Variation of natural fracture orientations in the Carnarvon Basin's Rankin Platform and Dampier Sub-Basin, NWS, Western Australia

Abstract

Natural fractures in the Carnarvon Basin's Rankin Platform and Dampier Sub-Basin are identified using electrical resistivity image logs from 10 petroleum wells. In-situ stresses are diagnosed for the area using data from these and four additional wells, with these results indicating it likely that this study area hosts a relatively isotropic in-situ stress field. Identified fractures occur at all orientations, and demonstrate no dominant trend. They do not reflect the in-situ stresses, nor the dominant north-northeast to northeast fault strikes. Rather, they most closely reflect the orientation of more local structures which the wells are adjacent to, demonstrating that natural fracture populations may be more dependent on local structure than dominant regional trends.