Testing fault transmissibility predictions in a structurally dominated reservoir: Ringhorne field, Norway

Abstract

AbstractAt Ringhorne field, in the North Sea, judicious well placement and high quality 3D seismic data allow good control over stratigraphic and structural frameworks. In particular, two near-horizontal producing wells about 150 m apart on both sides of a critical normal fault are key for deciphering the fault effects on flow. These elements make this field ideal for using production data to constrain a range of process-based fault permeability predictions in a siliciclastic reservoir. A high resolution (50 m×50 m×1.8 m) faulted geological model, constructed in Petrel™, was used as input to process-based fault permeability predictions. Subsequent multiphase simulation and testing identified critical stratigraphic connections across shale layers and structural connections along a faulted relay around an isolated fault block. The simulations were used systematically as a probe to investigate both these and other controls on production and determine the likely range for permeability of fault zone materials, which are inferred to include deformed shales, sands, and minor cements. This study leverages the most pertinent observations and best constrained interpretations in the field to attempt to extract accurate, quantitative information on fault properties. A range of predicted fault permeability cases, linked to particular fault movement timing scenarios, were tested. The middle case, from a fault timing perspective, was determined to provide the best overall flow simulation match to all actual production information, providing valuable feedback for our process-based fault property prediction approach. Establishing the link between predicted and actual flow, and pressure history in response to critical reservoir plumbing elements, is paramount for evaluating and improving fault permeability predictions.