Can a Cube Model Mitigate Parent-Child Effects and Improve Oil Recovery inthe Permian Basin

摘要

As the shale development activity in the Permian continues to be strong and oil prices recover, increasingnumbers of infill child wells are being drilled as operators want to improve recovery from each sectionand continue to meet their production targets. However, production data suggests that both parent and childwells suffer from production losses if they are located too close to one another. The cube model concept, which is also referred to as supersize fracturing, was first introduced about twoyears ago and has been piloted in the Permian Basin. In a cube model, multiple wells, usually more than30 horizontal wells with five to six wells in each different horizontal layer, are drilled and completed inthe same section. Operators produce those wells simultaneously with the objective of mitigating the parent-child effect of unconventional reservoirs. Nevertheless, with all wells producing at the same time and competing for production from the first day,will this benefit ultimate recovery? This question was investigated through comprehensive fracture andreservoir modeling and simulation. A reservoir dataset for the Spraberry Formation in the Permian Basinwas used to build a hydraulic fracture and reservoir simulation model. Different field development strategies were studied. Models representing a traditional parent-childscenario with five parent wells completed and produced one year before four infill child wells and atraditional parent-child scenario with five parent wells completed and produced five years before fourinfill child wells are compared. In these cases, a geomechanical finite-element model (FEM) was used toquantify the changes to the magnitude and azimuth of the in situ stresses from the various reservoir depletionscenarios. Next, a cube model with nine horizontal wells completed and produced simultaneously wasanalyzed. These three scenarios were expanded to include 19 horizontal wells with the same methodology. This study aims to help operators in the Permian Basin, as well as in other unconventional reservoirs tounderstand how different field development strategies affect ultimate hydrocarbon recovery and net presentvalue.