摘要
储层含水饱和度、压裂的注入方式和压裂用水矿化度都会影响致密砂岩气藏的水力压裂效果。为了掌握这三者对致密砂岩储层水力裂缝扩展的影响规律,利用大尺寸真三轴模拟压裂实验系统,研究了储层含水条件下,致密砂岩储层的水力裂缝生成和扩展形态;通过压裂液注入速率,模拟变排量工况;通过岩样被饱和水浸泡时间,模拟不同含水饱和度;通过盐水的密度,模拟压裂液用水矿化度。结果表明:提高压裂用水矿化度有利于水力裂缝的产生和扩展;变排量的注入方式,有助于孔喉的解堵,更有利于水力裂缝的产生和扩展;储层含水饱和度高,孔隙压力大,不利于水力裂缝的产生和扩展;正断层地应力条件下,主裂缝的走向基本与最大水平地应力方向一致。
The formation water saturation, the injected mode and salinity of the fracturing fluid can affect the effects of the hydraulic fracturing in tight sandstone gas reservoirs. In order to grasp the influencing laws of the three factors stated above on the fracture propagation in the reservoirs, with the help of the large-size real-triaxis simulating-fracturing experimental system, the hydraulic fracture initiation and propagation configurations were researched in the reservoirs under the formation water-bearing condition. with the help of the injection rate of the fracturing fluid, the operational conditions of the variable injection rate can be simulated, by means of the soaked time by the saturated water for the rock sample, different water saturations can be simulated, using the brine density, the required salinity for the fracturing fluid can be simulated. The results show that increasing the salinity can be conductive to the initiation and propagation;the variable injection rate can help to plug the removal of the pore throat, which is more conducive to the initiation and propagation of the hydraulic fracture;while the following two conditions are just on the contrary: the rises of the reservoir water saturation and pore pressure;under the condition of the earth stress of the normal fault, the propagation direction of the main fracture can be generally in the same direction of the maximum horizontal terrestrial stress.
作者
张健
ZHANG Jian(China United Coalbed Methane Co Ltd.,Beijing 100011, China)
出处
《大庆石油地质与开发》
CAS
CSCD
北大核心
2019年第2期153-158,共6页
Petroleum Geology & Oilfield Development in Daqing
基金
国家科技重大专项"临兴-神府地区煤系地层煤层气
致密气
页岩气合采示范工程"(2016ZX05066)
关键词
致密砂岩
水力裂缝扩展
含水条件
变排量
矿化度
tight sandstone
hydraulic fracture propagation
water-bearing condition
variable injection rate
salinity
