MTA固井方法提高煤层气井压裂成功率的研究
Study on MTA Well Cementing Method to improve fracturing success rate of coalbed methane well
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摘要: 针对煤层气直井水力压裂时常发生窜流导致压裂改造失败这一工程难题,引入泥饼仿地成凝饼(MTA)固井方法。通过室内模拟试验,研究了MTA固井方法应用于煤层气井的实用性和有效性,分析了该方法对提高煤层气井压裂成功率的意义。试验结果表明,MTA固井方法与煤层气井钻井液的配伍性好,能够满足煤层气井安全钻井对钻井液的要求;与原有固井方法相比,MTA固井方法可使煤层气井隔层界面抗剪切强度提高400%以上。原有固井方法的隔层界面窜流系数均大于1,窜流风险高,压裂成功率低;而MTA固井方法的隔层界面窜流系数均小于1,窜流风险低,压裂成功率高。该研究为提高煤层气井压裂成功率提供了一条新途径。Abstract: According to fracturing rebuilding failure caused by channeling during hydraulic fracturing of coalbed methane well,a Mud Cake To Agglomerated Cake( MT A) Well Cementing Method was introduced. With the indoor simulation experiment,MTA Well Cementing Method was studied. The paper analyzed the significance of the MT A Well Cementing Method to improve fracturing success rate of the coalbed methane. The experiment results showed that MTA Well Cementing Method had a good compat ibility with drilling fluid and the MTA Well Cementing Method could meet the safety requirements. Compared with original cementing technology at present,the MTA Method could enhance shear strength at barrier more than 400%. The channeling coefficient of the barrier interface of the previous cementing method was all over 1,channeling ris k was high and the fracturing success rate was low. The barrier interface channeling coefficient of the MTA Well Cementing Method was all below 1,the channeling risk was low and the fracturing success rate was high. The study could provide a new approach to improve the fracturing success rate of coalbed methane.
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