Sandeep Kumar Chandola

A Practical Example Why Anisotropy Matters - A CSEM Case Study From South East Asia

Summary A 3D CSEM survey was acquired in a frontier deepwater area in SE-Asia to provide input for portfolio ranking and risk mitigation. The interpretation process of the 3D data set was heavily driven by 3D inversion. Various 3D inversion approaches were tested and the results demonstrated the importance of including anisotropy. Interpretations based on the isotropic 3D inversion differ from the interpretation of the anisotropic result, the latter coinciding with the pre-survey geomodel. The final interpretation of the CSEM data suggested significant hydrocarbon charge to be restricted to only one-third of the original prospect area, off the crest of the structure, reducing the potential of the prospect significantly.

An Innovative Approach to 3D Survey Design to Meet Exploration and Development Objectives - An OBC Case History from Offshore Malaysia

PETRONAS conducted a 3D-2C Ocean Bottom Cable (OBC) survey in the year 2012 offshore Malaysia, to appraise a recent hydrocarbon discovery and assist the field development plan and production enhancement initiatives. The legacy 3D towed streamer data acquired in 1984 suffered from poor imaging of the faults and significant navigation errors.

Introduction to special section: Interpretation and integration of CSEM data

Marine controlled-source electromagnetic (CSEM) and magnetotelluric (MT) data can be interpreted to provide estimates of resistivity distribution in the subsurface. However, such measurements are complementary to those obtained from more conventional seismic methods, and are thus most powerful when

Evaluating low frequency passive seismic data against an exploration well program

Summary A low frequency passive seismic (LFPS) survey was acquired over a producing field and a series of leads and prospects in south-Asia. Efficient field operations and close coordination among all involved parties provided a good quality dataset with minimal environmental impact and HSE exposure in only 9 days of recording. Despite the presence of high levels of noise from exploitation activities during the survey and interference from a strong near surface effect, detailed analysis and careful processing of the dataset returned results that are reliable and consistent. The LFPS results show a good correlation to current well results, with both productive and dry areas correctly identified. Although primarily a pilot, the survey design also extended over undrilled prospects. The quality of the results over the known areas extends the usefulness of the survey as supplemental information to add to the total body of geophysical and geological knowledge for ranking further exploration and appraisal prospects in the area.