Study of Geomechanical Effects on Fracture Permeability in Naturally Fractured Reservoirs

• Main Authors: Yi-JieSu, 蘇意傑
• Other Authors: Bieng-Zih Hsieh
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/42424164703352268341

碩士 === 國立成功大學 === 資源工程學系碩博士班 === 100 === The purpose of this study was to use an analytical method to study the geomechanical effects on the fracture permeability and pressure response in stress-sensitive naturally fractured reservoirs. The characteristic properties and the approximate expression of the elastic intergral function, which was derived in Jabbari’s theory for stress-sensitive naturally fractured reservoirs, was analyzed and studied. The approximate solution of the bottom-hole pressure for the Jabbari theory was derived. The apparent linear equations for the early time and late time regions were then derived, as well as the equations for the starting time and ending time of the transition region. Based on the equations derived in this study, the estimation procedures for the fracture characteristic parameters and the elastic parameter of stress-sensitive naturally fractured reservoirs were established. A case study was used to validate the derived equations and the estimate procedures. The major results and conclusions obtained from this study are：（1）The approximate pressure solution for stress-sensitive reservoirs was derived. The apprent linear equations for the early time and late time regions were derived to improve the application of Jabbari’s theory in well testing analysis.（2）The equations for estimating the starting time and ending time of the transition regions were derived and can be expressed as:t_Da≅0.157*ω/λ and t_Db≅1.042*1/λ. The criteria used to analyze the the starting time and ending time of the transition regions was the dimensionless pressure of 0.1.（3）The estimation procedures established in this study for analyzing the fracture characteristic parameters and the elastic parameter of stress-sensitive naturally fractured reservoirs were validated from the case study analysis.（4）The pressure drop of stress-sensitive reservoirs was smaller than that of non- stress-sensitive(traditional) reservoirs. The pressure responses were not parallel straight lines in the early time and late time regions in stress-sensitive reservoirs. The formation permeability might be overestimated when traditional well testing analysis is used.