Impact of Well Orientation on Well Productivity

Abstract

Abstract Hydraulic fractures tend to propagate in a plane that is perpendicular to the least principal stress. As a result, unconventional oil and gas wells are typically drilled in the direction of minimum horizontal stress (Shmin) to maximize drainage area. However, in some regions, due to acreage constraints, wells are drilled to maximize the number of wells instead of the ideal orientation with respect to subsurface stresses. We studied the impact of changing well orientation on well productivity in the Bakken Play by simulating a wide range of operational scenarios including proppant loading, well spacing, cluster spacing, and depletion. Our simulation results were compared to historical Bakken well performance data filtered based on the same well orientations and completion designs. The simulation results show that drilling wells parallel to Shmin maximizes well productivity, consistent with the reported actual data. However, the degree of production uplift in actual data cannot be fully attributed to well orientation. We demonstrate that job size, depletion, cluster spacing, and well spacing all affect the impact of well orientation on performance. It is challenging to rigorously quantify the effect of well orientation versus completion design on well productivity in historical data. Simulation studies help to determine the impact of each parameter, helping operators optimize their development strategy. Simulation sensitivity analyses show that depletion, wider cluster spacing, and wider well spacing can lessen the effect of well orientation on well productivity.