Crushing and embedment of proppant packs under cyclic loading: An insight to enhanced unconventional oil/gas recovery  

作　　者：K.M.A.S.Bandara P.G.Ranjith T.D.Rathnaweera W.A.M.Wanniarachchi S.Q.Yang 

机构地区：[1]Department of Civil Engineering,Monash University,Building 60,Melbourne,Victoria,3800,Australia [2]State Key Laboratory for Geomechanics and Deep Underground Engineering,School of Mechanics and Civil Engineering,China University of Mining and Technology,Xuzhou 221116,China

出　　处：《Geoscience Frontiers》2021年第6期376-393,共18页地学前缘（英文版）

摘　　要：Crushing and embedment are two critical downhole proppant degradation mechanisms that lead to a significant drop in production outputs in unconventional oil/gas stimulation projects. These persistent production drops due to the non-linear responses of proppants under reservoir conditions put the future utilization of such advanced stimulation techniques in unconventional energy extraction in doubt. The aim of this study is to address these issues by conducting a comprehensive experimental approach. According to the results, whatever the type of proppant, all proppant packs tend to undergo significant plastic deformation under the first loading cycle.Moreover, the utilization of ceramic proppants(which retain proppant pack porosity up to 75%), larger proppant sizes(which retain proppant pack porosity up to 15.2%) and higher proppant concentrations(which retain proppant pack porosity up to 29.5%) in the fracturing stimulations with higher in-situ stresses are recommended to de-escalate the critical consequences of crushing associated issues. Similarly, the selection of resin-coated proppants over ceramic and sand proppants may benefit in terms of obtaining reduced proppant embedment.In addition, selection of smaller proppant sizes and higher proppant concentrations are suggested for stimulation projects at depth with sedimentary formations and lower in-situ stresses where proppant embedment predominates. Furthermore, correlation between proppant embedment with repetitive loading cycles was studied.Importantly, microstructural analysis of the proppant-embedded siltstone rock samples revealed that the initiation of secondary induced fractures. Finally, the findings of this study can greatly contribute to accurately select optimum proppant properties(proppant type, size and concentration) depending on the oil/gas reservoir characteristics to minimize proppant crushing and embedment effects.

关 键 词：PROPPANT Micro-CT analysis Proppant crushing Proppant embedment Secondary induced fractures Cyclic loading 

分 类 号：TE357[石油与天然气工程—油气田开发工程] TE377