摘要
川西LD气田为典型的低压低渗透致密气藏,该类气藏因地层压力低,加砂压裂改造时压裂液滤失量大,返排速度慢,返排率低,导致储层及裂缝受到伤害而影响改造效果,使依靠压裂建产的LD气田的稳产形势面临巨大挑战。通过室内实验,研制了低质量分数的稠化剂增能压裂液体系,降低了压裂液残渣对储层的伤害,结合储层地质特征,在液氮增能设计方法优选及施工关键参数计算方法研究的基础上,形成了液氮增能压裂技术,提高了压裂液的返排速率和返排率,最终形成了提高LD气田低压气藏改造效果的关键技术。现场10口井18层的应用结果证实,气井返排速率明显加快,压裂后平均测试时间由前期的10d缩短到2d,气井见气点火时间明显缩短,平均产气量为0.762 3×10~4m^3/d,比2008年增加了0.549 5×10~4m^3/d,有效实现了低压气藏低伤害压裂,为低压气藏开发提供了有效手段。
LD gas field in west Sichuan is a typical low-pressure and low-permeability tight gas reservoir,and due to low pressure, the enhancement treatment performance is hindered by reservoir and fracture's damage caused by high fracturing fluid filtration, slow flow-back speed and low flow-back rate during the sand fracturing.Therefore,the LD field's stable production relies mainly on the fracturing techniques faces enormous challenges.Through laboratory experiments,we develop a low-molecular densification agent to formulate the new fracturing fluid system which can reduce the damage caused by fracturing fluid residue;moreover, combined with the reservoir geology,and based on referring to the liquid nitrogen method and the key parameter calculation method used in fracturing,the liquid nitrogen energy-increment fracturing technique,which can improve the fracturing fluid's flow-back speed and rate,is formulated to improve the low pressure gas reservoir's development performance in LD gas field.The field application in 18 layers of 10 wells confirms that the flow-back rate is significantly accelerated,and the average test time after fracturing is shortened from the previous 10 d to 2 d,and the gas ignition time is significantly reduced.The average gas production so far is 0.762 3×10~4 m^3/d,increased by 0.549 5×10~4 m^3/d compared with 2008,so,the low damage fracturing can be realized effectively in the low-pressure gas reservoir,and the technique provides a cost-effective means for the low pressure gas reservoir development.
出处
《油气地质与采收率》
CAS
CSCD
北大核心
2011年第4期98-101,118,共4页
Petroleum Geology and Recovery Efficiency
基金
国家科技重大攻关专项"大型油气田及煤层气开发"(2008ZX050)下设专题"四川盆地低渗气藏储层改造工艺技术研究"(2008ZX05002-004-004)
关键词
低压气藏
改造效果
增能压裂液
液氮增能
现场应用
川西LD气田
low-pressure gas reservoir
enhancing treatment performance
energy increment fracturing fluid
liquid nitrogen energy increment
field application
LD gas field in west Sichuan
