As the cost of exploration wells continue to escalate, we need more than ever to evaluate each well quickly and efficiently to improve the appraisal process and avoid unnecessary expenditure. At the same time, an accurate reservoir characterization is the key to successful reservoir development. This is especially true in thinly laminated reservoirs which exhibit vertical heterogeneity and a wide range of flow properties. Therefore, it is critical to combine high resolution formation evaluation logs and formation tests to predict the well performance prior to the production test.
We present an integrated and structured approach for calculating the productivity of a laminated clastic reservoir and we illustrate the method with a field example from Malaysia. A single well predictive model incorporates logs, rock and PVT data, and formation tests to build a flow simulation model at the resolution of the petrophysical analysis. By calibrating the high resolution flow model with dynamic test data from a formation tester Interval Pressure Transient Test (IPTT), the model can be used to predict the well performance. We investigate several key characteristics of thinly laminated reservoirs that affect the well productivity, such as vertical communication between layers. In particular, we examine the effects of clay, silt and sand laminations geometry on the reservoirs productivity. For that purpose, we comment on the information from borehole electrical images, NMR logs, single probe and dual packer wireline formation testers, and production well tests.
The workflow is fast to implement as it can be accomplished quickly and efficiently after the well is drilled, in time for planning the well completion and production tests. The high resolution simulation model permits to conduct further engineering studies, whenever required, such as designing the injection and production test for multi-layer reservoirs and water or gas coning studies.