Porothermoelastic response of an oil sand formation subjected to injection and micro-fracturing in horizontal wells  

作　　者：Botao Lin Han Meng Jingjun Pan Sen Chen 

机构地区：[1]State Key Laboratory of Petroleum Resources and Prospecting&College of Petroleum Engineering,China University of Petroleum,Beijing 102249,China [2]Oil Production Technology Research Institute,PetroChina Xinjiang Oilfield Company,Karamay 834000,Xinjiang,China

出　　处：《Petroleum Science》2020年第3期687-700,共14页石油科学（英文版）

基　　金：the financial support from the National Major Science and Technology Projects of China(Grant No.2017ZX05009-003);the National Natural Science Foundation of China(No.51404281)

摘　　要：Stimulation of unconsolidated formations via horizontal wells has seen its vast implementation in the recent development of heavy oil reservoir to save the time and cost of preheating the reservoir before the steam-assisted gravity drainage(SAGD)process.A mathematical approach was proposed in this research that fully couples the hydraulic,mechanical and thermal responses of unconsolidated sandstone formations and also applies failure criteria for describing either shear dilation or tensile parting mechanism that generates microcracks.The approach was implemented to predict the porothermoelastic response of a pair of SAGD wells subject to injection and subsequent micro-fracturing using hot water.It was found that the predicted bottom hole pressures(BHPs)match closely with the field observed data.An elliptical dilation zone developed around the dual wells with relatively high pore pressure,porosity,permeability and temperature,implying good interwell hydraulic communication between both wells.The activation of microcracks dramatically accelerated the dissipation of pore pressure across the entire formation depth and also facilitated heat convection in between the dual wells,though to a lesser extent.In summary,the approach provides a convenient means to assist field engineers in the optimization of injection efficiency and evaluation of interference among multiple horizontal wells.

关 键 词：Porothermoelastic response Unconsolidated sandstone INJECTION Micro-fracturing MICROCRACKS Oil sand 

分 类 号：TE311[石油与天然气工程—油气田开发工程]