Method Integrates Pressure-Transient and Fracture Area To Detect Well Interference

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of URTeC paper 208395, “Integration of Pressure-Transient and Fracture Area for Detecting Unconventional-Well Interference,” by Mazher Ibrahim, SPE, Matt Sinkey, SPE, and Thomas Johnston, SPE, Shear Frac Group, et al. The paper has not been peer reviewed. Hydraulic fractures created during completions are assumed to produce back to the original well. While multiwell-pad completions increase efficiencies, they complicate fracture connectivity between wells. The proximity of newly completed wells to a pre-existing producing well suggests a depleted zone that can “steal” fracture surface area. The complete paper presents a real-time method to estimate the stage-to-stage interference and well-to-well interference and their implications on completions efficiency. Introduction The primary challenge for the industry with regard to unconventional resource development is to optimize well spacing to improve well net present value. Shale heterogeneity and completion design influence fracture orientation and geometry. The industry still lacks accurate methods in characterizing these. Fig. 1 shows three well-spacing types that the authors write could be classified as “good,” “bad,” or “ugly”—the A+ spacing type (good), the B spacing type (bad), and the C spacing type (ugly). The A+ spacing type has no interference between wells that perfectly drain the reservoir; however, it is hard to achieve. In the B spacing type, there may be 10–15% interference between either hydraulic or natural fracture systems. B spacing can be achieved with proper integration of reservoir and completion engineering. This spacing type usually can provide more predictable well-level estimated ultimate recovery (EUR). C spacing type is characterized by closer-than-needed spacing, resulting in shared stimulated reservoir volume (SRV) between wells. Some operators use this spacing when oil and gas prices are high in order to accelerate production.