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US 2003/0158669 A1Published application
Method for detecting direction and relative magnitude of maximum horizontal stress in earth's crust
AssigneePetrecon Australia Pty Ltd
InventorJohn Kenneth Davidson
Life of this patent
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Abstract
This invention relates to a method for determining direction and relative magnitude of maximum horizontal stress in sedimentary basins within Earth's crust. In particular the method uses seismic reflection data in determining the direction and magnitude of stresses. The method involves identifying from seismic data faults which cut the upper continental crust and uses those faults in conjunction with globally simultaneous compressional structures such as anticline to map the horizontal stresses. The invention has a particular application in the hydrocarbon exploration and production industry and has the advantage of providing the results pre-drill.
Claims83
A method of determining the direction of the maximum horizontal stress (SH) at a horizon within a prospect including the following steps:
- a) obtaining a plurality of seismic reflection lines within the prospect;
- b) selecting at least two seismic reflection lines which cross the prospect substantially in the direction of maximum dip;
- c) selecting at least one further seismic line which lies along a longitudinal axis of the prospect;
- d) identifying on the selected seismic lines at least one substantially vertical crust cutting fault;
- e) identifying on the selected seismic lines a plurality of horizons;
- f) determining and assigning the plurality of horizons with geological ages;
- g) identifying on the selected seismic lines at least one horizon produced during a compressional pulse period;
- h) selecting at least one horizon from step g which is cut by at least one of the identified crust cutting faults,
- i) mapping in plan the crust cutting fault at the horizon selected in step h,
- j) identifying at least one anticline within the horizon identified in step i,
- k) mapping in plan the anticline at the horizon identified in step j,
- l) selecting at least one mapped anticline which in plan view extends substantially parallel to the adjacent crust cutting faults mapped in step i;
- wherein SH is substantially perpendicular to the selected anticlines in that horizon.
10 more elements
A method of determining the direction of the maximum horizontal stress (SH) at a horizon within a prospect including the following steps:
- a) obtaining a plurality of seismic reflection lines within the prospect;
- b) selecting at least two seismic reflection lines which cross the prospect substantially in the direction of maximum dip;
- c) selecting at least one further seismic line which lies along a longitudinal axis of the prospect;
- d) identifying on the selected seismic lines at least one substantially vertical crust cutting fault;
- e) identifying on the selected seismic lines a plurality of horizons;
- f) determining and assigning the plurality of horizons with geological ages;
- g) identifying on the selected seismic lines at least one horizon produced during a compressional pulse period;
- h) selecting at least one horizon from step g which is cut by at least one of the identified crust cutting faults,
- i) mapping in plan the crust cutting fault at the horizon selected in step h,
- j) identifying at least one syncline within the horizon identified in step i,
- k) mapping in plan the syncline at the horizon identified in step j,
- l) selecting at least one mapped syncline which in plan view extends substantially parallel to the adjacent crust cutting faults mapped in step i;
- wherein SH is substantially perpendicular to the selected syncline in that horizon.
10 more elements
A method of determining the direction of the maximum horizontal stress (SH) at a horizon within a prospect including the following steps:
- a) obtaining a plurality of seismic reflection lines within the prospect;
- b) selecting at least two seismic reflection lines which cross the prospect substantially in the direction of maximum dip;
- c) selecting at least one further seismic line which lies along a longitudinal axis of the prospect;
- d) identifying on the selected seismic lines at least one substantially vertical crust cutting fault;
- e) identifying on the selected seismic lines a plurality of horizons;
- f) determining and assigning the plurality of horizons with geological ages;
- g) identifying on the selected seismic lines at least one horizon produced during a compressional pulse period;
- h) selecting at least one horizon from step g which is cut by at least one of the identified crust cutting faults,
- i) mapping in plan the crust cutting fault at the horizon selected in step h,
- j) identifying at least one reverse fault within the horizon identified in step i,
- k) mapping in plan the reverse fault at the horizon identified in step j,
- l) selecting at least one mapped reverse fault which in plan view extends substantially parallel to the adjacent crust cutting faults mapped in step i;
- wherein SH is substantially perpendicular to the selected reverse fault in that horizon.
10 more elements
A method of determining the direction of the maximum horizontal stress (SH) at a horizon within a prospect including the following steps:
- a) obtaining a plurality of seismic reflection lines within the prospect;
- b) selecting at least two seismic reflection lines which cross the prospect substantially in the direction of maximum dip;
- c) selecting at least one further seismic line which lies along a longitudinal axis of the prospect;
- d) identifying on the selected seismic lines at least one substantially vertical crust cutting fault;
- e) identifying on the selected seismic lines a plurality of horizons;
- f) determining and assigning the plurality of horizons with geological ages;
- g) identifying on the selected seismic lines at least one horizon produced during a compressional pulse period;
- h) selecting at least one horizon from step g which is cut by at least one of the identified crust cutting faults,
- i) mapping in plan the crust cutting fault at the horizon selected in step h,
- j) identifying at least one non crust cutting normal fault within the horizon identified in step i,
- k) mapping in plan the non crust cutting normal fault at the horizon identified in step j,
- l) selecting at least one mapped non crust cutting normal fault which in plan view extends substantially perpendicular to the adjacent crust cutting faults mapped in step i;
- wherein SH is substantially parallel to the selected non crust cutting normal faults in that horizon.
10 more elements
61 A method according to claim 49 wherein the determining and assigning step f includes obtaining survey wellbore data and conducting palaeontological analysis of that data to assign ages to the horizons.
A method of determining the direction of the maximum horizontal stress (SH) at a horizon within a prospect including the following steps:
- a) obtaining a plurality of seismic reflection lines within the prospect;
- b) selecting at least two seismic reflection lines which cross the prospect substantially in the direction of maximum dip;
- c) selecting at least one further seismic line which lies along a longitudinal axis of the prospect;
- d) identifying on the selected seismic lines at least one substantially vertical crust cutting fault;
- e) identifying on the selected seismic lines a plurality of horizons;
- f) determining and assigning the plurality of horizons with geological ages;
- g) identifying on the selected seismic lines at least one horizon produced during a compressional pulse period;
- h) selecting at least one horizon from step g which is cut by at least one of the identified crust cutting faults,
- i) mapping in plan the crust cutting fault at the horizon selected in step h,
- j) identifying at least one non crust cutting strike slip fault with a right or dextral sense of offset and a second non crust cutting strike slip fault with a left or sinistral sense of offset within the horizon step s
- k) mapping in plan the non crust cutting strike slip faults at the horizon identified in step j,
- l) selecting those mapped non crust cutting strike slip faults which in plan view extend substantially perpendicularly to the adjacent crust cutting faults mapped in step l,
- wherein SH is substantially parallel with the opposing approaching sectors formed by the selected dextral and sinistral non crust cutting strike slip faults in that horizon.
10 more elements
A method of determining the magnitude of the maximum horizontal stress (SH) relative to the maximum vertical stress (SV) at a horizon within a prospect including the following steps:
- a) obtaining a plurality of seismic reflection lines within the prospect;
- b) selecting at least two seismic reflection lines which cross the prospect substantially in the direction of maximum dip;
- c) selecting at least one further seismic line which lies along a longitudinal axis of the prospect;
- d) identifying on the selected seismic lines at least one substantially vertical crust cutting fault;
- e) identifying on the selected seismic lines a plurality of horizons;
- f) determining and assigning the plurality of horizons with geological ages;
- g) identifying on the selected seismic lines at least one horizon produced during a compressional pulse period;
- h) selecting at least one horizon from step g which is cut by at least one of the identified crust cutting faults,
- i) mapping in plan the crust cutting fault at the horizon selected in step h,
- j) identifying on the seismic line at the selected horizon produced during a compressional pulse period anticlines and non crust cutting reverse faults being structures extending parallel with crust cutting faults in the horizon,
- k) mapping in plan the identified anticlines and non crust cutting reverse faults for the selected horizon,
- l) identifying areas in the selected horizon where the anticlines are traversed vertically by non crust cutting reverse faults,
- m) identifying areas in the selected horizon where the anticlines are not traversed by any faults, wherein the magnitude of SH relative to SV is greater within those areas traversed by reverse faults.
10 more elements
Dependencies are inferred from the claim text.