This paper addresses the problem of how the static geologic description of a complex, low net/gross reservoir can be combined with dynamic production data into full-field reservoir simulation for use in development planning. The discussion focuses on an integrated petroleum engineering study of the LKCF of the Magnus field in the U.K. sector of the North Sea.
Past development of the Magnus field has focused on the prolific, high net/gross Magnus sandstone member (MSM) reservoir with less attention given to the geologically complex, low net/gross Lower Kimmeridge clay formation (LKCF). We viewed the LKCF as too complex to risk major capital expenditure; however, recent well results indicate that the LKCF could produce at far higher rates than had previously been estimated. An integrated reservoir study was initiated to review possible development opportunities and formulate a revised development plan for the LKCF. The study involved detailed reservoir description incorporating sedimentology, petrophysics, interference testing, and reservoir modeling. Stochastic modeling techniques were integrated into a classic (deterministic) reservoir model.
The study highlighted several options through which LKCF recovery efficiency could be improved significantly. Each option was screened for inherent uncertainty and risks. The resultant preferred development calls for a phased water-injection scheme. Water injection is required for incremental recovery. Phasing allows management of the considerable geological risks. This scheme would yield 60 MMSTB of incremental reserves (i.e., total LKCF reserves nearly 2.4 times the current estimate held).