长庆特低渗透油藏注水动态裂缝及井网加密调整模式研究

Research on Water Flooding Dynamic Fractures to Optimize Infill Drilling Spacing in Ultra-Low Permeability Reservoirs,Changqing Oilfield

王文环 彭缓缓 李光泉 雷征东 吕文峰

Wang Wenhuan Peng Huanhuan Li Guangquan Lei Zhengdong Lü Wenfeng

中国石油勘探开发研究院, 北京 100083; 中石化石油工程技术服务有限公司, 北京 100101

PetroChina Research Institute of Petroleum Exploration & Development, Beijing, 100083, China; Sinopec Oilfield Service Corporation, Beijing, 100101, China

为改善长庆特低渗透油藏中高含水期水驱开发效果,进一步提高采收率,综合运用储层地质力学、油藏工程及数值模拟等方法,研究了注水动态裂缝开启机理及延伸规律,给出了不同方向裂缝开启压力界限。当注水压力超过现今最小水平主应力时,单方向注水动态裂缝开启;注水压力越高,现今最大、最小水平主应力差越小,注采井连线与最大水平主应力方向夹角越小,越容易产生多方向注水动态裂缝。根据不同缝网匹配油藏剩余油分布规律,采取了不同的井网加密调整模式,限定注水压力控制多方向裂缝开启,沿现今最大水平主应力方向注水动态裂缝线性注水、侧向基质驱替等措施,改善了水驱效果,提高了油藏水驱采收率,为提高特低渗透油藏水驱采收率提供了新思路。

To improve water flooding effects and enhance the oil recovery of ultra-low permeability reservoirs passessing a high water cut, reservoir geomechanics, engineering and numerical simulation were combined to reveal the opening mechanism and propagation of dynamic fractures and define the pressure limits required to open fractures in different directions. When injection pressure exceeds minimum horizontal stress, dynamic fractures will open in the orientation of maximum horizontal stress.High injection pressure and low stress difference between maximum and minimum horizontal stresses would result in a low-angle between injection-production well orientation and the maximum horizontal stress direction, in which multiple dynamic fractures might be generated in various directions.Effective infilling modes and optimized spacing for reservoirs with different well pattern could help to improve water flooding effect and dramati-cally enhance the recovery of hydrocarbon, along with avoiding frac interference.The proposed development mode as linear water flooding well pattern along maximum horizontal stress, lateral matrix displacement, limit injection pressure and control multiple fractures opening, provides a new approach for improving water flooding recovery in ultra-low permeability reservoirs.

中国石油天然气股份有限公司油气田开发重大科技项目"低渗、特低渗透油田油藏工程与数模方法研究"(编号:2011B-1205)资助。

https://doi.org/10.11911/syztjs.201501018