In situ stresses in the southern Bonaparte Basin, in Australia: Implications for First- and Second-Order Controls on Stress Orientation

Abstract

<jats:p>Four‐arm dipmeter logs from six wells and a Formation MicroScanner (FMS) image log from one well in the southern Bonaparte Basin were interpreted for <jats:italic>in situ</jats:italic> stress indicators. Results of the analysis reveal a consistent NE‐SW <jats:italic>in situ</jats:italic> maximum horizontal stress (σ<jats:sub>Hmax</jats:sub>) orientation (055°N). This orientation is parallel to the average σ<jats:sub>Hmax</jats:sub> determined in the northern Bonaparte Basin, the onshore Canning Basin, and in New Guinea. The data support the interpretation that the NE‐SW σ<jats:sub>Hmax</jats:sub> orientation in the area reflects a first‐order stress pattern controlled by plate boundary forces along the northeastern margin of the Indo‐Australian Plate (IAP) and contradict the suggestion that NE‐SW σ<jats:sub>Hmax</jats:sub> in the northern Bonaparte Basin is a second‐order effect associated with boundary induced flexural stresses. Numerical modeling suggests that the divergence of σ<jats:sub>Hmax</jats:sub> from an orientation parallel to plate motion can be explained by the heterogeneous nature of the northeastern boundary of the IAP.</jats:p>