Method and device for evaluating porosity of oil-containing shale

Abstract

The invention provides an oil-containing shale porosity evaluation method, and belongs to the technical field of shale oil-gas exploration and development, and the method comprises the steps: obtaining a plurality of samples of a target oil-containing shale; measuring the free hydrocarbon content of the first sample; measuring the total volume, the skeleton volume and the sample mass of the second sample; measuring the crude oil density of the region where the target oil shale sample is located; determining the porosity value of the target oil-containing shale when the target oil-containing shale does not contain oil according to the total volume and the skeleton volume of the second sample, and calculating the porosity value of the target oil-containing shale when the target oil-containing shale contains oil according to the crude oil density, the free hydrocarbon content of the first sample, the total volume of the second sample, the skeleton volume and the sample mass; and determining the porosity of the target oil-containing shale sample according to the porosity value when the oil is not contained and the porosity value when the oil is contained. According to the method provided by the invention, the accuracy of porosity evaluation is improved, and meanwhile, as the test equipment is easily carried to the well site, the requirement of instantly testing the porosity in the well site is met.

Description

Technical Field

[0001] The present application belongs to the technical field of shale oil and gas exploration and development, and specifically relates to a porosity evaluation method and device for oil-bearing shale. Background Art

[0002] The porosity of rock samples is a crucial parameter for evaluating reservoir properties, oil and gas accumulation, and reserve estimation. With the expansion of oil and gas exploration, the brittleness, micropore development, water sensitivity, and crude oil filling of oil-bearing shale samples required for testing have led to significant variability in porosity measurement results. The preferred method for calculating porosity is to measure the skeleton volume and total volume of the rock sample. The errors in total and skeleton volume measurements have a similar impact on porosity accuracy. According to the definition of porosity, Φ = (Vtotal - Vbone) / Vtotal. Currently, laboratory porosity measurement technology is relatively mature, but compared to field porosity testing, it suffers from issues such as long testing cycles, significant artifacts in test results, and inconsistent sample preparation particle size. Crucially, crude oil filling can block pores and pores in oil-bearing shale samples, preventing gas from entering all primary pores during skeleton volume testing. Especially for some samples with good oil content and high oil density, gas porosity measurement can often only obtain partial connected porosity information, so that a large number of pores filled or semi-filled with crude oil cannot be quantitatively characterized, resulting in poor regularity of test results and inability to reflect the true reservoir characteristics of the samples.

[0003] However, current core porosity measurement methods have limitations when applied to oil-bearing shale samples, failing to determine the true porosity of the shale. Most existing methods overlook the fact that shale samples contain oil and that crude oil is difficult to extract, resulting in low porosity values. This is detrimental for evaluating the porosity of highly oil-bearing shale samples, and the parameters obtained fail to reflect the true petrophysical properties of shale oil reservoirs. Summary of the Invention

[0004] To address the above technical issues, this application proposes a porosity evaluation method and device for oil-bearing shale. This method calculates the actual porosity of shale by combining the porosity of the shale in its oil-bearing state, the free hydrocarbon content, the light hydrocarbon recovery correction coefficient, and the crude oil density. This method meets the real-time needs of wellsites and improves the applicability and accuracy of the data.

[0005] In a first aspect, the present application proposes a porosity evaluation method for oil shale, comprising:

[0006] obtaining several samples of the target oil-bearing shale;

[0007] Determine the free hydrocarbon content of the first sample;

[0008] Determine the total volume, skeleton volume, and sample mass of the second sample;

[0009] Determine the crude oil density in the area where the target oil-bearing shale sample is located;

[0010] Determining the porosity value of the target oil-bearing shale when free of oil based on the total volume and skeleton volume of the second sample, and calculating the porosity value of the target oil-bearing shale when containing oil based on the crude oil density, the free hydrocarbon content of the first sample, the total volume, skeleton volume, and sample mass of the second sample;

[0011] The porosity of the target oil-bearing shale sample is determined according to the porosity value when it is free of oil and the porosity value when it is containing oil.

[0012] The determining the porosity of the target oil-bearing shale sample according to the porosity value when the sample does not contain oil and the porosity value when the sample contains oil includes:

[0013] The porosity value when the oil is not present and the porosity value when the oil is present are added together to obtain the porosity of the target oil-bearing shale sample.

[0014] The porosity value calculation formula when there is no oil is as follows:

[0015]

[0016] in, is the porosity value without oil, V1 is the total volume of the second sample, and V2 is the skeleton volume of the second sample;

[0017] The porosity value when containing oil is calculated as follows:

[0018]

[0019] in, is the porosity value when containing oil, c is the shale light hydrocarbon recovery correction coefficient, m1 is the sample mass of the second sample, S1 is the free hydrocarbon content of the first sample; ρ1 is the crude oil density in the area containing the target oil-bearing shale sample.

[0020] Determining the free hydrocarbon content of the first sample comprises:

[0021] crushing the first sample into a first particle size to obtain a shale sample of a first particle size, wherein the value of the first particle size is selected based on the degree of combustion of the shale sample of the first particle size;

[0022] Weighing a first weight of a shale sample of a first particle size;

[0023] placing a shale sample of a first particle size and a first weight at a first constant temperature for a first time period to obtain a shale sample of the first particle size after constant temperature treatment;

[0024] The free hydrocarbon content of the first-size shale sample after constant temperature treatment was determined using a rock pyrolysis instrument.

[0025] Determining the total volume, skeleton volume, and sample mass of the second sample comprises:

[0026] crushing the second sample into a second particle size to obtain a shale sample of a second particle size, wherein the value of the second particle size is selected based on the requirement of measuring the total volume and skeleton volume of the shale sample of the second particle size;

[0027] Weighing a second weight of a shale sample of a second particle size;

[0028] drying a second weight of a shale sample of a second particle size at a second constant temperature for a second period of time;

[0029] The total volume of the dried second-size shale sample was determined using the variable density method;

[0030] The skeleton volume of the dried second-grained shale sample was measured using a helium porosimeter;

[0031] The dried shale sample of the second particle size is weighed to obtain a sample mass of the dried shale sample of the second particle size.

[0032] The value of the first granularity is greater than the value of the second granularity.

[0033] In a second aspect, the present application proposes a porosity evaluation device for oil-bearing shale, comprising: a sample acquisition module, a first measurement module, a second measurement module, a third measurement module, a porosity value calculation module, and a porosity determination module;

[0034] The sample acquisition module is connected to the first determination module, the second determination module, and the third determination module respectively, the first determination module, the second determination module, and the third determination module are respectively connected to the porosity value calculation module, and the porosity value calculation module is connected to the porosity determination module;

[0035] a sample acquisition module for several samples of target oil-bearing shale;

[0036] a first measuring module, for measuring the free hydrocarbon content of the first sample;

[0037] a second measuring module, for measuring the total volume, skeleton volume and sample mass of the second sample;

[0038] The third measurement module is used to measure the crude oil density in the area where the target oil-bearing shale sample is located;

[0039] a porosity value calculation module, configured to determine the porosity value of the target oil-bearing shale when free of oil based on the total volume and skeleton volume of the second sample, and to calculate the porosity value of the target oil-bearing shale when containing oil based on the crude oil density, the free hydrocarbon content of the first sample, the total volume, skeleton volume, and sample mass of the second sample;

[0040] The porosity determination module is used to determine the porosity of the target oil-bearing shale sample according to the porosity value when the shale is free of oil and the porosity value when the shale is containing oil.

[0041] In a third aspect, the present application proposes an electronic device comprising: one or more processors, and a memory, wherein the memory stores instructions, and when the instructions are executed by the one or more processors, the one or more processors execute the porosity evaluation method of oil-bearing shale.

[0042] In a fourth aspect, the present application proposes a computer-readable storage medium storing executable instructions, which, when executed, enable a processor to execute the porosity evaluation method for oil-bearing shale.

[0043] In a fifth aspect, the present application proposes a computer program product, comprising a computer program or instructions, which implement the porosity evaluation method of oil-bearing shale when executed by a processor.

[0044] Beneficial effects:

[0045] This application proposes a porosity evaluation method and device for oil-bearing shale, which takes into account the problem of low porosity test results caused by oil in shale samples. The porosity of the target oil-bearing shale sample is jointly determined by the porosity value when there is no oil and the porosity value when there is oil, thereby improving the accuracy of the porosity evaluation. At the same time, because the testing equipment can be easily carried to the well site, it meets the demand for immediate porosity testing at the well site. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 This is a flow chart of a porosity evaluation method for oil shale according to an embodiment of the present application;

[0047] Figure 2 This is a flow chart for determining the free hydrocarbon content of the first sample in an embodiment of the present application;

[0048] Figure 3 This is a flow chart for determining the total volume, skeleton volume, and sample mass of the second sample of the embodiment of the present application;

[0049] Figure 4 This is a flowchart of an example of a porosity evaluation method for oil shale in this application;

[0050] Figure 5Schematic diagram of the porosity evaluation method of oil-bearing shale in the embodiment of the present application and the evaluation results of the conventional gas logging method;

[0051] Figure 6 This is a principle block diagram of the porosity evaluation device for oil shale according to an embodiment of the present application. DETAILED DESCRIPTION

[0052] The present disclosure will be further described below with reference to the embodiments shown in the accompanying drawings.

[0053] Most of the existing porosity evaluation methods ignore the fact that shale samples contain oil and that crude oil is difficult to extract, resulting in low porosity tests. This is not conducive to the porosity evaluation of shale samples with high oil content, and the parameters obtained are difficult to reflect the true rock properties of shale oil reservoirs. The more representative methods and technologies are: ① CN102252948B mud shale porosity measurement method, which mainly involves a universal mud shale porosity measurement method. This method can avoid the inconvenience of drilling cores in mud shale, eliminate the adsorption of organic matter on the measuring gas, and avoid organic matter blocking the pore throat. It can also measure non-connected pores in mud shale before crushing, and can also determine the water saturation, oil saturation and gas saturation of mud shale. However, this method does not take into account the retained oil in the core, so the porosity occupied by the retained oil cannot be obtained. ②

[0054] CN105866002B is a precise method for testing the nuclear magnetic resonance porosity of oil-bearing shale, which involves a shale porosity testing method using nuclear magnetic resonance technology. It mainly tests the nuclear magnetic resonance T2 spectrum distribution and porosity of saturated kerosene shale with different waiting times and echo intervals, and calibrates the waiting time and echo interval by comparing with the helium porosity. The nuclear magnetic resonance T2 spectrum distribution at the optimal waiting time and echo interval can accurately characterize the physical properties of the oil-bearing shale reservoir. The cost of using nuclear magnetic resonance instruments to measure the porosity of rocks is relatively high, and there is a problem that the measuring medium cannot fully enter the shale pores. ③CN106483056B is a shale porosity measurement method and measurement device based on longitudinal wave velocity. This method overcomes the problem that conventional rock porosity measurement methods require a measuring medium and the measuring medium cannot fill all the pores of the shale. Based on the "formation acoustic factor formula", the relationship between porosity and longitudinal wave velocity is established, and the porosity of the shale is obtained through sediment compaction theory. However, this method has problems with the selection of logging curves and its applicability, and its effectiveness for oil-bearing shales is unknown.

[0055] The above analysis shows that the existing technology does not consider the oil content in shale samples, and the difficulty in extracting crude oil causes the porosity test to be low. In response to the above technical problems, this application proposes a porosity evaluation method for oil-bearing shale. This method considers the determination of the porosity of shale without oil in the pores on the one hand, and the porosity of oil-bearing shale on the other hand, and adds the two to obtain an accurate porosity evaluation result. This evaluation method abandons the large-scale equipment required for porosity determination in the existing technology. The measurement equipment used in this application can be brought to the site and can be analyzed at the development well site. This evaluation method meets the immediacy requirements of the well site, improves the applicability and accuracy of the data, and provides scientific experimental data for shale oil reservoir evaluation, sweet spot layer optimization, and reserve declaration.

[0056] Example 1

[0057] This embodiment proposes a porosity evaluation method for oil shale, such as Figure 1 As shown, including:

[0058] Step S1: obtaining several samples of target oil-bearing shale;

[0059] Most existing methods ignore the fact that shale samples contain oil and that crude oil is difficult to extract, resulting in problems such as low porosity test results. Therefore, the shale sample first obtained in this embodiment is oil-containing. In order to measure different parameters, this embodiment requires obtaining at least two samples.

[0060] Step S2: Determine the free hydrocarbon content of the first sample, such as Figure 2 As shown, including:

[0061] Step S2.1: crushing the first sample into a first particle size to obtain a shale sample of the first particle size;

[0062] Step S2.2: Weighing a first weight of a shale sample of a first particle size;

[0063] Step S2.3: placing a shale sample of a first particle size and a first weight at a first constant temperature for a first time period to obtain a shale sample of the first particle size after constant temperature treatment;

[0064] Step S2.4: Using a rock pyrolysis instrument, the free hydrocarbon content of the first-size shale sample after constant temperature treatment is measured.

[0065] Step S3: Determine the total volume, skeleton volume and sample mass of the second sample, such as Figure 3 As shown, including:

[0066] Step S3.1: crushing the oil-bearing shale sample into a second particle size to obtain a shale sample of the second particle size;

[0067] Step S3.2: Weighing a second weight of a shale sample of a second particle size;

[0068] Step S3.3: Drying the shale sample of the second weight and the second particle size at a second constant temperature for a second time.

[0069] In this embodiment, the target oil-bearing shale sample is crushed into a first particle size and a second particle size, respectively. The first particle size ranges from 100 mesh to 200 mesh, and the second particle size ranges from 1 mesh to 10 mesh. 1 mesh, 10 mesh, 100 mesh, and 200 mesh are all mesh numbers. The mesh number indicates the number of mesh holes per square centimeter. The larger the mesh number, the finer the material particle size; the smaller the mesh number, the larger the material particle size. In this embodiment, the oil-bearing shale sample is crushed to about 10 mesh and 200 mesh, respectively, to obtain a first particle size shale sample and a second particle size shale sample, i.e., a 200 mesh shale sample and a 10 mesh shale sample. In this embodiment, the value of the first particle size is greater than the value of the second particle size. On the one hand, the value of the first particle size is selected based on the degree of combustion of the first-size shale sample. Since the free hydrocarbon content of the 200-mesh shale sample needs to be measured in the subsequent steps, the 200-mesh shale sample needs to be burned when measuring the free hydrocarbon content. The finer the shale sample is crushed, the more conducive it is to complete combustion and the more accurate the free hydrocarbon content can be measured. The shale samples with a particle size of 100-200 mesh are in powder form and can be fully burned, resulting in accurate free hydrocarbon content measurement results. On the other hand, the value of the second particle size is selected based on the need to measure the total volume and skeleton volume of the second-size shale sample. Since the total volume and skeleton volume of the 10-mesh shale sample need to be measured in the subsequent steps, in order to facilitate volume testing, the oil-bearing shale sample is first crushed into a granular shale sample with a particle size of 1-10 mesh.

[0070] In this embodiment, a first weight of a shale sample of a first particle size is weighed, the first weight being 100 mg, and the first particle size being 200 mesh. The first weight of the shale sample of the first particle size is then placed at a first constant temperature for a first time period, the first constant temperature being 300° C., and the first time period being 3 minutes. That is, 100 mg of the 200 mesh shale sample is weighed, and the 100 mg 200 mesh shale sample is placed at a constant temperature of 300° C. for 3 minutes using a rock pyrolyzer, and the free hydrocarbon content S1 of the sample is measured. In a specific implementation, before the oil-bearing shale sample is crushed, the oil-bearing shale sample may be placed in a liquid nitrogen environment for more than 1 minute to reduce the loss of light hydrocarbons in the sample, thereby preventing the free hydrocarbon content S1 of the first particle size shale sample measured by the rock pyrolyzer from being too low.

[0071] In this embodiment, a second weight of a second particle size shale sample is weighed, and the second weight of the second particle size shale sample is dried at a second constant temperature for a second time, wherein the second weight is 10 g, the second constant temperature is a constant temperature of 105°C, and the second time is 24 hours. That is, 10 g of a 10-mesh shale sample is weighed and placed in an oven, dried at a constant temperature of 105°C for 24 hours to remove water and volatile impurities in the sample, and then placed in a dryer for testing.

[0072] Step S3.4: Determine the total volume of the dried shale sample of the second particle size using a variable density method;

[0073] Step S3.5: using a helium porosimeter to measure the skeletal volume of the dried shale sample of the second particle size;

[0074] Step S3.6: Weigh the dried shale sample of the second particle size to obtain the sample mass of the dried shale sample of the second particle size.

[0075] In this embodiment, the operations corresponding to step S3.4, step S3.5, and step S3.6 are performed in no particular order. The total volume V1 of the second particle size shale sample after drying in step S2 is determined by the variable density method, and the skeleton volume V2 of the second particle size shale sample after drying is determined by the He (helium) porosity analyzer. Finally, the dried second particle size shale sample is weighed and recorded as m1.

[0076] The total volume V1 of the dried shale sample of the second particle size after drying in step S3 can be determined using the variable density method. The medium environment of the shale sample of the second particle size can be changed by using a water displacement method or applying a magnetic field, and the total volume of the shale sample of the second particle size can be accurately obtained by density difference calculation. Preferably, the total volume of the shale sample of the second particle size obtained using a magnetic total volume analyzer is more accurate.

[0077] Step S4: Determine the crude oil density in the area where the target oil-bearing shale sample is located, including:

[0078] The density of crude oil in the area where the oil shale samples are located is measured using a densitometer.

[0079] The density of crude oil produced in the region is measured using a densitometer. Preferably, density testing is performed using crude oil samples collected during the production blowout phase of a shale oil well group, as this is closest to the physical properties of the actual crude oil in the formation.

[0080] Step S5: Determine the porosity value of the target oil-bearing shale when it is free of oil based on the total volume and skeleton volume of the second sample, and calculate the porosity value of the target oil-bearing shale when it is containing oil based on the crude oil density, the free hydrocarbon content of the first sample, the total volume, skeleton volume and sample mass of the second sample.

[0081] In this example, the porosity is first calculated using conventional methods. This porosity does not take into account the presence of oil in the shale sample and the difficulty in extracting crude oil, which can result in a low porosity test result. Based on the total volume and skeleton volume of the second sample, the porosity value when oil-free is calculated using the following formula:

[0082]

[0083] in, is the porosity value without oil, in %, V1 is the total volume of the second-size shale sample after drying, in cm 3 , V2 is the skeleton volume of the second-size shale sample after drying, in cm 3 .

[0084] In this embodiment, in addition to using conventional methods to calculate the porosity value when there is no oil, the porosity value when there is oil should also be calculated. The porosity value when there is oil represents the porosity calculation method when crude oil fills the pores. Only by adding the porosity value when there is no oil and the porosity value when there is oil can a more accurate porosity evaluation result be expressed.

[0085] The porosity value when containing oil is calculated as follows:

[0086]

[0087] in, is the porosity value when containing oil, in %, c is the shale light hydrocarbon recovery correction coefficient, m1 is the sample mass of the second particle size shale sample after drying, in g, S1 is the free hydrocarbon content of the first particle size shale sample, in mg / g; ρ1 is the crude oil density in the area where the oil-bearing shale sample is located, in cm 3 / g.

[0088] Step S6: Add the porosity value when there is no oil and the porosity value when there is oil to obtain the porosity of the oil-bearing shale sample.

[0089] The porosity of the oil-bearing shale sample can be obtained by adding the porosity value when it does not contain oil to the porosity value when it contains oil, that is, The porosity of oil shale samples can also be directly calculated using the following formula:

[0090]

[0091] in, is the porosity of the oil-bearing shale sample, in %, which is used as the evaluation result of the porosity of the oil-bearing shale sample.

[0092] In the above steps, it can be understood that there is no particular order for step S2, step S3 and step S4, and the order of obtaining the measurement parameters has no effect on the porosity evaluation result.

[0093] The porosity evaluation of oil-bearing shale samples is of great significance to shale oil and gas exploration and reserve declaration. However, with the current application of technology, it is usually necessary to combine a variety of large-scale instruments and technical methods in the laboratory, resulting in high labor costs and low work efficiency. On the one hand, this makes the analysis results unable to meet the on-site immediacy requirements for target window selection after drilling at the well site. On the other hand, the existing technology usually does not consider the crude oil filling characteristics in the shale pores, resulting in low test porosity. This embodiment proposes a porosity evaluation method for oil-bearing shale. All the equipment used are small test equipment. All test equipment can be brought to the development well site for implementation analysis. The actual porosity of the shale is calculated by combining the porosity of the shale in the oil-bearing state, free hydrocarbon content, light hydrocarbon recovery correction coefficient and crude oil density. The method of this embodiment is simple and easy to implement, meets the immediacy requirements of the well site, improves the applicability and accuracy of the data, and provides scientific experimental data for shale oil reservoir evaluation, sweet spot layer optimization and reserve declaration.

[0094] Example 2

[0095] In response to the needs of shale oil and gas exploration and development, considering that the existing rock sample porosity determination method cannot meet the analysis requirements of oil-bearing shale porosity, this application proposes a porosity evaluation method for oil-bearing shale, which provides effective support for the analysis of key parameters of shale oil reservoir petrophysical properties and provides an applicable and effective experimental method for shale oil and gas exploration and development. In order to more clearly describe the specific implementation process of the porosity evaluation method for oil-bearing shale, this embodiment is a specific example of embodiment 1, such as Figure 4 As shown, the following steps are included:

[0096] Step S100: crushing the shale sample into 10 mesh and 200 mesh respectively and drying;

[0097] In this example, the various experimental devices involved are debugged at the shale oil development well site to ensure the normal operation of various electronic equipment and sensors, and to ensure the stability of the basic functions of the instruments. The experimental devices include at least: a freeze crusher, an oven, a dryer, a rock pyrolyzer, a helium porosity analyzer, a magnetic total volume analyzer, and a density meter. These devices can be transported to the shale oil development well site, avoiding the problems of high labor costs and low work efficiency caused by a variety of large instruments in the existing technology. In this example, the shale sample is crushed to about 10 mesh. Weigh 10g of 10-mesh shale sample and put it into an oven, dry it at a constant temperature of 105℃ for 24 hours, and then place it in a dryer for testing. The mass of the sample after drying is recorded as m1;

[0098] Step S101: conducting a rock pyrolysis experiment on a 200-mesh shale sample to obtain the free hydrocarbon content S1 of the shale;

[0099] The specific process is as follows: shale samples are crushed to approximately 200 mesh using a cryo-crusher. 100 mg of the 200-mesh shale sample is weighed and the free hydrocarbon content (S1) of the 200-mesh shale sample is measured using a rock pyrolysis instrument. Both 200 mesh and 10 mesh are mesh numbers, which represent the number of holes per square centimeter. A larger mesh number indicates a finer particle size, while a smaller mesh number indicates a larger particle size.

[0100] Step S102: Performing a total volume test on a 10-mesh shale sample to obtain a total shale volume V1;

[0101] Specifically, the total volume V1 of a 10-mesh shale sample is measured using a magnetic volume analyzer using a magnetic variable density method. Alternatively, the medium environment of a shale sample of a second particle size can be modified using a water displacement method or the application of a magnetic field, and the total volume V1 of the shale can be accurately calculated using density difference. Preferably, the total volume V1 of the 10-mesh shale sample is obtained using a magnetic volume analyzer.

[0102] Step S103: Performing a skeleton volume test on a 10-mesh shale sample to obtain a shale skeleton volume V2;

[0103] Specifically: the skeleton volume V2 of the 10-mesh shale sample was measured by He porosity analyzer;

[0104] Step S104: measuring the density ρ1 of crude oil in the study area by using a densitometer;

[0105] Specifically, a densitometer is used to measure the density ρ1 of crude oil produced from adjacent wells in the same layer. Preferably, density testing is performed using crude oil samples collected from shale oil wells during the production blowout phase, as this is most similar to the actual physical properties of the crude oil in the formation.

[0106] Step S105: Calculate the porosity of the shale sample.

[0107] Specifically, the porosity is calculated according to the following formula:

[0108]

[0109] In this example, the letters have the following meanings: is the porosity of the shale sample, in %, as the evaluation result of the porosity of the oil-bearing shale sample. V1 is the total volume of the 10-mesh shale sample after drying, in cm 3 , V2 is the skeleton volume of the 10-mesh shale sample after drying, in cm 3 , V1 is the total volume of the 10-mesh shale sample after drying, in cm 3, c is the shale light hydrocarbon recovery correction coefficient, in this example, c = 1.55, m1 is the sample mass of the 10-mesh shale sample after drying, in g, S1 is the free hydrocarbon content of the 200-mesh shale sample, in mg / g; ρ1 is the crude oil density in the study area, in this example, it is 0.85 cm 3 / g, the evaluation results and various parameters are shown in Table 1. The comparison results of the porosity evaluation method in this example and the conventional gas testing method are shown in Figure 5 ,from Figure 5 It is obvious that the porosity value calculated in this example is higher than the porosity value obtained by conventional gas testing method.

[0110] Table 1: Porosity analysis results of 5 oil shale samples

[0111]

[0112] This example proposes a porosity evaluation method for oil-bearing shale, including crushing shale samples to 10-mesh and 200-mesh sizes and drying them. The 200-mesh shale sample undergoes a rock pyrolysis experiment to determine the free hydrocarbon content of the shale. The 10-mesh shale sample undergoes a total volume test to determine the total volume of the shale. The 10-mesh shale sample undergoes a skeleton volume test to determine the skeleton volume of the shale. The crude oil density in the study area is measured using a densitometer. The porosity of the shale samples is calculated based on the parameters obtained from these tests. This method is simple and easy to implement, meets the immediacy requirements of the well site, and improves the applicability and accuracy of the data.

[0113] Example 3:

[0114] This embodiment provides a porosity evaluation device for oil shale, such as Figure 6 As shown, it includes: a sample acquisition module, a first determination module, a second determination module, a third determination module, a porosity value calculation module and a porosity determination module;

[0115] The sample acquisition module is connected to the first determination module, the second determination module, and the third determination module respectively, the first determination module, the second determination module, and the third determination module are respectively connected to the porosity value calculation module, and the porosity value calculation module is connected to the porosity determination module;

[0116] a sample acquisition module for several samples of target oil-bearing shale;

[0117] a first measuring module, for measuring the free hydrocarbon content of the first sample;

[0118] a second measuring module, for measuring the total volume, skeleton volume and sample mass of the second sample;

[0119] The third measurement module is used to measure the crude oil density in the area where the target oil-bearing shale sample is located;

[0120] a porosity value calculation module, configured to determine the porosity value of the target oil-bearing shale when free of oil based on the total volume and skeleton volume of the second sample, and to calculate the porosity value of the target oil-bearing shale when containing oil based on the crude oil density, the free hydrocarbon content of the first sample, the total volume, skeleton volume, and sample mass of the second sample;

[0121] The porosity determination module is used to determine the porosity of the target oil-bearing shale sample according to the porosity value when the shale is free of oil and the porosity value when the shale is containing oil.

[0122] The first measuring module includes: a first crushing unit, a first weighing unit, a constant temperature treatment unit, and a hydrocarbon content measuring unit;

[0123] The first crushing unit is connected to the first weighing unit, the first weighing unit is connected to the constant temperature treatment unit, and the constant temperature treatment unit is connected to the hydrocarbon content determination unit;

[0124] The first crushing unit is used to crush the first sample into a first particle size to obtain a shale sample of the first particle size;

[0125] The first weighing unit is used to weigh a shale sample of a first particle size with a first weight;

[0126] The constant temperature treatment unit is used to place a shale sample of a first particle size and a first weight at a first constant temperature for a first time period to obtain a shale sample of the first particle size after constant temperature treatment;

[0127] The hydrocarbon content determination unit is used to determine the free hydrocarbon content of the shale sample of the first particle size after constant temperature treatment using a rock pyrolyzer.

[0128] The second measuring module includes: a second crushing unit, a second weighing unit, a sample drying unit, a total volume measuring unit, a skeleton volume measuring unit and a third weighing unit;

[0129] The second crushing unit is connected to the second weighing unit, the second weighing unit is connected to the sample drying unit, and the sample drying unit is respectively connected to the total volume measuring unit, the skeleton volume measuring unit and the third weighing unit;

[0130] The second crushing unit is used to crush the oil-bearing shale sample into a second particle size to obtain a shale sample of the second particle size;

[0131] The second weighing unit is used to weigh a second weight of a shale sample of a second particle size;

[0132] The sample drying unit is used to dry a shale sample of a second weight and a second particle size at a second constant temperature for a second time.

[0133] The total volume measuring unit is used to measure the total volume of the dried shale sample of the second particle size using a variable density method;

[0134] The skeleton volume measuring unit is used to measure the skeleton volume of the dried shale sample of the second particle size using a helium porosimeter;

[0135] The third weighing unit is used to weigh the dried shale sample of the second particle size to obtain the sample mass of the dried shale sample of the second particle size.

[0136] This embodiment proposes a porosity evaluation device for oil-bearing shale, which uses a sample to obtain several samples of target oil-bearing shale; uses a first measurement module, a second measurement module, and a third measurement module to respectively measure the free hydrocarbon content of the first sample, the total volume, the skeleton volume, and the sample mass of the second sample, as well as the crude oil density in the area where the target oil-bearing shale samples are located; uses a porosity value calculation module to determine the porosity value of the target oil-bearing shale when it is free of oil based on the total volume and the skeleton volume of the second sample, and calculates the porosity value of the target oil-bearing shale when it is containing oil based on the crude oil density, the free hydrocarbon content of the first sample, the total volume, the skeleton volume, and the sample mass of the second sample; finally, uses a porosity determination module to determine the porosity of the target oil-bearing shale sample based on the porosity value when it is free of oil and the porosity value when it is containing oil. This embodiment takes into account the problem of low porosity test results caused by oil content in shale samples. The porosity value when there is no oil and the porosity value when there is oil are used to jointly determine the porosity of the target oil-bearing shale sample, thereby improving the accuracy of the porosity evaluation. At the same time, because the testing equipment can be easily carried to the well site, the demand for immediate porosity testing at the well site is met.

[0137] Example 4:

[0138] This embodiment proposes an electronic device, including: one or more processors, and a memory, wherein the memory stores instructions, and when the instructions are executed by the one or more processors, the one or more processors execute the porosity evaluation method of oil-bearing shale.

[0139] The porosity evaluation method for oil shale comprises:

[0140] Step S1: obtaining several samples of target oil-bearing shale;

[0141] Step S2: Determine the free hydrocarbon content of the first sample, comprising:

[0142] Step S2.1: crushing the first sample into a first particle size to obtain a shale sample of the first particle size;

[0143] Step S2.2: Weighing a first weight of a shale sample of a first particle size;

[0144] Step S2.3: placing a shale sample of a first particle size and a first weight at a first constant temperature for a first time period to obtain a shale sample of the first particle size after constant temperature treatment;

[0145] Step S2.4: Using a rock pyrolysis instrument, the free hydrocarbon content of the first-size shale sample after constant temperature treatment is measured.

[0146] Step S3: Determining the total volume, skeleton volume, and sample mass of the second sample comprises:

[0147] Step S3.1: crushing the oil-bearing shale sample into a second particle size to obtain a shale sample of the second particle size;

[0148] Step S3.2: Weighing a second weight of a shale sample of a second particle size;

[0149] Step S3.3: drying the shale sample of the second weight and the second particle size at a second constant temperature for a second time;

[0150] Step S3.4: Determine the total volume of the dried shale sample of the second particle size using a variable density method;

[0151] Step S3.5: using a helium porosimeter to measure the skeletal volume of the dried shale sample of the second particle size;

[0152] Step S3.6: Weigh the dried shale sample of the second particle size to obtain the sample mass of the dried shale sample of the second particle size.

[0153] Step S4: measuring the crude oil density in the area where the target oil-bearing shale sample is located;

[0154] Step S5: determining the porosity value of the target oil-bearing shale when free of oil based on the total volume and skeleton volume of the second sample, and calculating the porosity value of the target oil-bearing shale when containing oil based on the crude oil density, the free hydrocarbon content of the first sample, the total volume, skeleton volume, and sample mass of the second sample;

[0155] The porosity value calculation formula when there is no oil is as follows:

[0156]

[0157] in, is the porosity value without oil, V1 is the total volume of the second sample, and V2 is the skeleton volume of the second sample;

[0158] The porosity value when containing oil is calculated as follows:

[0159]

[0160] in, is the porosity value when containing oil, c is the shale light hydrocarbon recovery correction coefficient, m1 is the sample mass of the second sample, S1 is the free hydrocarbon content of the first sample; ρ1 is the crude oil density in the area containing the target oil-bearing shale sample.

[0161] Step S6: Add the porosity value when there is no oil and the porosity value when there is oil to obtain the porosity of the oil-bearing shale sample.

[0162] The porosity of the oil-bearing shale sample can be obtained by adding the porosity value when it does not contain oil to the porosity value when it contains oil, that is, It can also be directly calculated using the following formula:

[0163]

[0164] in, is the porosity of the oil-bearing shale sample, in %, which is used as the evaluation result of the porosity of the oil-bearing shale sample.

[0165] The electronic device can be a mobile phone, computer, or tablet computer, and includes a memory and a processor. The memory stores a computer program that, when executed by the processor, implements the porosity evaluation method for oil shale as described in the embodiments. It is understood that the electronic device may also include an input / output (I / O) interface and a communication component.

[0166] The processor is configured to execute all or part of the steps of the porosity evaluation method for oil shale described in the above embodiment. The memory is configured to store various types of data, such as instructions for any application or method in the electronic device, as well as data related to the application.

[0167] The processor can be an application specific integrated circuit (ASIC), a digital signal processor (DSP), a programmable logic device (PLD), a field programmable gate array (FPGA), a controller, a microcontroller, a microprocessor, or other electronic components, and is used to execute the porosity evaluation method of oil shale described in the above embodiment.

[0168] Example 5

[0169] This embodiment provides a computer-readable storage medium storing executable instructions. When the instructions are executed, if they are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium.

[0170] The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the porosity evaluation method for oil shale described in various embodiments of the present application.

[0171] The aforementioned storage media include: flash memory, hard disk, multimedia card, card-type memory (for example, SD (Secure Digital Memory Card) or DX (Memory Data Register, MDR abbreviation, memory data register) memory, etc.), random access memory (RAM), static random access memory (SRAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), programmable read-only memory (PROM), magnetic memory, disk, CD, server, APP (Application, abbreviation of application software) application store, and other media that can store program verification codes, which store computer programs. When the computer program is executed by the processor, it can implement the various steps of the porosity evaluation method of oil shale described above.

[0172] The porosity evaluation method for oil shale comprises:

[0173] Step S1: obtaining several samples of target oil-bearing shale;

[0174] Step S2: Determine the free hydrocarbon content of the first sample, comprising:

[0175] Step S2.1: crushing the first sample into a first particle size to obtain a shale sample of the first particle size;

[0176] Step S2.2: Weighing a first weight of a shale sample of a first particle size;

[0177] Step S2.3: placing a shale sample of a first particle size and a first weight at a first constant temperature for a first time period to obtain a shale sample of the first particle size after constant temperature treatment;

[0178] Step S2.4: Using a rock pyrolysis instrument, the free hydrocarbon content of the first-size shale sample after constant temperature treatment is measured.

[0179] Step S3: Determining the total volume, skeleton volume, and sample mass of the second sample comprises:

[0180] Step S3.1: crushing the oil-bearing shale sample into a second particle size to obtain a shale sample of the second particle size;

[0181] Step S3.2: Weighing a second weight of a shale sample of a second particle size;

[0182] Step S3.3: drying the shale sample of the second weight and the second particle size at a second constant temperature for a second time;

[0183] Step S3.4: Determine the total volume of the dried shale sample of the second particle size using a variable density method;

[0184] Step S3.5: using a helium porosimeter to measure the skeletal volume of the dried shale sample of the second particle size;

[0185] Step S3.6: Weigh the dried shale sample of the second particle size to obtain the sample mass of the dried shale sample of the second particle size.

[0186] Step S4: measuring the crude oil density in the area where the target oil-bearing shale sample is located;

[0187] Step S5: determining the porosity value of the target oil-bearing shale when free of oil based on the total volume and skeleton volume of the second sample, and calculating the porosity value of the target oil-bearing shale when containing oil based on the crude oil density, the free hydrocarbon content of the first sample, the total volume, skeleton volume, and sample mass of the second sample;

[0188] The porosity value calculation formula when there is no oil is as follows:

[0189]

[0190] in, is the porosity value without oil, V1 is the total volume of the second sample, and V2 is the skeleton volume of the second sample;

[0191] The porosity value when containing oil is calculated as follows:

[0192]

[0193] in, is the porosity value when containing oil, c is the shale light hydrocarbon recovery correction coefficient, m1 is the sample mass of the second sample, S1 is the free hydrocarbon content of the first sample; ρ1 is the crude oil density in the area containing the target oil-bearing shale sample.

[0194] Step S6: Add the porosity value when there is no oil and the porosity value when there is oil to obtain the porosity of the oil-bearing shale sample.

[0195] The porosity of the oil-bearing shale sample can be obtained by adding the porosity value when it does not contain oil to the porosity value when it contains oil, that is, It can also be directly calculated using the following formula:

[0196]

[0197] in, is the porosity of the oil-bearing shale sample, in %, which is used as the evaluation result of the porosity of the oil-bearing shale sample.

[0198] Example 6

[0199] This embodiment provides a computer program product, including a computer program or instructions, which implement the porosity evaluation method of oil-bearing shale when executed by a processor.

[0200] Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or the part of the technical solution can be embodied in the form of a computer program product.

[0201] The porosity evaluation method for oil shale comprises:

[0202] Step S1: obtaining several samples of target oil-bearing shale;

[0203] Step S2: Determine the free hydrocarbon content of the first sample, comprising:

[0204] Step S2.1: crushing the first sample into a first particle size to obtain a shale sample of the first particle size;

[0205] Step S2.2: Weighing a first weight of a shale sample of a first particle size;

[0206] Step S2.3: placing a shale sample of a first particle size and a first weight at a first constant temperature for a first time period to obtain a shale sample of the first particle size after constant temperature treatment;

[0207] Step S2.4: Using a rock pyrolysis instrument, the free hydrocarbon content of the first-size shale sample after constant temperature treatment is measured.

[0208] Step S3: Determining the total volume, skeleton volume, and sample mass of the second sample comprises:

[0209] Step S3.1: crushing the oil-bearing shale sample into a second particle size to obtain a shale sample of the second particle size;

[0210] Step S3.2: Weighing a second weight of a shale sample of a second particle size;

[0211] Step S3.3: drying the shale sample of the second weight and the second particle size at a second constant temperature for a second time;

[0212] Step S3.4: Determine the total volume of the dried shale sample of the second particle size using a variable density method;

[0213] Step S3.5: using a helium porosimeter to measure the skeletal volume of the dried shale sample of the second particle size;

[0214] Step S3.6: Weigh the dried shale sample of the second particle size to obtain the sample mass of the dried shale sample of the second particle size.

[0215] Step S4: measuring the crude oil density in the area where the target oil-bearing shale sample is located;

[0216] Step S5: determining the porosity value of the target oil-bearing shale when free of oil based on the total volume and skeleton volume of the second sample, and calculating the porosity value of the target oil-bearing shale when containing oil based on the crude oil density, the free hydrocarbon content of the first sample, the total volume, skeleton volume, and sample mass of the second sample;

[0217] The porosity value calculation formula when there is no oil is as follows:

[0218]

[0219] in, is the porosity value without oil, V1 is the total volume of the second sample, and V2 is the skeleton volume of the second sample;

[0220] The porosity value when containing oil is calculated as follows:

[0221]

[0222] in, is the porosity value when containing oil, c is the shale light hydrocarbon recovery correction coefficient, m1 is the sample mass of the second sample, S1 is the free hydrocarbon content of the first sample; ρ1 is the crude oil density in the area containing the target oil-bearing shale sample.

[0223] Step S6: Add the porosity value when there is no oil and the porosity value when there is oil to obtain the porosity of the oil-bearing shale sample.

[0224] The porosity of the oil-bearing shale sample can be obtained by adding the porosity value when it does not contain oil to the porosity value when it contains oil, that is, It can also be directly calculated using the following formula:

[0225]

[0226] in, is the porosity of the oil-bearing shale sample, in %, which is used as the evaluation result of the porosity of the oil-bearing shale sample.

[0227] The various embodiments in the present disclosure are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments.

[0228] The scope of protection of the present disclosure is not limited to the above-described embodiments. Obviously, those skilled in the art may make various modifications and variations to the present disclosure without departing from the scope and spirit of the present disclosure. If such modifications and variations fall within the scope of the claims of the present disclosure and their equivalents, the present disclosure is intended to include such modifications and variations.

Claims

1. A porosity evaluation method for oil shale, characterized in that: include: obtaining several samples of the target oil-bearing shale; Determine the free hydrocarbon content of the first sample; Determine the total volume, skeleton volume, and sample mass of the second sample; Determine the crude oil density in the area where the target oil-bearing shale sample is located; Determining the porosity value of the target oil-bearing shale when free of oil based on the total volume and skeleton volume of the second sample, and calculating the porosity value of the target oil-bearing shale when containing oil based on the crude oil density, the free hydrocarbon content of the first sample, the total volume, skeleton volume, and sample mass of the second sample; The porosity of the target oil-bearing shale sample is determined according to the porosity value when it is free of oil and the porosity value when it is containing oil.

2. The porosity evaluation method for oil shale according to claim 1, characterized in that: The determining the porosity of the target oil-bearing shale sample according to the porosity value when the sample does not contain oil and the porosity value when the sample contains oil includes: The porosity value when the oil is not present and the porosity value when the oil is present are added together to obtain the porosity of the target oil-bearing shale sample.

3. The porosity evaluation method for oil shale according to claim 2, characterized in that: The porosity value calculation formula when there is no oil is as follows: in, is the porosity value without oil, V1 is the total volume of the second sample, and V2 is the skeleton volume of the second sample; The porosity value when containing oil is calculated as follows: in, is the porosity value when containing oil, c is the shale light hydrocarbon recovery correction coefficient, m1 is the sample mass of the second sample, S1 is the free hydrocarbon content of the first sample; ρ1 is the crude oil density in the area where the target oil-bearing shale sample is located.

4. The porosity evaluation method for oil shale according to claim 1, characterized in that: Determining the free hydrocarbon content of the first sample comprises: crushing the first sample into a first particle size to obtain a shale sample of a first particle size, wherein the value of the first particle size is selected based on the degree of combustion of the shale sample of the first particle size; Weighing a first weight of a shale sample of a first particle size; placing a shale sample of a first particle size and a first weight at a first constant temperature for a first time period to obtain a shale sample of the first particle size after constant temperature treatment; The free hydrocarbon content of the first-size shale sample after constant temperature treatment was determined using a rock pyrolysis instrument.

5. The porosity evaluation method for oil shale according to claim 1, characterized in that: Determining the total volume, skeleton volume, and sample mass of the second sample comprises: crushing the second sample into a second particle size to obtain a shale sample of a second particle size, wherein the value of the second particle size is selected based on the requirement of measuring the total volume and skeleton volume of the shale sample of the second particle size; Weighing a second weight of a shale sample of a second particle size; drying a second weight of a shale sample of a second particle size at a second constant temperature for a second period of time; The total volume of the dried second-size shale sample was determined using the variable density method; The skeleton volume of the dried second-grained shale sample was measured using a helium porosimeter; The dried shale sample of the second particle size is weighed to obtain a sample mass of the dried shale sample of the second particle size.

6. The porosity evaluation method for oil shale according to claim 4 or 5, characterized in that: The value of the first granularity is greater than the value of the second granularity.

7. A porosity evaluation device for oil shale, characterized in that: include: a sample acquisition module, a first determination module, a second determination module, a third determination module, a porosity value calculation module, and a porosity determination module; The sample acquisition module is connected to the first determination module, the second determination module, and the third determination module respectively, the first determination module, the second determination module, and the third determination module are respectively connected to the porosity value calculation module, and the porosity value calculation module is connected to the porosity determination module; a sample acquisition module for several samples of target oil-bearing shale; A first measuring module, for measuring the free hydrocarbon content of the first sample; a second measuring module, for measuring the total volume, skeleton volume and sample mass of the second sample; The third measurement module is used to measure the crude oil density in the area where the target oil-bearing shale sample is located; a porosity value calculation module, configured to determine the porosity value of the target oil-bearing shale when free of oil based on the total volume and skeleton volume of the second sample, and to calculate the porosity value of the target oil-bearing shale when containing oil based on the crude oil density, the free hydrocarbon content of the first sample, the total volume, skeleton volume, and sample mass of the second sample; The porosity determination module is used to determine the porosity of the target oil-bearing shale sample according to the porosity value when the shale is free of oil and the porosity value when the shale is containing oil.

8. An electronic device, characterized in that: include: One or more processors, and a memory, wherein the memory stores instructions, and when the instructions are executed by the one or more processors, the one or more processors execute the porosity evaluation method for oil shale according to any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that The device stores executable instructions, which, when executed, enable a processor to execute the porosity evaluation method for oil shale according to any one of claims 1 to 6.

10. A computer program product comprising a computer program or instructions, characterized in that When the computer program or instruction is executed by a processor, the porosity evaluation method for oil shale according to any one of claims 1 to 6 is implemented.

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