Yang Baojian，Liu Xiaomin，Li Wenlong，et al.Development and testing of _∅299 .0 mm monohole expandable casing[J].China PetroleumMachinery，2025，53（7）：141-148.

Development and Testing of o299. O mm Monohole Expandable Casing

Yang Baojian1Liu Xiaomin²Li Wenlong1Xue Xianbo²Fu Jianmin1Hua Zejun² （1.CNOOCchina limited，Tianjin Branch；2.COSL IntegratedSolutionamp; New Energy）

Abstract：Inorder to solve the problemofformationleakageinShahejieFormationin Bohai Oilfield，itis necessary todevelop expandablecasings withlarge diameter，high compressive strength and good sealing performance to seal the cracks or faults in complex formations.In China，the research onlarge-diameter monoholeexpandable casing isstillin the exploratoryand testing stage.Considering thecomplex geological conditionsand frmationleakage in Bohai Oilfield，a high-performance ℘ 299.0 mm monohole expandable casing has been developed. It is made of M65 steel，with the expansion cone angle optimized to 12^∘ ，and hydrogenated nitrile-butadiene rubber（HNBR） as the sealing rubber material.Laboratory test was conducted to analyze the comprehensive performance of the （20 o299.0 mm monohole expandable casing. The test results show that the ℘ 299.0 mm monohole expandable casing， after expansion，exhibits the external extrusion strength of12.7MPa，the internal pressure strength of 42.7MPa， and the expansion pressure of 15-20 MPa. It behaves smoothly during expansion and performs wellafter expansion. In the downhole field test，appropriate technical measures were takenagainst the problemsoflost circulation，borehole instability and fracture opening to ensure the safe entry of the ℘ 299.0 mm large-diameter expandable casing. The research and test results suggest thatthis proposed casing provides an efective solution to plug leaked formations in Bohai Oilfield while keeping the casing program intact.This technology is promising forfuture promotion.

Keywords：plug leaked formations；monohole expandable casing； expansion performance；expansion cone angle;downhole test

0 引言

渤海油田地质油藏复杂，油层多被断层分隔，钻遇断层、裂缝地层增多，极易引发薄弱井段井漏。根据渤海油田的130井次漏失情况统计，漏失情况占比由 17% 增加至 59% ，堵漏成功率随着漏失情况发生变化，呈下降趋势，从 92% 下降至86% 。采用常规堵漏效果差，封堵后地层承压低，下套管封隔漏失层存在套管开次多、完钻井眼小的问题，给后期施工带来困难。

海上油田井漏问题频发，传统的堵漏方法效果不佳，封堵后的地层承压能力低，套管开次多、完钻井眼小，影响后期施工；且等井径膨胀管系列钻井工具研究的井下试验不够完备，大多停留在理论层面[1-3]。研究发现，作为钻井领域的新兴技术，大直径等井径膨胀管裸眼封堵技术可以作为临时技术套管进行机械封堵，可在不改变钻头尺寸和井身结构的条件下，实现复杂地层封堵和无内径损失钻进。当深井钻遇复杂地层时，能够避免常规逐级变小的锥形井身结构，有利于钻至设计完钻井深[4-5]。国外的钻完井技术较国内相对成熟与完善，较为成熟的等井径膨胀管技术主要有Envexture公司的等直径系统（SameDrift）、Weatherford公司的等径井眼系统（MonoBore）以及BakerHughes公司的LinEXX等井径系统，大多数采用大直径等井径 _∞244.5mm 膨胀管进行现场作业[6-9]

目前国内对大直径等井径膨胀管的研究尚在初期且井下试验较少，但各大石油机械公司与高校研究院均对井下机械无内径损失封堵技术进行了攻关突破。吴柳根等10于2020年从变径膨胀锥、材料优选及……