Shallow hazards associated with dissolution karsting within the Castile formation of the Delaware basin of west Texas represent a significant drilling hazard. One operator encountered four karst related cavities within the first four hundred feet of section from two separate pad sites. The intersection of these dissolution cavities resulted in the loss of significant amounts of drilling fluids and concrete, resulting in the abandonment of the boreholes. Approximately 1100 line-km of Airborne Full Tensor Gradiometry (FTG) data are acquired at a nominal line spacing of 100 m and drape elevation at 80 m above the ground surface in order to rapidly identify and assess further risks to drilling in the adjacent lease acreage. 2.75D and 3D models are constructed to determine detectability and identify relevant wavelength and amplitudes based upon information collected from the karst cavities. Focused enhancements of the acquired data reveal correlation to the drilled cavities, but the wavelengths are too broad to assess drilling risks. Curvature analysis of the FTG data reveal a striking correlation to cavern analysis performed in outcropping areas of the Castile formation. Riskiest and safest drilling sites are identified by means of analyzing the curvature information.
Presentation Date: Tuesday, October 16, 2018
Start Time: 8:30:00 AM
Location: 207A (Anaheim Convention Center)
Presentation Type: Oral