Effect of parent well production on wellbore breakout of child well in coalbed methane reservoirs

Gao Qi, Han Songcai, Shi Xian, Li Yang, Cheng Yuanfang, Yan Chuanliang

Research output: Chapter in Book/Conference paperConference paperpeer-review


The accurate estimation of parent well production induced in-situ stress change is of great significance for evaluating wellbore breakout of child wells. For conventional reservoirs, poromechanical effect is considered to be the main factor that controls in-situ stress evolution. However, for coalbed methane (CBM) reservoirs, gas desorption-induced coal shrinkage also contributes to the stress change, which is rarely included in the theoretical models. In this work, the in-situ stress evolution during coalbed depletion is first investigated through combining the effect of poromechanics and gas desorption. Then, the calculated stresses are incorporated into the geomechanical model to analyze the effect of gas desorption-induced coal shrinkage on wellbore breakout of child wells. The obtained results indicate that with pore pressure decreasing, both the maximum and minimum horizontal stresses decrease at a larger rate when gas desorption effect is considered. For vertical wellbore section of child wells, the larger Langmuir strain leads to the smaller breakout length and width, while for horizontal wellbore section of child wells, the larger Langmuir strain leads to the larger breakout length and smaller breakout width. The modeling results offer new insights for understanding the wellbore breakout of child wells in CBM reservoirs.

Original languageEnglish
Title of host publication56th U.S. Rock Mechanics/Geomechanics Symposium
PublisherAmerican Rock Mechanics Association (ARMA)
ISBN (Electronic)9780979497575
Publication statusPublished - 2022
Event56th U.S. Rock Mechanics/Geomechanics Symposium - Santa Fe, United States
Duration: 26 Jun 202229 Jun 2022

Publication series

Name56th U.S. Rock Mechanics/Geomechanics Symposium


Conference56th U.S. Rock Mechanics/Geomechanics Symposium
Country/TerritoryUnited States
CitySanta Fe

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