Technical Presentations

It is well known that the coherence attribute computed from seismic data is a powerful tool for imaging discontinuities, including faults and fractures. Despite this, analysis of coherence data is rarely integrated in interpretation workflows. Interpreters continue to pick faults on reflectivity data and, at best, use coherence data to verify their work.

This paper presents a new approach to fault and fracture interpretation, FaultMagic®, which is based on the analysis of coherence and the integration of borehole data. It allows the interpreter to produce detailed and highly accurate fault and fracture maps using a data-driven approach. Interpreter bias is removed, and the speed and efficiency of mapping greatly increased.

A case study of the Magnus Field is presented in which this technique is used. The Magnus Field is in an advanced state of development with the lower reservoir, the Lower Kimmeridge Clay Formation (LKCF), being actively exploited. This low net:gross reservoir has a complexly distributed net sand volume that puts a premium on well locations and, in particular, producer-injector communication. Whilst the depositional model has contributed to the understanding of sandbody distribution, orientation and connectivity, it is essentially well based and cannot therefore address all the requirements of development well planning. This is particularly true as non-sedimentological factors almost certainly contribute to the reservoir’s overall communication and its compartmentalisation. The LKCF in the Magnus Field therefore presented an ideal test for the FaultMagic® approach, whereby the entire inter-well volume could examined and the resulting fault information integrated with the well data, core sedimentology, UBI and core derived fracture information and RFT data.

Ashbridge, J, Pryce, C, Coutel, F, Welch, M and Ashton, M. (2000) Fault and fracture prediction from coherence data analysis, a case study - The Magnus Field, UKCS. Paper presented at the EAGE 62nd Conference and Technical Exhibition, Glasgow, Scotland 29th May - 2nd June, 2000