Method for evaluating favorable geologic targets in complex structural areas

Abstract

The application discloses a method for evaluating favorable geological targets in a complex structure area, and is implemented according to the following steps: step 1, preparing and checking a structure data set of a work area; step 2, fitting a structure surface according to the structure data of step 1; step 3, calculating the maximum curvature Cmax, the minimum curvature Cmin and the direction factor δ of the fitted structure surface; step 4, calculating an evaluation parameter C IG ; and step 5, drawing a contour map of the evaluation parameter C IG , and determining favorable exploration geological targets in combination with a geological background. The application establishes a new evaluation parameter on the basis of a curvature algorithm, and good effects are achieved in production. Through the combination of the basic principles of geomechanics and differential geometry, the geological exploration targets in a complex structure area can be quickly and accurately quantitatively evaluated, and the success rate of exploration is increased.

Description

Technical Field

[0001] This invention belongs to the technical field of geological exploration methods, specifically relating to a method for evaluating favorable geological targets in complex tectonic zones. Background Technology

[0002] Finding favorable geological targets is one of the main tasks of exploration. As a new exploration field, limestone gas has a complex geological structure, dense reservoirs, and poor matrix pore connectivity compared to most areas. However, limestone is brittle, and the development of fractures (especially tensile fractures) can greatly improve reservoir properties. Meanwhile, structural uplifts are conducive to the accumulation and formation of natural gas reservoirs.

[0003] Currently, curvature technology is mainly used in the field of geosciences for fracture and fault prediction, but it has shortcomings in the evaluation of favorable geological bodies. Specifically, it can reflect the density of fractures, but not the nature of fractures; and it cannot reflect the positive or negative topography that geological explorers are concerned with. Summary of the Invention

[0004] The purpose of this invention is to provide an evaluation method for favorable geological targets in complex tectonic zones, which can quickly and accurately quantitatively evaluate geological exploration targets in tectonically complex zones and increase the exploration success rate.

[0005] The technical solution adopted in this invention is:

[0006] The evaluation method for favorable geological targets in complex tectonic zones is implemented according to the following steps:

[0007] Step 1: Prepare and check the work area construction dataset;

[0008] Step 2: Fit the construction surface based on the construction data from Step 1;

[0009] Step 3: Calculate the maximum curvature Cmax, minimum curvature Cmin, and direction factor δ of the fitted construction surface;

[0010] Step 4, calculate the evaluation parameter C IG ;

[0011] Step 5, plot the evaluation parameter C IG Planar contour maps, combined with geological background, are used to identify favorable geological targets for exploration.

[0012] The invention is further characterized by:

[0013] The data in the constructed dataset in step 1 includes the hash number, x-axis, y-axis, and constructed elevation.

[0014] In step 1, the data in the constructed dataset is obtained using drilling geological stratification data in work areas with high well density, and using seismic interpretation and well seismic data in areas with low well density.

[0015] After the dataset is prepared in step 1, check for outliers in the horizontal and vertical coordinates by sorting. If there are outliers, check the projection system and convert it to the same projection system.

[0016] Step 2 is implemented in the following steps:

[0017] Step 2.1: Import the data prepared in Step 1 into the geological mapping software Geomap 4.0 and draw the structural contour map of the work area;

[0018] Step 2.2: Check the drawn contour map;

[0019] Step 2.3: Identify the structural features in the contour map.

[0020] If singularities are found during the inspection process in step 2.2, check and modify the geological stratification data or seismic interpretation data of the well points, and then redraw the structural contour map.

[0021] Step 3 is implemented in the following steps:

[0022] Step 3.1: Load the construction data from Step 2 into Petrel2015 to calculate the maximum curvature Cmax and minimum curvature Cmin;

[0023] Step 3.2: If both the maximum curvature Cmax and the minimum curvature Cmin are greater than 0, then the direction factor δ is 1; otherwise, the direction factor δ is -1.

[0024] Evaluation parameter C IG The calculation is performed according to the following formula (1):

[0025] C IG =δ*Cmin*Cmax(1).

[0026] Step 5 is implemented in the following steps:

[0027] Step 5.1, the evaluation parameter C from step 4... IG Import into Geomap 4.0 plotting software and draw C. IG Create a contour map and check if it matches the tectonic background. If not, modify it manually.

[0028] Step 5.2, Analysis of favorable geological targets for exploration: CIG>0, the larger the |CIG|, the larger the distribution area, and the more likely it is to be a preferred exploration target.

[0029] The beneficial effects of this invention are: the evaluation method for favorable geological targets in complex structural areas established by this invention has created new evaluation parameters based on curvature algorithms, and has achieved good results in production. By combining the basic principles of geomechanics with differential geometry, it can quickly and accurately quantitatively evaluate geological exploration targets in structurally complex areas, thereby increasing the success rate of exploration. Attached Figure Description

[0030] Figure 1 This is a flowchart of the evaluation method for favorable geological targets in complex tectonic zones according to the present invention;

[0031] Figure 2 This is a contour map of the top surface structure of the target layer in the work area in Embodiment 1 of the present invention;

[0032] Figure 3 The evaluation parameter C for the target layer exploration in the work area in Embodiment 1 of this invention is... IG Contour map;

[0033] Figure 4 This is a comparison chart of the evaluation results and exploration results of the target layer exploration in the work area in Embodiment 1 of the present invention. Detailed Implementation

[0034] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0035] The technical solution adopted in this invention is a method for evaluating favorable geological targets in complex tectonic zones, which is implemented according to the following steps:

[0036] like Figure 1 As shown, step 1 involves preparing and checking the work area construction dataset;

[0037] The data in the constructed dataset in step 1 includes hash numbers, x-axis, y-axis, and constructed elevation;

[0038] In step 1, the data in the constructed dataset is obtained using drilling geological stratification data in work areas with high well density, and using seismic interpretation and well seismic data in areas with low well density.

[0039] After the dataset is prepared in step 1, check for outliers in the horizontal and vertical axes by sorting. If there are outliers, check the projection system and convert it to the same projection system.

[0040] Step 2: Fit the construction surface based on the construction data from Step 1;

[0041] Step 2 is implemented in the following steps:

[0042] Step 2.1: Import the data prepared in Step 1 into the geological mapping software Geomap 4.0 and draw the structural contour map of the work area;

[0043] Step 2.2: Check the drawn structural contour map; if singularities exist, check and modify the geological stratification data or seismic interpretation data of the well points, and then redraw the structural contour map.

[0044] Step 2.3: Identify structural features in the contour map; such as nasal ridges, depressions, and gentle slopes, etc.

[0045] Step 3: Calculate the maximum curvature Cmax, minimum curvature Cmin, and direction factor δ of the fitted construction surface;

[0046] Step 3 is implemented in the following steps:

[0047] Step 3.1: Load the construction data from Step 2 into Petrel2015 to calculate the maximum curvature Cmax and minimum curvature Cmin;

[0048] Step 3.2: If both the maximum curvature Cmax and the minimum curvature Cmin are greater than 0, then the direction factor δ is 1; otherwise, the direction factor δ is -1.

[0049] Step 4, calculate the evaluation parameter C IG ;

[0050] Evaluation parameter C IG The calculation is performed according to the following formula (1):

[0051] C IG =δ*Cmin*Cmax(1);

[0052] Step 5, plot the evaluation parameter C IG Planar contour maps, combined with geological background, are used to identify favorable geological targets for exploration.

[0053] Step 5 is implemented in the following steps:

[0054] Step 5.1, the evaluation parameter C from step 4... IG Import into Geomap 4.0 plotting software and draw C. IG Create a contour map and check if it matches the tectonic background. If not, modify it manually.

[0055] Step 5.2, Analysis of favorable geological targets for exploration: CIG>0, the larger the |CIG|, the larger the distribution area, and the more likely it is to be the preferred exploration target;

[0056] Step 5.3: In the geological target area of ​​exploration, well locations are deployed in combination with geological background such as reservoir properties, gas logging curves, and capping conditions.

[0057] The technical principle adopted in this invention is:

[0058] Assuming the brittle strata are horizontal, they will bend and deform under tectonic stress. The uplifted sections of the strata experience tensile stress, forming tensile fractures (concentrated in the upper and middle parts of the strata), while the depressed sections experience compression, easily forming compression fractures and sutures. The strata between the uplifted and depressed sections, due to relative sliding, are prone to shear fractures and cleavage. The uplifted sections, being structurally high, are conducive to natural gas accumulation and reservoir formation; furthermore, the well-developed tensile fractures promote reservoir development, making them the preferred geological targets for natural gas exploration.

[0059] Define evaluation parameter C IG It can quantitatively characterize favorable geological targets.

[0060] For a given stratum, assuming complex tectonic deformation, the maximum curvature C max With minimum curvature C min All are not equal to 0, that is: C max C min ≠0.

[0061] Define the direction factor δ:

[0062] If C max &&C min >0, δ=1

[0063] else δ=-1

[0064] end

[0065] The improved Gaussian curvature value is:

[0066] C IG =δ*C min *C max

[0067] Geological significance:

[0068] C IG When >0, the geological body is a positive topography, |C IG |↑, the more developed the tension cracks;

[0069] C IG When <0, the geological body is a negative topography, |C IG |↑, the more developed the extrusion seam;

[0070] C IG When the value is approximately 0, the geological body exhibits weak deformation and primarily develops shear fractures.

[0071] Therefore: C IG >0&&|C IG When |↑, the geological target ↑ is favorable.

[0072] Example 1

[0073] The method for evaluating favorable geological targets in complex tectonic zones according to the present invention is implemented according to the following steps:

[0074] Step 1: Obtain structural data of the work area through single-well geological stratification;

[0075] The structural data is obtained by subtracting the core elevation data from the drilling geological stratification data in Table 1. The obtained structural data is checked, paying attention to outliers in the region. If there are discontinuous values, the stratification data is checked again to see if it is correct, or it is removed.

[0076] Table 1 (partial)

[0077] S376 18743843 4278874.3 3751 986 S169 18730125.9 4259152.7 3751 482 S2 19271071.9 4251492.3 3505 697 S170 18747703.9 4255305.6 3780.2 897 S172 18743253.9 4239253.7 3754.8 785 S173 18745146 4213188.3 3752 865 S174 18733262.3 4198002.5 3777.2 882 S18 18760386.1 4261076.3 3680.8 823 S190 18733270.3 4209767.6 3784.4 880 S191 18744021.2 4160455.3 3879.2 886 S194 18755213.7 4202464.9 3748 854 S196 18758737.9 4195949.3 3751 786

[0078] Step 2: Fit the construction surface based on the construction data, such as... Figure 2 As shown;

[0079] Step 3: Calculate the maximum curvature Cmax, minimum curvature Cmin, and direction factor δ of the fitted construction surface, as shown in Table 2 below;

[0080] Table 2

[0081]

[0082] Step 4: Calculate the evaluation parameter C IG As shown in Table 3 below

[0083] Table 3

[0084] S376 18743843 4278874.3 3.1E-14 S169 18730125.9 4259152.7 2.8E-14 S2 19271071.9 4251492.3 4.1E-14 S170 18747703.9 4255305.6 -3.2E-14 S172 18743253.9 4239253.7 -5.1E-14 S173 18745146 4213188.3 3.1E-14 S174 18733262.3 4198002.5 6.2E-14 S18 18760386.1 4261076.3 5.3E-14 S190 18733270.3 4209767.6 2E-14 S191 18744021.2 4160455.3 5E-15 S194 18755213.7 4202464.9 1.8E-14 S196 18758737.9 4195949.3 4E-14

[0085] Step 5: Plot the evaluation parameter C IG Planar contour map, such as Figure 3 As shown;

[0086] Evaluation parameter C of favorable geological targets in the study area IG During the contour line drawing process, C was adjusted for ease of mapping. IG Integerization is performed, as shown in Table 4 below:

[0087] Table 4

[0088] S376 18743843 4278874.3 3.1 S169 18730125.9 4259152.7 2.8 S2 19271071.9 4251492.3 4.1 S170 18747703.9 4255305.6 -3.2 S172 18743253.9 4239253.7 -5.1 S173 18745146 4213188.3 3.1 S174 18733262.3 4198002.5 6.2 S18 18760386.1 4261076.3 5.3 S190 18733270.3 4209767.6 2 S191 18744021.2 4160455.3 0.5 S194 18755213.7 4202464.9 1.8 S196 18758737.9 4195949.3 4

[0089] Figure 2 This is a contour map of the top surface structure of the target layer in the work area. It can be seen that the structure of the area is complex, with ridges and depressions such as S476-S63-63, S51-60-S130, S52-S57, and S153-S163. Although the geological features are relatively obvious, they are difficult to evaluate quantitatively.

[0090] Figure 3 C is the evaluation parameter for the target layer exploration in the work area.IG The contour map shows that the red areas represent favorable geological target areas within complex tectonic zones. It can be seen that C... IG The contour map clearly reflects the favorable geological targets for exploration. Among these favorable targets, the area S467—S51-60—S63-63 is the C-value in the work area. IG It is one of the areas with the highest value and the largest area, and should be the primary exploration target.

[0091] Figure 4 This is a comparison chart of the evaluation results and exploration outcomes of the target layer in the work area. It can be seen that the gas-bearing layers and gas-filled layers interpreted by well logging are at the evaluation parameter C. IG The identified favorable areas include the risk exploration well YT1H deployed in the favorable area S467—S51-60—S63-63, which obtained a high-yield industrial gas flow of 540,000 cubic meters per day during testing, and the vertical well S51-60, which obtained a high-yield industrial gas flow of 132,200 cubic meters per day.

[0092] Example 2

[0093] The method for evaluating favorable geological targets in complex tectonic zones according to the present invention is implemented according to the following steps:

[0094] Step 1: Obtain structural data of the work area through single-well geological stratification;

[0095] The structural data is obtained by subtracting the core elevation data from the drilling geological stratification data in Table 5. The obtained structural data is checked, paying attention to outliers in the region. If there are discontinuous values, the stratification data is checked again to see if it is correct, or it is removed.

[0096] Table 5 (partial)

[0097] T2-18-15C4 19287116.9 4202845.9 3200 1181.0 T2-24-30C8 19298811.1 4194585.5 3240 1234.8 S28-12-67 19324611.3 4189687.6 3250 1294.6 S 8-2-92 19341259.7 4197759.6 3159 1235.0 S28-26-65 19324953.5 4177824.6 3196 1303.0 S28-4-68 19326772.8 4196123.8 3263 1180.3 S28-6-49 19307798.7 4194252.4 3256 1257.7

[0098] Step 2: Fit the construction surface based on the construction data;

[0099] Step 3: Calculate the maximum curvature Cmax, minimum curvature Cmin, and direction factor δ of the fitted construction surface, as shown in Table 6 below;

[0100] Table 6

[0101]

[0102] Step 4: Calculate the evaluation parameter C IG As shown in Table 7 below;

[0103] Table 7

[0104] T2-18-15C4 19287116.9 4202845.9 4.7E-14 T2-24-30C8 19298811.1 4194585.5 -8.4E-15 S28-12-67 19324611.3 4189687.6 6.4E-14 S 8-2-92 19341259.7 4197759.6 -3.2E-15 S28-26-65 19324953.5 4177824.6 -5.8E-14 S28-4-68 19326772.8 4196123.8 2.1E-14 S28-6-49 19307798.7 4194252.4 -8.5E-14

[0105] Step 5: Plot the evaluation parameter C IG Planar contour map;

[0106] Evaluation parameter C of favorable geological targets in the study area IG During the contour line drawing process, C was adjusted for ease of mapping. IG Perform integer conversion, as shown in Table 8 below:

[0107] Table 8

[0108] T2-18-15C4 19287116.9 4202845.9 4.7 T2-24-30C8 19298811.1 4194585.5 -0.8 S28-12-67 19324611.3 4189687.6 6.4 S 8-2-92 19341259.7 4197759.6 -0.3 S28-26-65 19324953.5 4177824.6 -5.8 S28-4-68 19326772.8 4196123.8 2.1 S28-6-49 19307798.7 4194252.4 -8.5

[0109] Example 3

[0110] The method for evaluating favorable geological targets in complex tectonic zones according to the present invention is implemented according to the following steps:

[0111] Step 1: Obtain structural data of the work area through single-well geological stratification;

[0112] The structural data is obtained by subtracting the core elevation data from the drilling geological stratification data in Table 9. The obtained structural data is checked, paying attention to outliers in the region. If there are discontinuous values, the stratification data is checked again to see if it is correct, or it is removed.

[0113] Table 9 (partial)

[0114]

[0115]

[0116] Step 2: Fit the construction surface based on the construction data;

[0117] Step 3: Calculate the maximum curvature Cmax, minimum curvature Cmin, and direction factor δ of the fitted construction surface, as shown in Table 10 below;

[0118] Table 10

[0119]

[0120] Step 4: Calculate the evaluation parameter C IG As shown in Table 11 below;

[0121] S295-18-13 19369883.46 4160048.94 1.89E-14 S295-3-10 19368274.77 4171746.54 8.36E-15 S68-10-79 19319953.84 4158070.84 -4.40E-14 J109-22 19316434.62 4204494.13 3.50E-15 J109-23 19317061.93 4204479.658 -6.48E-14 J50-40 19328030.99 4249220.06 2.12E-14 J50-67 19344801.72 4248176.96 2.75E-14 J51-58 19339712.95 4247146.84 3.22E-15 J51-60 19339476.97 4249764.81 -2.38E-14 J66-14 19311754.64 4237433.08 2.12E-14 S68-13-78 19320053.8 4154251.43 1.87E-14

[0122] Step 5: Plot the evaluation parameter C IG Planar contour map;

[0123] Evaluation parameter C of favorable geological targets in the study area IG During the contour line drawing process, C was adjusted for ease of mapping. IG Perform integer conversion, as shown in Table 12 below;

[0124] Table 12

[0125] S295-18-13 19369883.46 4160048.94 1.9 S295-3-10 19368274.77 4171746.54 0.8 S68-10-79 19319953.84 4158070.84 -4.4 J109-22 19316434.62 4204494.13 0.4 J109-23 19317061.93 4204479.658 6.5 J50-40 19328030.99 4249220.06 2.1 J50-67 19344801.72 4248176.96 2.8 J51-58 19339712.95 4247146.84 -0.3 J51-60 19339476.97 4249764.81 -2.4 J66-14 19311754.64 4237433.08 2.1 S68-13-78 19320053.8 4154251.43 1.9

[0126] Example 4

[0127] The method for evaluating favorable geological targets in complex tectonic zones according to the present invention is implemented according to the following steps:

[0128] Step 1: Obtain structural data of the work area through single-well geological stratification;

[0129] The structural data is obtained by subtracting the core elevation data from the drilling geological stratification data in Table 13. The obtained structural data is checked, paying attention to outliers in the region. If there are discontinuous values, the stratification data is checked again to see if it is correct, or it is removed.

[0130] Table 13 (partial)

[0131] L55 19245122.2 3964305.4 3924 1256.5 L56 19242892.7 4034531 4252.8 1203.9 L57 19239221.6 4011560.9 4137.2 1241 L63 18756463.6 4042771.4 4135 1185.8 L65 18749259.3 3980879.4 4282 1199.9 L66 18769680.9 4010117.7 4017.8 1211.6 L7 18748653.9 3974033.8 4266 1230 L74 18770168.9 3998282.9 4156.4 1232.4 CT1 19242224.4 3993034 3972.8 1185.4 CT2 19258419.7 3954161.4 3908.6 1202.4 CT3 19243064.2 3943093.6 3797 1231.4

[0132] Step 2: Fit the construction surface based on the construction data;

[0133] Step 3: Calculate the maximum curvature Cmax, minimum curvature Cmin, and direction factor δ of the fitted construction surface, as shown in Table 14 below;

[0134] Table 14

[0135]

[0136] Step 4: Calculate the evaluation parameter C IG As shown in Table 15 below;

[0137] Table 15

[0138] L55 19245122.2 3964305.4 -2.87E-14 L56 19242892.7 4034531 8.96E-15 L57 19239221.6 4011560.9 6.30E-14 L63 18756463.6 4042771.4 1.68E-15 L65 18749259.3 3980879.4 3.60E-14 L66 18769680.9 4010117.7 -1.26E-14 L7 18748653.9 3974033.8 2.75E-14 L74 18770168.9 3998282.9 6.00E-15 CT1 19242224.4 3993034 3.45E-14 CT2 19258419.7 3954161.4 2.96E-14 CT3 19243064.2 3943093.6 -2.07E-14

[0139] Step 5: Plot the evaluation parameter C IG Planar contour map;

[0140] Evaluation parameter C of favorable geological targets in the study area IG During the contour line drawing process, C was adjusted for ease of mapping. IG Perform integer conversion, as shown in Table 16 below;

[0141] Table 16

[0142] L55 19245122.2 3964305.4 -2.9 L56 19242892.7 4034531 0.9 L57 19239221.6 4011560.9 6.3 L63 18756463.6 4042771.4 0.2 L65 18749259.3 3980879.4 3.6 L66 18769680.9 4010117.7 -1.3 L7 18748653.9 3974033.8 2.8 L74 18770168.9 3998282.9 0.6 CT1 19242224.4 3993034 3.5 CT2 19258419.7 3954161.4 3.0 CT3 19243064.2 3943093.6 -2.1

Claims

1. A method for evaluating favorable geological targets in complex tectonic zones, characterized in that, The specific steps are as follows: Step 1: Prepare and check the work area construction dataset; Step 2: Fit the construction surface based on the construction data from Step 1; Step 3: Calculate the maximum curvature Cmax, minimum curvature Cmin, and direction factor δ of the fitted construction surface; Step 4, calculate the evaluation parameter C IG ; Step 5, plot the evaluation parameter C IG Planar contour maps, combined with geological background, are used to identify favorable geological targets for exploration. Step 3 is implemented in the following steps: Step 3.1: Load the construction data from Step 2 into Petrel2015 to calculate the maximum curvature Cmax and minimum curvature Cmin; Step 3.2: If both the maximum curvature Cmax and the minimum curvature Cmin are greater than 0, then the direction factor δ is 1; otherwise, the direction factor δ is -1. The evaluation parameter C IG The calculation is performed according to the following formula (1): C IG =δ*Cmin*Cmax(1) C IG When >0, the geological body is a positive topography, |C IG The larger the value, the more developed the tension cracks; C IG When <0, the geological body is a negative topography, |C IG The larger the value, the more developed the compression seam; C IG When C ≈ 0, the geological body deforms weakly, and shear fractures are the main feature; therefore: C IG >0 and |C IG The larger the value, the more advantageous the geological target.

2. The evaluation method for favorable geological targets in complex tectonic zones according to claim 1, characterized in that, The data in the constructed dataset in step 1 includes the hash number, x-axis, y-axis, and constructed elevation.

3. The evaluation method for favorable geological targets in complex tectonic zones according to claim 1, characterized in that, In step 1, the data in the constructed dataset is obtained using drilling geological stratification data in work areas with high well density, and using seismic interpretation and well seismic data in areas with low well density.

4. The evaluation method for favorable geological targets in complex tectonic zones according to claim 1, characterized in that, After the dataset is prepared in step 1, it is sorted to check for outliers in the horizontal and vertical coordinates. If there are outliers, the projection system is checked and converted to the same projection system.

5. The evaluation method for favorable geological targets in complex tectonic zones according to claim 1, characterized in that, Step 2 is implemented in the following steps: Step 2.1: Import the data prepared in Step 1 into the geological mapping software Geomap 4.0 to draw the structural contour map of the work area; Step 2.2: Check the drawn contour map; Step 2.3: Identify the structural features in the contour map.

6. The evaluation method for favorable geological targets in complex tectonic zones according to claim 5, characterized in that, If singularities are found during the inspection process in step 2.2, the geological stratification data or seismic interpretation data of the well points are checked and modified, and then the structural contour map is redrawn.

7. The evaluation method for favorable geological targets in complex tectonic zones according to claim 1, characterized in that, Step 5 is implemented in the following steps: Step 5.1, the evaluation parameter C from step 4... IG Import into Geomap 4.0 plotting software and draw C. IG Create a contour map and check if it matches the tectonic background. If not, modify it manually. Step 5.2, Analysis of favorable geological targets for exploration: CIG>0, the larger the |CIG|, the larger the distribution area, and the more likely it is to be a preferred exploration target.

Images