% silicone oil and dilute with 20 times of sherwood oils, stir with silica sand, volatilization was put into electric drying oven with forced convection and is heated to 180 ℃, constant temperature 8 hours after 20 hours under the room temperature;

2) the wet rock core of neutrality and water is made: with unprocessed silica sand and epoxy resin, adopt 20% dibutyl phthalate (DBP) to make hardening agent as toughner, 7% ethylenediamine, the synthetic core of made has the neutral wetting property of oleophylic partially;

(5) rock core pore texture control: get the low-permeability natural core, be crushed to 20-40 order particle, behind the synthetic core sand cutting, evenly add 30% natural core chip before the moulding, the synthetic core hole of made is shouted to distribute and is approached natural core after the extrusion forming.

Preferably, described core permeability is controlled to be under pressurization intensity 3MPa and σ=0.8 condition, selects for use Φ to be respectively 2.1,2.4,2.7,3.0,3.3,3.6,3.9 and 4.2 size composition and has made a series of synthetic cores.

In order to illustrate in greater detail technical scheme of the present invention, details are as follows with technology related to the present invention:

1.1 artificial consolidated core manufacturing technology

1.1.1 processing technology routine is selected

The task of physical model development is exactly to guarantee to improve its permeability, the isoparametric control accuracy of factor of porosity on its rerum natura basis similar to actual formation, making homogeneous and the non-homogeneous model produced have better repeatability.

Domestic artificial consolidated core cementation method mainly contains epoxy gluing and sintering process at present.Because sintering process needs higher temperature, and is bigger for the manufacture difficulty of large scale model, solidify and epoxy resin can normal temperature (room temperature-120 ℃), thereby the epoxide-resin glue connection has obtained using comparatively widely at home.This work is jointing compound with epoxy resin exactly, inquires into rock core and makes parameter control method.

On moulding process, grand celebration and Beijing petroleum exploration and development research institute adopt the rammer machine compacting method of shaking, and the mechanical shock that promptly utilizes the rammer machine that shakes to produce is tamped the silica sand after the glue mixing.This work is to have adopted pressure experiment machine pressurization manufacture craft.Compare with the compacting method, this technology has significantly improved the repeatability of model and the even type at each position, is that rock core is made comparatively desirable molding technology thereof.

1.1.2 core permeability control method

On the core permeability control method, forefathers adopt following method: the silica sand with size fractionated is mixed with benchmark sand according to a certain ratio, by adjusting the ratio of benchmark sand and fine sand, to make than the low-permeability rock core, the ratio of benchmark sand and coarse sand of adjusting is made the high osmosis rock core.Following method is adopted in this work:

For natural petroclastic rock, its particle size distribution has certain rules.Generally speaking, if the definition Φ=-log ₂D, wherein d is a particle diameter, then the Φ value distributes and is similar to normal distribution law.That is to say that the distribution parameter of petroclastic rock particle Φ value directly influences its physical parameter.

In the rock core manufacturing process, quartz sand size distributes and determines the principal element of rock core physical property beyond doubt, if control certain pressurization intensity, colloid consumption and size-grade distribution variances sigma, then certainly existing very strong dependence between Φ (Φ intermediate value) and the core permeability.

Under pressurization intensity 3MPa and σ=0.8 condition, select for use Φ to be respectively 2.1,2.4,2.7,3.0,3.3,3.6,3.9 and 4.2 size composition, made artificial consolidated core.Fig. 1 has provided the relation curve (curve 1) between Φ and the core permeability.As can be seen, has good correlativity between core permeability and the Φ.

With traditional preparation benchmark sand, to compare with the mode of fine sand (or coarse sand) proportioning control core permeability by adjusting benchmark sand, the mode of adjusting Φ control core permeability has certain advantage.On the one hand, because the size-grade distribution variances sigma is identical, pore texture is more approaching between the different permeability rock cores, thereby has more science.On the other hand, simplified datum curve workload (datum curve is kept to by two), thereby had more practicality.

In sum, selecting the reasonable size-grade distribution variances sigma of silica sand and controlling under the constant situation of manufacture craft condition,, can control core permeability preferably by adjusting quartz sand size distribution Φ value.This core permeability control method has science and practicality preferably.

1.1.3 core porosity control method

Rock core is made pressurization intensity and is directly affected physical parameters such as model permeability, factor of porosity.In order to study the influence of pressurization intensity, select the silica sand (Φ is respectively 2.1,2.4,2.7,3.0,3.3,3.6,3.9) of different proportionings for use, the pressurization intensity be respectively 3,5,7.5,10 and 15MPa under make rock core, drill through rock core behind the isothermal curing, analyze its rerum natura Changing Pattern.

Fig. 2 has provided the rock core of the silica sand made of different proportionings simultaneously, and its permeability and rock core are made the relation between the pressurization intensity.Therefrom as can be seen, with the raising of pressurization intensity, core permeability obviously reduces.

Fig. 3 has provided core porosity and has made pressure history with rock core.

By the combination of Fig. 1 and Fig. 3 typical curve, can reach the purpose of artificial glued core permeability of control and factor of porosity.But owing to restricted by the rock core manufacturing conditions, the selection that rock core is made pressure has certain scope, thereby the control of artificial glued core porosity has certain limitation.

1.1.4 core wettability control method

(1) the slightly oil-wet rock core is made

/ 3rd of a silica sand consumption is carried out silicone oil handle, make the rock core of producing be slightly oil-wet.

Part 40～60,60～100 and 100～200 order silica sands are handled with silicone oil, be prepared into silicon oil sand.From coarse to fine selecting for use always (at first carried out the silicone oil processing to coarse sand 40～60 orders with 1/3rd of sand weight when making rock core, if the sand amount of handling does not reach 1/3rd of total sand amount, handle 60～100 order sand again, up to total sand amount of handling account for whole sand amounts 1/3rd till.

The silicon oil sand preparation process is as follows: sand is weighed 1% silicone oil and dilute with 20 times of sherwood oils, stir with silica sand, volatilization was put into electric drying oven with forced convection and is heated to 180 ℃, constant temperature 8 hours after 20 hours under the room temperature.

(2) the wet rock core of neutrality and water is made

With unprocessed silica sand and epoxy resin (E-44), adopt 20% dibutyl phthalate (DBP) to make hardening agent as toughner, 7% ethylenediamine, the artificial consolidated core of made has the neutral wetting property of oleophylic partially.

Experimental study shows that except that quartz sand surface character the surface nature of jointing compound plays an important role to artificial glued core wettability equally.In hardening agent, add the wetting property that a certain amount of adjuvant can significantly change the made rock core.By a large amount of screening experiment work, determined a kind of oil-soluble non-ionics (OP-10), number percent is added in control, the artificial glued core wettability of making is transformed to water wettability by the inclined to one side lipophilicity of neutrality, go up the purpose of the artificial glued core wettability of control thereby acquire a certain degree.

Utilize the Amott method to measure the wetting state that said method is produced rock core.Table 1 has provided measurement result.Therefrom as can be seen, utilize said method, can control artificial glued core wettability preferably.

The core wettability that the silica sand that table 1. is handled through distinct methods is made is measured

Rock core	Silicon oil sand	Normal sands	??0.3％OP	??1.0％OP
					Wetting index	??0.4	??0.8	??1.4	??3.6
Wetting state	Slightly oil-wet	Neutral oleophylic partially	Neutrality is hydrophilic partially	Slightly water-wet

1.1.5 rock core pore texture control method

In natural core, the rock core hole that records with mercury intrusion method is shouted distribution curve and is bimodal attitude, and ordinary epoxy resin consolidated core pore size distribution is unimodal.Fig. 4 has contrasted the difference of the pore size distribution state of natural core and this artificial consolidated core.

The method of natural core chip is mixed in employing in silica sand can produce the artificial consolidated core with micropore.Get the low-permeability natural core, be crushed to 20-40 order particle; Behind artificial consolidated core sand cutting, evenly add 30% natural core chip before the moulding, the artificial consolidated core hole of made is shouted to distribute and is approached natural core (as shown in Figure 5) after the extrusion forming.

1.2 artificial consolidated core production standard

1. material is prepared:

A. silica sand: quartz content is more than 99%.Again screening with the riddler machine is that 40-60 order, 60-100 order, 100-200 order, 200 orders are with inferior several levels.

B. epoxy resin: E-44.

C. face dibatyl phithalate: more than the chemical pure.

D. ethylenediamine: more than the chemical pure.

D. acetone: more than the chemical pure.

F. sherwood oil: more than the chemical pure.

2. rock core manufacture craft principle

(1) processing technology routine is selected

After epoxy resin adds hardening agent and toughner, through after the acetone diluted with the abundant mix of silica sand, the mould extrusion forming of packing into, 120 ℃ of following isothermal curings.

(2) core permeability control method

According to preparation core permeability control criterion curve map 1,, realize artificial glued core permeability control by adjusting quartz sand size distribution Φ value

(3) core porosity control method

By the combination of Fig. 1 and Fig. 3 typical curve, can reach the purpose of artificial glued core permeability of control and factor of porosity

(4) core wettability control method

A. the slightly oil-wet rock core is made

/ 3rd of a silica sand consumption is carried out silicone oil handle, the rock core of producing is slightly oil-wet.

The silicon oil sand preparation process is as follows: sand is weighed 1% silicone oil and dilute with 20 times of sherwood oils, stir with silica sand, volatilization was put into electric drying oven with forced convection and is heated to 180 ℃, constant temperature 8 hours after 20 hours under the room temperature.

B. the wet rock core of neutrality and water is made

With unprocessed silica sand and epoxy resin (E-44), adopt 20% dibutyl phthalate (DBP) to make hardening agent as toughner, 7% ethylenediamine, the artificial consolidated core of made has the neutral wetting property of oleophylic partially.In hardening agent, add surfactant (OP-10), the artificial glued core wettability of making is transformed to water wettability by the inclined to one side lipophilicity of neutrality.

(5) rock core pore texture control method

Get the low-permeability natural core, be crushed to 20-40 order particle, behind artificial consolidated core sand cutting, evenly add 30% natural core chip before the moulding, the artificial consolidated core hole of made is shouted to distribute and is approached natural core after the extrusion forming.

3. rock core manufacture craft parameter is determined

(1) Φ and pressurization intensity are determined

Pressurization intensity and Φ value are determined by typical curve Fig. 3 by artificial glued core permeability and factor of porosity.

(2) content of epoxy resin

Make certain artificial consolidated core, if the following various component silica sand consumptions of 40～60 orders, 60～100 orders, 100～200 and 200 orders are respectively W1, W2, W3 and W4, according to epoxy resin and the proportional principle of specific area, the total epoxy consumption:

W＝C×(16.8×W1+29.0×W2+57.5×W3+150×W4)

Wherein constant C recommends to be chosen to be 0.0012.

(3) toughner consumption

Select for use adjacent benzene-dibutyl carboxylic acid as epoxy resin toughener, consumption is 20% of a content of epoxy resin.

(4) hardener dose

Epoxy curing agent is selected ethylenediamine for use, its preferably solidification range be 6～9% of content of epoxy resin, during modelling, its consumption is 7% of a weight epoxy.

(5) thinning agent consumption

Use acetone as thinning agent, its consumption X adopts and the proportional principle of silica sand specific surface, and various perviousness modellings are sand cutting preferably all:

X＝D×(16.8×W1+29.0×W2+57.5×W3+150×W4)

Wherein constant D is chosen to be 0.00065.

4. rock core manufacture craft flow process

1. by design permeability, factor of porosity and sand using amount, select Φ value and pressurization intensity, and calculate each grade silica sand (comprising silicon oil sand) consumption and jointing compound composition proportioning.

2. take by weighing each grade silica sand by prescription, mix and cross 20 mesh sieves thoroughly.

3. prepare the epoxy gluing agent in proportion.

4. sand cutting is also crossed 10 mesh sieves.

5. pack into mould and pressurizeing constant 10 minutes.

6. take apart a die, 120 ℃ of constant temperature are more than six hours.

7. as required, cut, drill through, shaping.

1.3 the large-scale three dimensional physical model is made and the installation of profit desaturate monitor system

1.3.1 the large-scale three dimensional physical model is made

Model adopts silica sand and epoxy gluing model, to each permeability, select the reasonable size-grade distribution meansquaredeviation of silica sand, by adjusting quartz sand size distribution Φ (intermediate value), determine the consumption and the content of epoxy resin of various particle diameter sands, after sand stirred, put into the mould extrusion forming.

Model plane geometry is of a size of 60cm * 60cm * 4.5cm, from geometric similarity, and its various injection-production method in can the imitation oil displacement experiment process.At four jiaos of model, the mid point and the foursquare center in sideline, each installs a bite well.Like this by to the switch of each well, just can realize Five-point method pattern, 9 method well patterns and seven-spat pattern injection-production method.This model that provides is respectively to open a bite well at cornerwise two ends of model, adopt notes one to adopt pattern shape, be used for simulating 1/4th of five-spot network unit, simulation be the interlayer non-homogeneous model, model synoptic diagram and parameter see Fig. 6, Fig. 7 and the table 3-1.

Table 3-1 interlayer non-homogeneous model basic physical properties parameter list

1.3.2 the installation of profit desaturate monitor system

Chemical displacement of reservoir oil water saturation monitoring system is made up of transmitting electrode, potential electrode, transmission cable, digital quantity output board, A/D transfer interface board and computing machine, potential electrode is made up of two copper enameled wires of diameter 1mm, potential electrode is before the compacting model, be inserted in the model, equidistantly distribute by 10mm on the plane; After potential electrode cloth is good, potential electrode and flat cable is welded, and link to each other with computing machine with the A/D change-over panel; This treatment scheme is 8 pairs of potential electrode of each row difference cloth of each row in the plane, have 64 potential electrode check points; Vertically go up the layering situation of pressing model, an end of potential electrode inserts layer to be measured middle part, and the other end exposes in mold surface.This has just realized the purpose that use is different constantly, the potential electrode of diverse location is measured saturation degree.

1.4 determining of chemical displacement of reservoir oil water saturation

1.4.1 chemical displacement of reservoir oil water saturation measuring principle

Usually the matrix of preserving hydrocarbon zone is nonconducting, and the water-soluble salt of having separated in the rock, salt ionization in water goes out positive and negative ion, under effect of electric field, and ion motion, thus form electric current.Salinity is big more, and conductance is big more, and resistivity is more little.Therefore, the variation of profit saturation degree can be determined by the variation of the inner each point resistivity value of model in the displacement process.The size of resistivity mainly is subjected to the influence of shape, water salinity and the oil-water ratio of pore media in the stratum.When pore media was constant, the size of resistivity was only relevant with the ratio of water salinity, oil-containing water.

2, one-dimensional model resistivity measurement step and resistivity are to the oil saturation transforming principle

Water drive to moisture 98% back implantation concentration is the super high molecular weight polymer solution 0.25PV of 1000mg/L, the concentration of reinjecting is the middle heavy polymer 0.32PV of 1000mg/L, polymer solution is surveyed each electrode resistance by the preparation of 1000mg/LKCl solution every half an hour.

Measured the resistivity on stratum, calculated water saturation by the Archie formula:

$I=\frac{\mathrm{Rt}}{\mathrm{Ro}}=\frac{b}{S{w}^n}---\left(1\right)$

$S_w={\left(\frac{b}{\left(\frac{R_t}{R_0}\right)}\right)}^{\frac{1}{n}}---\left(2\right)$

In the formula: Rt-rock oil-containing resistivity (resistivity of actual measurement);

The complete moisture resistivity of Ro-rock;

The Sw-water saturation;

The b-coefficient;

The n-saturation exponent.

The method of determining coefficient b and n has two kinds of rock core displacement test method and empirical coefficient methods, and clean sandstone is generally got b=1, n=2.

By the Archie formula resistivity that records is converted into water saturation, only contains You Heshui in the pore media because of the artificial model set up, because of S _w+ S _o=1, so just can obtain oil saturation S _o, again resistivity is depicted as oil saturation and resistivity relation curve with corresponding oil saturation, represent as Fig. 8.Oil saturation, resistivity relation curve that Fig. 8 measures for steady state method, wherein the change in resistance of each point has good consistance, illustrates that the each point profit is evenly distributed in the model, and relation curve is representative.

Draw out (Fig. 9) behind oil saturation-resistivity typical curve, when carrying out the saturation degree experiments of measuring, can be by the resistivity of each point in the rating model, corresponding oil saturation-resistivity typical curve adopts interpolation calculation to go out the profit saturation degree of each point.

1.4.2 saturation degree measuring technique

One of experiment purpose of flat plate model can obtain the percolation law under the simulating oil deposit condition exactly, and the measurement of saturation distribution rule is significant to research remaining oil distribution, analog computation and development and Design.Measuring saturation degree indirect method comparatively commonly used has: resistivity, microwave, sound wave, CT image method and NMR imaging method etc.Comparatively speaking, CT image method and NMR imaging method can obtain saturation distribution situation intuitively, but these two kinds of methods have strict restriction to empirical model and flow process, as moulded dimension etc.Sound wave and microwave method also have strict demand to experiment condition, and measuring accuracy is lower.Resistivity method is the simplest, and the advantage of resistivity method be can tell that test layer is moisture, oil-containing changes.Resistivity method has stronger measurement resolution characteristic, can effectively discern interior moisture, oil saturation.

1, measuring principle

Resistivity logging method comparatively commonly used comprises in the logging operation at present: inductolog, electrode system well logging, micro-SFL (MSFL) and laterolog etc.Its measuring principle is roughly the same: supplying with intensity by electrodes of A, B two electrodes is the electric current of I, sets up electric field around the borehole wall, promptly sets up electric field in the stratum, measures the potential difference (PD) Δ U of potential electrode M, N point-to-point transmission (between A, B two electrodes) then _MNΔ U _MNVariation promptly reflected along the variation of wellhole section formation resistivity.Figure 10 is the probe measurement synoptic diagram.

By power supply utmost point A and B supplying electric current I, in the stratum, set up electric field after, carry out potential difference measurement with potential electrode M, N, this potential difference (PD) has reflected electric field distribution characteristic, thereby the variation of reflected resistance rate.

Suppose that medium is a homogeneous isotropism, its resistivity is R, is the centre of sphere with the point source, is that radius is made a ball with r.Current density is on ball:

$j=\frac{1}{4\mathrm{\&pi;}{r}^2}---\left(3.1\right)$

According to Ohm law differential form,

$E=\frac{\mathrm{<figure-callout\; id="4"\; label="RI"\; filenames="H2010100008081E00011.png,H2010100008081E00012.png"\; state="\{\{state\}\}">RI</figure-callout>}}{4\mathrm{\&pi;}{r}^2}---\left(3.2\right)$

The E integration is got

$U=\frac{\mathrm{<figure-callout\; id="4"\; label="RI"\; filenames="H2010100008081E00011.png,H2010100008081E00012.png"\; state="\{\{state\}\}">RI</figure-callout>}}{4\mathrm{\&pi;r}}---\left(3.3\right)$

If electrode system is made up of A, M, N, then

$U_M=\frac{\mathrm{<figure-callout\; id="4"\; label="RI"\; filenames="H2010100008081E00011.png,H2010100008081E00012.png"\; state="\{\{state\}\}">RI</figure-callout>}}{4\mathrm{\&pi;}\stackrel{\&OverBar;}{\mathrm{AM}}},U_N=\frac{\mathrm{<figure-callout\; id="4"\; label="RI"\; filenames="H2010100008081E00011.png,H2010100008081E00012.png"\; state="\{\{state\}\}">RI</figure-callout>}}{4\mathrm{\&pi;}\stackrel{\&OverBar;}{\mathrm{AN}}}---\left(3.4\right)$

$\mathrm{\&Delta;}{U}_{\mathrm{MN}}=U_M-U_N=\frac{\mathrm{<figure-callout\; id="4"\; label="RI"\; filenames="H2010100008081E00011.png,H2010100008081E00012.png"\; state="\{\{state\}\}">RI</figure-callout>}}{4\mathrm{\&pi;}}(\frac{1}{\stackrel{\&OverBar;}{\mathrm{AM}}}-\frac{1}{\stackrel{\&OverBar;}{\mathrm{AN}}})=\frac{\stackrel{\&OverBar;}{\mathrm{MN}}}{4\mathrm{\&pi;}\stackrel{\&OverBar;}{\mathrm{AM}}\&CenterDot;\stackrel{\&OverBar;}{\mathrm{AN}}}\mathrm{RI}---\left(3.5\right)$

Then

$R=\frac{4\mathrm{\&pi;}\stackrel{\&OverBar;}{\mathrm{AM}}\&CenterDot;\stackrel{\&OverBar;}{\mathrm{AN}}}{\stackrel{\&OverBar;}{\mathrm{MN}}}\&CenterDot;\frac{\mathrm{\&Delta;}{U}_{\mathrm{MN}}}{I}---\left(3.6\right)$

K factor is:

$K=\frac{4\mathrm{\&pi;}\stackrel{\&OverBar;}{\mathrm{AM}}\&CenterDot;\stackrel{\&OverBar;}{\mathrm{AN}}}{\stackrel{\&OverBar;}{\mathrm{MN}}}---\left(3.7\right)$

Low frequency (the frequency stepping is adjustable) square wave ac is supplied with in resistivity measurement, measures the potential difference (PD) Δ U between M and the N _MnAnd be calculated as follows resistivity:

$R=K\frac{\mathrm{\&Delta;}{U}_{\mathrm{MN}}}{I}---\left(3.8\right)$

R＝KR _L????????????????????????????????????(3.9)

K is a K factor, it is only relevant with electric system size, type, can record by experiment, because electrode retaining collar size and electrode system size are on the same order of magnitude, can not satisfy the requirement of point source, can't determine K factor with analytic solution or numerical simulation, only the actual electrode coefficient of demarcating in the uniform dielectric of known conductivity; R _LBe two resistance values between electrode M, the N, so only need record R _LJust can get resistivity by calculating.

2, saturation degree measuring system

The saturation degree measuring system that the application is related, mainly be to measure two interelectrode resistance values of M, N, by adding accurate voltage for two sections at A, B, form a loop through the measuring resistance and the resistance between electrode value of precision again, magnitude of voltage between potential electrode, can obtain two interelectrode resistance values by converting, thereby calculate saturation degree by host computer.In order to obtain the percolation law under the flat plate model simulating oil deposit condition more accurately, count much so electrode can be done, native system is exported 16 way switch control signals by the PCI integrated circuit board, in collection plate, can control 128 points (64 groups of electrodes), in order to satisfy the needs of experiment, can continue to expand.

The saturation degree measuring probe adopts four electrode systems: A, B to be the power supply utmost point, and M, N are potential electrode, and three electrodes are arranged on electrode bar, and loop electrode B is at a distance.Will be in finite medium accurate measured resistivity, electrode system should be too not big, could satisfy the condition of point source as far as possible, but owing to be subjected to the restriction of probe manufacturing technology, that can not do is very little.The potential electrode diameter is 1.0mm at present, and two distance between electrodes are 10mm.

3, saturation computation

Measured the resistivity on stratum, calculated water saturation by the Archie formula:

$I=\frac{\mathrm{Rt}}{\mathrm{Ro}}=\frac{b}{S{w}^n}---\left(3.9\right)$

$S_w={\left(\frac{b}{\left(\frac{R_t}{R_0}\right)}\right)}^{\frac{1}{n}}---\left(3.10\right)$

Rt-rock oil-containing resistivity (resistivity of actual measurement) in the formula;

The complete moisture resistivity of Ro-rock;

The Sw-water saturation;

The b-coefficient;

The n-saturation exponent.

The method of determining coefficient b and n has two kinds of rock core displacement test method and empirical coefficient methods, and clean sandstone is generally got b=1, n=2.By the Archie formula resistivity that records is converted into water saturation, only contains You Heshui in the pore media because of the artificial model set up, because of S _w+ S _o=1, so just can obtain oil saturation S _o, again resistivity is depicted as oil saturation and resistivity relation curve with corresponding oil saturation,

Embodiment 1

Profit saturation distribution when providing different geology reservoir and adopting different classes of and heterogeneity polymer flooding, the oil-displacement mechanism of the in-depth various different chemical displacing agents of understanding (polymkeric substance, binary and ternary).

Use this technology,, carry out the poly-back of driving and use different chemical and drive (high concentration polymer, binary and ternary) and further improve recovery efficiency technique research at the western I4 of I1-Portugal of the Portugal oil reservoir of north, oil field in the Sa one, two row.Further investigate once the poly-back Remaining Oil Distribution of driving, provided poly-each stage profit saturation distribution that drives; Provided poly-profit saturation degree variation cloth in back applying high density polymkeric substance, binary and the ternary displacement process, the flow field situation of change that different chemical drives of driving; Determined that different chemical drives Remaining Oil Distribution and sweep efficiency size in non-homogeneous pay different layers position; The seepage flow mechanism of high concentration polymer, binary and ternary has been familiar with in in-depth; And quantizing coupling enlarges swept volume and improves oil displacement efficiency, the contribution in each stage of displacement to different pervious course recovery ratio.For this block remaining oil of further taping the latent power rationally, efficiently provides tachnical storage.

The mining site applicable cases.

Block is through changing follow-up water drive exploitation in Gudong field seven districts behind the polymer flooding, and the unit rate of water cut increase is fast, and production rate decline is rapid.Annotate poly-front and back profit saturation distribution as seen by analyzing this oil field major reservoir, after this block enters follow-up water drive, water logging is serious, the remaining oil high degree of dispersion, reduce gradually to the producing well oil saturation from injecting well, only between well and the relative enrichment of remaining oil in area, corner, but on the plane, interlayer and thick oil pay top a large amount of remaining oils of enrichment still.Carry out the measure of taping the latent power of following remaining oil according to profit saturation distribution rule: meticulous remaining oil research technology, improve injection-production pattern; Supporting remaining oil monitoring technology is administered and is annotated poly-deleterious and inefficacy well; Implement integral profile control, improve input profile.

Change the research of water drive rule by deepening the poly-back of driving, implements the moisture ascensional range of the supporting technology of taping the latent power and be effectively controlled, the actual moisture theoretical prediction trend that moves closer to, notes gather and increase oil and reached conceptual design and increase oil index.By the tired oil 106.8 * 10 that increases of in Dec, 2008 injection region ⁴T improves recovery ratio 6.13%, and the ton polymkeric substance increases oily 48.8t.Increase oil 40.7 * 10 after the follow-up water drive of its transfer ⁴T accounts for 38.1% of at present total oil increment, and the follow-up water drive stage is still the important stage that polymer flooding increases oil.

Embodiment 2

The profit saturation distribution of research in the displacement process to in-depth understanding oil-field development present situation, instructs that the oil field is meticulous taps the latent power, and to further raising oil recovery factor, and instructs follow-up injection region piece polymer flooding exploitation, and great important is arranged.

Use this skill,, carry out the poly-experimental study that drives together of water under the different mode of communicating at the two cc of piece second class reservoirs in north, Sa Bei development area.Provided poly-oil-water movement Changing Pattern, the oil saturation situation of change of driving the poly-contact zones place of profit saturation distribution situation, especially water in the process together of water under the different mode of communicating; Determined the poly-and water injection intensity of notes of optimum matching, poly-ly driven project setting and improve that second class reservoir is poly-to be driven the recovery ratio value and play crucial effects instructing from now on.

The mining site applicable cases.

Main road ditch three paneling history in oil field, Jingan County are shorter, and the operation initial stage has just entered middle Water-cut Period, moisture reaching more than 30%.Carry out testing research as seen by the profit saturation distribution to this district: long 231 floor water drive directions are subjected to the connective control of sand body, and the northwestward, more, the southern water logging direction of middle part water logging direction are less, and oil well is influenced by limit water; By calculating these long 231 layers of oil saturation mean values in calculation zone is 3532%, and the distribution of distribution of remaining oil and water drive direction and water saturation is closely related.This is the remaining oil distribution situation of understanding fully this district, direction of propulsion and the scope of injecting water, further gets the water filling present situation in this district at present clear and develops present situation and provide foundation for digging the remaining oil work of taping the latent power.

Embodiment 3

For poly-application of driving further the taping the latent power of back remaining oil, thick oil pay horizontal well technology, and instruct the oil-field development production planning and improve comprehensive benefit all significant.

Use this technology, carry out the research of thick oil pay upper water horizontal well waterflooding mechanism at high 246 blocks of lotus flower oil reservoirs.The horizontal well water displacing oil water saturation regularity of distribution and sweep efficiency size under the different well patterns have been provided; Determined the mechanism of action of the block horizontal wells in heavy oil reservoir crestal waterflood of thick-layer.

The mining site applicable cases.

By in the Sa, the research of Sa Bei and north one, two Pai Xi of BLOCK OF LAMADIAN OIL FIELD, northern two Xi Dong and northern 3 the typical injection region piece profit saturation distribution situations of northeast block, deeply be familiar with the exploitation present situation of this block, refinement the measure of taping the latent power.Under the prior art condition, mainly carried out the following measure of taping the latent power: mainly take on the water injection well " three is low " wellblock is prolonged poly-time of notes, well layering, the segmentation of well interval, water drive well pattern well perforations adding, long packing element type shutoff, well project setting; Take mainly on the producing well that high moisture closing well, thin difference lamination split, high Water Flooding Layer shutoff.

The effect of taping the latent power and evaluation: in August, (1) 2002, disconnected eastern piece was relatively low to poly-consumption in the Bei Yi district, the extraction well is moisture lower on every side, 29 mouthfuls of wells adopting low " three the is low " wellblock of poly-concentration prolong notes and gather, main on every side 21 mouthfuls of extraction well moon rate of water cut increase that are communicated with descend 0.16 percentage point, and declining rate of recovery controls to 0.53% by 6.9%.(2) when taking height infiltration, high liquids withdrawal point water blockoff, the thin difference layer of pressure break hyposmosis has been obtained tangible oil increasing precipitation effect.The injection region piece was total to 8 mouthfuls of wells of measure in 1996, and 23m falls under water in average individual well daily output ³, day produce oil increases that 14t is moisture to have descended 9.8%.Added up precipitation 21.4 * 10 up till now ⁴m ³, accumulative total increases oil 5.8 * 10 ⁴T.(3) at the poly-still more actual conditions of the thin difference layer remaining oil in back of driving, approach the difference layer more than the 4m and have the producing well of good interlayer to take the pressure break measure boring to meet with thick-layer, annotated poly-in 1996 in the Sa and injection region piece in 1998 in poly-back 50 mouthfuls of the pressure breaks altogether of driving, the average individual well oily 10.7t average effective phase 186d that increases day by day, accumulative total increases oil 10.2 * 10 ⁴T.Annotate the middle 1-P48 well group of piece in the poly-Bei Yi district in 1996 15-27 day in June, (4) 2004 and carry out the test of oily sludge depth profile control, inject mud 2655m altogether ³, mud density 1.2-1.52g/cm ³Injection pressure is 11.5Mpa behind the profile control, contrast injection pressure rising 3.7MPa before and after the profile control.3 mouthfuls of ordinary production wells that contrast is communicated with have 2 mouthfuls of well effects obvious, and day produce oil rises, water cut decreases.

As above-mentioned, the analog measurement method and the device of oil saturation in the clear a kind of stratum that describes the present invention's proposition in detail.Although the present invention is described and explained to the preferred embodiments of the present invention in detail, but this area those skilled in the art be appreciated that, under the situation of the spirit and scope of the present invention that do not deviate from the claims definition, can in form and details, make multiple modification.

Claims (7)

1. the analog measurement method of oil saturation in the stratum, this method may further comprise the steps:

(1) simulation actual formation, make the artificial consolidated core model of silica sand and epoxy gluing: at each permeability, select the silica sand of reasonable size-grade distribution meansquaredeviation, by adjusting quartz sand size distribution intermediate value Φ, determine the consumption and the content of epoxy resin of various particle diameter sands, after sand stirred, put into the mould extrusion forming;

(2) at four jiaos of artificial consolidated core model, the mid point and the foursquare center in sideline, each installs a bite well, is furnished with nine mouthfuls of simulation wells altogether, utilizes these nine mouthfuls of wells to come various injection-production methods in the imitation oil displacement experiment process; The electronics Closing Switch is installed in every mouthful of well,, realizes Five-point method pattern, 9 method well patterns or seven-spat pattern injection-production method by switch to each well.

(3) profit desaturate monitor system is set in artificial consolidated core model: this profit desaturate monitor system is made up of transmitting electrode, potential electrode, transmission cable, A/D transfer interface board, digital quantity output board and computing machine, potential electrode is made up of two copper enameled wires of diameter 1mm, potential electrode is before the compacting model, be inserted in the model, equidistantly distribute on the plane; After potential electrode cloth is good, potential electrode and flat cable is welded, and link to each other with computing machine with the A/D change-over panel;

(4) set up electric field around the borehole wall: supplying with intensity by electrodes of A, B two electrodes is the electric current of I, sets up electric field around the borehole wall, promptly sets up electric field in the stratum, measures the potential difference (PD) Δ U of potential electrode M, N point-to-point transmission (between A, B two electrodes) then _MNΔ U _MNVariation promptly reflected the variation of formation resistivity;

(5) return according to Archie equation, the resistivity of being measured is carried out inverse, determine diverse location on the artificial consolidated core model, different oil saturation constantly;

(6) utilize diverse location on the artificial consolidated core model, different oil saturation results constantly to obtain the oil saturation collection of illustrative plates of different pervious courses;

(7) according to the oil saturation collection of illustrative plates of the different pervious courses that obtain, determine reservoir reserve and grade in the simulated formation.

2. according to the analog measurement method of oil saturation in the stratum described in the claim 1, the resistivity that it is characterized in that setting the consolidated core model is R, is the centre of sphere with the point source in resistivity measurement, is that radius is made a ball with r, and current density is on ball:

$j=\frac{1}{4\mathrm{\&pi;}{r}^2}---\left(1.1\right)$

According to Ohm law differential form,

$E=\frac{\mathrm{RI}}{4\mathrm{\&pi;}{r}^2}---\left(1.2\right)$

The E integration is got

$U=\frac{\mathrm{RI}}{4\mathrm{\&pi;r}}---\left(1.3\right)$

If electrode system is made up of A, M, N, then

$U_M=\frac{\mathrm{RI}}{4\mathrm{\&pi;}\stackrel{\&OverBar;}{\mathrm{AM}}},$ $U_N=\frac{\mathrm{RI}}{4\mathrm{\&pi;}\stackrel{\&OverBar;}{\mathrm{AN}}}---(1.4)$

$\mathrm{\&Delta;}{U}_{\mathrm{MN}}=U_M-U_N=\frac{\mathrm{RI}}{4\mathrm{\&pi;}}(\frac{1}{\stackrel{\&OverBar;}{\mathrm{AM}}}-\frac{1}{\stackrel{\&OverBar;}{\mathrm{AN}}})=\frac{\stackrel{\&OverBar;}{\mathrm{MN}}}{4\mathrm{\&pi;}\stackrel{\&OverBar;}{\mathrm{AM}}\&CenterDot;\stackrel{\&OverBar;}{\mathrm{AN}}}\mathrm{RI}---\left(1.5\right)$

Then

$R=\frac{4\mathrm{\&pi;}\stackrel{\&OverBar;}{\mathrm{AM}}\&CenterDot;\stackrel{\&OverBar;}{\mathrm{AN}}}{\stackrel{\&OverBar;}{\mathrm{MN}}}\&CenterDot;\frac{\mathrm{\&Delta;}{U}_{\mathrm{MN}}}{I}---\left(1.6\right)$

K factor K is:

$K=\frac{4\mathrm{\&pi;}\stackrel{\&OverBar;}{\mathrm{AM}}\&CenterDot;\stackrel{\&OverBar;}{\mathrm{AN}}}{\stackrel{\&OverBar;}{\mathrm{MN}}}---\left(1.7\right)$

The low frequency square wave ac is supplied with in resistivity measurement, measures the potential difference (PD) Δ Umn between M and the N and is calculated as follows the resistivity of consolidated core model:

$R=K\frac{\mathrm{\&Delta;}{U}_{\mathrm{MN}}}{I}---\left(1.8\right)$

R＝KR _L????(1.9)

K is a K factor, and it is only relevant with electric system size, type; R _LBe two resistance values between electrode M, the N, so only need record R _LBy calculating the resistivity R that just can get the consolidated core model.

3. according to the analog measurement method of oil saturation in the stratum described in claim 1 or 2, wherein measure the resistivity on stratum, calculate water saturation by following formula:

$I=\frac{\mathrm{Rt}}{\mathrm{Ro}}=\frac{b}{S{w}^n}---\left(1\right)$

$S_w={\left(\frac{b}{\left(\frac{R_t}{R_0}\right)}\right)}^{\frac{1}{n}}---\left(2\right)$

In the formula: Rt-rock oil-containing resistivity (resistivity of actual measurement),

The complete moisture resistivity of Ro-rock,

The Sw-water saturation,

The b-coefficient,

The n-saturation exponent;

For clean sandstone, b=1, n=2;

By the Archie formula resistivity that records is converted into water saturation, only contains You Heshui in the pore media because of the artificial model set up, because of S _w+ S _o=1, so just can obtain oil saturation S _o

4. according to the analog measurement method of oil saturation in the stratum described in the claim 1-3, wherein a bite well is respectively opened at cornerwise two ends in artificial consolidated core model, adopt notes one to adopt pattern shape, can be used for simulating 1/4th element patterns of five-spot network unit.

5. the analogue measurement device of oil saturation in the stratum is characterized in that making and the akin artificial consolidated core of formation physical property, wherein makes artificial consolidated core and carries out according to following requirement:

(1) adopted pressure experiment machine pressurization manufacture craft, be that jointing compound is made artificial consolidated core with epoxy resin;

(2 reservoir physical properties according to the oil field of being simulated are selected the reasonable size-grade distribution variances sigma of silica sand, are controlling under the constant situation of manufacture craft condition, by adjusting quartz sand size distribution intermediate value Φ, control core permeability;

(3) core porosity control: pressurization intensity be respectively 3,5,7.5,10 and 15MPa under make a series of rock cores, drill through rock core behind the isothermal curing, analyze the Changing Pattern of factor of porosity with pressure;

(4) core wettability control:

1) the slightly oil-wet rock core is made: 1/3rd of silica sand consumption is carried out silicone oil handle, make the rock core of producing be slightly oil-wet;

Part 40～60,60～100 and 100～200 order silica sands are handled with silicone oil, be prepared into silicon oil sand.From coarse to fine selecting for use always (at first carried out the silicone oil processing to coarse sand 40～60 orders with 1/3rd of sand weight when making rock core, if the sand amount of handling does not reach 1/3rd of total sand amount, handle 60～100 order sand again, up to total sand amount of handling account for whole sand amounts 1/3rd till;

The silicon oil sand preparation process is as follows: sand is weighed 1% silicone oil and dilute with 20 times of sherwood oils, stir with silica sand, volatilization was put into electric drying oven with forced convection and is heated to 180 ℃, constant temperature 8 hours after 20 hours under the room temperature;

2) the wet rock core of neutrality and water is made: with unprocessed silica sand and epoxy resin, adopt 20% dibutyl phthalate (DBP) to make hardening agent as toughner, 7% ethylenediamine, the synthetic core of made has the neutral wetting property of oleophylic partially;

(5) rock core pore texture control: get the low-permeability natural core, be crushed to 20-40 order particle, behind the synthetic core sand cutting, evenly add 30% natural core chip before the moulding, the synthetic core hole of made is shouted to distribute and is approached natural core after the extrusion forming.

6. according to the analogue measurement device of oil saturation in the stratum described in the claim 5, wherein said core permeability is controlled to be under pressurization intensity 3MPa and σ=0.8 condition, selects for use Φ to be respectively 2.1,2.4,2.7,3.0,3.3,3.6,3.9 and 4.2 size composition and has made a series of synthetic cores.

7. method of making according to the analogue measurement device of oil saturation in the stratum described in the claim 5-6, it comprises makes artificial consolidated core according to the following steps:

1. by permeability, factor of porosity and sand using amount, select Φ value and pressurization intensity, and calculate each the grade silica sand consumption and the jointing compound that comprise silicon oil sand and form proportioning;

2. take by weighing each grade silica sand by prescription, mix and cross 20 mesh sieves thoroughly;

3. prepare the epoxy gluing agent in proportion;

4. sand cutting is also crossed 10 mesh sieves;

5. pack into mould and pressurizeing constant 10 minutes;

6. take apart a die, 120 ℃ of constant temperature are more than six hours;

7. as required, cut, drill through, shaping;

8. perm-plug method obtains needed artificial consolidated core.

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