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.

Modeling Interwell Fracture Interference and Huff-N-Puff Pressure Containment in Eagle Ford Using EDFM

“…This interwell communication can be portrayed as "pressure sinks" that interfere with induced fracture effectiveness, and might affect unconventional EOR methods efficacy if they are overridden or not accounted for. For instance, numerous documented studies have demonstrated fracture interference occurrence and assessed this phenomenon in unconventional reservoirs (Ambrose et al, 2011;Manchanda et al, 2013;Portis et al, 2013;Sardinha et al, 2014;Sani et al, 2015;Awada et al, 2016;Morales et al, 2016;Klenner et al, 2018;Seth et al, 2018;Yu and Sepehrnoori, 2018). The current interest is focused on warding off negative impacts caused by fracture hits interwell propagation and affecting further productive wells.…”

“…During the fracture treatment, fracture hits can be observed and monitored in offset wells. On the other hand, during production a fracture hit is identified when the pressure gradually decreases and drops to less than the closure pressure, closing any unpropped communication channels (Awada et al, 2016). The fracture hits characterization can provide an insight of the strength of the interaction among different wells.…”

“…Extensive studies have been conducted to demonstrate interwell communication. Awada et al (2016) concluded that the fracture hits and fracture fluid production that suddenly appear at offset producing wells are indications of communication, but they do not necessarily imply that a strong connection will be preserved throughout the life of the wells. Sardinha et al (2014) showed that the majority of pressure hits were found between adjacent or near-adjacent wells, so that each well delivered a high hit percentage to at least one other well in their neighboring pad, and often exhibited a strong connection with several wells even through different formations.…”

“…Next, analytical simulations should be performed to reveal the expected behavior for interference through fractures and reservoir matrix. Next, buildup trends changes could be foreseen, so that finally, the data could be history matched with numerical models to confirm the interference mechanism (Awada et al, 2016). Figure 2.9: Workflow to identify interwell interference (Awada et al, 2016).…”

Application of Machine Learning on Fracture Interference

“…In 2015 a procedure was created to identify and quantify interference from pressure response observations with a shut in well and changing rates with neighboring wells in a multi-well pad (Awada et al 2016). Interference was determined and classified through use of buildup tests, rate and pressure vs time plots, interference diagnostics, interference time, and history matching through the use of models (Esquivel et al 2017).…”