摘要
BZ油田沙三段低渗储层天然裂缝发育,水力裂缝垂向上与天然裂缝面相遇时的裂缝延伸方式直接影响水力压裂优化设计.基于岩层垂向上最小水平主应力分布近似相等的特征,将界面附近岩石简化为双层岩层受力分布;依据线弹性断裂力学理论,给出远场有效应力作用下垂直于水平岩层压裂裂缝的缝尖应力场;结合裂缝张性破坏和剪切破坏准则,建立了考虑岩层界面内聚力、摩擦系数（内摩擦角）及抗张强度影响下的水力裂缝滑移判据;根据储层原地应力场和岩石力学计算,分析了相应参数对水力裂缝穿越与滑移的影响.结果表明,BZ油田沙三段储层水力裂缝延伸到天然裂缝界面时表现为穿越现象,这对压裂优化设计具有重要指导意义.
The natural fractures in low-permeability reservoirs of BZ Oilfield are well developed, the fracture prop- agation behaviors when the vertical hydraulic fractures meeting with the fracture interfaces directly affect the optimi- zation design of the hydraulic fracturing. On the basis of the approximate and equal characteristics of the minimum horizontal principal stress distribution, the rocks nearby the interface are simplified and distributed by double-layer rock stress; according to the linear elastic fracturing mechanics theory, the stress field of the tip of induced frac- tures perpendicular to the horizontal stratum is presented under the action of effective stress from the far-field ; com- bined with the criteria of the crack tensile and shear failures, the hydraulic fracture slip criteria are established in the influences of rock interface cohesion, friction coefficient （ internal friction angle ） and tensile strength ; accord- ing to the calculations of the in-situ stress field and the rock mechanics, the effects of the corresponding parameters on the hydraulic fracture penetration or slip are analyzed. The results show that the phenomenon of the penetration occurs when the hydraulic fractures in Reservoir S-m of BZ Oilfield crossing the natural fracture interfaces. These behavoirs are of great significance to guide the hydraulic fracturing optimization design.
出处
《大庆石油地质与开发》
CAS
CSCD
北大核心
2014年第6期87-90,共4页
Petroleum Geology & Oilfield Development in Daqing
基金
中海石油“十二五”重点项目“海上低孔低渗油气藏有效开发模式方法与实用技术研究与实践”(12-PZT-071)
关键词
水力压裂
天然裂缝
界面
裂缝延伸
BZ油田
Hydraulic fracturing
natural fracture
interface
fracture extension/propagation
BZ Oilfield
