Optimizing Well Placement Planning in the Presence of Subsurface Uncertainty and Operational Risk Tolerance

This paper presents an automated workflow to accelerate the well placement planning process in the presence of subsurface uncertainty and operational risk. The system allows the user to screen and rank development options in minutes. This automated field development planning system is an optimization application, integrated with a larger seismic-to-simulation workflow. A key piece of technology in this system is a high-speed semi-analytical reservoir simulator, which enables an optimal strategy to be computed very rapidly. The system also embeds key technologies for optimization in the presence of uncertainty and risk which leverages an advanced uncertainty framework. The workflow starts with a reservoir model, along with existing wells and other operational constraints. Oil or gas production is computed using the high-speed reservoir simulator. Proposed well trajectories honor operational constraints, such as facility processing, water injection capacity, borehole dogleg severity, anti-collision with existing wells, and hazard avoidance on the surface and in the reservoir. The optimal strategy proposes well surface locations, trajectories, and completion locations and is calculated by optimizing the value e.g., net present value (NPV) or production. This new methodology has many applications in the field development planning context. We are able to rapidly screen multiple field development planning scenarios and produce an optimal new/infill drilling strategy with primary production or waterflooding consisting of both newly proposed and existing wells. The final result includes performance predictions based on an optimized field development plan (FDP), risk, and subsurface uncertainties. The most promising scenarios can if necessary be used subsequently for detailed numerical simulation in order to validate results.