A shale gas well gas production capacity rapid discrimination method and device

Abstract

The application discloses a kind of shale gas well gas production capacity's fast discrimination method and device, comprising the following steps: S1, collection single well total gas content and gas saturation;Organic matter maturity is tested to core sampling, and single well test production;S2, gas saturation and test production are carried out correlation analysis;S3, gas saturation and total gas content are carried out correlation analysis;S4, total gas content and organic matter maturity are carried out correlation analysis;S5, obtain commercial gas flow;S6, establish marine shale gas well gas production chart;S7, obtain logging gas saturation and organic matter maturity data point input marine shale gas well gas production chart, determine that the well can obtain commercial gas flow.The application can determine whether gas well obtains commercial gas flow in advance, under the premise of guaranteeing accuracy, improve the efficiency of discriminating shale gas well gas production capacity, reduce the time and cost of horizontal section drilling, fracturing and drainage, etc.Loss, to improve the economic benefit of shale gas development.

Description

Technical Field

[0001] This invention belongs to the field of shale gas exploration and development technology, and specifically relates to a method and device for rapidly determining the gas production capacity of shale gas wells. Background Technology

[0002] The Sichuan Basin and its surrounding Wufeng Formation-Longmaxi Formation are key areas for shale gas exploration and development in China, covering an area of ​​approximately 26 × 10⁻⁶. 4 km 2 The shale gas resources of the Wufeng Formation-Longmaxi Formation within the basin are estimated at approximately 40.38 × 10⁻⁶. 12 m 3 Shale gas resources in the Wufeng Formation-Longmaxi Formation of southern Sichuan: 15.12 × 10⁻⁶ 12 m 3 After the discovery of the Fuling shale gas field in 2013, its annual production exceeded 2.0 × 10⁻⁶. 8 m 3 As of 2018, my country's annual shale gas production exceeded 10 billion cubic meters.

[0003] Drilling and evaluation results show that low-resistivity shale reservoirs are prevalent in the Sichuan Basin. Low-resistivity reservoirs were encountered in both the Qiongzhusi Formation and the Wufeng-Longmaxi Formation, significantly impacting gas well production, with wells exhibiting no production, low production, and high production levels. Studies indicate that low resistivity is significantly influenced by gas saturation and organic matter maturity, resulting in substantial differences in gas content. The primary controlling factors for low resistivity differ across regions and wells, and it can be controlled by two factors simultaneously, leading to varying degrees of impact on shale gas production capacity. However, there is currently no rapid method to determine whether a shale gas well is commercially viable. Current methods primarily rely on post-fracturing and production testing to obtain shale gas production capacity, thereby determining commercial viability. While accurate, this method is time-consuming and costly, potentially leading to significant economic losses.

[0004] Therefore, it is necessary to establish a rapid method for determining the gas production capacity of shale gas wells. Summary of the Invention

[0005] In view of the above-mentioned shortcomings in the prior art, the present invention provides a method and device for rapid determination of the gas production capacity of shale gas wells, which solves the problems of low efficiency in determining the gas production capacity of shale gas wells and high time and value costs in shale gas exploration and development.

[0006] To achieve the above-mentioned objectives, the technical solution adopted by this invention is: a rapid method for determining the gas production capacity of shale gas wells, comprising the following steps: S1. Collect single-well logging data (including compensated neutron and deep resistivity), target layer logging interpretation parameters water saturation, and logging interpretation parameters total gas content and single-well test production, and convert water saturation into gas saturation. S2. Perform a correlation analysis between gas saturation and test production to obtain the gas saturation threshold when the gas well test production reaches commercial development. S3. Perform correlation analysis between gas saturation and total gas content to obtain the total gas content threshold corresponding to the gas saturation threshold. S4. Perform a correlation analysis between total gas content and organic matter maturity to obtain the organic matter maturity threshold of the target layer of the gas well corresponding to the total gas content threshold. S5. When the gas saturation is greater than the gas saturation threshold and the organic matter maturity is less than the organic matter maturity threshold, a commercial gas flow is obtained. S6. Establish a gas production chart for marine shale gas wells by using the gas saturation and organic matter maturity of commercial gas flows; S7. After the new vertical well is completed, the gas saturation and organic matter maturity data points can be obtained from the well logging. The obtained data points are then put into the gas production chart of marine shale gas wells. If the data points fall into the quadrant that is greater than the gas saturation threshold and less than the organic matter maturity threshold, it can be quickly determined that the well can obtain commercial gas flow.

[0007] Further: the gas saturation = 1 - water saturation.

[0008] Furthermore: the formula for calculating the organic matter maturity Ro is: When Ro < 3.5%, Ro = 0.0537d(GD) - 11.21 When Ro ≥ 3.5%, Ro = 1.1659h(Dh / Gh) + 2.7588 In the above formula, d(GD) is the peak spacing in the Raman spectrum, and h(Dh / Gh) is the peak height ratio in the Raman spectrum.

[0009] Further: The correlation analysis between gas saturation and test yield in step S2 is specifically performed by using gas saturation as the vertical axis and test yield as the horizontal axis, and performing linear regression.

[0010] Furthermore, the gas saturation threshold is 55%.

[0011] Furthermore, the correlation analysis between the gas saturation and the total gas content is specifically performed by using gas saturation as the abscissa and the total gas content as the ordinate, and then performing linear regression.

[0012] Furthermore: the total gas content threshold is 4m³. 3 / t.

[0013] Furthermore, the correlation analysis between the total gas content and the maturity of organic matter is specifically performed by using the maturity of organic matter as the abscissa and the total gas content as the ordinate, and conducting a linear analysis.

[0014] Furthermore, the organic matter maturity threshold is 3.7%.

[0015] Furthermore: A rapid system for determining the gas production capacity of shale gas wells, comprising: The water saturation collection device is used to collect single-well logging data, water saturation as a logging interpretation parameter of the target layer, and total gas content and single-well test production as logging interpretation parameters, and converts water saturation into gas saturation; the organic matter maturity is tested by laser Raman spectroscopy for core sampling; The correlation analysis device is used to perform correlation analysis between gas saturation and test production to obtain the gas saturation threshold; to perform correlation analysis between gas saturation and total gas content to obtain the total gas content threshold corresponding to the gas saturation threshold; and to perform correlation analysis between total gas content and organic matter maturity to obtain the organic matter maturity threshold of the target layer of the gas well corresponding to the total gas content threshold. The chart establishment device is used to obtain a commercial gas flow when the gas saturation is greater than the gas saturation threshold and the organic matter maturity is less than the organic matter maturity threshold; and to establish a gas production chart for marine shale gas wells based on the gas saturation and organic matter maturity of the commercial gas flow. The commercial gas flow determination device is used to obtain well logging data points on gas saturation and organic matter maturity after a new vertical well is completed. The obtained data points are then input into the gas production chart of marine shale gas wells. If the data points fall into the quadrant that is greater than the gas saturation threshold and less than the organic matter maturity threshold, it can be quickly determined that the well can obtain commercial gas flow.

[0016] The beneficial effects of this invention are as follows: This invention can determine in advance whether a gas well will obtain commercial gas flow, and improves the efficiency of judging the gas production capacity of shale gas wells while ensuring accuracy, and reduces the time and cost losses caused by horizontal drilling, fracturing and drainage, so as to improve the economic benefits of shale gas development. Attached Figure Description

[0017] Figure 1 This is a flowchart of the present invention; Figure 2 This is a graph showing the relationship between gas saturation and yield. Figure 3 This is a graph showing the relationship between gas saturation and total gas content. Figure 4 This is a graph showing the relationship between total gas content and organic matter maturity. Figure 5 This is a schematic diagram of shale gas well production. Figure 6 This is a schematic diagram illustrating the relationship between compensated neutrons and deep resistivity in an embodiment of the present invention; Figure 7 This is a schematic diagram of laser Raman maturity and the RTS / RT ratio of the well in an embodiment of the present invention. Detailed Implementation

[0018] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0019] like Figure 1 As shown, a rapid method for determining the gas production capacity of a shale gas well includes the following steps: S1. Collect water saturation from single well (including compensated neutron and deep resistivity) and target layer logging interpretation parameters, and convert it into gas saturation; total gas content from logging interpretation parameters; Gas saturation = 1 - water saturation.

[0020] The organic matter maturity (Ro) was tested using laser Raman spectroscopy in core sampling; and the production rate of each well was also tested. When Ro < 3.5%, use the formula Ro = 0.0537d(GD) - 11.21 (1) When Ro≥3.5%, use the formula Ro=1.1659h(Dh / Gh)+2.7588(2) d(GD) — Peak spacing in Raman spectra h(Dh / Gh) — Peak height ratio in Raman spectrum The calculation results for Ro are shown in Table 1.

[0021] Table 1 Relationship between Ro and logging parameters

[0022] As shown in Table 1, the calculation results are as follows: 1. When D (peak position) is 1328.69, G (peak position) is 1600.88, D (peak height) is 954.406, G (peak height) is 1231.06, D (half-width at half maximum) is 124.226, G (half-width at half maximum) is 50.4409, D (peak area) is 133009, G (peak area) is 68757.9, d (GD) is 272.19, h (Dh / Gh) is 0.775272, Ro (1) is 3.41%, Ro (2) is 3.66%; 2. When D (peak position) is 1325.3, G (peak position) is 1598.9, D (peak height) is 1021.9, G (peak height) is 1387.05, D (half-width at half maximum) is 126.103, G (half-width at half maximum) is 50.4409, D (peak area) is 139419, G (peak area) is 76243.1, d (GD) is 273.6, h (Dh / Gh) is 0.736743, Ro (1) is 3.48%, Ro (2) is 3.62%; 3. When D (peak position) is 1325.92, G (peak position) is 1598.05, D (peak height) is 1084.62, G (peak height) is 1422.48, D (half-width at half maximum) is 123.301, G (half-width at half maximum) is 47.6387, D (peak area) is 144806, G (peak area) is 75070.8, d (GD) is 272.13, h (Dh / Gh) is 0.762485, Ro (1) is 3.40%, Ro (2) is 3.65%; When the result of Ro calculated by formula (1) is around 3.5, the result of Ro calculated by formula (2) should be selected.

[0023] When laser Raman spectroscopy for organic matter maturity is performed without core testing, organic matter maturity (Ro) is calculated using well logging data: Compensating neutrons show a strong correlation with deep resistivity, such as Figure 6 As shown, apparent resistivity (RTs) is constructed using compensated neutrons from experimental wells. A plot of the apparent resistivity (RTs) / deep resistivity (RT) ratio and laser Raman maturity (Ro) shows a strong linear correlation, such as... Figure 7 As shown, the linear regression function is obtained as y = 0.0774ln(x) + 3.4027, R0. 2 =0.9575; By plotting the unknown experimental laser Raman maturity and the well's RTS / RT ratio onto the above chart, the organic matter maturity (Ro) can be directly obtained.

[0024] S2. A correlation analysis was performed between gas saturation and test production. Using gas saturation as the ordinate and test production as the abscissa, a linear regression was conducted to obtain the gas saturation threshold required for commercial development of the gas well's test production. Figure 2 As shown, the proposed commercial development test output of the gas well is 100,000 cubic meters per day, and it is clear that the gas saturation of the gas well to reach commercial development is greater than 55%.

[0025] S3. Perform a correlation analysis between gas saturation and total gas content. Plot gas saturation on the x-axis and total gas content on the y-axis, and perform linear regression to obtain the linear regression function. This will yield the total gas content threshold corresponding to the gas saturation threshold. Figure 3 As shown, the total gas content limit corresponding to the gas saturation threshold of 55% for commercial development in the target formation of the gas well is 4m³. 3 / t, considering a total gas content of 4m 3 Commercial development can also be achieved at a rate of / t or above.

[0026] S4. Correlation analysis was performed between total gas content and organic matter maturity. Using organic matter maturity as the x-axis and total gas content as the y-axis, a linear regression analysis was conducted, yielding the following linear regression function: R0 2 =0.6377, thus obtaining the organic matter maturity threshold of the target layer of the gas well corresponding to the total gas content threshold, such as Figure 4 As shown, the total gas content is 4m³. 3 The organic matter maturity of the target formation in gas wells with a capacity of / t or more is less than 3.7%.

[0027] S5. When the gas saturation is greater than the gas saturation threshold and the organic matter maturity is less than the organic matter maturity threshold, a commercial gas flow can be obtained; wells with gas saturation > 55% and maturity < 3.7% can usually obtain a commercial gas flow.

[0028] S6. Establish a gas production chart for marine shale gas wells based on the gas saturation and organic matter maturity of commercial gas flows, such as... Figure 5 As shown.

[0029] S7. After the new vertical well is completed, the gas saturation and organic matter maturity data points can be obtained from the well logging. The obtained data points are then used in the gas production chart of marine shale gas wells. If the data points fall into the quadrant of gas saturation > 55% and maturity < 3.7%, it can be quickly determined that the well can obtain commercial gas flow.

[0030] A rapid system for determining the gas production capacity of shale gas wells includes: The water saturation collection device is used to collect single-well logging data, water saturation as a logging interpretation parameter of the target layer, and total gas content and single-well test production as logging interpretation parameters, and converts water saturation into gas saturation; the organic matter maturity is tested by laser Raman spectroscopy for core sampling; Gas saturation = 1 - water saturation.

[0031] The organic matter maturity (Ro) was tested using laser Raman spectroscopy in core sampling; and the production rate of each well was also tested. When Ro < 3.5%, use the formula Ro = 0.0537d(GD) - 11.21 (1) When Ro≥3.5%, use the formula Ro=1.1659h(Dh / Gh)+2.7588(2) d(GD) — Peak spacing in Raman spectra h(Dh / Gh) — Peak height ratio in Raman spectrum As shown in Table 1, the calculation results are as follows: 1. When D (peak position) is 1328.69, G (peak position) is 1600.88, D (peak height) is 954.406, G (peak height) is 1231.06, D (half-width at half maximum) is 124.226, G (half-width at half maximum) is 50.4409, D (peak area) is 133009, G (peak area) is 68757.9, d (GD) is 272.19, h (Dh / Gh) is 0.775272, Ro (1) is 3.41%, Ro (2) is 3.66%; 2. When D (peak position) is 1325.3, G (peak position) is 1598.9, D (peak height) is 1021.9, G (peak height) is 1387.05, D (half-width at half maximum) is 126.103, G (half-width at half maximum) is 50.4409, D (peak area) is 139419, G (peak area) is 76243.1, d (GD) is 273.6, h (Dh / Gh) is 0.736743, Ro (1) is 3.48%, Ro (2) is 3.62%; 3. When D (peak position) is 1325.92, G (peak position) is 1598.05, D (peak height) is 1084.62, G (peak height) is 1422.48, D (half-width at half maximum) is 123.301, G (half-width at half maximum) is 47.6387, D (peak area) is 144806, G (peak area) is 75070.8, d (GD) is 272.13, h (Dh / Gh) is 0.762485, Ro (1) is 3.40%, Ro (2) is 3.65%; When the result of Ro calculated by formula (1) is around 3.5, the result of Ro calculated by formula (2) should be selected.

[0032] When laser Raman spectroscopy for organic matter maturity is performed without core testing, organic matter maturity (Ro) is calculated using well logging data: Compensating neutrons show a strong correlation with deep resistivity, such as Figure 6 As shown, apparent resistivity (RTs) is constructed using compensated neutrons from experimental wells. A plot of the apparent resistivity (RTs) / deep resistivity (RT) ratio and laser Raman maturity (Ro) shows a strong linear correlation, such as... Figure 7 As shown, the linear regression function is obtained as y = 0.0774ln(x) + 3.4027, R0.2 =0.9575; By plotting the unknown experimental laser Raman maturity and the well's RTS / RT ratio onto the above chart, the organic matter maturity (Ro) can be directly obtained.

[0033] The correlation analysis device is used to perform correlation analysis between gas saturation and test production to obtain the gas saturation threshold; to perform correlation analysis between gas saturation and total gas content to obtain the total gas content threshold corresponding to the gas saturation threshold; and to perform correlation analysis between total gas content and organic matter maturity to obtain the organic matter maturity threshold of the target layer of the gas well corresponding to the total gas content threshold. A correlation analysis was performed between gas saturation and test production. Using gas saturation as the ordinate and test production as the abscissa, a linear regression was conducted to obtain the gas saturation threshold required for commercial development of the gas well's test production. Figure 2 As shown, the proposed commercial development test output of the gas well is 100,000 cubic meters per day, and it is clear that the gas saturation of the gas well to reach commercial development is greater than 55%.

[0034] A correlation analysis was performed between gas saturation and total gas content. Linear regression was conducted with gas saturation on the x-axis and total gas content on the y-axis to obtain the linear regression function. This yielded the total gas content threshold corresponding to the gas saturation threshold. Figure 3 As shown, the total gas content limit corresponding to the gas saturation threshold of 55% for commercial development in the target formation of the gas well is 4m³. 3 / t, considering a total gas content of 4m 3 Commercial development can also be achieved at a rate of / t or above.

[0035] Correlation analysis was performed between total gas content and organic matter maturity. A linear regression analysis was conducted with organic matter maturity as the x-axis and total gas content as the y-axis, yielding the following linear regression function: R0 2 =0.6377, thus obtaining the organic matter maturity threshold of the target layer of the gas well corresponding to the total gas content threshold, such as Figure 4 As shown, the total gas content is 4m³. 3 The organic matter maturity of the target formation in gas wells with a capacity of / t or more is less than 3.7%.

[0036] The chart establishment device is used to obtain a commercial gas flow when the gas saturation is greater than the gas saturation threshold and the organic matter maturity is less than the organic matter maturity threshold; and to establish a gas production chart for marine shale gas wells based on the gas saturation and organic matter maturity of the commercial gas flow.

[0037] Commercial gas flow can be obtained when the gas saturation is greater than the gas saturation threshold and the organic matter maturity is less than the organic matter maturity threshold; wells with gas saturation > 55% and maturity < 3.7% can usually obtain commercial gas flow.

[0038] The commercial gas flow determination device is used to obtain well logging data points on gas saturation and organic matter maturity after a new vertical well is completed. The obtained data points are then input into the gas production chart of marine shale gas wells. If the data points fall into the quadrant that is greater than the gas saturation threshold and less than the organic matter maturity threshold, it can be quickly determined that the well can obtain commercial gas flow.

[0039] A gas production chart for marine shale gas wells is established by using the gas saturation of commercial gas flows and the maturity of organic matter, such as... Figure 5 As shown.

[0040] After the new vertical well is completed, well logging data points on gas saturation and organic matter maturity can be obtained. The obtained data points are then used in the marine shale gas well production chart. If the data points fall into the quadrant of gas saturation > 55% and maturity < 3.7%, it can be quickly determined that the well can obtain commercial gas flow.

[0041] This invention can determine in advance whether a gas well will obtain commercial gas flow. While ensuring accuracy, it improves the efficiency of judging the gas production capacity of shale gas wells and reduces the time and cost losses caused by horizontal drilling, fracturing and drainage, thereby improving the economic benefits of shale gas development.

Claims

1. A rapid method for determining the gas production capacity of shale gas wells, characterized in that, Includes the following steps: S1. Collect single-well logging data, target layer logging interpretation parameters water saturation, and logging interpretation parameters total gas content and single-well test production, and convert water saturation into gas saturation. The maturity of organic matter was tested using laser Raman spectroscopy on core samples. S2. Perform correlation analysis between gas saturation and test yield to obtain the gas saturation threshold. S3. Perform correlation analysis between gas saturation and total gas content to obtain the total gas content threshold corresponding to the gas saturation threshold. S4. Perform a correlation analysis between total gas content and organic matter maturity to obtain the organic matter maturity threshold of the target layer of the gas well corresponding to the total gas content threshold. S5. When the gas saturation is greater than the gas saturation threshold and the organic matter maturity is less than the organic matter maturity threshold, a commercial gas flow is obtained. S6. Establish a gas production chart for marine shale gas wells by using the gas saturation and organic matter maturity of commercial gas flows; S7. After the new vertical well is completed, obtain the gas saturation and organic matter maturity data points from the well logging. Put the obtained data points into the gas production chart of marine shale gas wells. If the data point falls into the quadrant that is greater than the gas saturation threshold and less than the organic matter maturity threshold, quickly determine that the well has obtained commercial gas flow.

2. The rapid method for determining the gas production capacity of shale gas wells according to claim 1, characterized in that, The gas saturation is equal to 1 minus the water saturation.

3. The rapid method for determining the gas production capacity of shale gas wells according to claim 1, characterized in that, The formula for calculating the organic matter maturity Ro is: When Ro < 3.5%, Ro = 0.0537d(GD) - 11.21 When Ro ≥ 3.5%, Ro = 1.1659h(Dh / Gh) + 2.7588 In the above formula, d(GD) is the peak spacing in the Raman spectrum, and h(Dh / Gh) is the peak height ratio in the Raman spectrum.

4. The rapid method for determining the gas production capacity of shale gas wells according to claim 1, characterized in that, The correlation analysis between gas saturation and test yield in step S2 specifically involves performing linear regression with gas saturation as the vertical axis and test yield as the horizontal axis.

5. The rapid method for determining the gas production capacity of shale gas wells according to claim 1, characterized in that, The gas saturation threshold is 55%.

6. The rapid method for determining the gas production capacity of shale gas wells according to claim 1, characterized in that, The correlation analysis between gas saturation and total gas content is specifically performed by using gas saturation as the horizontal axis and total gas content as the vertical axis to perform linear regression.

7. The rapid method for determining the gas production capacity of shale gas wells according to claim 1, characterized in that, The total gas content threshold is 4m. 3 / t.

8. The rapid method for determining the gas production capacity of shale gas wells according to claim 1, characterized in that, The correlation analysis between total gas content and organic matter maturity is specifically performed by using organic matter maturity as the abscissa and total gas content as the ordinate for linear analysis.

9. The rapid method for determining the gas production capacity of shale gas wells according to claim 1, characterized in that, The organic matter maturity threshold is 3.7%.

10. A rapid system for determining the gas production capacity of shale gas wells, characterized in that, include: The water saturation collection device is used to collect single-well logging data, target layer logging interpretation parameters water saturation, and logging interpretation parameters total gas content and single-well test production, and convert water saturation into gas saturation. The maturity of organic matter was tested using laser Raman spectroscopy on core samples. A correlation analysis device is used to perform correlation analysis between gas saturation and test yield to obtain a gas saturation threshold; and to perform correlation analysis between gas saturation and total gas content to obtain a total gas content threshold corresponding to the gas saturation threshold. Correlation analysis was performed between total gas content and organic matter maturity to obtain the organic matter maturity threshold of the target layer of the gas well corresponding to the total gas content threshold. The chart establishment device is used to obtain a commercial gas flow when the gas saturation is greater than the gas saturation threshold and the organic matter maturity is less than the organic matter maturity threshold; and to establish a gas production chart for marine shale gas wells based on the gas saturation and organic matter maturity of the commercial gas flow. The commercial gas flow determination device is used to obtain well logging data points on gas saturation and organic matter maturity after a new vertical well is completed. The obtained data points are then input into the gas production chart of marine shale gas wells. If the data point falls into the quadrant that is greater than the gas saturation threshold but less than the organic matter maturity threshold, the well is quickly determined to have obtained commercial gas flow.

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