Shale gas reservoir gas content testing system and method

Abstract

The invention relates to the technical field of formation testing, in particular to a shale gas reservoir gas content testing system and method.The system comprises a rock sample packaging module, a gas release regulation and control module, a gas metering analysis module, a dynamic balance correction module and an effect evaluation module. According to the invention, the gas release process is precisely regulated and controlled, so that the gas release instability which cannot be controlled in the traditional technology can be effectively handled, the relationship between the gas release characteristic and the test requirement can be precisely identified, the gas release process is optimized through a multi-stage progressive regulation and control strategy, the gas release fluctuation is effectively reduced, and the test accuracy is improved. The stability of test data is improved, the relationship between pressure recovery and gas release is optimized, the balance and precision of gas release are ensured, the problems that a traditional method is low in test precision and large in data fluctuation when facing a complex stratum are solved, accurate adjustment of the gas release process is achieved, and the accuracy and reliability of gas content test are improved. And the stability and adaptability of the test system are enhanced.

Description

Technical Field

[0001] This invention relates to the field of formation testing technology, and in particular to a system and method for testing the gas content of shale gas reservoirs. Background Technology

[0002] Formation testing technology involves engineering techniques for measuring and analyzing the physical and chemical characteristics of underground formations. Its core aspects include the acquisition and study of parameters such as formation permeability, porosity, pressure, temperature, and fluid content. This technology provides basic data support for oil and gas reservoir evaluation, reservoir characteristic identification, and development plan design by quantitatively measuring rocks and formation fluids during drilling, sampling, and experimental testing. The systematic content of formation testing covers well testing, surface rock sample analysis, gas and liquid content measurement, pressure recovery testing, and formation seepage characteristic analysis, and is an important part of the oil and gas exploration and development stage.

[0003] The traditional shale gas reservoir gas content testing system refers to a testing device used to determine the content of adsorbed, free, and dissolved gases in shale samples. This system involves taking core samples, sealing and preserving them, heating the samples using a constant-temperature desorption device to release adsorbed gases, measuring the volume of desorbed gases using a gas metering tube, and then combining residual gas measurement and adsorption isotherm experiments to obtain the total gas content of the shale sample. The traditional testing method mainly includes four steps: sampling, desorption, residual gas measurement, and data conversion. The quantitative determination of shale gas content is completed through physical heating, volumetric measurement, and gas composition analysis.

[0004] Existing technologies have certain limitations in testing the gas content of shale gas reservoirs. Traditional methods measure gas content through physical heating and gas volume methods, but they cannot effectively address the nonlinear characteristics of gas release from rock samples, leading to unstable gas release and affecting the accuracy of test results. In addition, traditional testing methods lack real-time monitoring and adjustment of dynamic factors such as gas release cycle and pressure recovery process, making it difficult to achieve precise control and thus affecting the accuracy of gas content determination. The limitations of traditional methods lead to unnecessary fluctuations and errors during the testing process, affecting the reliability and stability of the final data. This problem is particularly prominent in complex strata or special rock sample conditions. Summary of the Invention

[0005] To address the technical problems existing in the prior art, embodiments of the present invention provide a system and method for testing the gas content of shale gas reservoirs. The technical solution is as follows: On the one hand, a shale gas reservoir gas content testing system is provided, the system comprising: The rock sample encapsulation module acquires the initial state information of the shale rock sample, monitors the changing trends of rock sample temperature, pressure and gas release rate, records the degree of impact of gas release on the test environment, analyzes the correlation between gas release characteristics and test requirements, summarizes gas release data, and generates gas release characteristic trigger quantities. Based on the gas release characteristic trigger quantity, the gas release control module extracts the relationship between the gas release cycle and the pressure recovery time, formulates a multi-level progressive control strategy, analyzes the pressure recovery law and gas release demand, adjusts the control response timing, and obtains the control strategy execution command. The gas metering and analysis module executes instructions according to the control strategy, extracts the location distribution information of the gas release device, analyzes the control combination of gas release capacity and release point, schedules the gas release device to perform control operations, and generates a gas release execution sequence. The dynamic balance correction module analyzes the synchronicity of pressure change rate and gas composition before and after gas release according to the gas release execution sequence, adjusts the control weight of the release point, optimizes the dynamic balance of the test process, and obtains a set of dynamic balance evaluation indices for gas release.

[0006] As a further aspect of the present invention, the gas release characteristic triggering quantity includes the gas release critical rate, temperature and pressure change threshold and environmental impact coefficient; the control strategy execution instruction includes pressure recovery parameter, release cycle parameter and control level parameter; the gas release execution sequence includes release point sequence, release intensity parameter and execution timing parameter; and the gas release dynamic balance evaluation index set includes pressure balance index, component coordination index and system stability index.

[0007] As a further aspect of the present invention, the rock sample encapsulation module includes: The initial state monitoring submodule acquires the initial state information of the shale rock sample, extracts the changing trends of rock sample temperature, pressure and gas release rate, and generates a gas release characteristic sequence. The gas release impact analysis submodule extracts the degree of impact of gas release on the test environment based on the gas release characteristic sequence, analyzes the correlation between gas release characteristics and test requirements, and generates the gas release impact degree. The trigger quantity generation submodule extracts the integral calculation result of the gas release rate change trend and pressure change based on the gas release influence degree, and generates the gas release characteristic trigger quantity.

[0008] As a further aspect of the present invention, the gas release control module includes: The periodic extraction submodule extracts the relationship between the gas release period and the pressure recovery time based on the gas release characteristic triggering amount, analyzes the complexity of the gas release behavior, and generates a control time window. The priority determination submodule extracts the gas release demand and pressure recovery pattern based on the control time window, determines the control priority, and generates the distribution range of release points. The regulation strategy planning submodule identifies the compatibility between the regulation capability of the release points and the gas release demand based on the distribution range of the release points, formulates a multi-level progressive regulation strategy, and generates regulation strategy execution instructions.

[0009] As a further aspect of the present invention, the gas metering and analysis module includes: The release point distribution submodule executes instructions according to the control strategy, extracts the location distribution information and control capability of the gas release device, analyzes the control combination scheme of the release point, and generates the release point activation sequence. The regulation weight allocation submodule extracts the matching degree between the regulation weight of the release point and the gas release capacity based on the release point activation sequence, adjusts the regulation weight allocation ratio, and generates a gas release execution sequence.

[0010] As a further aspect of the present invention, the dynamic balance correction module includes: The pressure change rate analysis submodule calls the gas release execution sequence, extracts the pressure change rate before and after gas release, analyzes the consistency of the pressure change direction, and generates pressure change rate analysis results. The gas composition synchronicity analysis submodule extracts the relationship between gas composition concentration and volume fraction based on the pressure change rate analysis results, analyzes the gas composition synchronicity, and generates gas composition synchronicity analysis results. The balance optimization submodule adjusts the release point control weights based on the gas composition synchronization analysis results, optimizes the dynamic balance of the test process, and obtains a set of gas release dynamic balance evaluation indices.

[0011] As a further aspect of the present invention, the consistency of the pressure change direction refers to continuously monitoring the pressure changes during the gas release process and analyzing whether the pressure change direction is consistent in the differentiated stages. The gas composition synchronicity refers to determining whether the concentration changes of different gas components are coordinated and consistent by synchronously analyzing the concentration changes of each component in the gas.

[0012] As a further aspect of the present invention, the system also includes an effect evaluation module: The effect evaluation module, based on the gas release dynamic balance evaluation index set, extracts the compatibility between the gas content measurement accuracy and gas release characteristics after the test, evaluates the test effect and stability, analyzes the matching ability and fluctuation of the gas content after the test, and generates the test effect evaluation level. The test performance evaluation levels include measurement level, feature adaptation level, and test stability level.

[0013] As a further aspect of the present invention, the effect evaluation module includes: The accuracy assessment submodule extracts the gas content measurement accuracy after testing based on the gas release dynamic balance assessment index set, analyzes the deviation between the measured value and the true value, and generates the accuracy assessment result. The adaptability analysis submodule extracts the relationship between the gas release characteristic triggering amount and the matching degree based on the accuracy evaluation results, analyzes the adaptability of the gas release characteristics, and generates adaptability evaluation results. Based on the adaptability assessment results, the effect evaluation submodule extracts the matching ability and fluctuation of the gas content after the test, and generates the test effect evaluation level.

[0014] On the other hand, a method for testing the gas content of a shale gas reservoir, wherein the method is performed based on the aforementioned shale gas reservoir gas content testing system, includes the following steps: S1: Obtain the initial state information of shale rock samples, including the changing trends of rock sample temperature, pressure and gas release rate, extract gas release characteristic sequences and gas release influence, and generate gas release characteristic trigger quantities; S2: Based on the gas release characteristic triggering amount, extract the relationship between the gas release cycle and the pressure recovery time, formulate a multi-level progressive control strategy, determine the control priority and the distribution range of release points, and generate control strategy execution instructions; S3: Based on the control strategy, execute the command, identify the location distribution information and control capability of the gas release device, analyze the control combination scheme of the release point, and generate a gas release execution sequence; S4: Based on the gas release execution sequence, analyze the synchronicity of pressure change rate and gas composition before and after gas release, adjust the control weight of release point, optimize the dynamic balance of the test process, and obtain a set of gas release dynamic balance evaluation indices. S5: Based on the gas release dynamic balance evaluation index set, extract the compatibility between the gas content measurement accuracy and gas release characteristics after the test, evaluate the test effect, and generate the test effect evaluation level.

[0015] The beneficial effects of the technical solutions provided in the embodiments of the present invention include at least the following: By precisely controlling the gas release process, the instability of gas release, which is uncontrollable in traditional techniques, can be effectively addressed. Real-time monitoring of the temperature, pressure, and gas release rate trends of rock samples allows for accurate identification of the relationship between gas release characteristics and testing requirements. A multi-level progressive control strategy optimizes the gas release process, effectively reducing gas release fluctuations, improving the stability of test data, and optimizing the relationship between pressure recovery and gas release to ensure the balance and accuracy of gas release. This solves the problems of low testing accuracy and large data fluctuations in traditional methods when facing complex strata, achieving precise regulation of the gas release process, improving the accuracy and reliability of gas content testing, and enhancing the stability and adaptability of the testing system. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of a shale gas reservoir gas content testing system provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the system framework of the present invention; Figure 3 This is a flowchart of the rock sample encapsulation module in this invention; Figure 4 This is a flowchart of the gas release control module in this invention; Figure 5 This is a flowchart of the gas metering and analysis module in this invention; Figure 6 This is a flowchart of the dynamic balance correction module in this invention; Figure 7 This is a flowchart of the effect evaluation module in this invention; Figure 8 This is a flowchart of a method for testing the gas content of a shale gas reservoir provided in an embodiment of the present invention. Detailed Implementation

[0018] The technical solution of the present invention will now be described with reference to the accompanying drawings.

[0019] In embodiments of the present invention, words such as "example" and "for example" are used to indicate that something is exemplified, illustrated, or described. Any embodiment or design described as "example" in the present invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the word "example" is intended to present the concept in a concrete manner. Furthermore, in embodiments of the present invention, the meaning expressed by "and / or" can be both, or either one.

[0020] In the embodiments of this invention, the terms "image" and "picture" may sometimes be used interchangeably. It should be noted that, without emphasizing the distinction between them, they convey the same meaning. Similarly, the terms "of," "corresponding (relevant)," and "corresponding" may sometimes be used interchangeably. It should be noted that, without emphasizing the distinction between them, they convey the same meaning.

[0021] In this embodiment of the invention, sometimes a subscript such as W1 may be written in a non-subscript form such as W1. When the difference is not emphasized, the meaning they express is the same.

[0022] To make the technical problems, solutions, and advantages of this invention clearer, a detailed description will be provided below in conjunction with the accompanying drawings and specific embodiments.

[0023] This invention provides a shale gas reservoir gas content testing system, such as... Figure 1-2 The diagram shown illustrates a shale gas reservoir gas content testing system, which includes: The rock sample encapsulation module acquires the initial state information of the shale rock sample, monitors the changing trends of rock sample temperature, pressure and gas release rate, records the degree of impact of gas release on the test environment, analyzes the correlation between gas release characteristics and test requirements, summarizes gas release data, and generates gas release characteristic trigger quantities. The gas release control module extracts the relationship between the gas release cycle and the pressure recovery time based on the gas release characteristic trigger quantity, formulates a multi-level progressive control strategy, analyzes the pressure recovery law and gas release demand, adjusts the control response timing, and obtains the control strategy execution command. The gas metering and analysis module executes instructions according to the control strategy, extracts the location distribution information of the gas release device, analyzes the control combination of gas release capacity and release point, schedules the gas release device to perform control operations, and generates a gas release execution sequence. The dynamic balance correction module analyzes the synchronicity of pressure change rate and gas composition before and after gas release based on the gas release execution sequence, adjusts the control weight of the release point, optimizes the dynamic balance of the test process, and obtains a set of dynamic balance evaluation indices for gas release. The effect evaluation module is based on the dynamic equilibrium evaluation index set of gas release. It extracts the accuracy of gas content measurement and the adaptability of gas release characteristics after the test, evaluates the test effect and stability, analyzes the matching ability and fluctuation of gas content after the test, and generates the test effect evaluation level.

[0024] The gas release characteristic triggering quantities include the gas release critical rate, temperature and pressure change threshold, and environmental impact coefficient; the control strategy execution instructions include pressure recovery parameters, release cycle parameters, and control level parameters; the gas release execution sequence includes the release point sequence, release intensity parameters, and execution timing parameters; the gas release dynamic balance evaluation index set includes the pressure balance index, component coordination index, and system stability index; and the test effect evaluation level includes the measurement level, characteristic adaptation level, and test stability level.

[0025] Specifically, such as Figure 2 , 3 As shown, the rock sample encapsulation module includes: The initial state monitoring submodule acquires the initial state information of the shale rock sample, extracts the changing trends of rock sample temperature, pressure and gas release rate, and generates a gas release characteristic sequence. The shale sample SN202308-01 was obtained with an internal temperature of 25.0℃, an initial pressure of 10.0MPa, and a gas release rate of 0.00cm² at an initial time T=0s. 3 The data is recorded as initial state information at 1-second intervals within a 300-second initial state monitoring period. For example, at the 50th second, data on rock sample temperature, pressure, and gas release rate are continuously collected. 3 / s, at the 100th second, the temperature was 25.2℃, the pressure was 9.5MPa, and the gas release rate was 0.25cm. 3 At 200 seconds, the temperature was 25.3℃, the pressure was 8.9MPa, and the gas release rate was 0.18cm / s. 3 The submodule processes 300 sets of time series data per second to extract trends. Specifically, for temperature data, it quantifies temperature change by calculating the temperature difference between adjacent time points T=99s and T=100s (25.2℃-25.1℃=0.1℃), recording the temperature change sequence throughout the entire cycle. Similarly, it calculates the pressure difference between adjacent time points (9.5MPa-9.8MPa=-0.3MPa) and the gas release rate difference (0.25cm²) between adjacent time points. 3 / s-0.15cm 3 / s=0.10cm 3The pressure change sequence and the gas release rate change sequence are generated separately. The temperature change sequence, pressure change sequence, and gas release rate change sequence are aligned according to the timestamp and combined into a multidimensional time series to generate a gas release feature sequence.

[0026] The gas release impact analysis submodule extracts the degree of impact of gas release on the test environment based on the gas release characteristic sequence, analyzes the correlation between gas release characteristics and test requirements, and generates the gas release impact degree. Based on the gas release characteristic sequence, the gas release rate change sequence and pressure change sequence are extracted to assess the impact of gas release on the test environment. The pressure impact benchmark is set as the average rate of change of gas release causing a 1.0 MPa decrease in test environment pressure within 100 seconds, i.e., -0.01 MPa / s. This benchmark is set with reference to historical data of shale under similar test conditions. In this embodiment, by calculating the pressure decrease from 9.8 MPa to 9.2 MPa within the time window from the 50th to the 150th second, the average rate of change is (9.2-9.8) / 100 = -0.006 MPa / s. This value is greater than -0.01 MPa / s, and the impact is judged as "low". If the calculated average rate of change is in the range of -0.01 MPa / s to -0.03 MPa / s, it is judged as "medium". If it is less than -0.03 MPa / s, it is judged as "high". Next, the correlation between gas release characteristics and test requirements is analyzed. The requirement is to control pressure fluctuations within ±0.5 MPa throughout the entire test. The submodule compares the pressure change sequence in the gas release characteristic sequence with this requirement. Between the 100th and 200th seconds, the pressure drops from 9.5 MPa to 8.9 MPa, a change of 0.6 MPa, exceeding the 0.5 MPa threshold. This event is recorded as a "strongly correlated" event. If the change is between 0.2 MPa and 0.5 MPa, it is recorded as "medium correlated". If it is less than 0.2 MPa, it is recorded as "weakly correlated". Finally, the impact is quantified based on the "low" impact determination result and the recorded correlation (a strongly correlated event). The quantification rule is: "low" impact has a base score of 20 points, "medium" 50 points, and "high" 80 points. Each recorded "strongly correlated" event adds 10 points, "medium correlated" adds 5 points, and "weakly correlated" adds 1 point. In this embodiment, the calculation result is 20 + 10 = 30 points, generating the gas release impact score.

[0027] The trigger quantity generation submodule extracts the integral calculation results of the gas release rate change trend and pressure change based on the gas release influence degree, and generates the gas release characteristic trigger quantity. Based on a gas release impact score of 30, a gas release impact score threshold of 40 is set. This threshold references the maximum disturbance that the test equipment can withstand during stable operation. Experimental verification shows that when the gas release impact score exceeds 40, the accuracy of the test data will deviate by more than 5%. In this embodiment, the gas release impact score is less than 40. Next, the gas release rate change trend in the gas release characteristic sequence is extracted, i.e., the gas release rate change sequence. At the same time, the pressure change sequence is integrated. Specifically, from the start of monitoring T=0s to the current time T=300s, the pressure change is accumulated and summed. For example, within the first 10 seconds... The pressure drops from 10.0 MPa to 9.9 MPa, a change of -0.1 MPa. In the second 10 seconds, the pressure drops from 9.9 MPa to 9.75 MPa, a change of -0.15 MPa. Therefore, the integral calculation result for the first 20 seconds is (-0.1) + (-0.15) = -0.25 MPa. This process continues until T = 300 s, when the pressure drops from 10.0 MPa to 8.5 MPa, yielding an integral calculation result of -1.5 MPa. Combining the trend of the gas release rate with the integral calculation result of the pressure change, and using the maximum value of the gas release rate sequence (0.25 cm)... 3 The sum of / s and the pressure integral result -1.5MPa is weighted and summed. The rate weight α is set to 10 and the pressure integral weight β is set to 1. The two coefficients are obtained by regression analysis of historical experimental data. The calculation process is 0.25 multiplied by 10 plus the absolute value of -1.5 multiplied by 1 equals 4.0, which generates the gas release characteristic trigger quantity.

[0028] Specifically, such as Figure 2 , 4 As shown, the gas release control module includes: The periodic extraction submodule extracts the relationship between the gas release period and the pressure recovery time based on the gas release characteristic triggering amount, analyzes the complexity of the gas release behavior, and generates a control time window. Based on a gas release trigger value of 4.0, historical data analysis shows that when the trigger value is between 3.0 and 5.0, the corresponding gas release behavior exhibits a complete cycle consisting of a 60-second release phase and a 120-second recovery phase, with a total cycle of 180 seconds. The pressure recovery time is 120 seconds. This 180-second period is recorded as the current release cycle. Next, the complexity of the gas release behavior is analyzed. This complexity is quantified by calculating the number of fluctuations in the gas release rate within one cycle, with a fluctuation threshold set at 0.05 cm. 3 / s, an absolute value of the rate change exceeding this value is recorded as a valid fluctuation. In this embodiment, within a 180-second period, the gas release rate increases from 0.25cm / s. 3 / s decreased to 0.10cm 3 / s, during which the length exceeded 0.05cm 3 times. 3 The complexity of the fluctuation is determined by the following rules: 0-2 fluctuations are considered "low", 3-5 fluctuations are considered "medium", and more than 5 fluctuations are considered "high". The current complexity is determined to be "medium". Finally, based on the release period of 180 seconds and the complexity of "medium", a control time window is generated. The generation rule is that when the complexity is "low", the time window is the last 50% of the period, that is, 180 multiplied by 0.5 equals 90 seconds; when the complexity is "medium", the time window is the last 30% of the period, that is, 180 multiplied by 0.3 equals 54 seconds; and when the complexity is "high", the time window is the last 10% of the period, that is, 180 multiplied by 0.1 equals 18 seconds. In this embodiment, the time window is 54 seconds.

[0029] The priority determination submodule extracts the gas release demand and pressure recovery pattern based on the control time window, determines the control priority, and generates the distribution range of release points. Based on a 54-second control time window, the gas release demand is defined as the cumulative gas volume to be compensated in the next cycle, determined by the integral calculation of the pressure change minus 1.5 MPa. This requires a gas volume equivalent to 1.5 MPa of pressure. The pressure recovery pattern is expected to naturally recover 0.8 MPa within 120 seconds without intervention; this pattern is derived from historical data. Next, the control priority is determined. The priority determination rule is based on the gap between the compensation demand and the natural recovery capacity. The compensation demand of 1.5 MPa is subtracted from the natural recovery amount of 0.8 MPa, resulting in a net compensation demand of 0.7 MPa. A net compensation demand threshold of less than 0.5 MPa is set as a "low" priority. Priority is set to 1.0 MPa or less, and to "high" priority. In this embodiment, the net compensation requirement is 0.7 MPa, so the control priority is set to "medium". Finally, based on the "medium" priority, the distribution range is generated as follows: when the priority is "low", the release point furthest from the center of the rock sample is activated; when the priority is "medium", the two release points at a medium distance from the center of the rock sample are activated; and when the priority is "high", all three release points are activated. In this embodiment, the test device has three gas release points, located at 5 cm, 10 cm, and 15 cm from the center of the rock sample, respectively. Therefore, the two release points located at 10 cm and 15 cm are activated to generate the release point distribution range.

[0030] The regulation strategy planning submodule identifies the compatibility between the regulation capability of the release points and the gas release demand based on the distribution range of the release points, formulates a multi-level progressive regulation strategy, and generates regulation strategy execution instructions. Based on the distribution range of release points (activating release points at 10cm and 15cm), and according to equipment calibration data, the maximum release rate at release point P2 at 10cm is 0.5cm. 3 / s, the maximum release rate at the release point P3 at 15cm is 0.3cm. 3 / s, the total regulatory capacity of both is 0.8cm. 3 The gas release demand adaptability was analyzed. The current gas release demand is to compensate for a pressure loss of 0.7 MPa. According to the gas state equation, the average release rate needs to be 0.6 cm / s within a 54-second control time window. 3 / s, due to the total regulatory capacity of 0.8cm 3 / s is greater than the required rate by 0.6cm 3 / s, the adaptability is determined to be "satisfied". Next, a multi-level progressive control strategy is formulated, dividing the 54-second control window into three 18-second stages. The first stage (0-18 seconds) adopts a "compensation" strategy, setting the P2 rate to 0.4cm. 3 / s, P3 speed set to 0.24cm 3 / s, the total speed is 0.64cm 3 / s, the second phase (18-36 seconds) adopts a "maintenance" strategy, reducing the P2 rate to 0.25cm. 3 / s, P3 rate reduced to 0.15cm 3 / s, total speed is 0.4cm 3 / s, the third stage (36-54 seconds) employs a "fine-tuning" strategy, reducing the P2 rate to 0.1cm. 3 / s, P3 rate reduced to 0.06cm 3 / s, the total speed is 0.16cm 3 / s encodes a set of instructions containing three stages, each with a specific rate setting for each release point, to generate control strategy execution instructions.

[0031] Specifically, such as Figure 2 , 5 As shown, the gas metering and analysis module includes: The release point distribution submodule executes instructions according to the control strategy, extracts the location distribution information and control capability of the gas release device, analyzes the control combination scheme of the release point, and generates the release point activation sequence. According to the control strategy, the release point P2 is located at 10cm, and the control capability is 0.5cm. 3 / s, release point P3 is located at 15cm, and the regulation capability is 0.3cm. 3The submodule analyzes the control combination scheme of the release points. In the first stage (0-18 seconds), the instruction requires the activation of P2 and P3 to form the combination {P2, P3}. In the second stage (18-36 seconds) and the third stage (36-54 seconds), the combination {P2, P3} is activated again. The submodule confirms that the activated release point combination remains unchanged throughout the entire control time window, which is {P2, P3}. Then, based on this combination scheme, an activation instruction in the form of a time sequence is generated. This sequence sends an activation signal to the controllers of P2 and P3 at 0 seconds and sends a stop signal at 54 seconds. The sequence specifies which release points are in the working state within the control cycle, represented as [(T=0, P2=ON, P3=ON), (T=54, P2=OFF, P3=OFF)]. This sequence is the release point activation sequence.

[0032] The regulation weight allocation submodule extracts the matching degree between the regulation weight of the release point and the gas release capacity based on the release point activation sequence, adjusts the regulation weight allocation ratio, and generates the gas release execution sequence. Based on the activation sequence of the release points, the matching degree between the regulation weights of the release points and the gas release capacity is extracted. The initial regulation weights are allocated proportionally according to the maximum release capacity of the release points, with the maximum capacity of P2 being 0.5 cm. 3 / s, P3 is 0.3cm 3 / s, total capacity is 0.8cm 3 / s, therefore the initial weight of P2 is 0.5 divided by 0.8, which equals 0.625, and the initial weight of P3 is 0.3 divided by 0.8, which equals 0.375. Evaluating the matching degree of this weight allocation with the gas release demand, in the first stage, the total demand rate is 0.64 cm / s. 3 / s, based on the initial weighted distribution, the release rate of P2 should be 0.64 multiplied by 0.625, which equals 0.4cm. 3 The release rate of P3 should be 0.64 multiplied by 0.375, which equals 0.24 cm³ / s. 3 / s, this result is consistent with the rate setting in the control strategy execution instruction, and the matching degree is determined to be 100%. The same calculation and judgment are performed in the second and third stages. If the matching degree is lower than 95% (this threshold is set based on the fact that a value below this will lead to uneven pressure distribution), the weights are adjusted. For example, if a local low pressure occurs on the other side of the rock sample, P3 needs to undertake more compensation tasks, so the control weight allocation ratio can be adjusted, reducing the weight of P2 from 0.625 to 0.55 and increasing the weight of P3 from 0.375 to 0.45. In this embodiment, since the initial matching degree is 100%, no adjustment is required, and the confirmation will proceed. The weights P2 (0.625) and P3 (0.375) are combined with the total rate of each stage in the control strategy execution instruction to generate an instruction sequence containing the specific execution rate of each release point at each time point. For example, the sequence content is [(T=0-18s, P2_rate=0.4, P3_rate=0.24), (T=18-36s, P2_rate=0.25, P3_rate=0.15), (T=36-54s, P2_rate=0.1, P3_rate=0.06)]. This sequence is the gas release execution sequence.

[0033] Specifically, such as Figure 2 , 6 As shown, the dynamic balance correction module includes: The pressure change rate analysis submodule calls the gas release execution sequence, extracts the pressure change rate before and after gas release, analyzes the consistency of the pressure change direction, and generates pressure change rate analysis results. Consistency of pressure change direction refers to continuously monitoring pressure changes during the gas release process and analyzing whether the direction of pressure change is consistent in different stages. The gas release execution sequence was invoked. Before the start of gas release control (T=290s to T=300s), the pressure was monitored to decrease from 8.55MPa to 8.50MPa, with a pressure change rate of -0.005MPa / s. In the first stage of gas release control (T=300s to T=318s), due to gas compensation, the pressure was monitored to increase from 8.50MPa to 8.58MPa, with a pressure change rate of +0.0044MPa / s. In the second stage (T=318s to T=336s), the pressure increased from 8.58MPa to 8.62MPa, with a change rate of +0.0022MPa / s. The consistency of the pressure change direction was analyzed. By continuously monitoring the pressure changes during the gas release process, the pressure variation in the differentiated stages was analyzed. To determine whether the change direction is consistent, in this embodiment, the change direction before regulation is negative, and the change direction during regulation is positive. The two directions are inconsistent. In the first and second stages of the regulation process, the pressure change direction is positive, and the direction is consistent. The consistency of direction within this stage is determined to be "yes". The consistency judgment rule is that if the pressure change rate signs are the same at two consecutive monitoring time points, it is determined to be consistent. If more than 90% of the monitoring points are consistent in direction within a regulation stage, then the direction of that stage is consistent. Finally, the specific change rate values ​​of each stage and the judgment conclusion of the direction consistency (e.g., "change rate before regulation -0.005MPa / s, negative direction; change rate in the first stage +0.0044MPa / s, positive direction; consistency within the stage: yes") are integrated to generate the pressure change rate analysis result.

[0034] The gas composition synchronicity analysis submodule extracts the relationship between gas composition concentration and volume fraction based on the pressure change rate analysis results, analyzes the synchronicity of gas composition, and generates gas composition synchronicity analysis results. Gas composition synchronicity refers to determining whether the concentration changes of different gas components are coordinated and consistent by synchronously analyzing the concentration changes of each component in the gas. Based on the pressure change rate analysis, at T=300s before the start of regulation, online monitoring using a gas chromatograph revealed that the volume fraction of methane (CH4) in the released gas from the rock sample was 85%, ethane (C2H6) was 10%, and carbon dioxide (CO2) was 5%. At the end of the first stage of regulation at T=318s, due to the injection of compensation gas (99.9% pure methane), the volume fraction of methane in the mixed gas increased to 87%, ethane decreased to 8.5%, and carbon dioxide decreased to 4.5%. The synchronicity of the gas components was analyzed by synchronously analyzing the concentration changes of each component in the gas to determine whether the concentration changes of the differentiated gas components were coordinated. The criterion for coordination was the concentration changes of all non-compensation gas components (ethane and carbon dioxide). To determine whether the volume fraction decrease rates are close, a deviation threshold of 10% is set. This threshold is determined experimentally. A deviation below this threshold is considered a uniform dilution effect. In this embodiment, the volume fraction decrease rate of ethane is (10%-8.5%) divided by 10% equals 15%, and the volume fraction decrease rate of carbon dioxide is (5%-4.5%) divided by 5% equals 10%. The deviation between the two is |15%-10%|=5%. Since 5% is less than the set threshold of 10%, the gas component synchronicity is judged as "good". If the deviation is between 10% and 20%, it is "average", and if it is greater than 20%, it is "poor". Finally, this judgment of "good" and the specific volume fraction change data are integrated to generate the gas component synchronicity analysis result.

[0035] The balance optimization submodule adjusts the control weight of the release point based on the gas composition synchronization analysis results, optimizes the dynamic balance of the test process, and obtains a set of gas release dynamic balance evaluation indices. The gas composition synchronicity analysis result was "good," but it was noted that the 15% decrease in ethane was higher than the 10% decrease in carbon dioxide, indicating a slight unevenness in the dilution effect of the compensating gas. To further optimize, the release point control weights were fine-tuned. The adjustment rule was to assign lower weights to release points corresponding to areas with poor synchronicity. Specifically, the weight of P2 was slightly adjusted from 0.625 to 0.615 (a decrease of 0.01), and this weight was increased for P3, adjusting its weight from 0.375 to 0.385. The gas release execution sequence for the next round of control was recalculated, and its impact on dynamic equilibrium was simulated. Finally, a set of evaluation indices was obtained, including the pressure fluctuation amplitude. The predicted value decreased from 0.6 MPa to 0.2 MPa, the predicted value of component synchronicity deviation decreased from 5% to 3%, and a comprehensive dynamic balance index was calculated. This index was obtained by weighting pressure fluctuation and component synchronicity deviation, with pressure fluctuation weighting 0.7 and synchronicity deviation weighting 0.3. The calculation process is 100 minus the sum of 0.2 multiplied by 100 multiplied by 0.7 plus 0.03 multiplied by 100 multiplied by 0.3, and the result is 85.1. The indices {predicted pressure fluctuation: 0.2 MPa, predicted component synchronicity deviation: 3%, comprehensive dynamic balance index: 85.1} are combined to obtain the gas release dynamic balance assessment index set.

[0036] Specifically, such as Figure 2 , 7 As shown, the effect evaluation module includes: The accuracy assessment submodule is based on the dynamic equilibrium assessment index set of gas release, extracts the accuracy of gas content measurement after testing, analyzes the deviation between the measured value and the true value, and generates accuracy assessment results. Based on the dynamic equilibrium assessment index set for gas release, after completing the shale gas desorption experiment, the residual gas content of the rock sample was determined by mercury intrusion porosimetry, and the measured value was 3.5 m. 3 / t, through mass balance calculations, yields a baseline value of 3.6m. 3 Next, the deviation between the measured value and the reference value was analyzed, and the absolute deviation was calculated as |3.5-3.6|=0.1m. 3 The relative deviation is (0.1 / 3.6)×100%=2.78%. The accuracy evaluation rule is that a relative deviation between 0% and 3% is rated as "high" accuracy, between 3% and 5% as "medium" accuracy, and greater than 5% as "low" accuracy. In this embodiment, the relative deviation of 2.78% falls within the "high" accuracy category. This evaluation result and the specific deviation value (absolute deviation 0.1m) are then used. 3 The accuracy assessment results are generated by recording the relative deviation ( / t, 2.78%).

[0037] The adaptability analysis submodule extracts the relationship between the gas release characteristic trigger quantity and the matching degree based on the accuracy evaluation results, analyzes the adaptability of the gas release characteristics, and generates adaptability evaluation results. Based on the accuracy assessment result of "high", the initial calculated gas release characteristic trigger value in this test was 4.0, while the final comprehensive dynamic balance index achieved by the test was 85.1. This index can be regarded as the "matching degree" of the trigger value. The data pair (trigger value = 4.0, matching degree = 85.1) was recorded and compared with the data in the historical database. The database records the optimal matching degree under different trigger values. For example, for the trigger value of 4.0, the historical optimal matching degree is 88.0. The gas release characteristic adaptability was analyzed. The quantitative standard of adaptability is the ratio of the current matching degree to the historical optimal matching degree. The calculation process is 85.1 divided by 88.0, which equals 96.7%. The adaptability evaluation rule is that a ratio greater than 95% is "excellent", 90% to 95% is "good", and less than 90% is "needs optimization". In this embodiment, the ratio of 96.7% was rated as "excellent". This evaluation result "excellent" and the calculated ratio of 96.7% were recorded to generate the adaptability evaluation result.

[0038] Based on the adaptability assessment results, the effect evaluation submodule extracts the matching ability and fluctuation of gas content after the test, and generates the test effect evaluation level. Based on the "Excellent" fit assessment result, and considering the matching ratio of 96.7% and the relative deviation of 2.78% in the fluctuation, two core indicators (matching ability 96.7% and fluctuation 2.78%) are used as the evaluation criteria. Then, the test effect is finally graded according to a preset evaluation matrix. The evaluation matrix rules are as follows: if the matching ability is "Excellent" (>95%) and the fluctuation (relative deviation) is "High" accuracy (<3%), the test effect evaluation level is "Level 1"; if the matching ability is "Good" (90%-95%) or the fluctuation is "Medium" accuracy (3%-5%), the level is "Level 2"; if the matching ability is "Needs Optimization" (<90%) or the fluctuation is "Low" accuracy (>5%), the level is "Level 3". In this embodiment, the matching ability of 96.7% and the fluctuation of 2.78% meet the conditions for "Level 1". Finally, this conclusion is determined as the final effect evaluation level of this test, generating the test effect evaluation level.

[0039] Please see Figure 8 The method for testing the gas content of shale gas reservoirs is based on the aforementioned shale gas reservoir gas content testing system and includes the following steps: S1: Obtain the initial state information of shale rock samples, including the changing trends of rock sample temperature, pressure and gas release rate, extract gas release characteristic sequences and gas release influence, and generate gas release characteristic trigger quantities; S2: Based on the gas release characteristic trigger quantity, extract the relationship between gas release cycle and pressure recovery time, formulate a multi-level progressive control strategy, determine the control priority and release point distribution range, and generate control strategy execution instructions; S3: Based on the control strategy, execute commands, identify the location distribution information and control capability of the gas release device, analyze the control combination scheme of the release point, and generate a gas release execution sequence; S4: Based on the gas release execution sequence, analyze the synchronicity of pressure change rate and gas composition before and after gas release, adjust the control weight of release point, optimize the dynamic balance of the test process, and obtain a set of gas release dynamic balance evaluation indices. S5: Based on the dynamic equilibrium evaluation index set of gas release, extract the compatibility between the gas content measurement accuracy and gas release characteristics after the test, evaluate the test effect, and generate the test effect evaluation level.

[0040] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A shale gas reservoir gas content testing system, characterized in that, The system includes: The rock sample encapsulation module acquires the initial state information of the shale rock sample, monitors the changing trends of rock sample temperature, pressure and gas release rate, records the degree of impact of gas release on the test environment, analyzes the correlation between gas release characteristics and test requirements, summarizes gas release data, and generates gas release characteristic trigger quantities. Based on the gas release characteristic trigger quantity, the gas release control module extracts the relationship between the gas release cycle and the pressure recovery time, formulates a multi-level progressive control strategy, analyzes the pressure recovery law and gas release demand, adjusts the control response timing, and obtains the control strategy execution command. The gas metering and analysis module executes instructions according to the control strategy, extracts the location distribution information of the gas release device, analyzes the control combination of gas release capacity and release point, schedules the gas release device to perform control operations, and generates a gas release execution sequence. The dynamic balance correction module analyzes the synchronicity of pressure change rate and gas composition before and after gas release according to the gas release execution sequence, adjusts the control weight of the release point, optimizes the dynamic balance of the test process, and obtains a set of dynamic balance evaluation indices for gas release.

2. The shale gas reservoir gas content testing system according to claim 1, characterized in that: The gas release characteristic triggering parameters include the gas release critical rate, temperature and pressure change threshold, and environmental impact coefficient; the control strategy execution instructions include pressure recovery parameters, release cycle parameters, and control level parameters; the gas release execution sequence includes release point sequence, release intensity parameters, and execution timing parameters; and the gas release dynamic balance evaluation index set includes pressure balance index, component coordination index, and system stability index.

3. The shale gas reservoir gas content testing system according to claim 1, characterized in that: The rock sample encapsulation module includes: The initial state monitoring submodule acquires the initial state information of the shale rock sample, extracts the changing trends of rock sample temperature, pressure and gas release rate, and generates a gas release characteristic sequence. The gas release impact analysis submodule extracts the degree of impact of gas release on the test environment based on the gas release characteristic sequence, analyzes the correlation between gas release characteristics and test requirements, and generates the gas release impact degree. The trigger quantity generation submodule extracts the integral calculation result of the gas release rate change trend and pressure change based on the gas release influence degree, and generates the gas release characteristic trigger quantity.

4. The shale gas reservoir gas content testing system according to claim 3, characterized in that: The gas release control module includes: The periodic extraction submodule extracts the relationship between the gas release period and the pressure recovery time based on the gas release characteristic triggering amount, analyzes the complexity of the gas release behavior, and generates a control time window. The priority determination submodule extracts the gas release demand and pressure recovery pattern based on the control time window, determines the control priority, and generates the distribution range of release points. The regulation strategy planning submodule identifies the compatibility between the regulation capability of the release points and the gas release demand based on the distribution range of the release points, formulates a multi-level progressive regulation strategy, and generates regulation strategy execution instructions.

5. The shale gas reservoir gas content testing system according to claim 4, characterized in that: The gas metering and analysis module includes: The release point distribution submodule executes instructions according to the control strategy, extracts the location distribution information and control capability of the gas release device, analyzes the control combination scheme of the release point, and generates the release point activation sequence. The regulation weight allocation submodule extracts the matching degree between the regulation weight of the release point and the gas release capacity based on the release point activation sequence, adjusts the regulation weight allocation ratio, and generates a gas release execution sequence.

6. The shale gas reservoir gas content testing system according to claim 5, characterized in that: The dynamic balance correction module includes: The pressure change rate analysis submodule calls the gas release execution sequence, extracts the pressure change rate before and after gas release, analyzes the consistency of the pressure change direction, and generates pressure change rate analysis results. The gas composition synchronicity analysis submodule extracts the relationship between gas composition concentration and volume fraction based on the pressure change rate analysis results, analyzes the gas composition synchronicity, and generates gas composition synchronicity analysis results. The balance optimization submodule adjusts the release point control weights based on the gas composition synchronization analysis results, optimizes the dynamic balance of the test process, and obtains a set of gas release dynamic balance evaluation indices.

7. The shale gas reservoir gas content testing system according to claim 6, characterized in that: The consistency of the pressure change direction refers to the continuous monitoring of pressure changes during the gas release process and the analysis of whether the pressure change direction is consistent in the differentiated stages. The gas composition synchronicity refers to determining whether the concentration changes of different gas components are coordinated and consistent by synchronously analyzing the concentration changes of each component in the gas.

8. The shale gas reservoir gas content testing system according to claim 1, characterized in that: The system also includes an effectiveness evaluation module: The effect evaluation module, based on the gas release dynamic balance evaluation index set, extracts the compatibility between the gas content measurement accuracy and gas release characteristics after the test, evaluates the test effect and stability, analyzes the matching ability and fluctuation of the gas content after the test, and generates the test effect evaluation level. The test performance evaluation levels include measurement level, feature adaptation level, and test stability level.

9. The shale gas reservoir gas content testing system according to claim 8, characterized in that: The performance evaluation module includes: The accuracy assessment submodule extracts the gas content measurement accuracy after testing based on the gas release dynamic balance assessment index set, analyzes the deviation between the measured value and the true value, and generates the accuracy assessment result. The adaptability analysis submodule extracts the relationship between the gas release characteristic triggering amount and the matching degree based on the accuracy evaluation results, analyzes the adaptability of the gas release characteristics, and generates adaptability evaluation results. Based on the adaptability assessment results, the effect evaluation submodule extracts the matching ability and fluctuation of the gas content after the test, and generates the test effect evaluation level.

10. A method for testing the gas content of a shale gas reservoir, characterized in that, The shale gas reservoir gas content testing system according to any one of claims 1-9 is executed, comprising the following steps: S1: Obtain the initial state information of shale rock samples, including the changing trends of rock sample temperature, pressure and gas release rate, extract gas release characteristic sequences and gas release influence, and generate gas release characteristic trigger quantities; S2: Based on the gas release characteristic triggering amount, extract the relationship between the gas release cycle and the pressure recovery time, formulate a multi-level progressive control strategy, determine the control priority and the distribution range of release points, and generate control strategy execution instructions; S3: Based on the control strategy, execute the command, identify the location distribution information and control capability of the gas release device, analyze the control combination scheme of the release point, and generate a gas release execution sequence; S4: Based on the gas release execution sequence, analyze the synchronicity of pressure change rate and gas composition before and after gas release, adjust the control weight of release point, optimize the dynamic balance of the test process, and obtain a set of gas release dynamic balance evaluation indices. S5: Based on the gas release dynamic balance evaluation index set, extract the compatibility between the gas content measurement accuracy and gas release characteristics after the test, evaluate the test effect, and generate the test effect evaluation level.

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