复杂超深井KS1井四开尾管固井技术

为解决高温高压超深井KS1井存在的溢漏同存、岩盐层缩径、盐水层高压、顶替效率低、固井窜槽等固井难题，该井四开固井采用了特殊的固井工艺流程，先采用底部尾管悬挂固井工艺，再进行五开钻进、五开尾管固井、五开中完作业(钻塞、刮壁、电测等工序)后再下铣锥对四开铣喇叭口及回接筒进行修整，最后进行四开回接套管固井工艺。为了确保四开尾管固井作业顺利，根据钻井复杂情况，充分分析了固井作业存在的难点，从通井技术、下套管技术、水泥浆体系、固井排量、固井施工工艺等方面制定了详细的技术措施。固井质量测井解释表明，高压盐水层、漏失层、敏感地层均得到了有效封固，实现了“穿鞋戴帽”的目标，为后续油气开发、井筒完整性等创造了有利条件。该井的固井成功为今后类似复杂岩盐层固井作业提供了经验。

Fourth-section liner cementing technology used in the complex ultradeep well KS1

Well KS1 is a high-temperature, high-pressure and ultradeep well and it is faced with several cementing difficulties, e.g. coexistence of overflow and leakage, hole shrinkage in salt rock beds, high-pressure saline aquifer, low displacement efficiency and channeling. To solve these difficulties, a special cementing process is adopted in the fourth-section cementing of Well KS1. According to the special cementing process, the cementing process of bottom liner hanging is firstly performed. Then, the milling taper is run into the hole to dress the fourth-section milling bell mouth and tie back barrel after fifth-section drilling, fifth-section liner cementing and fifth-section intermediate completion operation (plug drilling, wall scraping and electric logging) are carried out. Finally, the fourth-section cementing of tie back casing is performed. In order to ensure the smooth implementation of the fourth-section liner cementing operation, the difficulties in the cementing operation were analyzed sufficiently on the basis of drilling complexities. Then, detailed technical measures were prepared from the aspects of drifting technology, casing running technology, slurry system, cementing displacement and cementing construction process. The logging interpretation of cementing quality shows that high-pressure saline aquifers, thief zones and sensitive zones are all plugged effectively and the target of “wearing shoes and hats” is realized, so as to create the favorable conditions for the subsequent oil/gas development and wellbore integrity. The successful cementing of Well KS1 provides the experience for the cementing operation in similar complex salt rock beds in the future.