US 11,940,589 B2
Analyzing borehole paths using stratigraphic turning points
Alice Butt, Abingdon (GB); Mykhailo Ponomarev, Houston, TX (US); and Einar Mageroy, Stavanger (NO)
Assigned to Landmark Graphics Corporation, Inc., Houston, TX (US)
Filed by Landmark Graphics Corporation, Houston, TX (US)
Filed on Jun. 29, 2022, as Appl. No. 17/852,982.
Prior Publication US 2024/0004101 A1, Jan. 4, 2024
Int. Cl. G01V 3/38 (2006.01); E21B 47/02 (2006.01); E21B 47/022 (2012.01); G01V 1/40 (2006.01)
CPC G01V 3/38 (2013.01) [E21B 47/022 (2013.01); G01V 1/40 (2013.01)] 23 Claims
OG exemplary drawing
 
1. A method, comprising:
receiving a set of directional survey points and input parameters, wherein the set of directional survey points is collected from a borehole along a borehole path, and the input parameters include stratigraphic data on one or more layers of a subterranean formation where the borehole path is through the subterranean formation;
calculating a set of intersection points of the borehole path and the one or more layers of the subterranean formation;
determining a layer type of each layer in the one or more layers of the subterranean formation, wherein at least one layer in the one or more layers has a layer type that is unconformable;
calculating a true stratigraphic thickness (TST), using the layer type, between a selected layer of the one or more layers and the borehole path, wherein one or more of the TST is calculated at each directional survey point in the set of directional survey points forming a set of TST;
computing a TST difference between adjacent TSTs in the set of TST forming a set of TST differences, wherein the adjacent TSTs are determined using a location for each of the TST along the borehole path, where the location is determined using the set of directional survey points;
generating a set of turning points in stratigraphy (TPS) using the set of TST differences where a linear transformation from a measured depth to each TST difference in the set of TST differences is used to calculate the set of TPS; and
adjusting an angle or a direction of a geo-steering system, using the set of TPS, to adjust an orientation of the borehole path relative to the set of TPS.