Is That Interference? A Work Flow for Identifying and Analyzing Communication Through Hydraulic Fractures in a Multiwell Pad

Abstract

Summary The topic of interwell communication in unconventional reservoirs has received significant attention because it has direct implications for well-spacing considerations. However, it has been the observation of the authors that interference is often inferred without direct evidence of its occurrence, or without an understanding of the various mechanisms of interference. Some common discussions on interference among engineers refer to fracture “hits” and fracture-fluid production that suddenly appears at offset producing wells. These are indications of communication, but do not necessarily imply that a strong connection will be maintained throughout the life of the wells. This paper presents a rigorous procedure for correctly identifying interference by use of data acquired during a typical multiwell-pad-production scheme. First, the various mechanisms of interference are defined. Next, analytical simulations are run to reveal the expected behavior for interference through fractures and reservoir matrix. Data provided from an eight-well pad in the Horn River basin are then scoured, revealing evidence of interference between at least two wells. Through this exercise, a procedure is developed for identifying interference by searching for changes in buildup trends while wells are staggered on/off production. Finally, the data are history matched with numerical models to confirm the interference mechanism. The procedure in this paper is designed to help production analysts diagnose interference and avoid common pitfalls. The work flow is generalized and can be applied to other multiwell-pad completions.