With the better understandings of well performance mechanisms from unconventional reservoirs and maturing technologies in drilling and completion, the industry has started realizing there could be significant potential value in those reservoirs. Improper development may leave significant resources unrecovered and significant value unrealized. The full field development concepts such as “tank” or “cube” developments are being implemented in the Permian Basin to maximize the asset value from developing those reservoirs. The paper first summarizes our analysis results of three full field developments implemented by three operators in the Northern Midland, and the paper presents optimal full field development plans (FDPs) in the Southern Midland Basin with our systematical workflow.

After we systematically review the main drivers of completion designs on the well performance and recovery efficiency, we then focus on a case history study we performed to compare the field development plans implemented by three operators in the same geologically similar area, including the well spacing and placement patterns, well completion designs, completion efficiency analysis, and corresponding well performance. We also performed long-term production forecast and economic analysis for those three field developments. Inspired by the outcome of the case history study, we then developed a systematic way (workflow) to optimize FDPs for any given unconventional reservoir.

The paper will illustrate the application of our workflow into the Wolfcamp formation in the Southern Midland Basin. We first build the numerical reservoir performance models based upon geological and reservoir properties, and calibrated those models with completion and well production history; We then assembled 155 different FDPs by combining different vertical and lateral well spacings and multiple completion designs; Next, we used those calibrated models to study the resource recovery and economics from those FDPs. Finally, we performed a sensitivity analysis of well cost structure and completion efficiency on the asset development values of those FDPs, from which an optimal FDP was proposed.

Based upon those two case studies, we observed that there is a sweet spot for well spacing and corresponding well completion design to maximize development value for a given reservoir. The study results also demonstrate that sub-optimal completion designs and well spacings could leave significant resource and values behind. Our study indicates that the drilling and completion cost structure and operation efficiency are very critical to realize potential value. Those two case studies show that the operator economic key driver, (such as Rate of Return Vs Net Present Value), will drive very different full field development decisions.

We are utilizing our workflow to study the optimal full field plan in the Delaware Basin. The workflow can be easily applied to optimize full field development plans to maximize the asset value for any unconventional reservoir, which may also minimize the number of pilot tests and parent-child well situations.

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