Perforating bullet penetration depth prediction method based on actual reservoir conditions

Abstract

The invention relates to a perforating bullet penetration depth prediction method based on actual reservoir conditions, comprising the following steps: S1, setting test parameters of a plurality of groups of simulation tests according to rock perforation test standards, and performing perforation tests to obtain test perforation depths; s2, obtaining instant effective stress of each group of test perforation; s3, acquiring the comprehensive compressive strength of the rock in each group of tests; and S4, a first relational expression between the test perforation depth and the comprehensive compressive strength of the rock is obtained in a fitting mode, and perforation penetration depth prediction under the actual reservoir condition is conducted according to the first relational expression. According to the method, perforation hole passage penetration depth prediction can be performed based on factors such as actual reservoir pressure conditions and rock characteristics, so that a design basis is provided for field perforation well completion optimization design, oil well productivity analysis and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of perforation completion, and mainly relates to a method for predicting the penetration depth of a perforating bullet based on actual reservoir conditions. Background Art

[0002] At present, during the perforation completion operation of oil and gas wells, there is a large difference between the perforation elastic performance test results based on the ground API concrete target and the actual perforation penetration depth under reservoir near-wellbore conditions. Therefore, the perforation penetration prediction model established under conventional conditions has great limitations in guiding the on-site completion optimization design.

[0003] At the same time, the API 19B ​​2021 version of "Evaluation of Well Perforators" published by the American Petroleum Institute stipulates the test conditions and standard procedures for stress rock perforation tests, but according to this standard, the penetration depth of perforating bullets under certain conditions can only be obtained through tests, which is time-consuming and expensive. However, the actual oil and gas reservoir conditions are complex and changeable, and different reservoirs have different requirements for perforation performance. Accurate prediction of perforation channel penetration depth is conducive to improving the prediction of oil well productivity. Therefore, the penetration depth prediction of perforating bullets is crucial to the optimization design of on-site perforation completion. Summary of the invention

[0004] In order to overcome the problems in the prior art, the present invention provides a method for predicting the penetration depth of perforating bullets under actual reservoir conditions. Compared with the traditional perforating penetration prediction model based on ground API concrete targets, this method can predict the penetration depth of perforating channels based on factors such as actual reservoir pressure conditions and rock characteristics, thereby realizing rapid and accurate acquisition of perforating penetration depth. To achieve the above purpose, the present invention provides the following solutions:

[0005] A method for predicting penetration depth of perforating bullets based on actual reservoir conditions comprises the following steps:

[0006] S1. According to the rock perforation test standard, set test parameters for multiple groups of simulation tests, conduct perforation tests, and obtain the test perforation depth;

[0007] S2, obtaining the instantaneous effective stress of each group of test perforations;

[0008] S3. Obtain the comprehensive compressive strength of rock for each test group;

[0009] S4. Obtain a first relationship between the test perforation depth and the comprehensive compressive strength of the rock by fitting, and predict the perforation penetration depth under actual reservoir conditions according to the first relationship.

[0010] Furthermore, in step S1, the test parameters include overburden pressure, pore pressure, wellbore pressure, uniaxial compressive strength of rock, and porosity.

[0011] Furthermore, in step S1, the multiple groups of simulation tests are at least two groups, which contain at least one group of soft rock and one group of hard rock.

[0012] Furthermore, the uniaxial compressive strength of the core of the soft rock tested under ground conditions is between 10 MPa and 60 MPa, and the uniaxial compressive strength of the core of the hard rock tested under ground conditions is greater than 60 MPa.

[0013] Furthermore, in step S2, the method for obtaining the effective stress at the moment of perforation is:

[0014]

[0015] Where: is the instantaneous effective stress at perforation, MPa; is the overburden pressure, MPa; a is the ballistic pore pressure influence coefficient; p p is the pore pressure, MPa.

[0016] Furthermore, in step S3, the method for obtaining the comprehensive compressive strength of rock is:

[0017]

[0018] Where: UCS res is the comprehensive compressive strength of rock under complex stress conditions, MPa; b is the rock stress influence coefficient; is the effective stress at the moment of perforation, MPa; UCS is the uniaxial compressive strength of rock tested under ground conditions, MPa.

[0019] Furthermore, the relationship between the uniaxial compressive strength of rock and the rock stress influence coefficient is obtained through a fitting method, so that the rock stress influence coefficient is indirectly obtained by measuring the uniaxial compressive strength of rock.

[0020] Furthermore, in step S4, the comprehensive compressive strength of the rock is calculated based on the overburden pressure, pore pressure and uniaxial compressive strength of the rock in the actual reservoir test, and the comprehensive compressive strength of the rock is substituted into the first relationship to predict the perforation penetration depth under actual reservoir conditions.

[0021] On the other hand, the present invention provides a computer device, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that when the processor executes the computer program, the steps of the method for predicting the penetration depth of a perforating bullet based on actual reservoir conditions as described in any one of the above claims are implemented.

[0022] On the other hand, the present invention provides a computer-readable storage medium having a computer program stored thereon, characterized in that when the computer program is executed by a processor, the steps of the method for predicting the penetration depth of a perforating bullet based on actual reservoir conditions as described in any one of the above claims are implemented.

[0023] The present invention has the following advantages: The method provided by the present invention performs simulated reservoir perforation tests according to the stress rock perforation procedure specified in the API 19B ​​2021 version of the "Evaluation of Well Perforators" standard, and establishes a penetration prediction method that takes into account the actual reservoir lithology and pressure conditions. The penetration parameters of the perforating bullet in the layer can be quickly predicted according to the rock type, physical properties and pressure conditions of the actual reservoirs of different oil reservoirs, providing a design basis for on-site perforation completion optimization design and oil well productivity analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0025] Figure 1 It is a diagram of the method steps of the present invention.

[0026] Figure 2 This is the prediction chart in the embodiment of the present invention. DETAILED DESCRIPTION

[0027] The present invention is further described below in conjunction with the accompanying drawings and embodiments. It should be noted that, in the absence of conflict, the embodiments in this application and the technical features in the embodiments can be combined with each other. It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meanings as those generally understood by those of ordinary skill in the art to which this application belongs. The words "including" or "comprising" and the like used in the disclosure of the present invention mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects.

[0028] In order to solve the problem of insufficient adaptability and accuracy of traditional perforating bullet penetration prediction methods, such as Figure 1 As shown, the present invention provides a method for predicting the penetration depth of perforating bullets based on actual reservoir conditions, thereby providing technical support for optimizing perforating completion plans, optimizing mining processes, and improving recovery rates.

[0029] In order to study the relationship between the penetration depth of perforating bullets and rock strength, the inventors used different sandstone targets (carbonate rocks / sand conglomerates with the same lithology may also be preferred), where the rock strength of the sandstone targets was controlled within the range of 0-100 MPa, and the same perforating bullets were used to conduct perforating tests under ground conditions. The test data were analyzed according to the relevant steps in the API 19B ​​2021 version of "Evaluation of Well Perforators", and the relationship between the penetration depth of perforating bullets and the rock strength was obtained as follows:

[0030]

[0031] Where: Dop is the penetration depth of the perforating bullet into the sandstone reservoir, m; Dop ref is the penetration depth of the perforating bullet into the test core, m; α is the perforating elastic energy coefficient, m; UCS ref is the rock strength of the test core, MPa; UCS is the rock strength of the sandstone reservoir, MPa.

[0032] Specifically, during the test, according to the stress rock perforating procedure specified in the API 19B ​​2021 edition "Evaluation of Well Perforators" standard, multiple sets of overburden pressure, pore pressure, wellbore pressure, rock uniaxial compressive strength, and porosity test conditions were set, and the penetration data of the perforating bullets were obtained.

[0033] Specifically, when conducting the test, the rock strength selected should include soft rock and hard rock, where the uniaxial compressive strength of the soft rock core tested under ground conditions is required to be between 10MPa and 60MPa, and the uniaxial compressive strength of the hard rock core tested under ground conditions is required to be greater than 60MPa.

[0034] Under actual reservoir conditions, due to the existence of complex stress conditions, the internal structure of the rock will deform after being constrained by the complex stress conditions, resulting in changes in the microscopic pore structure. In order to simplify the complex stress conditions of the reservoir, the inventor established an effective stress model for the reservoir at the moment of perforation and calculated the effective stress at the moment of perforation. The calculation method is as follows:

[0035]

[0036] Where: is the instantaneous effective stress at perforation, MPa; is the overburden pressure, MPa; a is the ballistic pore pressure influence coefficient; p p is the pore pressure, MPa.

[0037] The vertical geostress of the reservoir is taken as the overlying rock pressure, and the formation pressure before the reservoir is put into production is taken as the pore pressure.

[0038] In one embodiment, according to the improved definition of B. Grove effective stress, the perforation test results of cores with different porosities under different effective stress conditions are analyzed, and the expression of the ballistic pore pressure influence coefficient is obtained by power function fitting:

[0039]

[0040] in, is the core porosity.

[0041] Rocks become denser under stress conditions, but as the strength of the rock itself increases, its sensitivity to stress weakens. Based on a large number of triaxial stress tests on rocks, a relationship model between the comprehensive compressive strength of rocks and effective stress was established:

[0042]

[0043] Where: UCS res is the comprehensive compressive strength of rock under complex stress conditions, MPa; b is the rock stress influence coefficient; is the effective stress at the moment of perforation, MPa; UCS is the uniaxial compressive strength of rock tested under ground conditions, MPa.

[0044] The rock stress influence coefficient b is obtained by fitting the uniaxial compressive strength of the core rock tested under ground conditions. In one embodiment, the fitting relationship is:

[0045] b=0.85·e -0.005·UCS

[0046] Where UCS is the uniaxial compressive strength of rock tested under ground conditions.

[0047] After the above steps, the relationship between the test perforation depth and the comprehensive compressive strength of the rock is obtained by fitting. After obtaining the relationship between the corresponding lithology, the overburden pressure, pore pressure, and uniaxial compressive strength of the rock tested on the ground are input to calculate the comprehensive compressive strength of the rock, so that the perforation penetration depth under actual reservoir conditions can be predicted using the relationship.

[0048] Example 1

[0049] In Example 1, a 127-type ultra-deep penetration perforating bullet (SDP46) of Wuhua Energy Technology Company was used, with a charge type of RDX and a charge amount of 45g. A penetration prediction chart for this type of perforating bullet was established, and the penetration performance of this type of perforating bullet in the Huangliu reservoir in the Ledong-Lingshui Sag in the South China Sea was predicted.

[0050] First, according to the statistical analysis of logging data, the reservoirs of the Huangliu Formation in the Ledong-Lingshui Depression are mainly composed of siltstone and fine sandstone, with a rock strength of about 80MPa. The well depth in this block is 3000-5000m, the average overburden rock pressure is 65MPa, and the average formation pressure is 40MPa. The porosity of the Huangliu Formation reservoir in the Central Canyon is mainly between 16% and 35%, with an average porosity of 27.79%; the permeability is mainly distributed in the range of 10×10 -3 ~1000×10 -3 μm 2 The average permeability is 433.14×10 -3 μm 2 The overall reservoir properties are characterized by medium porosity-extra-high porosity and medium permeability-extra-high permeability, and there is a good positive correlation between porosity and permeability.

[0051] Two groups of simulated reservoir perforation tests were carried out using SDP46 perforating bullets according to the stress rock perforating procedure specified in the API 19B ​​2021 edition "Evaluation of Well Perforators" standard: Group A selected rock with a uniaxial compressive strength of 30MPa and a porosity of 20%, and set the overburden pressure to 25MPa, pore pressure to 18MPa, and wellbore pressure to 15MPa; Group B selected sandstone with a uniaxial compressive strength of 80MPa and a porosity of 15%, and set the overburden pressure to 50MPa, pore pressure to 40MPa, and wellbore pressure to 35MPa for perforation tests. The test results of the SDP46 perforating bullet under the test conditions were 750mm and 410mm, respectively.

[0052] According to the two sets of test conditions, the effective stresses at the moment of perforation were calculated to be 16.5MPa and 33.2MPa respectively.

[0053] The comprehensive compressive strength of rock calculated based on the two sets of test conditions is 42.1MPa and 98.9MPa.

[0054] The test results of the two groups of perforating bullets were exponentially fitted with the corresponding rock comprehensive compressive strength obtained by calculation, and the penetration model and prediction chart of SDP46 perforating bullet were obtained, as shown in the figure. Figure 2 shown.

[0055] In order to predict the perforation penetration depth of the Huangliu reservoir rock in the Ledong-Lingshui Sag of the South China Sea, the basic parameters of the reservoir were used to calculate the comprehensive compressive strength of 105 MPa. Figure 2 The penetration depth prediction chart of SDP46 perforating bullet for sandstone shows that the predicted penetration depth of the perforating bullet under the Huangliu Formation in Ledong-Lingshui Sag in the South China Sea is 387 mm.

[0056] It can be seen that the present invention is based on the rock perforation test standard specified in API 19B, conducts perforation elastic performance testing and evaluation under simulated actual reservoir temperature, pressure and lithology conditions, and studies the correlation between the penetration performance of perforating bullets and rock physical properties and pressure conditions based on the test data under the standard conditions, establishes a perforating bullet penetration prediction method based on actual reservoir conditions, and realizes the perforating bullet penetration prediction under different oil and gas reservoir conditions, which is of great significance for adjusting the perforation completion optimization plan, improving the prediction accuracy of single well production capacity, optimizing the mining process, and improving the recovery rate.

[0057] The above description is only a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any technician familiar with the profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of the technical solution of the present invention.

Claims

1. A method for predicting penetration depth of perforating bullets based on actual reservoir conditions, characterized in that: The following steps are involved: S1. According to the rock perforation test standard, set test parameters for multiple groups of simulation tests, conduct perforation tests, and obtain the test perforation depth; S2, obtaining the instantaneous effective stress of each group of test perforations; S3. Obtain the comprehensive compressive strength of rock for each test group; S4. Obtain a first relationship between the test perforation depth and the comprehensive compressive strength of the rock by fitting, and predict the perforation penetration depth under actual reservoir conditions according to the first relationship.

2. According to the method for predicting penetration depth of perforating charges according to claim 1, in step S1, the test parameters include overburden pressure, pore pressure, wellbore pressure, uniaxial compressive strength of rock, and porosity.

3. The method for predicting penetration depth of a perforating charge according to claim 1, wherein in step S1, the plurality of simulation tests are at least two groups, each of which contains at least one group of soft rock and one group of hard rock.

4. According to the perforator penetration prediction method of claim 3, the uniaxial compressive strength of the core of the soft rock tested under ground conditions is between 10MPa and 60MPa, and the uniaxial compressive strength of the core of the hard rock tested under ground conditions is greater than 60MPa.

5. The method for predicting penetration depth of a perforating charge according to claim 1, wherein in step S2, a method for obtaining effective stress at the moment of perforation is: Where: is the instantaneous effective stress at perforation, MPa; is the overburden pressure, MPa; a is the ballistic pore pressure influence coefficient; p p is the pore pressure, MPa.

6. The method for predicting penetration depth of perforating bullets according to claim 1, wherein in step S3, the method for obtaining the comprehensive compressive strength of rock is: Where: UCS res is the comprehensive compressive strength of rock under complex stress conditions, MPa; b is the rock stress influence coefficient; is the effective stress at the moment of perforation, MPa; UCS is the uniaxial compressive strength of rock tested under ground conditions, MPa.

7. According to the method for predicting penetration depth of perforating charges according to claim 6, a relationship between the uniaxial compressive strength of rock and the rock stress influence coefficient is obtained by a fitting method, thereby indirectly obtaining the rock stress influence coefficient by measuring the uniaxial compressive strength of rock.

8. According to the method for predicting penetration depth of perforating bullets according to claim 1, in step S4, the comprehensive compressive strength of rock is calculated according to the overburden pressure, pore pressure and uniaxial compressive strength of rock tested on the ground of the actual reservoir, and the comprehensive compressive strength of rock is substituted into the first relationship to predict the penetration depth of perforating bullets under actual reservoir conditions.

9. A computer device comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that: When the processor executes the computer program, the steps of the perforating charge penetration prediction method according to any one of claims 1 to 8 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method for predicting penetration depth of a perforating charge according to any one of claims 1 to 8 are implemented.

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