CN114000835B - Corrosion-proof, scale-proof and eccentric wear-proof method for lining oil pipe used for oil field pumping well - Google Patents
Corrosion-proof, scale-proof and eccentric wear-proof method for lining oil pipe used for oil field pumping well Download PDFInfo
- Publication number
- CN114000835B CN114000835B CN202111039335.0A CN202111039335A CN114000835B CN 114000835 B CN114000835 B CN 114000835B CN 202111039335 A CN202111039335 A CN 202111039335A CN 114000835 B CN114000835 B CN 114000835B
- Authority
- CN
- China
- Prior art keywords
- sucker rod
- oil
- well
- rod
- pump
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B17/00—Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Cables; Casings; Tubings
- E21B17/10—Wear protectors; Centralising devices, e.g. stabilisers
- E21B17/1085—Wear protectors; Blast joints; Hard facing
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B41/00—Equipment or details not covered by groups E21B15/00 - E21B40/00
- E21B41/02—Equipment or details not covered by groups E21B15/00 - E21B40/00 in situ inhibition of corrosion in boreholes or wells
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/12—Methods or apparatus for controlling the flow of the obtained fluid to or in wells
- E21B43/121—Lifting well fluids
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B47/00—Survey of boreholes or wells
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A10/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE at coastal zones; at river basins
- Y02A10/40—Controlling or monitoring, e.g. of flood or hurricane; Forecasting, e.g. risk assessment or mapping
Abstract
The invention discloses an anti-corrosion, anti-scale and anti-eccentric wear method for an oil field pumping well by using a lining oil pipe, which comprises the following steps: step one: collecting finishing data; step two: checking the matching condition of ground equipment; step three: the oil pump is designed in a shape selection way; step four: designing a pumping string; step five: sucker rod string design; the design scheme of corrosion prevention, scale prevention and eccentric wear prevention is characterized in that economic benefits of each link are maintained, and meanwhile, the economy and reliability of the whole well and even the whole oilfield sucker rod system are considered. The integrated design is that the device is applied for 32 times in total from 2020 to 2021, the maintenance-free period of 32 oil wells is prolonged from 169 days to 298 days when the maintenance-free period of the mechanical pumping well is seen, the oil pipe and the sucker rod keep good effectiveness when the observation effect is seen when the monitoring well is seen from 3, the device can still be continuously used for a period of time, and the device has popularization and application values in other oil fields when the application effect is seen, so that good economic benefits can be generated.
Description
Technical Field
The invention belongs to the technical field of lining oil pipes used for oil pumping wells in oil fields, and particularly relates to an anti-corrosion, anti-scale and anti-eccentric wear method for the lining oil pipes used for the oil pumping wells in oil fields.
Background
With deep development of oil fields, three serious effects are caused on the oil pipe and the sucker rod for the middle and deep well after gradually entering a middle and high water-containing period: firstly, the produced water in the oil field is rich in CO 2 And chlorine ions with higher concentration, which act together to cause serious corrosion and frequent corrosion breaking of the sucker rod; secondly, HCO produced by stratum -3 Ions with reduced partial pressure of produced liquid and small amount of CO 2 Escape, a part forms CO 2- 3 With Ca 2+ 、Mg 2+ The plasma cations are combined to form scale substances, and the scale substances are attached to the oil pipe to cause the problems of unsmooth flow channel, well blockage and the like; thirdly, the well structure and the water-containing ascending lubricity are poor, so that the eccentric wear is aggravated, and the breakage frequency of the oil pipe and the breaking and stripping frequency of the sucker rod are greatly increased. In view of the problems of corrosion, scaling and eccentric wear caused by the rising of water content in oil fields, research and exploration are continuously carried out on each oil field in China since nineties of the last century, and a plurality of corrosion protection are carried outThe anti-scale and anti-bias products have developed and lined tubing has been used in small scale in oil fields as a significant and effective material. The lining oil pipe used at present is made of high-density polyethylene with the thickness of 3-5mm or other substituted plastics which are lined in the common oil pipe, so that the lining oil pipe has the characteristics of small friction coefficient, high wear resistance, very smooth inner wall, relatively similar elastic modulus of steel and the like, and therefore, the lining oil pipe has the functions of corrosion prevention, scale prevention and eccentric wear prevention compared with the common oil pipe. Especially, after the preparation technology of the high-density polyethylene plastic is mature more recently, the application of the lining oil pipe for corrosion prevention, scale prevention and eccentric wear prevention has wide application prospect.
Although each oil field is actively popularized and applied to the lining oil pipe to carry out corrosion prevention, scale prevention and eccentric wear prevention, each oil field cannot be popularized and applied on a large scale in actual application, and the oil field is mainly restricted by the following factors: 1. the diameter of the common oil pipe is reduced after lining, and the outer diameter of the original well-entering sucker rod, the oil pump, accessories and the like needs to be designed again. 2. After the lining oil pipe is installed, the overflow area between the rod pipes is reduced, the descending friction force between the sucker rod and the liquid column is increased, so that the descending resistance and the stress amplitude of the sucker rod are increased, and the sucker rod is easy to fail prematurely; meanwhile, part of the well section uses a lining oil pipe, and when the stroke frequency is higher, the eccentric wear point is caused to move upwards. 3. After the lining oil pipe is used, the oil pipe is not influenced by the corrosion of well liquid, and the electrochemical corrosion of the well liquid acts on the sucker rod, so that the corrosion of the sucker rod can be aggravated. 4. The lining material of the lining tubing is generally different from the modulus of elasticity just before, and meanwhile, in a working environment of high temperature in the well, the elongation of the lining tubing is necessarily larger than that of the tubing, so that downhole liquid is easy to permeate into a gap between the inverted tubing and the lining through the end part of the tubing. 5. The application cost of the lining oil pipe is 3-5 times of that of a common oil pipe, and the large-scale application cost is high.
Disclosure of Invention
In order to overcome the problems, the invention provides an anti-corrosion, anti-scaling and anti-eccentric wear method for an oil field pumping well by using a lining oil pipe.
The technical scheme adopted by the invention is as follows:
an anti-corrosion, anti-scale and anti-eccentric wear method for an oil field pumping well by using a lining oil pipe comprises the following steps:
step one: collecting and arranging data:
step 1.1: oil deposit engineering: including the geological profile of the hydrocarbon reservoir area, burial depth, gas-to-oil ratio, reservoir physical properties and characteristics, well fluid properties, original formation pressure, well structure, casing conditions, pressure, temperature;
step 1.2: oil extraction engineering: initial and current occurrence and accumulation conditions, current design thought of a pumping pipe and rod column, auxiliary parameters of a downhole pipe and rod pump and accessories, a ground pumping unit, a motor and a gathering and delivery flow, and history of operation well history in the past;
step 1.3: after the data is collected, the data is arranged and analyzed, and the following preliminary conclusion in several aspects is obtained;
step 1.3.1: according to statistical analysis of historical materials of past operation and replacement conditions of underground materials, finding out a block, a single well eccentric wear well section and a corrosion well section, and preliminarily determining eccentric wear, corrosion degree and characteristics;
step 1.3.2: according to corrosion and scaling characteristics, water quality full analysis, well fluid properties and corrosion scaling product components, the corrosion scaling type is obtained, and the corrosion scaling type belongs to carbon dioxide, hydrogen sulfide, chloride ions or comprehensive corrosion, and is considered as an important factor in design;
step 1.3.3: carrying out column stress analysis according to the design and the current production of the rod-tube pump, carrying out corresponding calculation, rechecking the result and the site eccentric wear well section position, and correcting model parameters; suspension point load and neutral point position are calculated by taking the following stroke as an example:
during the downstroke of a sucker rod string, the static load experienced by the string is mainly 2: the dead weight G rod of the sucker rod string and the buoyancy load F received by the rod string in the well fluid float; meanwhile, the rod column is subjected to various dynamic loads such as upward inertial load F inertial of the sucker rod, friction load F friction between the pipe rods and other friction loads F friction, fluid flow resistance F resistance in the well and half-dry friction force F friction of the oil pump; the distance between the neutral point of the sucker rod column and the pump is L, and the dead weight G rod of the L section sucker rod is:
G rod ＝F Floating device +F Inertial measurement unit +F Friction wheel +F Resistance resistor +F Dry friction (1)
In the method, in the process of the invention, d 0 the diameter of the sucker rod on the pump is mm; gamma is the weight of the sucker rod, 78500N/m 3 ；γ y To the weight of well liquid, N/m 3 The method comprises the steps of carrying out a first treatment on the surface of the D is the diameter of the oil pump, and is mm; mu is the flow coefficient, and 0.60 to 0.62 is taken; s is stroke, m; n is the stroke frequency, 1/min; delta is the gap of the oil pump, mm; η is the number of travelling valves of the oil pump, and 1 is taken; f is plunger area, m 2 The method comprises the steps of carrying out a first treatment on the surface of the f is the cross-sectional area of the floating valve seat hole, m 2 The method comprises the steps of carrying out a first treatment on the surface of the The formula of the instability bending length of the sucker rod is deduced by combining the formula:
comparing the calculation with the actual eccentric wear section on site, checking the well combination well structure data out of the range, drawing a three-dimensional view of the well bore for section-by-section comparison, and checking the influence of the well structure on the eccentric wear;
step two: and (3) checking the matching condition of ground equipment:
in view of the adaptation scene that the oil field enters a middle-high water content development period, the ground pumping unit and motor matched equipment are applied to maturity, and the maximum load, torque, maximum stroke, minimum stroke, stroke frequency and motor power parameters which are allowed to be used by the existing pumping unit are mastered according to the actual condition of the oil field;
step three: and (3) selecting and designing an oil pump:
step 3.1: pump selection:
two types of tube pumps and rod pumps are seen according to a fixed mode; selecting a tube pump with simple and reliable structure and low cost;
the structural characteristics of the conventional tubing pump determine that the sucker rod below the neutralization point is pressed in the down stroke process to generate unstable bending and the breathing effect of the oil pipe to cause eccentric wear of the pipe rod, so that the eccentric wear prevention method is a method for preventing eccentric wear by changing the stress direction of the sucker rod and keeping the oil pipe relatively stable by using the change of the structure of the pump from the principle of the unstable bending of the rod in the eccentric wear prevention design; the hydraulic feedback thick oil pump applied in thick oil development belongs to the type, and the stress change principle is as follows: the hydraulic feedback effect is realized by the synergistic effect of the oil inlet valve and the oil outlet valve on the large plunger and the small plunger of the oil pump through connecting two non-equal-diameter oil pumps in series; in the down stroke, the oil outlet valve is in a closed state, the upper end of the pump is provided with a rod column gravity, a liquid column load, a friction inertia load and other forces, the lower end of the pump is provided with an oil sleeve annular sinking pressure, the two forces have a liquid column pressure difference, and under the action of the pressure difference, the small plunger generates downward force in the direction, namely hydraulic feedback force;
according to the structural characteristics of the oil pump, carrying out stress analysis, and deriving a hydraulic feedback pump pole instability distance calculation formula by combining the formulas (1) and (2) as follows:
in the method, in the process of the invention,d 1 the diameter of a small plunger of the hydraulic feedback pump is mm; ρ is the well fluid mixing severity, N/m 3 The method comprises the steps of carrying out a first treatment on the surface of the h is the depth of the working fluid level, m;
compared with a common tube pump, the hydraulic feedback oil pump has the function of easy descending as seen in the step (3); meanwhile, the density of the liquid in the shaft is in direct proportion to the feedback force, and the greater the density is, the greater the feedback force is, the easier the descending is; from the field application condition of the oil field, the maximum hydraulic feedback force reaches 20KN, and the phenomenon of downward movement of the neutralization point is obvious, so that the hydraulic feedback force has a good eccentric wear prevention function and is taken as a key consideration means in the design stage;
step 3.2: and (3) designing fixed displacement parameters:
determining production parameters under the condition of meeting the production allocation, selecting an oil pump within a theoretical displacement range according to the production allocation liquid amount given by an oil reservoir, and predicting the pump efficiency of a designed well by combining the gas-liquid ratio of an oil field and the pump efficiency of a normal production well so as to determine the stroke and the stroke frequency;
theoretical displacement calculation of a conventional oil pump: q (Q) t ＝f p sn
Wherein f p For plunger area, m 2 The method comprises the steps of carrying out a first treatment on the surface of the s is the stroke of the polish rod, m; n is the impulse number, times/min;
after the hydraulic feedback pump is selected, the theoretical displacement calculation formula is as follows:
wherein D is Big size The diameter of the large plunger is m; d (D) Small size The diameter of the small plunger is m;
step four: designing a pumping string:
the length of the oil pumping pipe column is mainly determined by the sinking degree or the pumping hanging length, the pipe diameter is generally matched according to the liquid amount and the size of an oil pump, and the design principle mainly comprises two steps: firstly, ensuring the effects of corrosion prevention, scale prevention and eccentric wear prevention, and according to collected and tidied data, applying a lining pipe to a corrosion, scale formation and eccentric wear well section, and secondly, independently applying the lining pipe when the pipe column is designed for preventing eccentric wear, and simultaneously taking the change of the inner diameter of an oil pipe as an important design content; thirdly, when the flushing frequency is larger, the length of the lining oil pipe is 200-300m longer than that of the eccentric wear section, so that a better eccentric wear prevention effect can be achieved after the eccentric wear section moves upwards; fourthly, the principle that no lining is needed is followed, so that the cost investment is reduced;
in the process of pumping down the well, the sucker rod is bent under pressure or bent in a well inclination manner, and friction is generated when the sucker rod is contacted with an oil pipe under pressure, so that the pipe rod is eccentrically worn; under the condition of equal stress, the deformation amplitude generated by the compression of the sucker rod is fixed, when the inner diameter of the oil pipe is increased, the contact point of the sucker rod and the oil pipe is reduced, and the lateral force is reduced, so that the abrasion strength of the sucker rod is reduced, and the service life of the pipe rod can be prolonged;
step five: sucker rod string design:
after the pipe diameter of the lining oil pipe is reduced, the resistance between the fluid in the well and the sucker rod coupling can be greatly changed and is increased from several times to hundreds of times, so that the resistance after the inner diameter is changed is demonstrated before design;
step 5.1: friction resistance between liquid and rod body in lining oil pipe:
the friction force between the sucker rod and the well fluid occurs in the downstroke, the direction is upward, the resistance changes along with the descending speed change of the sucker rod string, a certain relation exists between the resistance and the ratio of the inner diameter of the oil pipe to the diameter of the sucker rod, and the smaller the inner diameter is, the larger the resistance is; the value of which can be calculated by the following formula:
fγl is the friction force between the sucker rod and the well fluid, N; l is the length of the sucker rod, m; mu is the viscosity of the well fluid and Pa.S; m is the ratio of the inner diameter of the oil pipe to the diameter of the sucker rod; θ max′ The maximum descending speed of the sucker rod is m/s;
the smaller the inner diameter is, the larger the resistance of the fluid in the well to the sucker rod is under the condition of larger stroke frequency, and the numerical value is in direct proportion to the viscosity of the well fluid;
step 5.2: friction resistance between liquid in lined tubing and sucker rod collar:
the geometrical shape of the coupling is complex, the well fluid changes quickly, the true stress state of the coupling is difficult to simulate, and meanwhile, the friction resistance is small and is ignored in engineering application, so that the research significance is not great; however, in the application of lining oil pipes, due to the shrinkage of the inner diameter of the oil pipe and the deviation of the outer diameter of the coupling, the annular space between the coupling and the oil pipe is shrunk, and the geometric progression is increased after the annular space is to a certain extent, so that the annular space cannot be ignored;
the pumping rod resistance is related to the pumping rod diameter/oil pipe diameter and the pumping rod coupling/oil pipe diameter, and if other conditions are unchanged, the relation among the three can be expressed by the following formula:
c is a resistance coefficient, and is related to the fluid speed in the well, the stroke frequency and the length of the sucker rod; m is the ratio of the diameter of the sucker rod to the diameter of the oil pipe; a is the ratio of the diameter of the coupling to the diameter of the oil pipe;
the change of the diameter of the lining oil pipe is required to be properly adjusted, and the data can not be quantified, but the maximum adjustment scale can be calculated according to the proportion relation, which is one of the conditions which must be considered in the design of the lining oil pipe;
in view of the above-mentioned resistance analysis and calculation, when designing the sucker rod string, firstly, the matching of the inner diameter of the oil pipe and the sucker rod coupling should be performed, so as to avoid increasing the downward resistance of the sucker rod due to too small overflow area, and the value of the downward resistance is not more than the order of magnitude of change compared with the conventional design overflow area after the above-mentioned analysis process is referred to; secondly, the influence of the change of the stroke frequency on the eccentric wear is larger, and the phenomenon that the eccentric wear moves upwards when the stroke frequency of the lining pipe is overlarge is also explained in the analysis and calculation process, so that the long stroke and the low stroke frequency are considered as much as possible in design, the length of the lining oil pipe is increased, and the righting length of the sucker rod is increased; finally, the reducing coupling of the sucker rod is directly selected in the well with larger liquid quantity, so that the overflow area is enlarged, and the resistance influence is reduced;
5.3 after the step: full-cladding and half-cladding sucker rod design:
the semi-cladding rod is mainly formed by PE cladding on a sucker rod body, coating a thermal stress area with a coating, and applying a spray welding anti-abrasion coupling in a matched manner to protect the sucker rod from corrosion and eccentric wear in the stress concentration area;
the fully-coated rod is characterized in that the parts, which are easy to be damaged and corroded, of the thermal stress areas of the rod heads at the two ends of the sucker rod are processed into reducing joints by using corrosion-resistant alloy materials, and then the reducing joints are additionally arranged at the two ends of the sucker rod to replace the original wrench side, the original pushing bearing surface and the original flange, and the reducing joints are tightly combined with the PE coating layer of the rod body so as to realize fully coating and protect the whole sucker rod from corrosion and eccentric wear;
the maximum thickness of the coating layer is 2.5mm, the coupling comprises a conventional coupling and a reducing coupling, and the resistance calculation is carried out according to the steps and the tubular column matching is carried out during the design; meanwhile, the current temperature resistance of the coated sucker rod is 90 ℃ at the maximum, the ground temperature condition is considered when the on-site design is carried out, and the coated sucker rod is selected and applied;
step 5.4: and (5) checking the strength of the sucker rod string:
under the action of alternating load, most of the sucker rods are broken and broken due to fatigue, so that the strength of the sucker rod column is checked and calculated according to the fatigue strength; performing pumping rod strength check and rod column design by adopting an Okinger and a modified Goldman diagram;
step six: the design scheme of corrosion prevention, scale prevention and eccentric wear prevention is characterized in that economic benefits of each link are required, and meanwhile, the economy and reliability of the whole well and even the whole oilfield sucker rod system are required to be considered:
step 6.1: the scheme is designed according to the actual corrosion, eccentric wear and scaling conditions of a single well and an oil field, so that the cost is increased due to the full-well design of the eccentric cover for pursuing the effect is avoided;
step 6.2: the underground pipe string has a longer logging period, the period should be prolonged properly when economic benefit measurement or evaluation is carried out, the representative and scale application can be carried out, and the evaluation period is 3-5 years.
Wherein in the step 1.3.3, the friction resistance in the thin oil field is less than 10KN, most of the friction resistance is in the range of 3KN, compared with the gravity of a rod column and a liquid column, the friction resistance is negligible, and the viscosity of fluid in a thick oil well can be increased to millions from tens of, so that the influence of temperature and viscosity change on friction force should be fully considered when the thick oil field uses the formula to calculate.
The invention has the following advantages:
the integrated design is that the device is applied for 32 times in total from 2020 to 2021, the maintenance-free period of the 32 oil wells is prolonged from 169 days to 298 days when the maintenance-free period of the mechanical pumping well is seen, the oil pipe and the sucker rod keep good effectiveness when the observation effect is seen from 3 monitoring wells, and the device can still be used for a period of time continuously.
From the application effect, the method has popularization and application values in other oil fields, and can generate good economic benefit.
Detailed Description
The invention is further described below, but is not limited to these.
An anti-corrosion, anti-scale and anti-eccentric wear method for an oil field pumping well by using a lining oil pipe comprises the following steps:
step one: collecting and arranging data:
step 1.1: oil deposit engineering: including the geological profile of the hydrocarbon reservoir area, burial depth, gas-to-oil ratio, reservoir physical properties and characteristics, well fluid properties, original formation pressure, well structure, casing conditions, pressure, temperature;
step 1.2: oil extraction engineering: initial and current occurrence and accumulation conditions, current design thought of a pumping pipe and rod column, auxiliary parameters of a downhole pipe and rod pump and accessories, a ground pumping unit, a motor and a gathering and delivery flow, and history of operation well history in the past;
step 1.3: after the data is collected, the data is arranged and analyzed, and the following preliminary conclusion in several aspects is obtained;
step 1.3.1: according to statistical analysis of past operation well history materials and underground material replacement conditions, a block, a single well eccentric wear well section and a corrosion well section are found, the eccentric wear degree, the corrosion degree and the characteristics are preliminarily determined, for example, the maximum eccentric wear of a certain oil field is 0.8 mm/year, the average pump depth is 2235m, the on-site statistical eccentric wear well section is located on the pump at 160-1500 m, and the characteristic of the length of the eccentric wear well section is presented.
Step 1.3.2: obtaining corrosion and scaling types according to the corrosion and scaling characteristics combined with water quality full analysis, well fluid properties and corrosion scaling product components, wherein the corrosion and scaling types belong to carbon dioxide, hydrogen sulfide, chloride ions or comprehensive corrosion types; if the total analysis of the water quality of a certain oil field shows that the produced liquid contains a large amount of HCO 3 - 、CL - And Ca 2+ 、Mg 2+ Ion, pH value is 6.8, slightly acidic; meanwhile, the oil outlet pipe and the sucker rod are inspected on site, the sucker rod and the oil pipe below 1500m are seriously corroded, the oil pipe is in a spot and pit shape, the oil pipe is perforated, and the main reason of corrosion is described as CO 2 The method comprises the steps of carrying out a first treatment on the surface of the Sampling and assaying scale formation product, the main component of which is CaCO 3 And FeCO 3 The method comprises the steps of carrying out a first treatment on the surface of the From this, CO is seen 2 Has a relatively high level of pumping system in the oil fieldThe design is considered as an important factor for the large influence.
Step 1.3.3: carrying out column stress analysis according to the design and the current production of the rod-tube pump, carrying out corresponding calculation, rechecking the result and the site eccentric wear well section position, and correcting model parameters; suspension point load and neutral point position are calculated by taking the following stroke as an example:
during the downstroke of a sucker rod string, the static load experienced by the string is mainly 2: the dead weight G rod of the sucker rod string and the buoyancy load F received by the rod string in the well fluid float; meanwhile, the rod column is subjected to various dynamic loads such as upward inertial load F inertial of the sucker rod, friction load F friction between the pipe rods and other friction loads F friction, fluid flow resistance F resistance in the well, semi-dry friction force F friction of the oil pump and the like; assuming that the distance between the neutral point of the sucker rod string and the pump is L, the dead weight G rod of the L section sucker rod is:
G rod ＝F Floating device +F Inertial measurement unit +F Friction wheel +F Resistance resistor +F Dry friction (1)
In the method, in the process of the invention, d 0 the diameter of the sucker rod on the pump is mm; gamma is the weight of the sucker rod, 78500N/m 3 ；γ y To the weight of well liquid, N/m 3 The method comprises the steps of carrying out a first treatment on the surface of the D is the diameter of the oil pump, and is mm; mu is the flow coefficient, and 0.60 to 0.62 is taken; s is stroke, m; n is the stroke frequency, 1/min; delta is the gap of the oil pump, mm; η is the number of travelling valves of the oil pump, and 1 is taken; f is plunger area, m 2 The method comprises the steps of carrying out a first treatment on the surface of the f is the cross-sectional area of the floating valve seat hole, m 2 The method comprises the steps of carrying out a first treatment on the surface of the The formula of the instability bending length of the sucker rod is deduced by combining the formula:
according to the formula (2), a sucker rod is designed according to an API principle in a thin oil field, a 86 combination mode is adopted, the water content is 96%, the average pump hanging depth is 2235m, the neutral point of the sucker rod is positioned between 226 m and 694m on a pump, and the average length of the whole oil field is 567m; in thin oil fields, the friction resistance is smaller than 10KN, most of the friction resistance is in the range of 3KN, compared with the gravity of a rod column and a liquid column, the friction resistance is negligible, and the viscosity of fluid in a thick oil well can be increased from tens to millions, so that the influence of temperature and viscosity changes on friction force should be fully considered when the thick oil field uses the formula for calculation.
Comparing the calculation with the actual eccentric wear section on site, checking the well combination well structure data out of the range, drawing a three-dimensional view of the well bore for section-by-section comparison, and checking the influence of the well structure on the eccentric wear; in this embodiment, the well section of 700-1500 m still has serious eccentric wear phenomenon, and the well deviation data show that the oil field has a non-straight well structure below 700m, a more and large dogleg and a closing distance exceeding 150m accounting for 43%, so that the upper eccentric wear is considered to be caused by the well structure, but the influence of the eccentric wear on the whole design should not be ignored;
step two: and (3) checking the matching condition of ground equipment:
in view of the fact that the adaptation scene of the invention is that an oil field enters a middle-high water content development period, the ground pumping unit and motor matched equipment are applied to maturity, and the maximum load, torque, maximum stroke, minimum stroke, stroke frequency and motor power parameters which are allowed to be used by the existing pumping unit are mastered according to the actual condition of the oil field; for the convenience of the following embodiment design description, in the embodiment of the application, a pumping unit with the model IICYJQ14-6-73HP is taken as an example, and the pumping unit with the model has the maximum load of 140KN, the maximum stroke of 6 meters, the minimum stroke of 3 meters, the maximum stroke of 5 times/min, the minimum stroke of 3 times/min and the maximum torque of 73KN x m; the optional types of motors are 37, 30 and 28 KW; the design for ensuring the operation safety of the oil pumping unit should not exceed 80% of the maximum allowable range;
step three: and (3) selecting and designing an oil pump:
step 3.1: pump selection:
two types of tube pumps and rod pumps are seen according to a fixed mode; selecting a tube pump with simple and reliable structure and low cost;
the structural characteristics of the conventional tubing pump determine that the sucker rod below the neutralization point is pressed in the down stroke process to generate unstable bending and the breathing effect of the oil pipe to cause eccentric wear of the pipe rod, so that the eccentric wear prevention method is a method for preventing eccentric wear by changing the stress direction of the sucker rod and keeping the oil pipe relatively stable by using the change of the structure of the pump from the principle of the unstable bending of the rod in the eccentric wear prevention design; the hydraulic feedback thick oil pumping pump applied in the development of thick oil at present belongs to the type, and the stress change principle is as follows: the hydraulic feedback effect is realized by the synergistic effect of the oil inlet valve and the oil outlet valve on the large plunger and the small plunger of the oil pump through connecting two non-equal-diameter oil pumps in series; in the down stroke, the oil outlet valve is in a closed state, the upper end of the pump is provided with a rod column gravity, a liquid column load, a friction inertia load and other forces, the lower end of the pump is provided with an oil sleeve annular sinking pressure, the two forces have a liquid column pressure difference, and under the action of the pressure difference, the small plunger generates downward force in the direction, namely hydraulic feedback force;
according to the structural characteristics of the oil pump, the stress analysis is carried out, and the calculation formula of the instability distance of the hydraulic feedback pump pole can be deduced by combining the formulas (1) and (2), wherein the calculation formula is as follows:
in the method, in the process of the invention,d 1 the diameter of a small plunger of the hydraulic feedback pump is mm; ρ is the well fluid mixing severity, N/m 3 The method comprises the steps of carrying out a first treatment on the surface of the h is the depth of the working fluid level, m;
compared with a common tube pump, the hydraulic feedback oil pump has the function of easy descending as can be seen from the step (3); meanwhile, the density of the liquid in the shaft is in direct proportion to the feedback force, and the greater the density is, the greater the feedback force is, the easier the descending is; from the field application condition of the oil field, the maximum hydraulic feedback force can reach 20KN, and the phenomenon of downward movement of the neutralization point is obvious, so that the hydraulic feedback force has a better eccentric wear prevention function, and is taken as an important consideration means in the design stage;
step 3.2: and (3) designing fixed displacement parameters:
determining production parameters under the condition of meeting the production allocation, selecting an oil pump within a theoretical displacement range according to the production allocation liquid amount given by an oil reservoir, and predicting the pump efficiency of a designed well by combining the gas-liquid ratio of an oil field and the pump efficiency of a normal production well so as to determine the stroke and the stroke frequency;
theoretical displacement calculation of a conventional oil pump: q (Q) t ＝f p sn
Wherein f p For plunger area, m 2 The method comprises the steps of carrying out a first treatment on the surface of the s is the stroke of the polish rod, m; n is the impulse number, times/min;
after the hydraulic feedback pump is selected, the theoretical displacement calculation formula is as follows:
wherein D is Big size The diameter of the large plunger is m; d (D) Small size The diameter of the small plunger is m; assuming that the stroke of the pumping unit is 6m, the theoretical displacement calculation results of various oil pumps under different stroke times are shown in table 1
Table 1 various pump theoretical displacement calculation results tables
；
Step four: designing a pumping string:
the length of the oil pumping pipe column is mainly determined by the sinking degree or the pumping hanging length, the pipe diameter is generally matched according to the liquid amount and the size of an oil pump, and the design is based on the corrosion prevention, scale prevention and eccentric wear prevention effects and economic benefit design; the design principle is mainly two: firstly, ensuring the effects of corrosion prevention, scale prevention and eccentric wear prevention, and according to collected and tidied data, applying a lining pipe to a corrosion, scale formation and eccentric wear well section, and secondly, independently applying the lining pipe when the pipe column is designed for preventing eccentric wear, and simultaneously taking the change of the inner diameter of an oil pipe as an important design content; thirdly, when the flushing frequency is larger, the length of the lining oil pipe is 200-300m longer than that of the eccentric wear section, so that a better eccentric wear prevention effect can be achieved after the eccentric wear section moves upwards; fourthly, the principle that no lining is needed is followed, so that the cost investment is reduced;
in the process of pumping down the well, the sucker rod is bent under pressure or bent in a well inclination manner, and friction is generated when the sucker rod is contacted with an oil pipe under pressure, so that the pipe rod is eccentrically worn; under the condition of equal stress, the deformation amplitude generated by the compression of the sucker rod is fixed, when the inner diameter of the oil pipe is increased, the contact point of the sucker rod and the oil pipe is reduced, and the lateral force is reduced, so that the abrasion strength of the sucker rod is reduced, and the service life of the pipe rod can be prolonged; for example, conventional phi 89mm liner tubing is substituted for conventional phi 73mm tubing in a severe deviated wellbore section;
step five: sucker rod string design:
after the pipe diameter of the lining oil pipe is reduced, the resistance between the fluid in the well and the sucker rod coupling can be greatly changed and is increased from several times to hundreds of times, so that the resistance after the inner diameter is changed is demonstrated before design;
step 5.1: friction resistance between liquid and rod body in lining oil pipe:
the friction force between the sucker rod and the well fluid occurs in the downstroke, the direction is upward, the resistance changes along with the descending speed change of the sucker rod string, a certain relation exists between the resistance and the ratio of the inner diameter of the oil pipe to the diameter of the sucker rod, and the smaller the inner diameter is, the larger the resistance is; the value of which can be calculated by the following formula:
fγl is the friction force between the sucker rod and the well fluid, N; l is the length of the sucker rod, m; mu is the viscosity of the well fluid and Pa.S; m is the ratio of the inner diameter of the oil pipe to the diameter of the sucker rod; θ max′ The maximum descending speed of the sucker rod is m/s; the calculation shows that the resistance of the phi 73mm oil pipe lining and the common oil pipe to the phi 25mm sucker rod is about 2 times different under the condition of thin oil; under the condition that the inner diameter of the oil pipe and the diameter of the rod are the same, 3 times of comparison is carried out with 5 times of comparison, and the difference between the two times is 1.5-2 times; therefore, the resistance of the fluid in the well to the sucker rod is larger under the conditions of smaller inner diameter and larger stroke frequency, and the numerical value is in direct proportion to the viscosity of the well fluid;
step 5.2: friction resistance between liquid in lined tubing and sucker rod collar:
the geometrical shape of the coupling is complex, the well fluid changes rapidly, the true stress state of the coupling is difficult to simulate, and meanwhile, the friction resistance is small and can be ignored in engineering application, so that the research significance is not great; however, in the application of lining oil pipes, due to the shrinkage of the inner diameter of the oil pipe and the deviation of the outer diameter of the coupling, the annular space between the coupling and the oil pipe is reduced, and the geometric progression is increased to a certain extent, so that the geometric progression is not negligible;
according to the experimental study of the resistance of a sucker rod in viscous fluid in Changfeng 1994, the sucker rod resistance has a larger relation with the diameter of the sucker rod/the diameter of the oil pipe and the diameter of the sucker rod coupling/the oil pipe, and if other conditions are unchanged, the relation among the three can be expressed by the following formula:
c is a resistance coefficient, and is related to the fluid speed in the well, the stroke frequency and the length of the sucker rod; m is the ratio of the diameter of the sucker rod to the diameter of the oil pipe; a is the ratio of the diameter of the coupling to the diameter of the oil pipe; assuming that the inner diameter of a common oil pipe is 62mm, the diameter of a lining oil pipe is 55mm, and the diameter of a coupling is 54mm, the resistance of the common oil pipe and the coupling is increased by at least 7 times, so that the diameter of the coupling is required to reduce the resistance as much as possible under the conditions of no flow and meeting the tensile strength, and certain requirements are also provided for the thickness of the lining of the oil pipe; in other words, the change of the diameter of the lining oil pipe must be properly adjusted, and although the data cannot be quantified, the maximum adjustment scale can be calculated according to the above proportional relation, which is one of the conditions that must be considered in the design of the lining oil pipe;
in view of the above-mentioned resistance analysis and calculation, when designing the sucker rod string, firstly, matching the inner diameter of the oil pipe with the sucker rod coupling, so as to avoid increasing the downward resistance of the sucker rod as much as possible because of too small overflow area, and comparing the value with the conventional design overflow area by no more than the order of magnitude change after the analysis process is referred to; secondly, the influence of the change of the stroke frequency on the eccentric wear is larger, and the phenomenon that the eccentric wear moves upwards when the stroke frequency of the lining pipe is overlarge is also explained in the analysis and calculation process, so that the long stroke and the low stroke frequency are considered as much as possible in design, the length of the lining oil pipe is increased, and the righting length of the sucker rod is increased; finally, the reducing coupling of the sucker rod is directly selected in the well with larger liquid quantity, so that the overflow area is enlarged as much as possible, and the resistance influence is reduced;
step 5.3: full-cladding and half-cladding sucker rod design:
the semi-cladding rod is mainly formed by PE cladding on a sucker rod body, coating a thermal stress area with a coating, and applying a spray welding anti-abrasion coupling in a matched manner to protect the sucker rod from corrosion and eccentric wear in the stress concentration area;
the fully-coated rod is characterized in that the parts, which are easy to be damaged and corroded, of the thermal stress areas of the rod heads at the two ends of the sucker rod are processed into reducing joints by using corrosion-resistant alloy materials, and then the reducing joints are additionally arranged at the two ends of the sucker rod to replace the original wrench side, the original pushing bearing surface and the original flange, and the reducing joints are tightly combined with the PE coating layer of the rod body so as to realize fully coating and protect the whole sucker rod from corrosion and eccentric wear;
the maximum thickness of the coating layer is 2.5mm, the coupling comprises a conventional coupling and a reducing coupling, and the resistance calculation and the tubular column matching are carried out according to the steps in the design process; meanwhile, the current temperature resistance of the coated sucker rod is maximally 90 ℃, the ground temperature condition is considered in field design, and the coated sucker rod is selected and applied.
Step 5.4: and (5) checking the strength of the sucker rod string:
under the action of alternating load, most of the sucker rods are broken and broken due to fatigue, so that the strength of the sucker rod column is checked and calculated according to the fatigue strength; at present, the method is widely adopted for carrying out the strength check and the pole design of the sucker rod by using the Okinger and the modified Goldman diagram, and the two schemes can be implemented by referring to the related content in the oil extraction engineering principle and design of Zhang Qi master code;
step six: the design scheme of corrosion prevention, scale prevention and eccentric wear prevention is characterized in that economic benefits of each link are required, and meanwhile, the economy and reliability of the whole well and even the whole oilfield sucker rod system are required to be considered:
step 6.1: the scheme is designed according to the actual corrosion, eccentric wear and scaling conditions of a single well and an oil field, and the specific design is carried out, so that the whole well design covered for the purpose of pursuing the effect is avoided, and the cost is doubled or even more.
Step 6.2: the well logging period of the underground pipe column is generally longer, the period should be properly prolonged when economic benefit measurement or evaluation is carried out, the representative and large-scale application can be selected for evaluation, and the period should be generally selected as an evaluation period for 3-5 years.
It is pointed out that several variations and modifications can be made by a person skilled in the art without departing from the inventive concept, which fall within the scope of the invention.
Claims (2)
1. An anti-corrosion, anti-scale and anti-eccentric wear method for an oil field pumping well by using a lining oil pipe is characterized in that: the method comprises the following steps:
step one: collecting and arranging data:
step 1.1: oil deposit engineering: including the geological profile of the hydrocarbon reservoir area, burial depth, gas-to-oil ratio, reservoir physical properties and characteristics, well fluid properties, original formation pressure, well structure, casing conditions, pressure, temperature;
step 1.2: oil extraction engineering: initial and current occurrence and accumulation conditions, current design thought of a pumping pipe and rod column, auxiliary parameters of a downhole pipe and rod pump and accessories, a ground pumping unit, a motor and a gathering and delivery flow, and history of operation well history in the past;
step 1.3: after the data is collected, the data is arranged and analyzed, and the following preliminary conclusion in several aspects is obtained;
step 1.3.1: according to statistical analysis of historical materials of past operation and replacement conditions of underground materials, finding out a block, a single well eccentric wear well section and a corrosion well section, and preliminarily determining eccentric wear, corrosion degree and characteristics;
step 1.3.2: according to corrosion and scaling characteristics, water quality full analysis, well fluid properties and corrosion scaling product components, the corrosion scaling type is obtained, and the corrosion scaling type belongs to carbon dioxide, hydrogen sulfide, chloride ions or comprehensive corrosion, and is considered as an important factor in design;
step 1.3.3: carrying out column stress analysis according to the design and the current production of the rod-tube pump, carrying out corresponding calculation, rechecking the result and the site eccentric wear well section position, and correcting model parameters; suspension point load and neutral point position are calculated by taking the following stroke as an example:
during the downstroke of a sucker rod string, the static load experienced by the string is mainly 2: the dead weight G rod of the sucker rod string and the buoyancy load F received by the rod string in the well fluid float; at the same time, the rod column is also subjected to upward inertial load F of the sucker rod, between the pipe rods and other friction loads F Friction wheel Resistance F to fluid flow in well Resistance resistor Half-dry friction force F of oil pump Dry friction A plurality of dynamic loads; the distance between the neutral point of the sucker rod column and the pump is L, and the dead weight G rod of the L section sucker rod is:
G rod ＝F Floating device +F Inertial measurement unit +F Friction wheel +F Resistance resistor +F Dry friction (1)
In the method, in the process of the invention, d 0 the diameter of the sucker rod on the pump is mm; gamma is the weight of the sucker rod, 78500N/m 3 ；γ y To the weight of well liquid, N/m 3 The method comprises the steps of carrying out a first treatment on the surface of the D is the diameter of the oil pump, and is mm; mu is the flow coefficient, and 0.60 to 0.62 is taken; s is stroke, m; n is the stroke frequency, 1/min; delta is the gap of the oil pump, mm; η is the number of travelling valves of the oil pump, and 1 is taken; f is plunger area, m 2 The method comprises the steps of carrying out a first treatment on the surface of the f is the cross-sectional area of the floating valve seat hole, m 2 The method comprises the steps of carrying out a first treatment on the surface of the The formula of the instability bending length of the sucker rod is deduced by combining the formula:
comparing the calculation with the actual eccentric wear section on site, checking the well combination well structure data out of the range, drawing a three-dimensional view of the well bore for section-by-section comparison, and checking the influence of the well structure on the eccentric wear;
step two: and (3) checking the matching condition of ground equipment:
in view of the adaptation scene that the oil field enters a middle-high water content development period, the ground pumping unit and motor matched equipment are applied to maturity, and the maximum load, torque, maximum stroke, minimum stroke, stroke frequency and motor power parameters which are allowed to be used by the existing pumping unit are mastered according to the actual condition of the oil field;
step three: and (3) selecting and designing an oil pump:
step 3.1: pump selection:
two types of tube pumps and rod pumps are seen according to a fixed mode; selecting a tube pump with simple and reliable structure and low cost;
the structural characteristics of the conventional tubing pump determine that the sucker rod below the neutralization point is pressed in the down stroke process to generate unstable bending and the breathing effect of the oil pipe to cause eccentric wear of the pipe rod, so that the eccentric wear prevention method is a method for preventing eccentric wear by changing the stress direction of the sucker rod and keeping the oil pipe relatively stable by using the change of the structure of the pump from the principle of the unstable bending of the rod in the eccentric wear prevention design; the hydraulic feedback thick oil pump applied in thick oil development belongs to the type, and the stress change principle is as follows: the hydraulic feedback effect is realized by the synergistic effect of the oil inlet valve and the oil outlet valve on the large plunger and the small plunger of the oil pump through connecting two non-equal-diameter oil pumps in series; in the down stroke, the oil outlet valve is in a closed state, the upper end of the pump is provided with a rod column gravity, a liquid column load, a friction inertia load and other forces, the lower end of the pump is provided with an oil sleeve annular sinking pressure, the two forces have a liquid column pressure difference, and under the action of the pressure difference, the small plunger generates downward force in the direction, namely hydraulic feedback force;
according to the structural characteristics of the oil pump, carrying out stress analysis, and deriving a hydraulic feedback pump pole instability distance calculation formula by combining the formulas (1) and (2) as follows:
in the method, in the process of the invention,d 1 the diameter of a small plunger of the hydraulic feedback pump is mm; ρ is the well fluid mixing severity, N/m 3 The method comprises the steps of carrying out a first treatment on the surface of the h is the depth of the working fluid level, m;
compared with a common tube pump, the hydraulic feedback oil pump has the function of easy descending as seen in the step (3); meanwhile, the density of the liquid in the shaft is in direct proportion to the feedback force, and the greater the density is, the greater the feedback force is, the easier the descending is; from the field application condition of the oil field, the maximum hydraulic feedback force reaches 20KN, and the phenomenon of downward movement of the neutralization point is obvious, so that the hydraulic feedback force has a good eccentric wear prevention function and is taken as a key consideration means in the design stage;
step 3.2: and (3) designing fixed displacement parameters:
determining production parameters under the condition of meeting the production allocation, selecting an oil pump within a theoretical displacement range according to the production allocation liquid amount given by an oil reservoir, and predicting the pump efficiency of a designed well by combining the gas-liquid ratio of an oil field and the pump efficiency of a normal production well so as to determine the stroke and the stroke frequency;
theoretical displacement calculation of a conventional oil pump: q (Q) t ＝f p sn
Wherein f p For plunger area, m 2 The method comprises the steps of carrying out a first treatment on the surface of the s is the stroke of the polish rod, m; n is the impulse number, times/min;
after the hydraulic feedback pump is selected, the theoretical displacement calculation formula is as follows:
wherein D is Big size The diameter of the large plunger is m; d (D) Small size The diameter of the small plunger is m;
step four: designing a pumping string:
the length of the oil pumping pipe column is mainly determined by the sinking degree or the pumping hanging length, the pipe diameter is generally matched according to the liquid amount and the size of an oil pump, and the design principle mainly comprises two steps: firstly, ensuring the effects of corrosion prevention, scale prevention and eccentric wear prevention, and according to collected and tidied data, applying a lining pipe to a corrosion, scale formation and eccentric wear well section, and secondly, independently applying the lining pipe when the pipe column is designed for preventing eccentric wear, and simultaneously taking the change of the inner diameter of an oil pipe as an important design content; thirdly, when the flushing frequency is larger, the length of the lining oil pipe is 200-300m longer than that of the eccentric wear well section; fourthly, follow the principle that no lining is needed;
in the process of pumping down the well, the sucker rod is bent under pressure or bent in a well inclination manner, and friction is generated when the sucker rod is contacted with an oil pipe under pressure, so that the pipe rod is eccentrically worn; under the condition of equal stress, the deformation amplitude generated by the compression of the sucker rod is fixed, when the inner diameter of the oil pipe is increased, the contact point of the sucker rod and the oil pipe is reduced, and the lateral force is reduced, so that the abrasion strength of the sucker rod is reduced, and the service life of the pipe rod can be prolonged;
step five: sucker rod string design:
after the pipe diameter of the lining oil pipe is reduced, the resistance between the fluid in the well and the sucker rod coupling can be greatly changed and is increased from several times to hundreds of times, so that the resistance after the inner diameter is changed is demonstrated before design;
step 5.1: friction resistance between liquid and rod body in lining oil pipe:
the friction force between the sucker rod and the well fluid occurs in the downstroke, the direction is upward, the resistance changes along with the descending speed change of the sucker rod string, a certain relation exists between the resistance and the ratio of the inner diameter of the oil pipe to the diameter of the sucker rod, and the smaller the inner diameter is, the larger the resistance is; the value of which can be calculated by the following formula:
F γ1 the friction force between the sucker rod and the well fluid is N; l is the length of the sucker rod, m; mu is the viscosity of the well fluid and Pa.S; m is the ratio of the inner diameter of the oil pipe to the diameter of the sucker rod; θ max′ The maximum descending speed of the sucker rod is m/s;
the smaller the inner diameter is, the larger the resistance of the fluid in the well to the sucker rod is under the condition of larger stroke frequency, and the numerical value is in direct proportion to the viscosity of the well fluid;
step 5.2: friction resistance between liquid in lined tubing and sucker rod collar:
the geometrical shape of the coupling is complex, the well fluid changes quickly, the true stress state of the coupling is difficult to simulate, and meanwhile, the friction resistance is small and is ignored in engineering application, so that the research significance is not great; however, in the application of lining oil pipes, due to the shrinkage of the inner diameter of the oil pipe and the deviation of the outer diameter of the coupling, the annular space between the coupling and the oil pipe is shrunk, and the geometric progression is increased after the annular space is to a certain extent, so that the annular space cannot be ignored;
the pumping rod resistance is related to the pumping rod diameter/oil pipe diameter and the pumping rod coupling/oil pipe diameter, and if other conditions are unchanged, the relation among the three can be expressed by the following formula:
c is a resistance coefficient, and is related to the fluid speed in the well, the stroke frequency and the length of the sucker rod; m is the ratio of the diameter of the sucker rod to the diameter of the oil pipe; a is the ratio of the diameter of the coupling to the diameter of the oil pipe;
the change of the diameter of the lining oil pipe is required to be properly adjusted, and the data can not be quantified, but the maximum adjustment scale can be calculated according to the proportion relation, which is one of the conditions which must be considered in the design of the lining oil pipe;
in view of the above-mentioned resistance analysis and calculation, when designing the sucker rod string, firstly, the matching of the inner diameter of the oil pipe and the sucker rod coupling should be performed, so as to avoid increasing the downward resistance of the sucker rod due to too small overflow area, and the value of the downward resistance is not more than the order of magnitude of change compared with the conventional design overflow area after the above-mentioned analysis process is referred to; secondly, the influence of the change of the stroke frequency on the eccentric wear is larger, and the phenomenon that the eccentric wear moves upwards when the stroke frequency of the lining pipe is overlarge is also explained in the analysis and calculation process, so that the long stroke and the low stroke frequency are considered as much as possible in design, the length of the lining oil pipe is increased, and the righting length of the sucker rod is increased; finally, the reducing coupling of the sucker rod is directly selected in the well with larger liquid quantity, so that the overflow area is enlarged, and the resistance influence is reduced;
5.3 after the step: full-cladding and half-cladding sucker rod design:
the semi-cladding rod is mainly formed by PE cladding on a sucker rod body, coating a thermal stress area with a coating, and applying a spray welding anti-abrasion coupling in a matched manner to protect the sucker rod from corrosion and eccentric wear in the stress concentration area;
the fully-coated rod is characterized in that the parts, which are easy to be damaged and corroded, of the thermal stress areas of the rod heads at the two ends of the sucker rod are processed into reducing joints by using corrosion-resistant alloy materials, and then the reducing joints are additionally arranged at the two ends of the sucker rod to replace the original wrench side, the original pushing bearing surface and the original flange, and the reducing joints are tightly combined with the PE coating layer of the rod body so as to realize fully coating and protect the whole sucker rod from corrosion and eccentric wear;
the maximum thickness of the coating layer is 2.5mm, the coupling comprises a conventional coupling and a reducing coupling, and the resistance calculation is carried out according to the steps and the tubular column matching is carried out during the design; meanwhile, the current temperature resistance of the coated sucker rod is 90 ℃ at the maximum, the ground temperature condition is considered when the on-site design is carried out, and the coated sucker rod is selected and applied;
step 5.4: and (5) checking the strength of the sucker rod string:
under the action of alternating load, most of the sucker rods are broken and broken due to fatigue, so that the strength of the sucker rod column is checked and calculated according to the fatigue strength; performing pumping rod strength check and rod column design by adopting an Okinger and a modified Goldman diagram;
step six: the design scheme of corrosion prevention, scale prevention and eccentric wear prevention is characterized in that economic benefits of each link are required, and meanwhile, the economy and reliability of the whole well and even the whole oilfield sucker rod system are required to be considered:
step 6.1: the scheme is designed according to the actual corrosion, eccentric wear and scaling conditions of a single well and an oil field, so that the cost is increased due to the full-well design of the eccentric cover for pursuing the effect is avoided;
step 6.2: the underground pipe string has a longer logging period, the period should be prolonged properly when economic benefit measurement or evaluation is carried out, the representative and scale application can be carried out, and the evaluation period is 3-5 years.
2. The method for corrosion protection, scale prevention and eccentric wear prevention of an oilfield rod-pumped well using a liner tubing according to claim 1, wherein the method comprises the steps of: in the step 1.3.3, the friction resistance in the thin oil field is less than 10KN, most of the friction resistance is in the range of 3KN, compared with the gravity of a rod column and a liquid column, the friction resistance is negligible, and the viscosity of fluid in a thick oil well can be increased to millions from tens of, so that the influence of temperature and viscosity change on friction force should be fully considered when the thick oil field uses the formula for calculation.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111039335.0A CN114000835B (en) | 2021-09-06 | 2021-09-06 | Corrosion-proof, scale-proof and eccentric wear-proof method for lining oil pipe used for oil field pumping well |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111039335.0A CN114000835B (en) | 2021-09-06 | 2021-09-06 | Corrosion-proof, scale-proof and eccentric wear-proof method for lining oil pipe used for oil field pumping well |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114000835A CN114000835A (en) | 2022-02-01 |
| CN114000835B true CN114000835B (en) | 2023-08-01 |
Family
ID=79921189
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111039335.0A Active CN114000835B (en) | 2021-09-06 | 2021-09-06 | Corrosion-proof, scale-proof and eccentric wear-proof method for lining oil pipe used for oil field pumping well |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114000835B (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101397898A (en) * | 2008-09-16 | 2009-04-01 | 中国石油化工股份有限公司江苏油田分公司 | Eccentric wear prevention method for pumping well with pole |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8261841B2 (en) * | 2009-02-17 | 2012-09-11 | Exxonmobil Research And Engineering Company | Coated oil and gas well production devices |
-
2021
- 2021-09-06 CN CN202111039335.0A patent/CN114000835B/en active Active
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101397898A (en) * | 2008-09-16 | 2009-04-01 | 中国石油化工股份有限公司江苏油田分公司 | Eccentric wear prevention method for pumping well with pole |
Non-Patent Citations (1)
| Title |
|---|
| 抽油井防偏磨配套技术应用效果分析;郝洪峰;侯连英;赵华;;石油和化工节能(第05期);23-28/41 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114000835A (en) | 2022-02-01 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Takacs | Sucker-rod pumping handbook: production engineering fundamentals and long-stroke rod pumping | |
| US3682256A (en) | Method for eliminating wear failures of well casing | |
| USRE36362E (en) | Polymer liners in rod pumping wells | |
| US10584546B1 (en) | Rotator apparatus and method therefor | |
| CN108104795B (en) | Real-time early warning method for casing wear risk | |
| CN105239966B (en) | A kind of method for selecting oil well lifting technology | |
| Mitra | Principles of artificial lift | |
| CN106761680B (en) | A kind of judgment method of chemical viscosity reduction auxiliary threaded rod pump lifting heavy oil process | |
| CN114000835B (en) | Corrosion-proof, scale-proof and eccentric wear-proof method for lining oil pipe used for oil field pumping well | |
| CN104153982B (en) | A kind of acquisition characteristic method and device of rod-pumped well downhole system | |
| CN103485719B (en) | A kind of gas water horizontal well drilling rig structure | |
| CN114542043B (en) | Method and device for optimizing and improving rock stratum fracturing permeability based on fracturing fluid viscosity | |
| CN115111146A (en) | Anti-abrasion load-shedding oil pumping device of three-dimensional curved well and using method thereof | |
| CN2797613Y (en) | Vertical rotating combination type off-axis wear proof device | |
| US10907420B1 (en) | Roller coupling apparatus and method therefor | |
| CN112392461B (en) | Method for rapidly calculating water content of mixed liquid in oil well shaft | |
| CN111241684B (en) | Method for analyzing shaft passing capacity of cable pumping clustering perforation pipe string | |
| CN112683712B (en) | Method for determining corrosion life of sucker rod | |
| CN108952590B (en) | Working matching tool and construction method of carbon fiber continuous sucker rod | |
| CN206397723U (en) | The wear-resisting soft sealing oil pump plunger of sand control | |
| CN205936420U (en) | Inclined to one side abrasionproof tubular column is prevented to directional well | |
| Win | Optimization of Rod String Design for cker Rod Pumping System in Mann Oil Field | |
| Xie et al. | The reason and prevention measures for the rod and tubing wear of the pumping unit in the Bei 301 operation area | |
| CN2721855Y (en) | Forced righting device for preventing incline of sucker rod | |
| Tomuz | Comparison of Sucker Rod String Design Methods, Types and Applications |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| TA01 | Transfer of patent application right |
Effective date of registration: 20230630 Address after: 250100 room 1-205, xinyuanxin center, 125 Huaneng Road, Licheng District, Jinan City, Shandong Province Applicant after: Shandong Hongchang Petroleum Technology Co.,Ltd. Address before: 250100 room 1-205, xinyuanxin center, 125 Huaneng Road, Licheng District, Jinan City, Shandong Province Applicant before: Shandong Yiyuan Petroleum Technology Co.,Ltd. |
|
| TA01 | Transfer of patent application right | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |