Calculation method for representing vertical migration mode of oil gas

Abstract

The invention discloses a calculation method for characterizing a vertical migration mode of oil and gas, which comprises the following steps of: determining source reservoir thickness Hi of hydrocarbon source rock and an oil and gas reservoir in each well in a work area by using logging information, depicting all sandstone sections between the hydrocarbon source rock and the oil and gas reservoir in each well according to characteristics of a GR curve and an AC curve, and counting the real thickness hi of all sandstones; calculating the source storage sand-to-ground ratio ri of each well, counting the monthly yield yi of each well in the first week, drawing a scatter diagram of the source storage sand-to-ground ratio and the monthly yield in the first week in the research area, establishing a relational expression of the source storage sand-to-ground ratio and the monthly yield in the first week, judging the size of a source storage correlation coefficient R2, and further determining whether the oil-gas migration mode of the work area belongs to vertical migration or not. The method provided by the invention solves the problem that the existing method is limited by samples, cannot accurately judge the overall oil-gas dominant migration channel of the research area, or is high in required cost.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil and gas exploration methods, and in particular relates to a calculation method for characterizing the vertical migration mode of oil and gas. Background Art

[0002] The types of oil and gas migration channels can be divided into four types: connected pores, cracks (slits), unconformities, and faults. The first three are related to the sandstone itself and can be summarized as matrix migration. The understanding of the migration effects of these four types is relatively unified, but there are large differences in the understanding of which of the matrix and faults is the dominant channel in oil and gas migration. Through a large number of simulation experiments and numerical simulation studies by scholars from various countries, it has been confirmed that oil and gas migration only occurs through limited dominant channels. The dominant migration channel for oil and gas migration can be any of connected pores, cracks (slits), unconformities, and faults. The dominant migration channel controls the migration and accumulation of oil and gas.

[0003] At present, the main methods for determining the dominant migration pathways of oil and gas include fluid tracer method, inclusion research method, illite dating method, fluid group analysis method, nitrogen compound analysis method, isotope analysis method, physical simulation method and numerical simulation method. Although the above experimental results can intuitively determine the dominant migration pathways of oil and gas, they also have their limitations. First, due to sample limitations, it is impossible to accurately determine the dominant migration pathways of oil and gas in the study area as a whole. Second, the above experiments require high costs. Therefore, it is very important to use an indirect and widely applicable calculation method to describe the dominant migration pathways of oil and gas. Summary of the invention

[0004] The purpose of the present invention is to provide a calculation method for characterizing the vertical migration mode of oil and gas, which solves the problem that the existing methods are limited by samples and cannot accurately determine the overall dominant oil and gas migration channel in the study area, or the cost is high.

[0005] The technical scheme adopted by the present invention is: a calculation method for characterizing the vertical migration mode of oil and gas, using logging data to determine the source-reservoir thickness Hi of the source rock and the oil and gas reservoir in each well in the work area, characterizing all sandstone sections between the source rock and the oil and gas reservoir in each well according to the characteristics of the GR curve and the AC curve, counting the true thickness hi of all sandstones, calculating the source-reservoir-sand-land ratio ri of each well, counting the initial weekly monthly production yi of each well, drawing a scatter plot of the source-reservoir-sand-land ratio and the initial weekly monthly production in the study area, establishing a relationship between the source-reservoir-sand-land ratio and the initial weekly monthly production, and judging the source-reservoir correlation coefficient R 2 The size of the oil and gas can be determined by the vertical migration mode.

[0006] The technical solution adopted by the present invention is also characterized in that:

[0007] Furthermore, the calculation method for characterizing the vertical migration mode of oil and gas is implemented in the following steps:

[0008] Step 1: Collect geological and logging data in the work area to determine the source reservoir thickness Hi of the source rock layer and oil and gas reservoir layer of each well;

[0009] Step 2, characterize all sandstone sections between the source rock layer and the oil and gas reservoir layer of each well according to the characteristics of the GR curve and the AC curve;

[0010] Step 3, calculating the sum hi of the true thickness of the sandstone between the source rock layer and the oil and gas reservoir layer of each well;

[0011] Step 4, calculate the proportion of the sandstone section between the source rock layer and the oil and gas reservoir layer of each well, i.e., the source-reservoir-sandstone-land ratio;

[0012] Step 5, calculate the initial weekly and monthly production of each well yi;

[0013] Step 6, draw a two-dimensional scatter plot of the source-sand-reservoir-land ratio and the initial weekly monthly production in the study area;

[0014] Step 7, using scatter plot regression to obtain the relationship between the source-reservoir-sand-land ratio and the initial weekly monthly production in the region;

[0015] Step 8: Obtain the source-reservoir correlation coefficient R through scatter plot regression 2 , and through the source-reservoir correlation coefficient R 2 Determine the correlation between the source-reservoir-sand-land ratio and the initial weekly monthly production, and then determine the oil and gas migration mode in the work area.

[0016] Furthermore, in step 2, all sandstone sections between the source rock layer and the reservoir layer are characterized according to the GR and AC curve characteristics, and the ratio of the actual thickness of the sandstone section to the entire formation thickness from the source rock layer to the reservoir layer is calculated.

[0017] Furthermore, the specific calculation method of ri in step 4 is: ri=hi / Hi.

[0018] Furthermore, in step 5, for each oil well, the initial weekly monthly production of each well is calculated using the oil test data, and a correlation is established with the source-reservoir-sand-land ratio.

[0019] Furthermore, the scatter plot regression curve in step 7 is specifically: yi=k×ri+b.

[0020] Furthermore, in step 7, the source-reservoir correlation coefficient obtained from the scatter plot regression curve can quantitatively characterize that the oil and gas reach the reservoir through vertical migration.

[0021] Furthermore, in step 8, the source-reservoir correlation coefficient R 2 The higher it is, the more it proves that the oil and gas migration mode in this work area is vertical migration, and the migration matrix is ​​sand body.

[0022] The beneficial effects of the present invention are:

[0023] The present invention utilizes existing geological, drilling, and production data to obtain the source-reservoir-sand-to-land ratio and initial monthly production data of a single well in the study area, and for the first time proposes the concepts of source-reservoir-sand-to-land ratio and source-reservoir correlation coefficient. A two-dimensional scatter plot and linear regression method are used to obtain the relationship between the source-reservoir-sand-to-land ratio and initial monthly production of a single well and the source-reservoir correlation coefficient, so as to judge the dominant channel for oil and gas migration in the study area, and to finely characterize the sand body of a single well and accurately measure the oil and gas production of a single well. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic flow chart of a calculation method for characterizing the vertical migration mode of oil and gas according to the present invention;

[0025] Figure 2 is a well location distribution pattern diagram of the study area in Example 3 of the present invention;

[0026] Figure 3 is a single well formation model diagram in Example 3 of the present invention;

[0027] Figure 4 This is a schematic diagram for determining the oil and gas migration mode in Example 3 of the present invention;

[0028] Figure 5 This is a schematic diagram for determining the oil and gas migration mode in Example 4 of the present invention;

[0029] Figure 6 This is a schematic diagram for determining the oil and gas migration mode in Example 5 of the present invention;

[0030] Figure 7 This is a schematic diagram for determining the oil and gas migration mode in Example 6 of the present invention. DETAILED DESCRIPTION

[0031] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings.

[0032] The present invention provides a calculation method for characterizing the vertical migration mode of oil and gas, using logging data to determine the source-reservoir thickness Hi of the source rock and the oil and gas reservoir in each well in the work area, characterizing all sandstone sections between the source rock and the oil and gas reservoir in each well according to the characteristics of the GR curve and the AC curve, counting the true thickness hi of all sandstones, calculating the source-reservoir-sand-land ratio ri of each well, counting the initial weekly monthly production yi of each well, drawing a scatter plot of the source-reservoir-sand-land ratio and the initial weekly monthly production in the study area, establishing a relationship formula yi=k×ri+b between the source-reservoir-sand-land ratio and the initial weekly monthly production, and judging the source-reservoir correlation coefficient R 2 The size of the oil and gas can be determined by the vertical migration mode.

[0033] The specific process is as follows Figure 1 As shown, the following steps are included:

[0034] The technical solution adopted by the present invention is a calculation method for characterizing the dominant channel of vertical migration of oil and gas. Figure 1 As shown, specifically including:

[0035] Step 1: In the clastic rock reservoir work area, collect geological and logging data to determine the source reservoir thickness Hi (i=1, 2, 3, ..., n) of the source rock layer and the oil and gas reservoir layer of each well;

[0036] Step 2: characterize all sandstone sections between the source rock layer and the oil and gas reservoir layer of each well according to the characteristics of the GR curve (gamma logging curve) and the AC curve (acoustic time difference logging curve), and calculate the ratio of the actual thickness of the sandstone section to the entire formation thickness from the source rock layer to the reservoir layer;

[0037] Step 3, counting the sum of the true thickness of the sandstone between the source rock layer and the reservoir layer of each well hi (i=1, 2, 3, ..., n);

[0038] Step 4, calculate the proportion of the sandstone section between the source rock layer and the oil and gas reservoir layer of each well ri (i = 1, 2, 3, ..., n), that is, the source-reservoir-sand-land ratio, and the specific calculation method of ri is: ri = hi / Hi;

[0039] Step 5, count the initial weekly monthly production of each well yi (i=1, 2, 3, ..., n);

[0040] Step 6: Draw a two-dimensional scatter plot of the source-reservoir-sand-land ratio and the initial weekly monthly production in the study area. For each oil well, use the oil test data to calculate the initial weekly monthly production of each well and establish a correlation with the source-reservoir-sand-land ratio;

[0041] Step 7, using scatter plot regression to obtain the relationship between the source-reservoir-sand-land ratio and the initial weekly monthly production in the region, yi=k×ri+b (i=1, 2, 3, ..., n). The source-reservoir correlation coefficient obtained from the scatter plot regression curve can quantitatively characterize that oil and gas migrate vertically to the reservoir.

[0042] Step 8: Use the source-reservoir correlation coefficient R 2 Determine the correlation between the source-reservoir sand-land ratio and the initial weekly monthly production. The higher the source-reservoir correlation coefficient, the more it proves that the oil and gas migration mode in the study area is vertical migration and the migration matrix is ​​sand body.

[0043] The composition of the present invention is further described below by way of examples and drawings.

[0044] Example 1

[0045] The calculation method for characterizing the vertical migration mode of oil and gas is to use the logging data to determine the source-reservoir thickness Hi of the source rock and the oil and gas reservoir in each well in the work area, characterize all the sandstone sections between the source rock and the oil and gas reservoir in each well according to the characteristics of the GR curve and the AC curve, count the true thickness hi of all sandstones, calculate the source-reservoir-sand-land ratio ri of each well, ri=hi / Hi, count the initial weekly monthly production yi of each well, draw a scatter plot of the source-reservoir-sand-land ratio and the initial weekly monthly production in the study area, establish the relationship between the source-reservoir-sand-land ratio and the initial weekly monthly production yi=k×ri+b, and determine the source-reservoir correlation coefficient R 2 The size of the source-reservoir correlation coefficient R 2 The higher it is, the more it proves that the oil and gas migration mode in this work area is vertical migration, and the migration matrix is ​​sand body.

[0046] Example 2

[0047] The calculation method for characterizing the vertical migration mode of oil and gas is implemented in the following steps:

[0048] Step 1: In the clastic rock reservoir work area, collect geological and logging data to determine the source reservoir thickness Hi (i=1, 2, 3, ..., n) of the source rock layer and the oil and gas reservoir layer of each well;

[0049] Step 2: characterize all sandstone sections between the source rock layer and the oil and gas reservoir layer of each well according to the characteristics of the GR curve (gamma logging curve) and the AC curve (acoustic time difference logging curve), and calculate the ratio of the actual thickness of the sandstone section to the entire formation thickness from the source rock layer to the reservoir layer;

[0050] Step 3, counting the sum of the true thickness of the sandstone between the source rock layer and the reservoir layer of each well hi (i=1, 2, 3, ..., n);

[0051] Step 4, calculate the proportion of the sandstone section between the source rock layer and the oil and gas reservoir layer of each well ri (i = 1, 2, 3, ..., n), that is, the source-reservoir-sand-land ratio, and the specific calculation method of ri is: ri = hi / Hi;

[0052] Step 5, count the initial weekly monthly production of each well yi (i=1, 2, 3, ..., n);

[0053] Step 6: Draw a two-dimensional scatter plot of the source-reservoir-sand-land ratio and the initial weekly monthly production in the study area. For each oil well, use the oil test data to calculate the initial weekly monthly production of each well and establish a correlation with the source-reservoir-sand-land ratio;

[0054] Step 7, using scatter plot regression to obtain the relationship between the source-reservoir-sand-land ratio and the initial weekly monthly production in the region, yi=k×ri+b (i=1, 2, 3, ..., n). The source-reservoir correlation coefficient obtained from the scatter plot regression curve can quantitatively characterize that oil and gas migrate vertically to the reservoir.

[0055] Step 8: Use the source-reservoir correlation coefficient R 2 Determine the correlation between the source-reservoir sand-land ratio and the initial weekly monthly production. The higher the source-reservoir correlation coefficient, the more it proves that the oil and gas migration mode in the study area is vertical migration and the migration matrix is ​​sand body.

[0056] Example 3

[0057] In order to further demonstrate the effectiveness of the method of the present invention, the method proposed in Example 2 was applied to an actual work area. The geological and logging data in the work area were collected, the target layer section was determined and the sandstone section of the target layer section was characterized, the initial monthly production of a single well and the source-reservoir-sand-land ratio were counted, a vertical migration pattern diagram of oil and gas in the study area was drawn, the source-reservoir correlation coefficient was regressed, and the dominant migration channel of oil and gas was determined.

[0058] In the clastic reservoir area, geological, well logging data and mud logging data are collected to determine the area where source rocks are developed as the study area and the oil wells in the area as the research objects, such as Figure 2 As shown in the figure, the logging curve characteristics and logging data are used to characterize all sandstone sections between the source rock layer and the oil and gas reservoir layer of each well and determine the true thickness of each sandstone section. The sum of the sand body thickness ti of a single well and the vertical distance Hi from the top of the source rock layer to the bottom of the reservoir are calculated, as shown in the figure. Figure 3 As shown in Table 1, the source-reservoir thickness is the same as that of the reservoir. According to the above method, similar operations are performed on all oil wells in the study area, and the oil test data of all oil wells in the study area are statistically analyzed to form a statistical table of source-reservoir thickness, sandstone thickness, source-reservoir sand-to-land ratio, and initial weekly monthly production, as shown in Table 1. Based on the statistical data in Table 1, a two-dimensional scatter plot of the sand-to-land ratio and initial weekly monthly production in the study area is drawn, namely, a migration pattern diagram, as shown in Table 1. Figure 4 As shown in the figure, the relationship between the source-reservoir sand-to-ground ratio and the initial weekly monthly production in the region is obtained by scatter plot regression y=11.325x-0.588, and the source-reservoir correlation coefficient R 2 =0.63, the source-reservoir correlation coefficient is good, indicating that the main mode of oil and gas migration in the study area is vertical migration, and the migration matrix is ​​mainly sand body.

[0059] Table 1 Parameters for determining migration patterns in the study area

[0060]

[0061]

[0062] Although the present invention has been described above in conjunction with exemplary embodiments and the accompanying drawings, it should be clear to those skilled in the art that various modifications or equivalent substitutions may be made to the above-mentioned embodiments without departing from the spirit and scope of the present invention. All modifications or equivalent substitutions may be made to the above-mentioned embodiments without departing from the purpose and scope of the technical solution of the present invention, and all shall be included in the protection scope of the present invention.

[0063] Example 4

[0064] The method proposed in Example 2 is applied to the X block.

[0065] The crude oil of Chang 6 reservoir in Block X comes from the Chang 7 source rock layer. There are currently 32 test wells. The sand bodies of these test wells are characterized using GR curves and AC curves. The thickness of the source reservoir stratum, the thickness of the source reservoir sandstone and the test oil production are counted, and the source reservoir sandstone-to-soil ratio of each well is calculated to form the migration mode judgment parameters in the study area as shown in Table 2:

[0066] Table 2 Parameters for determining migration patterns in the study area

[0067]

[0068]

[0069] Based on the above data, a two-dimensional scatter plot of the source-sand-reservoir-land ratio and the initial weekly monthly production in the study area is drawn as follows: Figure 5 As shown, we can see that the source-reservoir correlation coefficient R 2 =0.3954, the source-reservoir correlation is good, indicating that the dominant channel for crude oil migration in this area is mainly sand body matrix, and the migration mode is mainly vertical migration.

[0070] Example 5

[0071] The method proposed in Example 2 is applied to the Q block.

[0072] The crude oil of Chang 2 reservoir in Q block comes from Chang 7 source rock layer. There are 48 test wells at present. The sand bodies of these test wells are characterized by using GR curve and AC curve. The thickness of source reservoir stratum, source reservoir sandstone thickness and test oil production are counted, and the source reservoir sandstone-to-soil ratio of each well is calculated to form the migration mode judgment parameters of the study area as shown in Table 3:

[0073] Table 3 Parameters for determining migration patterns in the study area

[0074]

[0075]

[0076] Based on the above data, a two-dimensional scatter plot of the source-reservoir sand-to-ground ratio and the initial weekly monthly production in the study area is drawn as shown in Figure 6. It can be seen that the source-reservoir correlation coefficient R 2 =0.1236. Although there is a positive correlation trend, the correlation is poor due to the large source reservoir thickness, indicating that the dominant channel for crude oil migration in this area is not dominated by sand body matrix, and fractures may participate in the migration of crude oil.

[0077] Example 6

[0078] The method proposed in Example 2 is applied to the T block.

[0079] The N1 oil reservoir in the T block is a structural oil reservoir. There are currently 41 test wells. The sand bodies of these test wells are characterized using the GR curve and AC curve. The source reservoir stratum thickness, source reservoir sandstone thickness and test oil production are counted, and the source reservoir sandstone-to-sand ratio of each well is calculated to form the migration mode judgment parameters in the study area as shown in Table 4:

[0080] Table 4 Parameters for determining migration patterns in the study area

[0081]

[0082]

[0083] Based on the above data, a two-dimensional scatter plot of the source-sand-reservoir-land ratio and the initial weekly monthly production in the study area is drawn as follows: Figure 7 As shown, we can see that the source-reservoir correlation coefficient R 2 =0.0.23, the correlation between the two is poor, because the oil reservoirs in this area are structural reservoirs, and structural fractures are the dominant channels for crude oil in this area.

Claims

1. A calculation method for characterizing the vertical migration pattern of oil and gas, characterized in that: The logging data was used to determine the source-reservoir thickness Hi of the source rock and the oil and gas reservoir in each well in the work area. All sandstone sections between the source rock and the oil and gas reservoir in each well were characterized according to the characteristics of the GR curve and the AC curve. The true thickness hi of all sandstones was counted, the source-reservoir-sand-land ratio ri of each well was calculated, the initial weekly monthly production yi of each well was counted, and a scatter plot of the source-reservoir-sand-land ratio and the initial weekly monthly production in the study area was drawn. The relationship between the source-reservoir-sand-land ratio and the initial weekly monthly production was established, and the source-reservoir correlation coefficient R was determined. 2 The size of the oil and gas can be determined by the vertical migration mode.

2. The calculation method for characterizing the vertical migration mode of oil and gas according to claim 1 is characterized in that: Please follow the steps below to implement: Step 1: Collect geological and logging data in the work area to determine the source reservoir thickness Hi of the source rock layer and oil and gas reservoir layer of each well; Step 2, characterize all sandstone sections between the source rock layer and the oil and gas reservoir layer of each well according to the characteristics of the GR curve and the AC curve; Step 3, calculating the sum hi of the true thickness of the sandstone between the source rock layer and the oil and gas reservoir layer of each well; Step 4, calculate the proportion of the sandstone section between the source rock layer and the oil and gas reservoir layer of each well, i.e., the source-reservoir-sandstone-land ratio; Step 5, calculate the initial weekly and monthly production of each well yi; Step 6, draw a two-dimensional scatter plot of the source-sand-reservoir-land ratio and the initial weekly monthly production in the study area; Step 7, using scatter plot regression to obtain the relationship between the source-reservoir-sand-land ratio and the initial weekly monthly production in the region; Step 8: Obtain the source-reservoir correlation coefficient R through scatter plot regression 2 , and through the source-reservoir correlation coefficient R 2 Determine the correlation between the source-reservoir-sand-land ratio and the initial weekly monthly production, and then determine the oil and gas migration mode in the work area.

3. The calculation method for characterizing the vertical migration mode of oil and gas according to claim 2 is characterized in that: In step 2, all sandstone sections between the source rock layer and the reservoir layer are characterized according to the GR and AC curve characteristics, and the ratio of the actual thickness of the sandstone section to the entire formation thickness from the source rock layer to the reservoir layer is calculated.

4. The calculation method for characterizing the vertical migration mode of oil and gas according to claim 2 is characterized in that: The specific calculation method of ri in step 4 is: ri=hi / Hi.

5. The calculation method for characterizing the vertical migration mode of oil and gas according to claim 2 is characterized in that: In step 5, for each oil well, the initial weekly monthly production of each well is calculated using the oil test data, and a correlation is established with the source-reservoir-sand-land ratio.

6. The calculation method for characterizing the vertical migration mode of oil and gas according to claim 2 is characterized in that: The scatter plot regression curve in step 7 is specifically: yi=k×ri+b.

7. The calculation method for characterizing the vertical migration mode of oil and gas according to claim 5 is characterized in that: In step 7, the source-reservoir correlation coefficient obtained from the scatter plot regression curve can quantitatively indicate that the oil and gas reaches the reservoir through vertical migration.

8. The calculation method for characterizing the vertical migration mode of oil and gas according to claim 2 is characterized in that: In step 8, the source-reservoir correlation coefficient R 2 The higher it is, the more it proves that the oil and gas migration mode in this work area is vertical migration, and the migration matrix is ​​sand body.

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