CN115711123A

CN115711123A - Method and device for determining porosity of shale reservoir and computer storage medium

Info

Publication number: CN115711123A
Application number: CN202110898972.7A
Authority: CN
Inventors: 陈丽清; 吴伟; 石学文; 刘文平; 陈玉龙; 刘佳; 伍秋姿; 朱逸青; 杨雨然; 刘燊阳
Original assignee: Petrochina Co Ltd
Current assignee: Petrochina Co Ltd
Priority date: 2021-08-04
Filing date: 2021-08-04
Publication date: 2023-02-24

Abstract

The embodiment of the application discloses a method and a device for determining the porosity of a shale reservoir and a computer storage medium, and belongs to the technical field of shale gas exploration and development. The method comprises the following steps: acquiring logging data of a target single well aiming at a target shale reservoir stratum; sequentially determining a first change relation between the organic carbon content in the target shale reservoir and the reservoir density and a second change relation between the organic carbon content in the target shale reservoir and the reservoir volume according to the logging data; and determining the porosity of the target shale reservoir after the influence of the organic carbon content in the target shale reservoir is eliminated according to the first variation relation, the second variation relation and the logging data. According to the embodiment of the application, the porosity of the target shale reservoir after the influence of the organic carbon content in the target shale reservoir is eliminated is determined according to the relation between the organic carbon content in the target shale reservoir and the reservoir density and the relation between the organic carbon content and the reservoir volume, so that the accuracy of determining the porosity of the shale reservoir is improved.

Description

Method and device for determining porosity of shale reservoir and computer storage medium

Technical Field

The embodiment of the application relates to the technical field of shale gas exploration and development, in particular to a method and a device for determining the porosity of a shale reservoir and a computer storage medium.

Background

With the rapid development of shale gas in the global energy field, the exploration and development of shale gas are more and more emphasized. Because shale reservoirs in different regions and different wells have differences, such as high-yield wells, low-yield wells, non-production wells and the like, and the productivity of the shale reservoir is related to the porosity of the shale reservoir, the shale porosity needs to be determined.

However, some shale reservoirs have high resistivity and low resistivity, that is, when the resistivity is less than a certain threshold value, the shale reservoirs are low-resistivity shale reservoirs. At present, the porosity of a low-resistance shale reservoir is determined by a porosity determination mode for a normal-resistivity shale reservoir, which causes the determined porosity of the low-resistance shale reservoir to be inaccurate, and further causes the capacity estimation of the low-resistance shale reservoir to be inaccurate.

Disclosure of Invention

The embodiment of the application provides a method and a device for determining the porosity of a shale reservoir and a computer storage medium, which can be used for solving the problem of inaccurate determination of the porosity of a low-resistance shale reservoir in the related art.

The technical scheme is as follows:

in one aspect, a method for determining the porosity of a shale reservoir is provided, and the method comprises the following steps:

acquiring logging data of a target single well aiming at a target shale reservoir stratum;

according to the logging data, sequentially determining a first variation relation between the content of organic carbon in the target shale reservoir and the reservoir density and a second variation relation between the content of organic carbon in the target shale reservoir and the reservoir volume;

and determining the porosity of the target shale reservoir after the influence of the organic carbon content in the target shale reservoir is eliminated according to the first variation relation, the second variation relation and the logging data.

In some embodiments, the well log data comprises a natural gamma log, a resistivity curve, a sonic moveout curve, and a density curve;

sequentially determining a first variation relation between the content of organic carbon in the target shale reservoir and the reservoir density and a second variation relation between the content of organic carbon in the target shale reservoir and the reservoir volume according to the logging data, wherein the first variation relation comprises the following steps:

determining a logging curve segment corresponding to an organic matter-rich interval and a logging curve segment corresponding to an organic matter-poor interval in the target shale reservoir according to the natural gamma logging curve, the resistivity curve and the acoustic time difference curve;

determining an organic carbon content determination model of the target shale reservoir according to the logging curve segment corresponding to the organic matter-rich interval and the logging curve segment corresponding to the organic matter-poor interval;

performing linear fitting on the reciprocal of the density curve and the organic carbon content model to obtain the first change relation;

and determining the second variation relation according to the organic carbon content determination model and the first variation relation.

In some embodiments, the determining, according to the natural gamma log, the resistivity curve and the sonic moveout curve, a log curve segment corresponding to an organic-rich interval and a log curve segment corresponding to an organic-poor interval in the target shale reservoir includes:

overlapping the resistivity curve and the sound wave time difference curve to obtain an overlapping curve;

according to the position of a curve corresponding to a non-organic matter layer section in the natural gamma curve, removing the curve corresponding to the non-organic matter layer section in the overlapping curve to obtain an organic matter overlapping curve;

and determining a logging curve segment corresponding to an organic matter-rich interval and a logging curve segment corresponding to an organic matter-poor interval from the organic matter overlapping curve, wherein the logging curve segment corresponding to the organic matter-rich interval is a logging curve segment which is not overlapped and has different trends of the resistivity curve and the acoustic wave time difference curve in the organic matter overlapping curve, and the logging curve segment corresponding to the organic matter-poor interval is a logging curve segment which is overlapped and has the same trend of the resistivity curve and the acoustic wave time difference curve in the organic matter overlapping curve.

In some embodiments, the determining an organic carbon content determination model of the target shale reservoir according to the logging curve segment corresponding to the organic-rich interval and the logging curve segment corresponding to the organic-poor interval includes:

acquiring the formation resistivity of the target shale reservoir and the organic carbon content corresponding to different formations;

determining an acoustic time difference baseline and a resistivity baseline in a logging curve section corresponding to the organic-poor layer section, wherein the acoustic time difference baseline is a baseline corresponding to an acoustic wave in a logging curve section overlapping part corresponding to the organic-poor layer section, and the resistivity baseline is a baseline corresponding to a resistivity in a logging curve section overlapping part corresponding to the organic-poor layer section;

determining a reference acoustic wave time difference baseline and a reference resistivity baseline in the logging curve section corresponding to the organic-rich layer section according to the acoustic wave time difference baseline and the resistivity baseline corresponding to the organic-poor layer section respectively, and determining a reference acoustic wave time difference curve in the logging curve section corresponding to the organic-rich layer section;

determining organic matter reference abundances corresponding to different strata according to the reference acoustic time difference baseline, the reference resistivity baseline, the reference acoustic time difference curve and the stratum resistivity;

and performing linear fitting on the reference abundance of the organic matters corresponding to the different stratums and the organic carbon content corresponding to the different stratums to obtain the organic carbon content determination model.

In some embodiments, said determining said second variation from said model of organic carbon content determination and said first variation comprises:

determining densities corresponding to the organic carbon contents of 0 and 100% respectively from the first variation relation;

determining the density corresponding to the organic carbon content of 0 as the rock skeleton density of the target shale reservoir, and determining the density corresponding to the organic carbon content of 100% as the density of the organic carbon content;

and determining the second variation relation according to the organic carbon content density, the organic carbon content determination model and reference densities corresponding to different stratums, wherein the reference densities corresponding to the different stratums are obtained through the density curve.

In some embodiments, the determining the porosity of the target shale reservoir after eliminating the influence of the organic carbon content in the target shale reservoir according to the first variation relationship and the second variation relationship includes:

determining the stratum densities of different stratums of the target shale reservoir after the influence of the organic carbon content is eliminated according to the second variation relation, the densities of the organic carbon content described in the first variation relation and reference densities corresponding to the different stratums;

and determining the porosity of the different strata according to the stratum densities of the different strata, the rock skeleton density and the fluid density of the fluid in the target shale reservoir.

In another aspect, an apparatus for determining porosity of a shale reservoir is provided, the apparatus comprising:

the acquisition module is used for acquiring logging data of a target single well aiming at a target shale reservoir;

the first determining module is used for sequentially determining a first variation relation between the content of organic carbon in the target shale reservoir and the reservoir density and a second variation relation between the content of organic carbon in the target shale reservoir and the reservoir volume according to the logging data;

and the second determining module is used for determining the porosity of the target shale reservoir after the influence of the organic carbon content in the target shale reservoir is eliminated according to the first variation relation, the second variation relation and the logging data.

In some embodiments, the well log data includes a natural gamma log curve, a resistivity curve, a sonic moveout curve, and a density curve;

the first determining module includes:

the first determining sub-module is used for determining a logging curve section corresponding to an organic matter-rich interval and a logging curve section corresponding to an organic matter-poor interval in the target shale reservoir according to the natural gamma logging curve, the resistivity curve and the acoustic time difference curve;

the second determining sub-module is used for determining an organic carbon content determining model of the target shale reservoir according to the logging curve segment corresponding to the organic matter-rich interval and the logging curve segment corresponding to the organic matter-poor interval;

the fitting submodule is used for carrying out linear fitting on the reciprocal of the density curve and the organic carbon content model to obtain the first change relation;

and the third determining submodule is used for determining the second variation relation according to the organic carbon content determining model and the first variation relation.

In some embodiments, the first determination submodule is to:

overlapping the resistivity curve and the acoustic wave time difference curve to obtain an overlapping curve;

In some embodiments, the second determination submodule is to:

determining an acoustic time difference base line and a resistivity base line in a logging curve section corresponding to the poor organic matter interval, wherein the acoustic time difference base line is a base line corresponding to an acoustic wave in a logging curve section overlapping part corresponding to the poor organic matter interval, and the resistivity base line is a base line corresponding to a resistivity in a logging curve section overlapping part corresponding to the poor organic matter interval;

determining organic matter reference abundances corresponding to different strata according to the reference acoustic wave time difference baseline, the reference resistivity baseline, the reference acoustic wave time difference curve and the stratum resistivity;

In some embodiments, the third determination submodule is to:

In some embodiments, the second determining module comprises:

a fourth determining submodule, configured to determine, according to the second variation relationship, the density of the organic carbon content described in the first variation relationship, and reference densities corresponding to different strata, the stratum densities of different strata of the target shale reservoir after the influence of the organic carbon content is eliminated;

and the fifth determining submodule is used for determining the porosity of the different strata according to the stratum densities of the different strata, the rock skeleton density and the fluid density of the fluid in the target shale reservoir.

In another aspect, a computer-readable storage medium is provided, having instructions stored thereon, which when executed by a processor, implement any of the above-described methods for determining the porosity of a shale reservoir.

The beneficial effects that technical scheme that this application embodiment brought include at least:

in the embodiment of the application, the porosity of the target shale reservoir after the influence of the organic carbon content in the target shale reservoir is eliminated can be determined through the relationship between the organic carbon content in the target shale reservoir and the reservoir density and the relationship between the organic carbon content and the reservoir volume, so that the accuracy of determining the porosity of the shale reservoir is improved, and the accuracy of estimating the capacity of the low-resistance shale reservoir is further improved.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the description below are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

Fig. 1 is a flowchart of a method for determining porosity of a shale reservoir according to an embodiment of the present disclosure;

fig. 2 is a flowchart of a method for determining the porosity of a shale reservoir according to an embodiment of the present application;

fig. 3 is a schematic diagram illustrating a relationship between organic carbon content and reservoir density in a target shale reservoir provided by an embodiment of the present application;

FIG. 4 is a schematic diagram illustrating a relationship between organic carbon content and reservoir volume in a target shale reservoir provided by an embodiment of the present application;

fig. 5 is a schematic structural diagram of a porosity determination apparatus for a shale reservoir provided in an embodiment of the present application;

fig. 6 is a schematic structural diagram of a first determining module provided in an embodiment of the present application;

fig. 7 is a schematic structural diagram of a second determining module according to an embodiment of the present application;

fig. 8 is a schematic structural diagram of a terminal according to an embodiment of the present application.

Detailed Description

To make the objects, technical solutions and advantages of the embodiments of the present application clearer, the embodiments of the present application will be described in further detail below with reference to the accompanying drawings.

Before explaining the method for determining the porosity of the shale reservoir provided by the embodiment of the present application in detail, an application scenario provided by the embodiment of the present application is explained first.

Because the porosity of the shale is an important physical property characteristic for evaluating the shale reservoir, the method can be used for clearing the porosity of the shale reservoir in the exploration and development of shale oil and shale gas, and can provide a basis and foundation for evaluating the occurrence mode, the flow state, the retrievability and the like of the shale oil and shale gas. However, the porosity of the low-resistivity shale reservoir is determined by determining the porosity of the normal-resistivity shale reservoir at present, which causes inaccuracy in the determined porosity of the low-resistivity shale reservoir and further causes inaccuracy in the estimation of the capacity of the low-resistivity shale reservoir.

Based on the application scenario, the embodiment of the application provides a method for determining the porosity of the shale reservoir, which can improve the accuracy of determining the porosity of the low-resistivity shale reservoir.

Fig. 1 is a flowchart of a method for determining a porosity of a shale reservoir provided in an embodiment of the present application, where the method for determining a porosity of a shale reservoir may include the following steps:

step 101: and obtaining well logging data of a target single well aiming at the target shale reservoir.

Step 102: and sequentially determining a first change relation between the organic carbon content in the target shale reservoir and the reservoir density and a second change relation between the organic carbon content in the target shale reservoir and the reservoir volume according to the logging data.

Step 103: and determining the porosity of the target shale reservoir after eliminating the influence of the organic carbon content in the target shale reservoir according to the first variation relation, the second variation relation and the logging data.

In the embodiment of the application, the porosity of the target shale reservoir after the influence of the organic carbon content in the target shale reservoir is eliminated can be determined through the relation between the organic carbon content in the target shale reservoir and the reservoir density and the relation between the organic carbon content and the reservoir volume, so that the accuracy of determining the porosity of the shale reservoir is improved, and the accuracy of estimating the capacity of the low-resistance shale reservoir is improved.

according to the logging data, sequentially determining a first variation relation between the content of organic carbon in the target shale reservoir and the reservoir density and a second variation relation between the content of organic carbon in the target shale reservoir and the reservoir volume, wherein the first variation relation comprises the following steps:

determining a logging curve section corresponding to an organic matter rich layer section and a logging curve section corresponding to an organic matter poor layer section in the target shale reservoir according to the natural gamma logging curve, the resistivity curve and the acoustic wave time difference curve;

In some embodiments, determining a log curve segment corresponding to an organic-rich interval and a log curve segment corresponding to an organic-poor interval in the target shale reservoir from the natural gamma log, the resistivity curve, and the sonic moveout curve includes:

according to the position of the curve corresponding to the non-organic matter layer section in the natural gamma curve, eliminating the curve corresponding to the non-organic matter layer section in the overlapping curve to obtain an organic matter overlapping curve;

and determining a logging curve section corresponding to the organic matter-rich layer section and a logging curve section corresponding to the organic matter-poor layer section from the organic matter overlapping curve, wherein the logging curve section corresponding to the organic matter-rich layer section is a logging curve section which is different in trend of the resistivity curve and the sonic wave time difference curve in the organic matter overlapping curve and does not coincide with each other, and the logging curve section corresponding to the organic matter-poor layer section is a logging curve section which is identical in trend of the resistivity curve and the sonic wave time difference curve in the organic matter overlapping curve and coincides with each other.

In some embodiments, determining an organic carbon content determination model of the target shale reservoir and a logging curve segment corresponding to the organic-poor interval according to the logging curve segment corresponding to the organic-rich interval includes:

determining an acoustic time difference baseline and a resistivity baseline in a logging curve section corresponding to the organic-poor layer section, wherein the acoustic time difference baseline is a baseline corresponding to acoustic waves in an overlapping part of the logging curve section corresponding to the organic-poor layer section, and the resistivity baseline is a baseline corresponding to resistivity in the overlapping part of the logging curve section corresponding to the organic-poor layer section;

determining the reference abundance of organic matters corresponding to different strata according to the reference acoustic wave time difference baseline, the reference resistivity baseline, the reference acoustic wave time difference curve and the stratum resistivity;

In some embodiments, determining the second variation relationship based on the organic carbon content determination model and the first variation relationship comprises:

determining the densities corresponding to the organic carbon contents of 0 and 100% respectively from the first variation relation;

and determining the second variation relation according to the organic carbon content density, the organic carbon content determination model and reference densities corresponding to different strata, wherein the reference densities corresponding to the different strata are obtained through the density curve.

In some embodiments, determining the porosity of the target shale reservoir after eliminating the effect of the organic carbon content in the target shale reservoir based on the first variation relationship and the second variation relationship comprises:

determining the stratum densities of different stratums of the target shale reservoir after the influence of the organic carbon content is eliminated according to the second variation relation, the densities of the organic carbon content described in the first variation relation and the reference densities corresponding to the different stratums;

and determining the porosity of the different strata according to the stratum density of the different strata, the rock skeleton density and the fluid density of the fluid in the target shale reservoir.

All the above optional technical solutions can be combined arbitrarily to form an optional embodiment of the present application, and the present application embodiment is not described in detail again.

Fig. 2 is a flowchart of a method for determining the porosity of a shale reservoir provided in an embodiment of the present application, and this embodiment is exemplified by applying the method for determining the porosity of a shale reservoir to a terminal, where the method for determining the porosity of a shale reservoir may include the following steps:

step 201: and the terminal acquires the logging data of a target single well aiming at the target shale reservoir.

Because the logging data of a single well can have a relationship with the porosity of the shale reservoir, the terminal can acquire the logging data of the target single well for the target shale reservoir in order to determine the porosity of the target shale reservoir. The target shale reservoir can be any low resistivity shale reservoir and the target individual well is any individual well within the scope of the target shale reservoir.

As an example, the terminal can acquire the logging data of the target single well from a locally stored file when receiving the acquisition instruction. That is, the terminal can acquire and store the logging data of the target single well in advance, and when receiving the acquisition instruction, acquire the logging data of the target single well from the locally stored file. Or the terminal can also send an acquisition request to other equipment when receiving the acquisition instruction, wherein the acquisition request carries the single well identification of the target single well; and other equipment returns the logging data of the target single well to the terminal according to the single well identification of the target single well when receiving an acquisition request generated by the terminal, so that the terminal acquires the logging data of the target single well.

It should be noted that the obtaining instruction is triggered when the user acts on the terminal through a specified operation, where the specified operation includes a voice operation, a click operation, a slide operation, and the like.

In some embodiments, the well log data includes at least a natural gamma log (GR), a resistivity curve (Rt), a sonic time difference curve, and a density curve.

Step 202: and the terminal determines a first change relation between the organic carbon content in the target shale reservoir and the reservoir density and a second change relation between the organic carbon content in the target shale reservoir and the reservoir volume in sequence according to the logging data.

Because the organic carbon content in the target shale reservoir affects the reservoir density and volume and further affects the porosity of the target shale reservoir, the terminal needs to determine a first change relationship between the organic carbon content in the target shale reservoir and the reservoir density and a second change relationship between the organic carbon content in the target shale reservoir and the reservoir volume in sequence according to logging data.

As an example, the operation of the terminal sequentially determining, according to the log data, a first variation relationship between the content of organic carbon in the target shale reservoir and the reservoir density, and a second variation relationship between the content of organic carbon in the target shale reservoir and the reservoir volume at least includes: determining a logging curve section corresponding to an organic matter rich layer section and a logging curve section corresponding to an organic matter poor layer section in a target shale reservoir according to a natural gamma logging curve, a resistivity curve and a sound wave time difference curve; determining an organic carbon content determination model of the target shale reservoir according to the logging curve segment corresponding to the organic matter-rich interval and the logging curve segment corresponding to the organic matter-poor interval; performing linear fitting on the reciprocal of the density curve and the organic carbon content model to obtain a first change relation; and determining a second variation relation according to the organic carbon content determination model and the first variation relation.

Because the interval affecting the porosity of the target shale reservoir is mainly an organic matter interval, the terminal needs to determine a logging curve segment corresponding to an organic matter-rich interval and a logging curve segment corresponding to an organic matter-poor interval in the target shale reservoir according to a natural gamma logging curve, a resistivity curve and a time difference curve.

As an example, the operation of determining, by the terminal, a logging curve segment corresponding to an organic-rich interval and a logging curve segment corresponding to an organic-poor interval in the target shale reservoir according to the natural gamma logging curve, the resistivity curve and the wave time difference curve includes: overlapping the resistivity curve and the acoustic wave time difference curve to obtain an overlapping curve; according to the position of a curve corresponding to a non-organic matter layer section in a natural gamma curve, eliminating the curve corresponding to the non-organic matter layer section in an overlapping curve to obtain an organic matter overlapping curve; and determining a logging curve section corresponding to the organic matter-rich layer section and a logging curve section corresponding to the organic matter-poor layer section from the organic matter overlapping curve, wherein the logging curve section corresponding to the organic matter-rich layer section is a logging curve section which is different in trend of a resistivity curve and a time difference curve of the sound wave in the organic matter overlapping curve and does not coincide with each other, and the logging curve section corresponding to the organic matter-poor layer section is a logging curve section which is identical in trend of the resistivity curve and the time difference curve of the sound wave in the organic matter overlapping curve and coincides with each other.

In some embodiments, the terminal overlapping the resistivity curve and the acoustic time difference curve means that the acoustic time difference curve with scales is overlapped on the resistivity curve in the depth direction, so that an overlapped curve is obtained.

It should be noted that, the operation of overlapping the resistivity curve and the acoustic wave time difference curve by the terminal can refer to the related art, and this is not repeated in this embodiment of the application.

Because the non-organic matter layer section has no influence or almost negligible influence on the porosity of the target shale reservoir and the natural gamma curve can reflect different reservoir structures, the terminal can remove the curve corresponding to the non-organic matter layer section in the overlapping curve according to the position of the non-organic matter layer section in the natural gamma curve to obtain the organic matter overlapping curve.

In some embodiments, the terminal can identify curve positions corresponding to non-organic matter intervals such as an oil layer and evaporite from a natural gamma curve, and according to the curve positions corresponding to the non-organic matter intervals in the natural gamma curve, eliminate curves corresponding to the non-organic matter intervals in an overlapping curve to obtain an organic matter overlapping curve.

Because the organic matter overlapping curve may include a logging curve segment corresponding to the organic matter poor interval and a logging curve segment corresponding to the organic matter rich interval, the terminal can also determine the logging curve segment corresponding to the organic matter rich interval and the logging curve segment corresponding to the organic matter poor interval from the organic matter overlapping curve.

In some embodiments, the terminal can determine a logging curve segment in which the resistivity curve and the sonic wave time difference curve in the organic matter overlap curve have the same trend and are overlapped as a logging curve segment corresponding to an organic matter poor interval (generally, non-hydrocarbon source rock). And determining the logging curve segment which has different trends of the resistivity curve and the time difference curve of the acoustic wave in the organic matter overlapping curve and does not coincide as the logging curve segment corresponding to the organic matter-rich layer segment.

In some embodiments, the operation of the terminal determining the organic carbon content determination model of the target shale reservoir according to the logging curve segment corresponding to the organic-rich interval and the logging curve segment corresponding to the organic-poor interval includes: acquiring the formation resistivity of a target shale reservoir and the organic carbon content corresponding to different formations; determining an acoustic time difference base line and a resistivity base line in a logging curve section corresponding to the poor organic matter layer section, wherein the acoustic time difference base line is a base line corresponding to an acoustic wave in an overlapping part of the logging curve section corresponding to the poor organic matter layer section, and the resistivity base line is a base line corresponding to a resistivity in the overlapping part of the logging curve section corresponding to the poor organic matter layer section; determining a reference acoustic time difference baseline and a reference resistivity baseline in a logging curve corresponding to the organic-rich layer section according to the acoustic time difference baseline and the resistivity baseline corresponding to the organic-poor layer section respectively, and determining a reference acoustic time difference curve in the logging curve corresponding to the organic-rich layer section; determining the reference abundance of organic matters corresponding to different stratums according to the reference acoustic time difference baseline, the reference resistivity baseline, the reference acoustic time difference curve and the stratum resistivity; and performing linear fitting on the reference abundance of the organic matters corresponding to different strata and the organic carbon content corresponding to different strata to obtain an organic carbon content determination model.

Because the organic carbon contents corresponding to different depths of the stratum in the target shale reservoir are different, the terminal needs to obtain the stratum resistivity of the target shale reservoir and the organic carbon contents corresponding to different strata.

And because the influence of the organic poor interval on the porosity is almost negligible, and the resistivity baseline and the acoustic wave time difference baseline in the organic poor interval are related to the resistivity baseline and the acoustic wave time difference baseline in the organic rich interval, the terminal can determine the resistivity baseline and the acoustic wave time difference baseline in the organic poor interval first, and then determine the corresponding reference acoustic wave time difference baseline and the reference resistivity baseline in the logging curve section corresponding to the organic rich interval according to the resistivity baseline and the acoustic wave time difference baseline in the organic poor interval respectively.

In some embodiments, the terminal can determine the resistivity baseline and the acoustic wave time difference baseline in the organic-poor interval as a reference resistivity baseline and a reference acoustic wave time difference baseline corresponding to the organic-rich interval, respectively.

It should be noted that the reference acoustic time difference curve is an acoustic time difference curve of any section in the logging curve section corresponding to the organic-rich interval.

In some embodiments, the terminal can determine the reference abundance of organic matter corresponding to different strata according to the reference acoustic time difference baseline, the reference resistivity baseline, the reference acoustic time difference curve and the stratum resistivity through the following first formula.

In the first formula (1), index is the reference abundance of organic matter corresponding to different strata, and R is _t Is a reference resistivity baseline, Δ t is a reference acoustic moveout curve, R _bl Is formation resistivity, Δ t _bl When it is a reference sound waveA difference baseline, D is a constant.

In some embodiments, the terminal linearly fits the reference abundance of organic matter corresponding to different strata and the organic carbon content corresponding to different strata, and the obtained organic carbon content determination model can be represented by the image shown in fig. 3 below, or by a formula shown in a second formula below.

TOC＝A+B*index (2)

In the second formula (2), a and B are both constants, TOC is the organic carbon content, and index is the reference abundance of organic matter corresponding to different strata.

In order to determine a first variation relationship between organic carbon content and reservoir density within a target shale reservoir, the terminal can fit a density curve of the target shale reservoir to the organic carbon content. Namely, the terminal performs linear fitting on the reciprocal of the density curve and the organic carbon content model to obtain a first change relation.

Note that, after fitting the organic carbon content model to the reciprocal of the density curve, the first change relationship shown in fig. 4 can be obtained.

Because the reservoir volume will change along with the change of the organic carbon content and the density, the terminal can determine the model and the first change relation according to the organic carbon content and determine the second change relation.

In some embodiments, the terminal determines the model and the first variation relationship based on the organic carbon content, and the operation of determining the second variation relationship includes: determining densities corresponding to the organic carbon content of 0% and 100%, respectively, from the first variation; determining the density corresponding to the organic carbon content of 0 as the rock skeleton density of the target shale reservoir, and determining the density corresponding to the organic carbon content of 100% as the density of the organic carbon content; and determining a second variation relation according to the organic carbon content density and the reference density corresponding to the organic carbon content determination model and different stratums, wherein the reference densities corresponding to the different stratums are obtained through a density curve.

Because the first variation relation is the relation between the organic carbon content in the target shale reservoir and the reservoir density, when the organic carbon content is 0, the reservoir density of the target shale reservoir at the moment is the rock skeleton density of the target shale reservoir, and when the organic carbon content is 100%, the reservoir density of the target shale reservoir at the moment is the density of the organic carbon content.

As an example, the terminal determines the second variation relationship by the following third formula according to the density of the organic carbon content, the organic carbon content determination model and the reference densities corresponding to different strata.

V _k ＝(TOC*ρ _b *υ)/ρ _k (3)

In the third formula (3), V is _k The volumes corresponding to different strata (or called different depth strata), TOC is the organic carbon content, rho, determined by the second equation (2) above _b Reference density, p, for different strata _k Is the density of the organic carbon content (i.e. the density corresponding to 100% organic carbon content), and υ is constant, typically 1.19.

Step 203: and the terminal determines the porosity of the target shale reservoir after the influence of the organic carbon content in the target shale reservoir is eliminated according to the first variation relation and the second variation relation.

As an example, the operation of determining, by the terminal according to the first variation relation and the second variation relation, the porosity of the target shale reservoir after eliminating the influence of the organic carbon content in the target shale reservoir includes: determining stratum densities of different stratums of the target shale reservoir after the influence of the organic carbon content is eliminated according to the second variation relation, the densities of the organic carbon content described in the first variation relation and reference densities corresponding to the different stratums; and determining the porosity of different strata according to the stratum density, the rock skeleton density and the fluid density of the fluid in the target shale reservoir.

In some embodiments, the terminal determines the formation densities of the different formations of the target shale reservoir after eliminating the influence of the organic carbon content according to the second variation relationship, the density of the organic carbon content described in the first variation relationship, and the reference densities corresponding to the different formations by the following fourth formula.

ρ _bc ＝(ρ _b -V _k *ρ _k )/(1-V _k ) (4)

In the fourth formula (4), ρ _bc In order to eliminate the influence of organic carbon content on the stratum density, V, of different strata of the target shale reservoir _k The volumes, p, corresponding to different strata determined by the third equation (second relationship) _b Reference density, p, for different formations _k Is the density of the organic carbon content.

In some embodiments, the terminal determines the porosity of the different formations according to the formation density, the rock skeleton density, and the fluid density of the fluid in the target shale reservoir of the different formations by the following fifth formula.

φ＝(ρ _ma -ρ _bc )/(ρ _ma -ρ _f ) (5)

It should be noted that in the fifth formula (5), phi is the porosity of different strata of the target rock reservoir, ρ _bc To eliminate the influence of organic carbon content on the formation density, rho, of different strata of a target shale reservoir _ma Rock skeleton density, ρ, for a target shale reservoir _f Is the fluid density.

Step 204: and the terminal prompts the porosity of the target shale reservoir through the first prompt message.

In order to enable workers to clearly know the porosity of the target shale reservoir, the terminal can prompt the porosity of the target shale reservoir through the first prompt message after determining the porosity of the target shale reservoir.

In some embodiments, in order to enable the operator to know the difference between the measured porosity and the actually obtained porosity, the terminal is further capable of comparing the measured porosity with the porosity obtained in the above manner, and prompting the comparison result through the second prompting message.

The first prompt message and the second prompt message can be prompt messages in at least one form of characters, images, videos and the like.

In the embodiment of the application, the terminal can determine the porosity of the target shale reservoir after the influence of the organic carbon content in the target shale reservoir is eliminated through the relationship between the organic carbon content in the target shale reservoir and the reservoir density and the relationship between the organic carbon content and the reservoir volume, so that the accuracy of determining the porosity of the shale reservoir is improved, and the accuracy of estimating the capacity of the low-resistance shale reservoir is further improved.

Fig. 5 is a schematic structural diagram of a porosity determination apparatus for a shale reservoir provided in an embodiment of the present application, where the porosity determination apparatus for the shale reservoir may be implemented by software, hardware, or a combination of the two. The apparatus for determining the porosity of the shale reservoir may include: an acquisition module 501, a first determination module 502, and a second determination module 503.

The obtaining module 501 is configured to obtain logging data of a target single well for a target shale reservoir;

a first determining module 502, configured to sequentially determine, according to the logging data, a first variation relationship between the content of organic carbon in the target shale reservoir and the reservoir density, and a second variation relationship between the content of organic carbon in the target shale reservoir and the reservoir volume;

a second determining module 503, configured to determine, according to the first variation relation, the second variation relation, and the log data, the porosity of the target shale reservoir after the influence of the content of organic carbon in the target shale reservoir is eliminated.

referring to fig. 6, the first determining module 502 includes:

the first determining submodule 5021 is used for determining a logging curve section corresponding to an organic matter rich layer section and a logging curve section corresponding to an organic matter poor layer section in the target shale reservoir according to the natural gamma logging curve, the resistivity curve and the acoustic wave time difference curve;

the second determining sub-module 5022 is used for determining an organic carbon content determining model of the target shale reservoir according to the logging curve segment corresponding to the organic-rich layer section and the logging curve segment corresponding to the organic-poor layer section;

the fitting submodule 5023 is used for performing linear fitting on the reciprocal of the density curve and the organic carbon content model to obtain the first change relation;

a third determining submodule 5024, configured to determine the second variation relationship according to the organic carbon content determining model and the first variation relationship.

In some embodiments, the first determination submodule 5021 is configured to:

and determining a logging curve section corresponding to the organic matter-rich interval and a logging curve section corresponding to the organic matter-poor interval from the organic matter overlapping curve, wherein the logging curve section corresponding to the organic matter-rich interval is a logging curve section which is different in trend of the resistivity curve and the sound wave time difference curve in the organic matter overlapping curve and does not coincide with each other, and the logging curve section corresponding to the organic matter-poor interval is a logging curve section which is identical in trend of the resistivity curve and the sound wave time difference curve in the organic matter overlapping curve and does not coincide with each other.

In some embodiments, the second determination submodule 5022 is configured to:

determining a reference acoustic wave time difference baseline and a reference resistivity baseline in the logging curve section corresponding to the organic-rich interval according to the acoustic wave time difference baseline and the resistivity baseline corresponding to the organic-poor interval respectively, and determining a reference acoustic wave time difference curve in the logging curve section corresponding to the organic-rich interval;

and performing linear fitting on the reference abundance of the organic matters corresponding to the different strata and the organic carbon content corresponding to the different strata to obtain the organic carbon content determination model.

In some embodiments, the third determination submodule 5024 is configured to:

In some embodiments, referring to fig. 7, the second determining module 503 comprises:

a fourth determining sub-module 5031, configured to determine, according to the second variation relationship, the densities of the organic carbon content described in the first variation relationship, and reference densities corresponding to different strata, the stratum densities of different strata of the target shale reservoir after the influence of the organic carbon content is eliminated;

the fifth determining sub-module 5032 is configured to determine the porosity of the different strata according to the formation density of the different strata, the rock skeleton density and the fluid density of the fluid in the target shale reservoir.

In the embodiment of the application, the terminal can determine the porosity of the target shale reservoir after the influence of the organic carbon content in the target shale reservoir is eliminated through the relationship between the organic carbon content in the target shale reservoir and the reservoir density and the relationship between the organic carbon content and the reservoir volume, so that the accuracy of determining the porosity of the shale reservoir is improved, and the accuracy of estimating the capacity of the low-resistance shale reservoir is improved.

It should be noted that: when determining the porosity of the shale reservoir, the device for determining the porosity of the shale reservoir provided in the above embodiment is only illustrated by the division of the above functional modules, and in practical applications, the above function distribution may be completed by different functional modules according to needs, that is, the internal structure of the device is divided into different functional modules, so as to complete all or part of the above described functions. In addition, the porosity determination device for the shale reservoir provided by the above embodiment and the porosity determination method for the shale reservoir belong to the same concept, and specific implementation processes thereof are described in the method embodiments in detail and are not described herein again.

Fig. 8 shows a block diagram of a terminal 800 according to an exemplary embodiment of the present application. The terminal 800 may be: a smart phone, a tablet computer, an MP3 player (Moving Picture Experts Group Audio Layer III, motion video Experts compression standard Audio Layer 3), an MP4 player (Moving Picture Experts Group Audio Layer IV, motion video Experts compression standard Audio Layer 4), a notebook computer, or a desktop computer. The terminal 800 may also be referred to by other names such as user equipment, portable terminal, laptop terminal, desktop terminal, etc.

In general, the terminal 800 includes: a processor 801 and a memory 802.

The processor 801 may include one or more processing cores, such as a 4-core processor, an 8-core processor, and so forth. The processor 801 may be implemented in at least one hardware form of DSP (Digital Signal Processing), FPGA (Field-Programmable Gate Array), PLA (Programmable Logic Array). The processor 801 may also include a main processor and a coprocessor, where the main processor is a processor for Processing data in an awake state, and is also called a Central Processing Unit (CPU); a coprocessor is a low power processor for processing data in a standby state. In some embodiments, the processor 801 may be integrated with a GPU (Graphics Processing Unit) which is responsible for rendering and drawing the content required to be displayed by the display screen. In some embodiments, the processor 801 may further include an AI (Artificial Intelligence) processor for processing computing operations related to machine learning.

Memory 802 may include one or more computer-readable storage media, which may be non-transitory. Memory 802 may also include high speed random access memory, as well as non-volatile memory, such as one or more magnetic disk storage devices, flash memory storage devices. In some embodiments, the non-transitory computer readable storage medium in the memory 802 is for storing at least one instruction for execution by the processor 801 to implement the method for porosity determination of shale reservoirs provided by the method embodiments herein.

In some embodiments, the terminal 800 may further optionally include: a peripheral interface 803 and at least one peripheral. The processor 801, memory 802, and peripheral interface 803 may be connected by buses or signal lines. Various peripheral devices may be connected to peripheral interface 803 by a bus, signal line, or circuit board. Specifically, the peripheral device includes: at least one of a radio frequency circuit 804, a display 805, a camera assembly 806, an audio circuit 807, a positioning assembly 808, and a power supply 809.

The peripheral interface 803 may be used to connect at least one peripheral device related to I/O (Input/Output) to the processor 801 and the memory 802. In some embodiments, the processor 801, memory 802, and peripheral interface 803 are integrated on the same chip or circuit board; in some other embodiments, any one or two of the processor 801, the memory 802, and the peripheral interface 803 may be implemented on separate chips or circuit boards, which is not limited by the present embodiment.

The Radio Frequency circuit 804 is used for receiving and transmitting RF (Radio Frequency) signals, also called electromagnetic signals. The radio frequency circuitry 804 communicates with communication networks and other communication devices via electromagnetic signals. The rf circuit 804 converts an electrical signal into an electromagnetic signal to be transmitted, or converts a received electromagnetic signal into an electrical signal. Optionally, the radio frequency circuit 804 includes: an antenna system, an RF transceiver, one or more amplifiers, a tuner, an oscillator, a digital signal processor, a codec chipset, a subscriber identity module card, and so forth. The radio frequency circuit 804 may communicate with other terminals via at least one wireless communication protocol. The wireless communication protocols include, but are not limited to: metropolitan area networks, various generation mobile communication networks (2G, 3G, 4G, and 5G), wireless local area networks, and/or WiFi (Wireless Fidelity) networks. In some embodiments, the radio frequency circuit 804 may further include NFC (Near Field Communication) related circuits, which are not limited in this application.

The display screen 805 is used to display a UI (User Interface). The UI may include graphics, text, icons, video, and any combination thereof. When the display 805 is a touch display, the display 805 also has the ability to capture touch signals on or above the surface of the display 805. The touch signal may be input to the processor 801 as a control signal for processing. At this point, the display 805 may also be used to provide virtual buttons and/or a virtual keyboard, also referred to as soft buttons and/or a soft keyboard. In some embodiments, the display 805 may be one, providing the front panel of the terminal 800; in other embodiments, the display 805 may be at least two, respectively disposed on different surfaces of the terminal 800 or in a folded design; in other embodiments, the display 805 may be a flexible display disposed on a curved surface or a folded surface of the terminal 800. Even further, the display 805 may be arranged in a non-rectangular irregular pattern, i.e., a shaped screen. The Display 805 can be made of LCD (Liquid Crystal Display), OLED (Organic Light-Emitting Diode), and other materials.

The camera assembly 806 is used to capture images or video. Optionally, camera assembly 806 includes a front camera and a rear camera. Generally, a front camera is disposed at a front panel of the terminal, and a rear camera is disposed at a rear surface of the terminal. In some embodiments, the number of the rear cameras is at least two, and each rear camera is any one of a main camera, a depth-of-field camera, a wide-angle camera and a telephoto camera, so that the main camera and the depth-of-field camera are fused to realize a background blurring function, and the main camera and the wide-angle camera are fused to realize panoramic shooting and VR (Virtual Reality) shooting functions or other fusion shooting functions. In some embodiments, camera head assembly 806 may also include a flash. The flash lamp can be a monochrome temperature flash lamp or a bicolor temperature flash lamp. The double-color-temperature flash lamp is a combination of a warm-light flash lamp and a cold-light flash lamp and can be used for light compensation under different color temperatures.

The audio circuit 807 may include a microphone and a speaker. The microphone is used for collecting sound waves of a user and the environment, converting the sound waves into electric signals, and inputting the electric signals to the processor 801 for processing or inputting the electric signals to the radio frequency circuit 804 to achieve voice communication. For the purpose of stereo sound collection or noise reduction, a plurality of microphones may be provided at different portions of the terminal 800. The microphone may also be an array microphone or an omni-directional pick-up microphone. The speaker is used to convert electrical signals from the processor 801 or the radio frequency circuit 804 into sound waves. The loudspeaker can be a traditional film loudspeaker or a piezoelectric ceramic loudspeaker. When the speaker is a piezoelectric ceramic speaker, the speaker can be used for purposes such as converting an electric signal into a sound wave audible to a human being, or converting an electric signal into a sound wave inaudible to a human being to measure a distance. In some embodiments, the audio circuitry 807 may also include a headphone jack.

The positioning component 808 is used to locate the current geographic position of the terminal 800 for navigation or LBS (Location Based Service). The Positioning component 808 may be a Positioning component based on the GPS (Global Positioning System) in the united states, the beidou System in china, the graves System in russia, or the galileo System in the european union.

Power supply 809 is used to provide power to various components in terminal 800. The power supply 809 can be ac, dc, disposable or rechargeable. When the power source 809 comprises a rechargeable battery, the rechargeable battery may support wired or wireless charging. The rechargeable battery can also be used to support fast charge technology.

In some embodiments, terminal 800 also includes one or more sensors 810. The one or more sensors 810 include, but are not limited to: acceleration sensor 811, gyro sensor 812, pressure sensor 813, fingerprint sensor 814, optical sensor 815 and proximity sensor 816.

The acceleration sensor 811 may detect the magnitude of acceleration in three coordinate axes of the coordinate system established with the terminal 800. For example, the acceleration sensor 811 may be used to detect components of the gravitational acceleration in three coordinate axes. The processor 801 may control the display 805 to display the user interface in a landscape view or a portrait view according to the gravitational acceleration signal collected by the acceleration sensor 811. The acceleration sensor 811 may also be used for acquisition of motion data of a game or a user.

The gyro sensor 812 may detect a body direction and a rotation angle of the terminal 800, and the gyro sensor 812 may cooperate with the acceleration sensor 811 to acquire a 3D motion of the user with respect to the terminal 800. From the data collected by the gyro sensor 812, the processor 801 may implement the following functions: motion sensing (such as changing the UI according to a user's tilting operation), image stabilization while shooting, game control, and inertial navigation.

Pressure sensors 813 may be disposed on the side frames of terminal 800 and/or underneath display 805. When the pressure sensor 813 is disposed on the side frame of the terminal 800, the holding signal of the user to the terminal 800 can be detected, and the processor 801 performs left-right hand recognition or shortcut operation according to the holding signal collected by the pressure sensor 813. When the pressure sensor 813 is disposed at a lower layer of the display screen 805, the processor 801 controls the operability control on the UI interface according to the pressure operation of the user on the display screen 805. The operability control comprises at least one of a button control, a scroll bar control, an icon control and a menu control.

The fingerprint sensor 814 is used for collecting a fingerprint of the user, and the processor 801 identifies the identity of the user according to the fingerprint collected by the fingerprint sensor 814, or the fingerprint sensor 814 identifies the identity of the user according to the collected fingerprint. Upon identifying the user as a trusted identity, the processor 801 authorizes the user to perform relevant sensitive operations, including unlocking the screen, viewing encrypted information, downloading software, paying for and changing settings, etc. Fingerprint sensor 814 may be disposed on the front, back, or side of terminal 800. When a physical button or a vendor Logo is provided on the terminal 800, the fingerprint sensor 814 may be integrated with the physical button or the vendor Logo.

The optical sensor 815 is used to collect ambient light intensity. In one embodiment, the processor 801 may control the display brightness of the display 805 based on the ambient light intensity collected by the optical sensor 815. Specifically, when the ambient light intensity is high, the display brightness of the display 805 is increased; when the ambient light intensity is low, the display brightness of the display 805 is adjusted down. In another embodiment, the processor 801 may also dynamically adjust the shooting parameters of the camera assembly 806 based on the ambient light intensity collected by the optical sensor 815.

A proximity sensor 816, also known as a distance sensor, is typically disposed on a front panel of the terminal 800. The proximity sensor 816 is used to collect the distance between the user and the front surface of the terminal 800. In one embodiment, when the proximity sensor 816 detects that the distance between the user and the front surface of the terminal 800 is gradually reduced, the display 805 is controlled by the processor 801 to switch from a bright screen state to a dark screen state; when the proximity sensor 816 detects that the distance between the user and the front surface of the terminal 800 becomes gradually larger, the display 805 is controlled by the processor 801 to switch from the breath-screen state to the bright-screen state.

Those skilled in the art will appreciate that the configuration shown in fig. 8 is not intended to be limiting of terminal 800 and may include more or fewer components than those shown, or some components may be combined, or a different arrangement of components may be used.

Embodiments of the present application also provide a non-transitory computer-readable storage medium, where instructions of the storage medium, when executed by a processor of a terminal, enable the terminal to perform the method for determining the porosity of a shale reservoir provided in the above embodiments.

Embodiments of the present application further provide a computer program product containing instructions, which when run on a terminal, cause the terminal to perform the method for determining the porosity of a shale reservoir provided in the above embodiments.

It will be understood by those skilled in the art that all or part of the steps for implementing the above embodiments may be implemented by hardware, or may be implemented by a program instructing relevant hardware, where the program may be stored in a computer-readable storage medium, and the above-mentioned storage medium may be a read-only memory, a magnetic disk or an optical disk, etc.

The above description is only a preferred embodiment of the present application and should not be taken as limiting the present application, and any modifications, equivalents, improvements, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method for determining porosity of a shale reservoir, the method comprising:

sequentially determining a first change relation between the organic carbon content in the target shale reservoir and the reservoir density and a second change relation between the organic carbon content in the target shale reservoir and the reservoir volume according to the logging data;

2. The method of claim 1, wherein the well log data comprises a natural gamma log, a resistivity curve, a sonic moveout curve, and a density curve;

the sequentially determining a first variation relation between the content of organic carbon in the target shale reservoir and the reservoir density and a second variation relation between the content of organic carbon in the target shale reservoir and the reservoir volume according to the logging data comprises the following steps:

3. The method of claim 2, wherein determining the log segments for the organic-rich interval and the organic-lean interval in the target shale reservoir based on the natural gamma log, the resistivity curve, and the moveout curve comprises:

according to the position of a curve corresponding to a non-organic matter layer section in the natural gamma curve, eliminating the curve corresponding to the non-organic matter layer section in the overlapping curve to obtain an organic matter overlapping curve;

4. The method of claim 2, wherein determining the organic carbon content determination model for the target shale reservoir from the log segments for the organic-rich interval and the lean organic interval comprises:

determining a corresponding reference acoustic wave time difference baseline and a reference resistivity baseline in a logging curve section corresponding to the organic-rich interval according to the acoustic wave time difference baseline and the resistivity baseline corresponding to the organic-poor interval respectively, and determining a reference acoustic wave time difference curve in the logging curve section corresponding to the organic-rich interval;

5. The method of claim 2, wherein said determining the second variation from the organic carbon content determination model and the first variation comprises:

6. The method of claim 1, wherein the determining the porosity of the target shale reservoir after eliminating the effect of the organic carbon content in the target shale reservoir based on the first variation relationship and the second variation relationship comprises:

7. An apparatus for determining porosity of a shale reservoir, the apparatus comprising:

8. The apparatus of claim 7, wherein the well log data comprises a natural gamma log, a resistivity curve, a sonic moveout curve, and a density curve;

the first determining module includes:

the fitting submodule is used for performing linear fitting on the reciprocal of the density curve and the organic carbon content model to obtain the first change relation;

9. The apparatus of claim 8, wherein the first determination submodule is to:

10. The apparatus of claim 8, wherein the second determination submodule is to:

determining organic matter reference abundances corresponding to different strata according to the reference acoustic time difference base line, the reference resistivity curve, the reference acoustic time difference curve and the stratum resistivity;

11. The apparatus of claim 8, wherein the third determination submodule is to:

12. The apparatus of claim 7, wherein the second determining module comprises:

13. A computer-readable storage medium having stored thereon instructions which, when executed by a processor, carry out the steps of the method of any of the preceding claims 1 to 6.