延长气田易漏失井不规则井眼固井技术　　

Irregular borehole cementing technology in leakage wells of Yanchang gas field

曾艳军 姚平均 陈道元 苟明 蒋洪顺 杨代明

ZENG Yanjun YAO Pingjun CHEN Daoyuan GOU Ming JIANG Hongshun YANG Daiming

中原石油勘探局固井工程处，河南濮阳　457331 西南钻井公司，四川南充　637000

Zhongyuan Petroleum Exploration Bureau Cementing Company, Puyang 457331, China South West Drilling Company of Zhongyuan Oilfield, Nanchong 637000, China

延长气田地层压力系数低，气层段长，地层含水丰富，不稳定的泥岩、煤层交互存在，形成典型的“糖葫芦”井眼，固井漏失水泥浆低返、环空气、水、钻井液窜槽现象严重，固井优良率仅为16%。通过开展水泥浆体系优选，合理设计浆柱结构，依据孔隙压力、岩石密度、钻速、压力剖面等资料确定较为薄弱的地层，选择分级箍安放位置，正注反挤工艺等一系列措施，成功解决了固井过程中井漏和候凝期间气、水窜槽问题，使固井质量优良率提高到了93.54%，实现了全井水泥有效封固的目的。

The formation in the Yanchang gas field is characterized by low pressure coefficient, thick gas bearing formation, rich groundwater, and destabilization shale, coalbed interaction complex formation, which result in “tomatoes on stick” borehole. There are some troubles occurred during the cementing operation, such as insufficient cement slurry return due to lost circulation, serious channeling among annular gas, water and drilling fluid, and only 16% cementing quality up to excellence. By optimizing cement slurry system, designing rational column structure, figuring out the weak formation through data of pore pressure, rocky density, drilling rate and pressure profile, selecting reasonable riding position of stage collar, and applying positive injecting and negative infusing completion technique, successful solve the problems of lost circulation in the process of well cementing and gas, water channeling during curing time. The results show that the cementing quality excellent rate is up to 93.54% by the treatment, which realize the target of whole well effectively cementing by cement slurry.