双套压力体系侧钻井尾管及悬挂器段铣技术

沈301S井是辽河油田古潜山区块的一口双套压力体系侧钻井。原井完井过程中，用?177.8 mm技术套管封隔上部高压地层，下部低压储层悬挂?127 mm尾管完井。侧钻时，若在悬挂器上方开窗，面临两套压力体系，钻进过程中因上塌下漏现象严重，无法钻至目的层位；若在?127 mm尾管内部开窗，则存在深井小井眼开窗侧钻、施工泵压高、完井难度大等问题。若采取高效段铣技术将?177.8 mm技术套管内的?127 mm尾管悬挂器及尾管段铣至潜山面以下再侧钻，则可同时解决上述问题。为此，优选了适配的钻井液体系，研制了专门的段铣工具，通过优化段铣参数和施工工艺，成功实现了沈301S井的老井侧钻。该井仅用12.4 d（其中纯段铣时间6.63 d）就完成了183.14 m的?127 mm尾管段铣任务，单只工具折合进尺可达200 m以上。高效段铣技术为有尾管悬挂的小井眼多套压力体系侧钻、有尾管悬挂的水平井调层、钻井阻卡管柱处理、挖潜剩余油提供了一种行之有效的技术手段。

Section milling technology of liners and hangers of sidetracking wells under double-sets pressure system

Well Shen 301S is a sidetracking well under double-sets pressure system in burial hill block of Liaohe Oilfield. In the original well completion process, the intermediate casing with ?177.8 mm was used for isolating the upper high pressure formation and the liner with ?127 mm was hanged for the completion in the lower low-pressured reservoir. During sidetracking, if the window was opened above the hanger, two sets of pressure system would be faced and the target horizon could not be drilled to because of the serious phenomena of upper collapse and lower loss in the drilling process; if the window was opened inside the liner with ?127 mm, the problems such as window sidetracking in the slim hole of the deep well, high pump pressure in the construction, great difficulty in well completion would occur. However, if sidetracking was carried out after the liner hanger with ?127 mm in the intermediate casing with ?177.8 mm and the liner were section milled below the burial hill surface by adopting high-efficient section milling technology, the above problems would be solved at the same time. Therefore, adaptive drilling fluid system was optimized and special section milling tools were developed. Then sidetracking for the old well Shen 301S was successfully achieved by optimization of section milling parameters and construction technology. The section milling task of the liner with ?127 mm for 183.14 m was finished only in 12.4 days (pure section milling time was 6.63 days) for this well and reduced footage of the single tool could reach over 200 m. High-efficient section milling technology provides a kind of effective technical method for sidetracking in multi-sets of pressure system in the slim hole hanged with liners, layer adjusting in the horizontal well hanged with liners, sticking pipe string treatment during drilling and producing remaining oil.