Shale oil porosity determination method, device, equipment and storage medium

Abstract

Embodiments of the present invention provide a shale oil porosity determination method, device, equipment, and storage medium, belonging to the field of oilfield development technology. The shale oil porosity determination method includes: obtaining a shale oil core sample and a shale oil wellhead fluid sample, using a first sample cylinder and a second sample cylinder to determine the volume of the shale oil core sample and the volume of the shale oil wellhead fluid sample, further using the first sample cylinder and the second sample cylinder to determine the gas dissolved in the pore fluid of the shale oil core and the gas dissolved in the shale oil wellhead fluid, and finally determining the shale oil porosity based on the volume of the shale oil core sample, the volume of the shale oil wellhead fluid sample, the gas dissolved in the pore fluid of the shale oil core, and the gas dissolved in the shale oil wellhead fluid. The shale oil porosity determination method provided by the embodiment of the present invention has a wider measurement range, and the sample does not need to be washed with oil, which ensures integrity and improves measurement accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of oilfield development, and in particular to a shale oil porosity measurement method, a shale oil porosity measurement device, an electronic device and a readable storage medium. Background Art

[0002] As a new type of oil resource, shale oil is crucial in the process of reserve calculation and development plan formulation. The key parameters of reserve calculation are of vital importance, especially the porosity parameter, which is the basis for understanding the oil storage situation of the oil layer, dividing the main layer, determining the physical boundaries of the effective thickness and interlayer, calculating reserves, and analyzing the production situation of the oil field.

[0003] Commonly used methods for measuring the porosity of rock samples include liquid saturation weighing method, gas porosity determination method, nuclear magnetic resonance method, etc. For oil-bearing rock samples, these porosity measurement methods all require the rock samples to be washed with oil and saturated with fluid before the porosity measurement is performed. However, for shale oil cores, there are many difficulties in washing the oil: First, the shale core is dense and has extremely low permeability. The solvent washing and dewatering cycle is very long, and the crude oil in some pores is difficult to be washed out, which has a great impact on the subsequent accurate measurement of porosity; second, there are a large number of bedding fractures and microcracks in the shale core. These cracks are important fluid storage spaces. In the process of porosity measurement, it is necessary to accurately measure the porosity of the shale core containing cracks. However, during the long-term oil washing process, these already very fragile crack systems are very easy to collapse and destroy. The integrity of the core is affected, making subsequent porosity measurement experiments difficult. Even if measurements are performed, the pore volume of the fractured part is lost, resulting in large errors. Third, shale oil cores contain organic pores and inorganic pores, both of which contain fluids. During the oil washing process with organic solvents, solvents with strong dissolving ability will destroy the organic pores composed mainly of kerogen, affecting the subsequent porosity measurement results. Fourth, shale oil has complex lithofacies and strong heterogeneity. The porosity measurement results of small samples cannot reflect the actual formation conditions. Summary of the Invention

[0004] The purpose of the embodiments of the present invention is to provide a shale oil porosity measurement method, device, equipment and storage medium to solve the above technical problems.

[0005] To achieve the above objectives, an embodiment of the present invention provides a method for measuring shale oil porosity, the method comprising:

[0006] Obtaining a shale oil core sample and a shale oil wellhead fluid sample; wherein the shale oil core sample is located in a first sample cylinder, and the shale oil wellhead fluid sample is located in a second sample cylinder;

[0007] Determining the volume of a shale oil core sample and a shale oil wellhead fluid sample using the first sample cylinder and the second sample cylinder;

[0008] Using the first sample cylinder and the second sample cylinder, determining the gas dissolved content of the pore fluid of the shale oil core and the gas dissolved content of the shale oil wellhead fluid;

[0009] The shale oil porosity is determined based on the volume of the shale oil core sample, the volume of the shale oil wellhead fluid sample, the gas solubility of the shale oil core pore fluid and the gas solubility of the shale oil wellhead fluid.

[0010] Optionally, the first sample cylinder is connected to a first gas cylinder via a first pipe, and the second sample cylinder is connected to a second gas cylinder via a second pipe, wherein the first pipe and the second pipe are respectively provided with valves for realizing on-off control of the corresponding pipes;

[0011] The volume of shale oil core samples and the volume of shale oil wellhead fluid samples were measured by:

[0012] Injecting a preset low-pressure gas into the first gas cylinder and continuously detecting a first gas cylinder pressure value in the first gas cylinder, and recording the first gas cylinder pressure value after the injection is completed and the pressure in the first gas cylinder is stable;

[0013] Opening a valve between the first sample cylinder and the first gas cylinder and continuously detecting a first sample cylinder pressure value in the first sample cylinder, and recording the first sample cylinder pressure value after the pressure in the first sample cylinder stabilizes;

[0014] determining a volume of the shale oil core sample based on the first gas cylinder pressure value and the first sample cylinder pressure value;

[0015] Injecting a preset low-pressure gas into the second gas cylinder and continuously detecting a second gas cylinder pressure value in the second gas cylinder, and recording the second gas cylinder pressure value after the injection is completed and the pressure in the second gas cylinder is stable;

[0016] Opening the valve between the second sample cylinder and the second gas cylinder and continuously detecting the second sample cylinder pressure value in the second sample cylinder, and recording the second sample cylinder pressure value after the pressure in the second sample cylinder stabilizes;

[0017] The volume of the shale oil wellhead fluid sample is determined according to the second gas cylinder pressure value and the second sample cylinder pressure value.

[0018] Optionally, determining the volume of the shale oil core sample according to the first gas cylinder pressure value and the first sample cylinder pressure value includes:

[0019] The volume of the shale oil core sample is calculated based on the first gas cylinder pressure value and the first sample cylinder pressure value using formula (1):

[0020]

[0021] In formula (1), V 样品 is the volume of the shale oil core sample, V1 is the volume of the first gas cylinder, V2 is the volume of the first sample cylinder, P1 is the pressure value of the first gas cylinder, and P2 is the pressure value of the first sample cylinder.

[0022] Optionally, the dissolved gas content of the pore fluid in the shale oil core and the dissolved gas content of the shale oil wellhead fluid are measured by:

[0023] Close the valve between the first sample cylinder and the first gas cylinder;

[0024] exhausting the preset low-pressure gas in the first gas cylinder and the first sample cylinder;

[0025] Injecting a preset high-pressure gas into the first gas cylinder and continuously detecting the pressure value of the third gas cylinder in the first gas cylinder. After the injection is completed and the pressure in the first gas cylinder is stable, recording the pressure value of the third gas cylinder;

[0026] Open the valve between the first sample cylinder and the first gas cylinder and continuously detect the pressure value of the third sample cylinder in the first sample cylinder. After the pressure in the first sample cylinder stabilizes, record the pressure value of the third sample cylinder.

[0027] determining the amount of gas dissolved in the pore fluid of the shale oil core according to the third gas cylinder pressure value and the third sample cylinder pressure value;

[0028] Close the valve between the second sample cylinder and the second gas cylinder;

[0029] exhausting the preset low-pressure gas in the second gas cylinder and the second sample cylinder;

[0030] Injecting a preset high-pressure gas into the second gas cylinder and continuously detecting a fourth gas cylinder pressure value in the second gas cylinder, and recording the fourth gas cylinder pressure value after the injection is completed and the pressure in the second gas cylinder is stable;

[0031] Open the valve between the second sample cylinder and the second gas cylinder and continuously detect the pressure value of the fourth sample cylinder in the second sample cylinder. After the pressure in the second sample cylinder stabilizes, record the pressure value of the fourth sample cylinder.

[0032] The gas dissolved amount of the shale oil wellhead fluid is determined according to the fourth gas cylinder pressure value and the fourth sample cylinder pressure value.

[0033] Optionally, determining the amount of dissolved gas in the pore fluid of the shale oil core according to the third gas cylinder pressure value and the third sample cylinder pressure value includes:

[0034] According to the pressure value of the third gas cylinder and the pressure value of the third sample cylinder, the gas dissolved in the pore fluid of the shale oil core is calculated using formula (2):

[0035]

[0036] In formula (2), n 样品 is the gas dissolved in the pore fluid of the shale oil core, P3 is the pressure value of the third gas cylinder, P4 is the pressure value of the third sample cylinder, V1 is the volume of the first gas cylinder, V2 is the volume of the first sample cylinder, Z3 is the gas compressibility factor at the pressure of P3, Z4 is the gas compressibility factor at the pressure of P4, R is the ideal gas constant, and T is the experimental temperature.

[0037] Optionally, the determining of the shale oil porosity based on the volume of the shale oil core sample, the volume of the shale oil wellhead fluid sample, the gas dissolved content of the pore fluid of the shale oil core, and the gas dissolved content of the shale oil wellhead fluid further includes:

[0038] Determining the pore volume of the shale oil sample based on the volume of the shale oil wellhead fluid sample, the gas dissolved content of the pore fluid of the shale oil core, and the gas dissolved content of the shale oil wellhead fluid;

[0039] The porosity of shale oil is determined based on the pore volume of the shale oil sample and the volume of the shale oil core sample.

[0040] Optionally, determining the pore volume of the shale oil sample based on the volume of the shale oil wellhead fluid sample, the gas dissolved content of the pore fluid of the shale oil core, and the gas dissolved content of the shale oil wellhead fluid includes:

[0041] According to the volume of the shale oil wellhead fluid sample, the gas dissolved amount of the shale oil core pore fluid and the gas dissolved amount of the shale oil wellhead fluid, the pore volume of the shale oil sample is calculated using formula (3):

[0042]

[0043] In formula (3), V 样品孔隙 is the pore volume of shale oil sample, V 流体 is the volume of shale oil wellhead fluid sample, n 样品 is the gas dissolved in the pore fluid of the shale oil core, n 流体 is the amount of dissolved gas in shale oil wellhead fluid;

[0044] The method of determining the shale oil porosity based on the pore volume of the shale oil sample and the volume of the shale oil core sample includes:

[0045] Based on the pore volume of the shale oil sample and the volume of the shale oil core sample, the shale oil porosity is calculated using formula (4):

[0046]

[0047] In formula (4), φ is the porosity of shale oil, V 样品孔隙 is the pore volume of shale oil sample, V 样品 is the volume of the shale oil core sample.

[0048] In a second aspect of an embodiment of the present invention, a shale oil porosity measuring device is provided, comprising:

[0049] A sample acquisition device for acquiring a shale oil core sample and a shale oil wellhead fluid sample; wherein the shale oil core sample is located in a first sample cylinder, and the shale oil wellhead fluid sample is located in a second sample cylinder;

[0050] A volume determination device for determining the volume of a shale oil core sample and a shale oil wellhead fluid sample using the first sample cylinder and the second sample cylinder;

[0051] A gas dissolved amount determination device is used to determine the gas dissolved amount of the shale oil core pore fluid and the gas dissolved amount of the shale oil wellhead fluid using the first sample cylinder and the second sample cylinder;

[0052] A porosity calculation device is used to determine the shale oil porosity based on the volume of the shale oil core sample, the volume of the shale oil wellhead fluid sample, the gas solubility of the shale oil core pore fluid and the gas solubility of the shale oil wellhead fluid.

[0053] A third aspect of the present application provides an electronic device configured to execute the above-mentioned shale oil porosity determination method.

[0054] A fourth aspect of the present application provides a machine-readable storage medium having instructions stored thereon. When the instructions are executed by a processor, the processor is configured to execute the above-mentioned shale oil porosity determination method.

[0055] The embodiment of the present invention obtains a shale oil core sample and a shale oil wellhead fluid sample, and uses a first sample cylinder and a second sample cylinder to determine the volume of the shale oil core sample and the volume of the shale oil wellhead fluid sample. The first sample cylinder and the second sample cylinder are further used to determine the gas dissolved content of the shale oil core pore fluid and the gas dissolved content of the shale oil wellhead fluid. Finally, the shale oil porosity is determined based on the volume of the shale oil core sample, the volume of the shale oil wellhead fluid sample, the gas dissolved content of the shale oil core pore fluid, and the gas dissolved content of the shale oil wellhead fluid. The shale oil porosity determination method provided by the embodiment of the present invention has a wider measurement range and does not require oil washing of the sample, thereby ensuring integrity and improving measurement accuracy.

[0056] Other features and advantages of the embodiments of the present invention will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following detailed description, they are used to explain the embodiments of the present invention, but do not constitute a limitation of the embodiments of the present invention. In the accompanying drawings:

[0058] Figure 1 1 is a flow chart of a shale oil porosity determination method provided by an embodiment of the present invention;

[0059] Figure 2 It is the connection diagram of the measuring device;

[0060] Figure 3 This is a schematic diagram of the functional modules of a shale oil porosity measurement device provided by an embodiment of the present invention;

[0061] Figure 4 It is a line graph of the changes in the gas solubility of shale oil wellhead fluid under different pressure conditions. DETAILED DESCRIPTION

[0062] The following describes the specific implementation of the embodiment of the present invention in detail with reference to the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the embodiment of the present invention and is not used to limit the embodiment of the present invention.

[0063] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs. The terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0064] In the description of the embodiments of this application, the technical terms "first," "second," etc. are used only to distinguish different objects and should not be understood to indicate or imply relative importance or to implicitly indicate the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise specifically defined.

[0065] Example 1

[0066] Please refer to Figure 1 , Figure 1 Schematic diagram of a shale oil porosity determination method provided in this embodiment.

[0067] Step S100: Obtain shale oil core samples and shale oil wellhead fluid samples; wherein the shale oil core samples are located in the first sample cylinder, and the shale oil wellhead fluid samples are located in the second sample cylinder.

[0068] Specifically, shale oil core samples and shale oil wellhead fluid samples can be obtained from pre-set wells in the target area. These shale oil core samples and shale oil wellhead fluid samples can be fresh or aged, and can be regular or irregular. The shale oil wellhead fluid sample and the shale oil core sample are from the same shale oil well, so the fluid sample obtained is consistent with the fluid present in the shale oil core, and the shale oil wellhead fluid sample does not contain gas.

[0069] In order to facilitate the measurement of shale oil core samples and shale oil wellhead fluid samples, this embodiment places the shale oil core sample in a first sample cylinder and the shale oil wellhead fluid sample in a second sample cylinder. The first sample cylinder is connected to the second sample cylinder through a preset pipeline, and the connection or disconnection between the first sample cylinder and the second sample cylinder is controlled by a valve on the preset pipeline.

[0070] Step S200: using the first sample cylinder and the second sample cylinder, determining the volume of the shale oil core sample and the volume of the shale oil wellhead fluid sample.

[0071] It is understood that in this embodiment, the first gas cylinder and the second gas cylinder are respectively provided corresponding to the first sample cylinder and the second sample cylinder, and the first gas cylinder and the second gas cylinder are respectively connected to the gas source. For example, the connection diagram of the measuring device can be represented by Figure 2 As shown, precision pressure gauges are provided for measuring the pressure in the first gas cylinder and the first sample cylinder respectively, and a switch valve is provided on the preset pipeline between the first sample cylinder and the first gas cylinder to control the on-off of the pipeline; a gas source valve is provided on the pipeline between the first gas cylinder and the gas source to control the process of the gas source injecting gas into the first gas cylinder.

[0072] Similarly, precision pressure gauges are set up to measure the pressure in the second gas cylinder and the second sample cylinder respectively, and a switch valve is set on the preset pipeline between the second sample cylinder and the second gas cylinder to control the on-off of the pipeline; a gas source valve is set on the pipeline between the second gas cylinder and the gas source to control the process of gas injection from the gas source into the second gas cylinder.

[0073] This step specifically includes: closing the valve between the first sample cylinder and the first gas cylinder, injecting a preset low-pressure gas into the first gas cylinder, and continuously detecting the first gas cylinder pressure value in the first gas cylinder; after the injection is completed and the pressure in the first gas cylinder is stable, recording the first gas cylinder pressure value; when the first gas cylinder pressure is stable, opening the valve between the first sample cylinder and the first gas cylinder, and continuously detecting the first sample cylinder pressure value in the first sample cylinder; after the pressure in the first sample cylinder is stable, recording the first sample cylinder pressure value; and calculating the volume of the shale oil core sample according to the first gas cylinder pressure value and the first sample cylinder pressure value using formula (1);

[0074] Inject a preset low-pressure gas into the second gas cylinder and continuously detect the second gas cylinder pressure value in the second gas cylinder. After the injection is completed and the pressure in the second gas cylinder is stable, record the second gas cylinder pressure value. Open the valve between the second sample cylinder and the second gas cylinder and continuously detect the second sample cylinder pressure value in the second sample cylinder. After the pressure in the second sample cylinder is stable, record the second sample cylinder pressure value. According to the second gas cylinder pressure value and the second sample cylinder pressure value, use formula (1) to calculate the volume of the shale oil wellhead fluid sample. Wherein, the preset low-pressure gas can be nitrogen, helium, etc., and formula (1) is as follows:

[0075]

[0076] In formula (1), if the volume of shale oil core sample is calculated, then V 样品 is the volume of the shale oil core sample, V1 is the volume of the first gas cylinder, V2 is the volume of the first sample cylinder, P1 is the pressure value of the first gas cylinder, and P2 is the pressure value of the first sample cylinder.

[0077] Similarly, if we calculate the volume of shale oil wellhead fluid sample, then V 样品 is the volume of the shale oil wellhead fluid sample, V1 is the volume of the second gas cylinder, V2 is the volume of the second sample cylinder, P1 is the pressure value of the second gas cylinder, and P2 is the pressure value of the second sample cylinder.

[0078] Step S300: using the first sample cylinder and the second sample cylinder, determining the gas dissolved amount of the pore fluid in the shale oil core and the gas dissolved amount of the shale oil wellhead fluid.

[0079] It is understandable that when the pressure continues to drop, the gas will gradually diffuse and dissolve into the shale oil pore fluid, which can provide a data basis for calculating the subsequent shale oil pores. Therefore, this step specifically includes: closing the valve between the first sample cylinder and the first gas cylinder, exhausting the preset low-pressure gas in the first gas cylinder and the first sample cylinder, injecting the preset high-pressure gas into the first gas cylinder and continuously detecting the pressure value of the third gas cylinder in the first gas cylinder, after the injection is completed and the pressure in the first gas cylinder is stable, recording the pressure value of the third gas cylinder, opening the valve between the first sample cylinder and the first gas cylinder and continuously detecting the pressure value of the third sample cylinder in the first sample cylinder, after the pressure in the first sample cylinder is stable, recording the pressure value of the third sample cylinder, and according to the pressure value of the third gas cylinder and the pressure value of the third sample cylinder, using formula (2), calculating the gas dissolved amount in the shale oil core pore fluid;

[0080] Close the valve between the second sample cylinder and the second gas cylinder, exhaust the preset low-pressure gas in the second gas cylinder and the second sample cylinder, inject the preset high-pressure gas into the second gas cylinder and continuously detect the pressure value of the fourth gas cylinder in the second gas cylinder. After the injection is completed and the pressure in the second gas cylinder is stable, record the pressure value of the fourth gas cylinder. Open the valve between the second sample cylinder and the second gas cylinder and continuously detect the pressure value of the fourth sample cylinder in the second sample cylinder. After the pressure in the second sample cylinder is stable, record the pressure value of the fourth sample cylinder. According to the pressure value of the fourth gas cylinder and the pressure value of the fourth sample cylinder, use formula (2) to calculate the gas dissolved content of the shale oil wellhead fluid. This embodiment also provides a line graph of the change of the gas dissolved content of the shale oil wellhead fluid under different pressure conditions, such as Figure 4 As shown, the greater the pressure, the greater the amount of gas dissolved in the shale oil wellhead fluid. The preset high-pressure gas can be carbon dioxide, hydrogen sulfide, etc., and formula (2) is as follows:

[0081]

[0082] In formula (2), if the gas dissolved in the pore fluid of shale oil core is measured, then n 样品 is the gas dissolved in the pore fluid of the shale oil core, P3 is the pressure value of the third gas cylinder, P4 is the pressure value of the third sample cylinder, V1 is the volume of the first gas cylinder, V2 is the volume of the first sample cylinder, Z3 is the gas compressibility factor at the pressure of P3, Z4 is the gas compressibility factor at the pressure of P4, R is the ideal gas constant, and T is the experimental temperature;

[0083] Similarly, if the gas dissolved in shale oil wellhead fluid is measured, then n 样品is the gas dissolved content of shale oil wellhead fluid, P3 is the pressure value of the fourth gas cylinder, P4 is the pressure value of the fourth sample cylinder, V1 is the volume of the second gas cylinder, V2 is the volume of the second sample cylinder, Z3 is the gas compressibility factor at the pressure of P3, Z4 is the gas compressibility factor at the pressure of P4, R is the ideal gas constant, and T is the experimental temperature.

[0084] Step S400: Determine the shale oil porosity based on the volume of the shale oil core sample, the volume of the shale oil wellhead fluid sample, the gas solubility of the shale oil core pore fluid, and the gas solubility of the shale oil wellhead fluid.

[0085] Since the solubility of gas in fluid is a constant under the same pressure conditions, the amount of dissolved gas in the fluid is proportional to the volume of the fluid. Therefore, this step specifically includes calculating the pore volume of the shale oil sample using formula (3) based on the volume of the shale oil wellhead fluid sample, the gas dissolved amount of the pore fluid of the shale oil core, and the gas dissolved amount of the shale oil wellhead fluid. Further, based on the pore volume of the shale oil sample and the volume of the shale oil core sample, the shale oil porosity is calculated using formula (4). Wherein, formulas (3) and (4) are specifically as follows:

[0086]

[0087] In formula (3), V 样品孔隙 is the pore volume of shale oil sample, V 流体 is the volume of shale oil wellhead fluid sample, n 样品 is the gas dissolved in the pore fluid of the shale oil core, n 流体 is the amount of dissolved gas in shale oil wellhead fluid;

[0088]

[0089] In formula (4), φ is the porosity of shale oil, V 样品孔隙 is the pore volume of shale oil sample, V 样品 is the volume of the shale oil core sample.

[0090] This embodiment obtains a shale oil core sample and a shale oil wellhead fluid sample, and uses a first sample cylinder and a second sample cylinder to determine the volume of the shale oil core sample and the volume of the shale oil wellhead fluid sample. The first sample cylinder and the second sample cylinder are further used to determine the gas dissolved in the pore fluid of the shale oil core and the gas dissolved in the shale oil wellhead fluid. Finally, the shale oil porosity is determined based on the volume of the shale oil core sample, the volume of the shale oil wellhead fluid sample, the gas dissolved in the pore fluid of the shale oil core, and the gas dissolved in the shale oil wellhead fluid. The shale oil porosity determination method provided by the embodiment of the present invention has a wider measurement range and does not require oil washing of the sample, thereby ensuring integrity and improving measurement accuracy.

[0091] Example 2

[0092] Please refer to Figure 3 , Figure 3 This is a functional module diagram of a shale oil porosity measurement device 200 provided in an embodiment of the present application.

[0093] The sample acquisition device 210 is used to obtain shale oil core samples and shale oil wellhead fluid samples;

[0094] The volume determination device 220 is used to determine the volume of the shale oil core sample and the volume of the shale oil wellhead fluid sample using the first sample cylinder and the second sample cylinder;

[0095] The dissolved gas content determination device 230 is used to determine the dissolved gas content of the pore fluid in the shale oil core and the dissolved gas content of the shale oil wellhead fluid using the first sample cylinder and the second sample cylinder;

[0096] The porosity calculation device 240 is used to determine the shale oil porosity based on the volume of the shale oil core sample, the volume of the shale oil wellhead fluid sample, the gas solubility of the shale oil core pore fluid and the gas solubility of the shale oil wellhead fluid.

[0097] It should be understood that this device corresponds to the aforementioned shale oil porosity determination method embodiment and is capable of performing each of the steps involved in the aforementioned method embodiment. The specific functions of this device can be found in the description above, and a detailed description is omitted here to avoid repetition. The device includes at least one software functional module that can be stored in a memory in the form of software or firmware or embedded in the device's operating system (OS).

[0098] Example 3

[0099] In this embodiment, the following steps are included:

[0100] (1) Obtain samples. Obtain shale oil samples from the target block. Due to the presence of bedding fractures and the drilling and coring process, the fresh shale oil samples obtained are irregular in shape.

[0101] (2) Obtaining shale oil wellhead fluid samples. Obtain fluid samples from the wellhead of the oil well corresponding to the shale oil core sample. The fluid samples do not include gas.

[0102] (3) Measure the apparent volume of the shale oil core sample. Carry out subsequent experiments at room temperature of 25°C. Place the shale oil core sample into the sample cylinder of the measuring device and connect the process. Close the valve between the sample cylinder and the gas cylinder, fill the gas cylinder with low-pressure nitrogen, close the gas source valve, and use a precision pressure gauge to record the pressure of the gas cylinder when it is stable, which is 0.8MPa. Open the valve between the sample cylinder and the gas cylinder to connect the two, and use a precision pressure gauge to record the pressure of the sample cylinder, which is 0.466MPa. At this time, the pressures of the sample cylinder and the gas cylinder are the same. The volume of the sample cylinder is 100ml and the volume of the gas cylinder is 100ml. According to the Pomars law: The apparent volume of the shale oil core sample is 28.33 cm 3 .

[0103] (4) Measure the amount of gas dissolved in the pore fluid of the shale oil core. Vent the gas in step 3, close the valve between the sample cylinder and the gas cylinder, fill the gas cylinder with high-pressure nitrogen, close the gas source valve, and use a precision pressure gauge to record the pressure of the gas cylinder when it is stable at 30MPa. Open the valve between the sample cylinder and the gas cylinder to connect the two. At this time, it can be observed that the pressure of the entire system is continuously decreasing. At this time, the gas gradually diffuses and dissolves into the pore fluid of the shale oil core. After the pressure stabilizes, use a precision pressure gauge to record the stable pressure of the sample cylinder at 16.311MPa. Using the formula The amount of nitrogen dissolved in the pore fluid is calculated to be 0.010393 mol.

[0104] (5) Draw a chart of dissolved gas in shale oil wellhead fluid under different pressure conditions. Take out the shale oil core sample from the sample cylinder and clean the entire experimental process. Fill the sample cylinder with shale oil wellhead fluid and repeat step 3 to obtain the volume of 20ml of shale oil wellhead fluid. Repeat step 4 to obtain the amount of gas dissolved in shale oil wellhead fluid under different pressure conditions. Draw a chart of the amount of gas dissolved in shale oil with a volume of 20ml and different pressure conditions, as shown in the figure. Figure 4 The relationship between the amount of dissolved gas and pressure is shown in the figure. The relationship between the amount of dissolved gas and pressure is: n = -3×10 -6 P 3 +6×10 -5 P 2 +5×10 -3 P. Using this chart, we can conclude that the amount of dissolved gas corresponding to a shale oil volume of 20 ml and a pressure of 16.311 MPa is 0.084499 mol.

[0105] (6) Since the solubility of gas in fluid is constant under the same pressure conditions, the amount of dissolved gas in the fluid is proportional to the volume of the fluid. Using the data from steps 4 and 5, we can conclude that the pore volume of the sample at 16.311 MPa is 2.46 ml. Using the formula The porosity of the shale oil sample was calculated to be 8.68%.

[0106] In a typical configuration, a computing device includes one or more processors (CPUs), input / output interfaces, network interfaces, and memory.

[0107] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

[0108] Computer-readable media includes permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. The information can be computer-readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer-readable media does not include transitory computer-readable media (transitory media), such as modulated data signals and carrier waves.

[0109] An embodiment of the present invention also provides a computer-readable storage medium, which stores instructions, which are used to execute a program with steps of a shale oil porosity determination method when executed by a processor.

[0110] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0111] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0112] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0113] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0114] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. To avoid unnecessary repetition, the embodiments of the present invention will not further describe various possible combinations.

[0115] In addition, the functional modules in each embodiment of the present application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0116] It should also be noted that the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, commodity, or apparatus that includes a series of elements includes not only those elements but also other elements not explicitly listed, or includes elements inherent to such process, method, commodity, or apparatus. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, commodity, or apparatus that includes the element.

[0117] The above are merely embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should all be included within the scope of the claims of the present application.

Claims

1. A method for measuring shale oil porosity, characterized in that: The method comprises: Obtaining a shale oil core sample and a shale oil wellhead fluid sample; wherein the shale oil core sample is located in a first sample cylinder, and the shale oil wellhead fluid sample is located in a second sample cylinder; Determining the volume of a shale oil core sample and a shale oil wellhead fluid sample using the first sample cylinder and the second sample cylinder; Using the first sample cylinder and the second sample cylinder, determining the gas dissolved content of the pore fluid of the shale oil core and the gas dissolved content of the shale oil wellhead fluid; The shale oil porosity is determined based on the volume of the shale oil core sample, the volume of the shale oil wellhead fluid sample, the gas solubility of the shale oil core pore fluid and the gas solubility of the shale oil wellhead fluid.

2. The shale oil porosity determination method according to claim 1, characterized in that: The first sample cylinder is connected to the first gas cylinder via a first pipe, and the second sample cylinder is connected to the second gas cylinder via a second pipe, wherein the first pipe and the second pipe are respectively provided with valves for realizing on-off control of the corresponding pipes; The volume of shale oil core samples and the volume of shale oil wellhead fluid samples were measured by: Injecting a preset low-pressure gas into the first gas cylinder and continuously detecting a first gas cylinder pressure value in the first gas cylinder, and recording the first gas cylinder pressure value after the injection is completed and the pressure in the first gas cylinder is stable; Opening a valve between the first sample cylinder and the first gas cylinder and continuously detecting a first sample cylinder pressure value in the first sample cylinder, and recording the first sample cylinder pressure value after the pressure in the first sample cylinder stabilizes; determining a volume of the shale oil core sample based on the first gas cylinder pressure value and the first sample cylinder pressure value; Injecting a preset low-pressure gas into the second gas cylinder and continuously detecting a second gas cylinder pressure value in the second gas cylinder, and recording the second gas cylinder pressure value after the injection is completed and the pressure in the second gas cylinder is stable; Opening the valve between the second sample cylinder and the second gas cylinder and continuously detecting the second sample cylinder pressure value in the second sample cylinder, and recording the second sample cylinder pressure value after the pressure in the second sample cylinder stabilizes; The volume of the shale oil wellhead fluid sample is determined according to the second gas cylinder pressure value and the second sample cylinder pressure value.

3. The shale oil porosity determination method according to claim 2, characterized in that: According to the pressure value of the first gas cylinder and the pressure value of the first sample cylinder, the volume of the shale oil core sample is calculated using formula (1): In formula (1), V 样品 is the volume of the shale oil core sample, V1 is the volume of the first gas cylinder, V2 is the volume of the first sample cylinder, P1 is the pressure value of the first gas cylinder, and P2 is the pressure value of the first sample cylinder.

4. The shale oil porosity determination method according to claim 2, characterized in that: The dissolved gas content of shale oil core pore fluids and shale oil wellhead fluids is measured by the following methods: Close the valve between the first sample cylinder and the first gas cylinder; exhausting the preset low-pressure gas in the first gas cylinder and the first sample cylinder; Injecting a preset high-pressure gas into the first gas cylinder and continuously detecting the pressure value of the third gas cylinder in the first gas cylinder. After the injection is completed and the pressure in the first gas cylinder is stable, recording the pressure value of the third gas cylinder; Open the valve between the first sample cylinder and the first gas cylinder and continuously detect the pressure value of the third sample cylinder in the first sample cylinder. After the pressure in the first sample cylinder stabilizes, record the pressure value of the third sample cylinder. determining the amount of gas dissolved in the pore fluid of the shale oil core according to the third gas cylinder pressure value and the third sample cylinder pressure value; Close the valve between the second sample cylinder and the second gas cylinder; exhausting the preset low-pressure gas in the second gas cylinder and the second sample cylinder; Injecting a preset high-pressure gas into the second gas cylinder and continuously detecting a fourth gas cylinder pressure value in the second gas cylinder, and recording the fourth gas cylinder pressure value after the injection is completed and the pressure in the second gas cylinder is stable; Open the valve between the second sample cylinder and the second gas cylinder and continuously detect the fourth sample cylinder pressure value in the second sample cylinder. After the pressure in the second sample cylinder stabilizes, record the fourth sample cylinder pressure value; determine the gas dissolved content of the shale oil wellhead fluid based on the fourth gas cylinder pressure value and the fourth sample cylinder pressure value.

5. The shale oil porosity determination method according to claim 4, characterized in that: According to the pressure values ​​of the third gas cylinder and the third sample cylinder, the gas dissolved in the pore fluid of the shale oil core is calculated using formula (2): In formula (2), n 样品 is the gas dissolved in the pore fluid of the shale oil core, P3 is the pressure value of the third gas cylinder, P4 is the pressure value of the third sample cylinder, V1 is the volume of the first gas cylinder, V2 is the volume of the first sample cylinder, Z3 is the gas compressibility factor at the pressure of P3, Z4 is the gas compressibility factor at the pressure of P4, R is the ideal gas constant, and T is the experimental temperature.

6. The shale oil porosity determination method according to claim 1, characterized in that: The method of determining the shale oil porosity based on the volume of the shale oil core sample, the volume of the shale oil wellhead fluid sample, the gas dissolved content of the pore fluid of the shale oil core, and the gas dissolved content of the shale oil wellhead fluid further includes: The pore volume of the shale oil sample is determined based on the volume of the shale oil wellhead fluid sample, the gas dissolved content of the pore fluid of the shale oil core, and the gas dissolved content of the shale oil wellhead fluid; The porosity of shale oil is determined based on the pore volume of the shale oil sample and the volume of the shale oil core sample.

7. The shale oil porosity determination method according to claim 6, characterized in that: According to the volume of shale oil wellhead fluid sample, the gas dissolved content of shale oil core pore fluid and the gas dissolved content of shale oil wellhead fluid, the pore volume of shale oil sample is calculated using formula (3): In formula (3), V 样品孔隙 is the pore volume of shale oil sample, V 流体 is the volume of shale oil wellhead fluid sample, n 样品 is the gas dissolved in the pore fluid of the shale oil core, n 流体 is the amount of dissolved gas in shale oil wellhead fluid; Based on the pore volume of the shale oil sample and the volume of the shale oil core sample, the shale oil porosity is calculated using formula (4): In formula (4), φ is the porosity of shale oil, V 样品孔隙 is the pore volume of shale oil sample, V 样品 is the volume of the shale oil core sample.

8. A shale oil porosity measuring device, characterized in that: The device comprises: A sample acquisition device for acquiring a shale oil core sample and a shale oil wellhead fluid sample; wherein the shale oil core sample is located in a first sample cylinder, and the shale oil wellhead fluid sample is located in a second sample cylinder; A volume determination device for determining the volume of a shale oil core sample and a shale oil wellhead fluid sample using the first sample cylinder and the second sample cylinder; A gas dissolved amount determination device is used to determine the gas dissolved amount of the shale oil core pore fluid and the gas dissolved amount of the shale oil wellhead fluid using the first sample cylinder and the second sample cylinder; A porosity calculation device is used to determine the shale oil porosity based on the volume of the shale oil core sample, the volume of the shale oil wellhead fluid sample, the gas solubility of the shale oil core pore fluid and the gas solubility of the shale oil wellhead fluid.

9. An electronic device, characterized in that: include: A processor and a memory, wherein the memory stores machine-readable instructions executable by the processor, and when the machine-readable instructions are executed by the processor, the shale oil porosity determination method according to any one of claims 1 to 7 is executed.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium stores instructions for enabling a machine to execute the shale oil porosity determination method according to any one of claims 1 to 7.

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