青海油田开2井高密度钻井液应用技术

青海油田开特米里克构造地质条件复杂,存在高压盐水层、长井段膏盐层、高低压共存层。钻井施工中,上油砂组大段泥岩容易坍塌,下油砂组井漏、井涌、井塌、地层出水问题频发,深部干柴沟组邻井从未钻达,地质资料不明。介绍了高密度聚磺钻井液防井喷、漏、塌、卡、抗高温、抗盐水以及维护井壁稳定技术在开2井的应用情况。

High Density Drilling Fluid Technology for Well Kai - 2 in Qinghai Oilfield

The geological condition is very complex in Katmerica structure of Qinghai Oilfield, due to the existence of high-pressured slat water layer, long section of gypsum salt zone, and interlayer existing of high pressure and low pressure at the same time. Drilling was extremely difficult as hole collapses were likely to happen in the upper oil-sand group containing long section of shale, while such problems as lost circulation, well kick, hole sloughing and formation water frequently took place in the lower oil-sand group; furthermore, the deep groups were never penetrated by offset wells, thus there was no geological information available. High density polysulfonated drilling fluid was used in well Kai-2, to control and solve the problems of blowout, lost circulation, hole collapse, pipe sticking, high temperature and slat water, as well as to stabilize the bore wall.