Structural trend predictor for 2D cross sections
Systems and methods include a computer-implemented method for identifying geological structural trends. A cross section with visible geological fault markers for geological structures is received. An angle of inclination of a fault is measured. An average seismic velocity to convert z-axis values from a two-way travel time to a depth is determined. A depth conversion is implemented. A horizontal scale and a vertical scale are compared to determine an aspect ratio of a depth section of the cross section, including determining a vertical exaggeration. The aspect ratio of the depth section is corrected for the vertical exaggeration to obtain an accurate measurement of fault inclination in the cross section. A structural style and an expected true fault inclination are determined for the depth section. An angle of obliquity and a structural trend are determined using the expected true fault inclination compared with the measured angle of inclination of the fault.
1 . A computer-implemented method, comprising:
receiving a cross section with visible geological fault markers for geological structures;
measuring, using the cross section, a fault inclination angle;
determining, using the cross section, an average seismic velocity to convert z-axis values from a two-way travel time to a depth, and implement a depth conversion;
comparing a horizontal scale and a vertical scale to determine an aspect ratio of a depth section of the cross section, comprising determining a vertical exaggeration;
correcting the aspect ratio of the depth section for the vertical exaggeration to obtain an accurate measurement of the fault inclination angle in the cross section;
determining, for the depth section, a structural style and an expected true fault inclination;
determining, using the expected true fault inclination compared with the angle of inclination of the fault, an angle of obliquity and a structural trend; and
adjusting drilling operations of a well, by modifying drilling parameters of a drill bit, relative to the angle of obliquity and the structural trend.
2 . The computer-implemented method of claim 1 , wherein the cross section is a two-dimensional (2D) reflection seismic line.
3 . The computer-implemented method of claim 1 , wherein the cross section is a potentiometric field profile or seismic refraction line.
4 . The computer-implemented method of claim 1 , wherein determining the average seismic velocity is based on knowledge of rock types and corresponding average seismic velocities.
5 . The computer-implemented method of claim 1 , wherein determining the vertical exaggeration is based on an equation tan δ″=VE tan δ′ where δ′ is the inclination of a line observed on a 1:1 aspect ratio section, VE is a vertical exaggeration, and δ″ is the fault inclination on the cross section that is vertically exaggerated.
6 . The computer-implemented method of claim 1 , wherein an angle of obliquity greater than zero and less than 90° includes two possible intersections with a given cross section.
7 . The computer-implemented method of claim 1 , wherein the angle of obliquity is positive or negative with respect to a cross section line.
8 . A non-transitory, computer-readable medium storing one or more instructions executable by a computer system to perform operations comprising:
receiving a cross section with visible geological fault markers for geological structures;
measuring, using the cross section, a fault inclination angle;
determining, using the cross section, an average seismic velocity to convert z-axis values from a two-way travel time to a depth, and implement a depth conversion;
comparing a horizontal scale and a vertical scale to determine an aspect ratio of a depth section of the cross section, comprising determining a vertical exaggeration;
correcting the aspect ratio of the depth section for the vertical exaggeration to obtain an accurate measurement of the fault inclination angle in the cross section;
determining, for the depth section, a structural style and an expected true fault inclination;
determining, using the expected true fault inclination compared with the angle of inclination of the fault, an angle of obliquity and a structural trend; and
adjusting drilling operations of a well, by modifying drilling parameters of a drill bit, relative to the angle of obliquity and the structural trend.
9 . The non-transitory, computer-readable medium of claim 8 , wherein the cross section is a two-dimensional (2D) reflection seismic line.
10 . The non-transitory, computer-readable medium of claim 8 , wherein the cross section is a potentiometric field profile or seismic refraction line.
11 . The non-transitory, computer-readable medium of claim 8 , wherein determining the average seismic velocity is based on knowledge of rock types and corresponding average seismic velocities.
12 . The non-transitory, computer-readable medium of claim 8 , wherein determining the vertical exaggeration is based on an equation tan δ″=VE tan δ′ where δ′ is the inclination of a line observed on a 1:1 aspect ratio section, VE is a vertical exaggeration, and δ″ is the fault inclination on the cross section that is vertically exaggerated.
13 . The non-transitory, computer-readable medium of claim 8 , wherein an angle of obliquity greater than zero and less than 90° includes two possible intersections with a given cross section.
14 . The non-transitory, computer-readable medium of claim 8 , wherein the angle of obliquity is positive or negative with respect to a cross section line.
15 . A computer-implemented system, comprising:
one or more processors; and
a non-transitory computer-readable storage medium coupled to the one or more processors and storing programming instructions for execution by the one or more processors, the programming instructions instructing the one or more processors to perform operations comprising:
receiving a cross section with visible geological fault markers for geological structures;
measuring, using the cross section, a fault inclination angle;
determining, using the cross section, an average seismic velocity to convert z-axis values from a two-way travel time to a depth, and implement a depth conversion;
comparing a horizontal scale and a vertical scale to determine an aspect ratio of a depth section of the cross section, comprising determining a vertical exaggeration;
correcting the aspect ratio of the depth section for the vertical exaggeration to obtain an accurate measurement of the fault inclination angle in the cross section;
determining, for the depth section, a structural style and an expected true fault inclination;
determining, using the expected true fault inclination compared with the angle of inclination of the fault, an angle of obliquity and a structural trend; and
adjusting drilling operations of a well, by modifying drilling parameters of a drill bit, relative to the angle of obliquity and the structural trend.
16 . The computer-implemented system of claim 15 , wherein the cross section is a two-dimensional (2D) reflection seismic line.
17 . The computer-implemented system of claim 15 , wherein the cross section is a potentiometric field profile or seismic refraction line.
18 . The computer-implemented system of claim 15 , wherein determining the average seismic velocity is based on knowledge of rock types and corresponding average seismic velocities.
19 . The computer-implemented system of claim 15 , wherein determining the vertical exaggeration is based on an equation tam δ″=VE tan δ′ where δ′ is the inclination of a line observed on a 1:1 aspect ratio section, VE is a vertical exaggeration, and δ″ is the fault inclination on the cross section that is vertically exaggerated.
20 . The computer-implemented system of claim 15 , wherein an angle of obliquity greater than zero and less than 90° includes two possible intersections with a given cross section.