泽43-12x井为泽43潜山一口重点开发井,奥陶系目的层裂缝孔洞发育,揭开潜山面时,发生失返性漏失,进而导致盖层泥岩段井壁垮塌,井下形成桥塞,提前下技术套管利用砂桥对第三系3810.77 m以上地层承压固井,但3810.77~3853.61 m泥岩段未封固,存在后期掩埋潜山储层的风险.通过分析三开完井的技术难点,提出双封双承托完井管柱设计思路,开展了配套工艺和工具等方面的研究,完成了尾管悬挂器优选、各工具压力级别及地层封隔系统设计,研制开发了岩屑承托与地层封隔一体化工具,实现了多套不同内径、不同岩性地层的有效封隔,并且承托工具弹簧钢精密钢带式设计可以满足不规则井壁封隔需求,实现自动调节.泽43-12x井的成功应用表明,该技术可实现复杂井段一趟管柱非固井封隔,为同类井的复杂井段封隔提供了借鉴.%Well Ze 43-12x is a key development well in Ze 43 buried hill, and its target layer of Ordovician is characterized by de-veloped fractures and pores, so total circulation loss happens when the surface of the buried hill is drilled. And consequently, the borehole in the mudstone section of cap rocks is collapsed and bridge plug is formed in the downhole. To deal with this situation, the technical casing is run in advance to carry out pressure cementing in the Tertiary strata above 3 810.77 m by using the sand bridge. However, the mudstone section of 3 810.77~3 853.61 m is not cemented, so it is faced with the risk that buried-hill reservoir is buried in the late stage. In this paper, the technical difficulties of the third spud completion were analyzed, and accordingly the design idea of double-packer and double-retainer completion string was proposed. Then, the support technologies and tools were researched. As a result, the liner hanger was selected, the pressure level of each tool and formation sealing system were designed, the integrated tool of cuttings retainer and for-mation packer was developed, multiple effective sealing of different internal diameters in different lithological strata was realized and the precise steel belt design of spring steel of retaining tool can satisfy the requirements of irregular borehole sealing, achieving automatic regulation. The successful application of this technology in Well Ze 43-12x indicates that by virtue of this technology, non-cementing packoff in the complicated hole section can be realized by one trip string. It provides the reference for the packoff of complicated hole sections in similar wells.
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