The objective of this work is to present an integrated methodology/workflow for optimizing lateral well spacing and fracture spacing for unconventional reservoirs based on multiple experience in Marcellus shale gas development. Optimal well plans and completion designs, based on geology and reservoir characterization, are key elements in developing economic projects. Well performance and reserves at a pad level can be improved thought coordinated efforts from multi-functional disciplines.
Workflow incorporates data integration and main analysis to be performed from all involved disciplines. Main disciplines are geology, reservoir and production engineering, drilling and completions teams, decision and economic evaluation and cost assurance process. A full set of reservoir modeling, economic analysis tools are described in the document. Workflow is optimized with a loop, where main routine and non-routine surveillance is used mainly for interference analysis and further optimization on both spacing for the factory-style development.
Reservoir simulation fed into two separate workflows. One is a single pad economic model and or DOE which incorporates decision analysis techniques. The other is a portfolio analysis with pads scheduled to fill a midstream capacity constraint through time. Both cases balance the increased capital costs against accelerated and increased production. The portfolio analysis tool is useful in understanding impacts of tighter well lateral and cluster spacing, particularly how they influenced capital costs over time. Additionally, results are compared with analog data and competitor analysis.
Methodology was field tested. Workflow application demonstrates that optimum lateral well spacing and cluster spacing in dry gas core area would have a positive impact on EUR (estimated ultimate recovery) at a pad level. Also, pad drilling and Completion optimizations provide increased NPV (net present value) and incremental DPI (discount profit investment) ratio.
The experience in lateral well and perf cluster spacing for shale dry gas for geometric completions is an example of how to manage uncertainty through cross-functional collaboration.
Workflow can be used as inputs in pilot test for well spacing and as a process to justify surveillance needs using value of information techniques.