Understanding the Structural Evolution of Structurally Complex Areas Through Integration of Data

Abstract

Exploration studies are often challenging due to large data gaps leading to large subsurface uncertainty ranges. A robust conceptual model informed by in-field analogues and regional data, can help mitigate the data shortage. Building the conceptual model requires strong cross-disciplinary integration. To successfully evaluate discovered and undiscovered hydrocarbon volumes in the Field A’s block – a growth fault sliver in South Asia offshore, required construction of a robust conceptual model and use of an integrated decision-based approach to address poor quality/sparse data and significant complexity. The decision focus in the ‘Identify’ phase helped to manage and define the workscope. Key risks were identified and managed through a quality framing, detailed work planning and a fit for purpose, multi-disciplinary modelling strategy in line with IRM principles. This approach helped the study team to: detect the impact of poorly imaged faults impacting volumetrics, interpret into areas with poor seismic character, correlate sands where log responses were inconclusive, and define a set of deterministic subsurface realisations that cover the uncertainty range. An example is supplementing seismic interpretation with dipmeter analysis to constrain fault position uncertainty, a key parameter of GRV.

The use of Shell sandbox models supplemented the seismic interpretation of the complex structures and assisted in conceptual modelling. Quality of interpretation was further improved by involving Shell Global PTEs and SMEs and integrating seismic, regional HC migration concepts, depositional models, welllogs, dipmeter, pressure and PVT data.

This holistic approach in the very front-end for a field’s development should reduce the risk of significant conceptual iteration later in the Hydrocarbon Development Process (HDP). As an outcome of the project, Shell has decided to further study the undiscovered potential of the Sliver block.

AAPG Datapages/Search and Discovery Article #90323 ©2018 AAPG Annual Convention and Exhibition, Salt Lake City, Utah, May 20-23, 2018