保护煤储层固井技术的探讨

煤储层与一般的油气层相比，埋藏浅，微孔隙和裂缝发育，煤层的机械强度低，渗透率低，孔隙压力小，易坍塌，易污染，中国目前虽然钻了多口煤层气井，由于在钻井完井过程中没有注意加强对煤储层的保护，致使部分井的试气不理相，产量比较低，影响了煤煤层气的开发，探讨了固井过程中保护煤储层的必要性，分析了固井施工对煤层造成的伤害以及保护煤储层方面存在的主要问题，提出了保护煤储层的固井技术措施，即应根据煤层的压力情况，设计合理的固井工艺及水泥浆体系，保征固井质量阿与降低对煤层的伤害相结合，严格控制水泥浆性能，具有低失水，高早强，微膨胀等特点的水泥浆体系不但能提高固井质量，而且能降低对煤储层的伤害,尽量控制水泥浆液柱压力，实现近平衡压力固井，介绍了保护煤储层固井技术在现场的成功应用，并提出了煤层气井固井尚待研究解决的问题。

An investigation on the cementing technology for coalbed reservoir protection

Formation damages in coalbed methane wells are more severe than oil and gas wells during drilling and completion. This paper focuses on the cementing technology for the coalbed methane well, i. e. , select the reasonable cementing method and cement slurry systems according to the formation pressure, adopt near balanced cementing and control the hydro column pressure of cement slurry, control the properties of cement slurry and use the cement of low water loss, high early strength and slight swelling to improve cementing quality and minimize formation damage. It also presents the successful field cementing history cases; as well as some problems still exist.