水平井趾端压裂关键工具设计与试验

大牛地气田和东胜气田水平井采用连续油管底封拖动或桥塞泵送压裂工艺，趾端首段压裂施工时存在封隔器解封困难、电缆射孔施工工期长和费用高等问题。为解决这些问题，结合现场压裂工艺，研究了水平井趾端滑套分段压裂技术，研制了趾端延时滑套、密封锁紧座等关键工具，以满足水平井套管柱试压需求，实现水平井趾端免射孔全通径压裂。地面性能试验结果表明，设计的水平井趾端压裂关键工具能够实现压裂滑套定压延时开启、固井碰压锁紧密封等功能，趾端延时滑套爆破阀在压力达到82.0 MPa时启动，延时29 min后滑套完全打开，且滑套承压达到105.0 MPa；密封锁紧座与配套胶塞可实现碰压锁紧，反向承压能力达到52.5 MPa，具备现场应用可行性。水平井趾端压裂工具的成功研制，为今后替代水平井射孔作业、降低国内致密油气藏开发成本提供了技术支持。 

Design and Test of Key Tools in Horizontal Well Toe-End Fracturing

For the coiled tubing undersealing drag technology or bridge plug pumping fracturing technology adopted in the horizontal wells in Daniudi Gas Field and Dongsheng Gas Field,there are many problems in the first stage of toe-end fracturing,such as difficulty in unseating packer,long construction period and high cost of wireline perforation.Based on the field technology,the toe-end sliding sleeve staged fracturing technology was studied,and some key tools,such as toe-end time delay sliding sleeve and seal locking seat,were designed to meet the pressure test requirements of casing string in horizontal wells,and to realize the toe-end non-perforation and full bore fracturing in horizontal wells.Ground test results showed that the key fracturing tools designed in toe-end can realize the functions of locking and sealing in cementing bumping and constant pressure time delay opening of fracturing sliding sleeve.The blasting valve of the toe end time delay sliding sleeve was initiated at the pressure of 82.0 MPa,the sliding sleeve was successfully opened after 29 minutes’ delay,and the bearing pressure of the sliding sleeve reached 105.0 MPa;the seal locking seat and the matching rubber plug can realize the locking of cementing bumping,and the reverse pressure sealing ability reached 52.5 MPa.It was verified that the technology has the feasibility of field application.The successful development of the toe-end fracturing tools for horizontal wells could provide technical support for replacing the perforation operation of horizontal wells and reducing the development cost of domestic tight oil and gas reservoirs in the future.