Benefits of Assessing the Solids Production Risk in a North Sea Reservoir using Elastoplastic Modelling

Abstract A reliable, non-conservative assessment of the risk of solids production is essential in order to identify the optimal completion strategy. A technique for such an assessment is developed in this paper through a geomechanical study of the Everest Complex of the North Sea, involving wells 22/10a-T2 and 22/10a-T6. This process is based on calibrating depth indexed measurements at discrete points using core data. The core samples were selected to be representative of the complete range of porosities and various clay volumes throughout the reservoir. The first step is the construction of the reservoir mechanical model by combining geophyscial well logs, the results of laboratory tests on core samples, and other field data, particularly drilling histories. In the second step, critical calibrated using predictions determined at single points using an elastoplastic theory (Bradford and Cook 1) which incorporates the influences of plastic hardening and delation. Results calculated using a new elastic-perfectly plastic model, which is derived in this paper, are also included. This model is suitable for use with log data. Results have been verified by simulating production through a perforation with thick wall cylinder tests on whole core form 22/10a-T2 (Nicholson et al.10). The results of the modelling provide formation failure data to build a map of the sanding potential in the Everest reservoirs. P. 261