Integrated geophysical exploration in onshore frontier basins

Abstract

Faced with the challenge of rapidly screening a huge expanse of frontier exploration acreage, often characterized by sparse vintage data, it is our experience that a combination of appropriate air‐ and ground‐based geophysical techniques contributes positively to the exploration value chain. Airborne gravity gradiometry in conjunction with conventional gravity and magnetic data, as well as geological knowledge, add significant value to the screening process. This combination can subsequently assist in optimizing the location of the more time‐consuming and expensive seismic programme. In addition, analysis and inversion of passive seismic data have also proven useful in providing depth to basement estimates, and results derived from all the techniques investigated have been consistent within several study areas. Following initial tests, where the data were independently analysed and cross‐checked for consistency (including comparisons with active source seismic data and well data, when available), the company now routinely adopts the integration of these techniques in our frontier exploration acreage to support sedimentary basin delineation and mapping. This allows the optimal positioning and focussing of the higher spend and higher footprint programmes, such as active reflection seismic.

2D seismic design on frontier basins using potential field data, a case study in the south of the eastern arm of the East African Rift System

“…The potential field data and geological information have been used for the optimization of the exploration costs by delineating the sedimentary basins to reduce the area of exploration (de‐risking) for further exploration activities. The methodology showed good results in the analogue rift basins of Albertine and Omo within the EARS (Martini et al., 2019). The gravity and magnetic data, as it has been applied in the current study, were used to estimate the depth of the basement in these basins.…”