水平井出水段高强度封堵配套工艺技术

针对目前水平井出水段堵水作业的需求，研制出了适合水平井堵水的触变膨胀型高强度堵剂及分段注入封堵工艺。堵剂性能评价结果表明，该触变膨胀型高强度堵剂具有较强的触变性，流动切力为10～15 kPa，适用温度为30～120℃，抗压强度大于13 MPa，稠化时间大于6 h，固化后体积膨胀1.0%～1.5%，解决了常用凝胶类堵剂强度低，堵水有效率低、有效期短等问题，克服了常用水泥类堵剂在水平段易与压井液混相及安全性差的问题，实现了对水平井出水段安全可靠及长效封堵。研究了用于堵剂注入过程中保护堵剂段塞的自降解溶胶，有效防止堵剂注入过程中与压井液混相，优选了堵剂分段注入的配套工具，实现对出水段分段封堵。截至目前，该水平井分段堵水技术在大港、青海等油田完成水平井堵水现场应用5井次，施工成功率为100%，累计增产原油量为5 849 t，天然气量为1.4×104 m3，证明了该水平井分段堵水工艺具有较高的可靠性和长效安全性。 

Technologies for Strengthened Shutoff of Water Producing Sections of a Horizontal Well

A thixotropic expandable high strength water shutoff agent and a technology of staged injection of the shutoff agent have been developed to satisfy the needs of water shutoff operation in horizontal wells. Laboratory evaluation showed that the water shutoff agent had good thixotropy and yield point of 10-15 kPa. It was suitable for use at temperatures between 30℃ and 120℃. The compressive strength of the water shutoff agent was greater than 13 MPa, and the thickening time was longer than 6 h. The volume of the water shutoff agent after solidification expanded by 1.0%-1.5%. As a high strength water shutoff agent, it increases the efficiency of water shutoff, prolongs the life of water shutoff, and overcomes the problems often encountered in horizontal section such as the mixing of cement water shutoff agent and kill mud, and poor application safety of other water shutoff agents commonly available. A self-degradable sol was developed to protect the water shutoff agent plug from being mixed with kill mud during injection. Tools for staged injection of water shutoff agent were selected for the staged shutoff of the water producing sections. This technology has been successfully applied on 5 wells in Dagang Oilfield and Qinghai Oilfield, with oil and gas production increased by 5 849 t and 1.4 ×104 m3 in total, respectively, demonstrating the reliability and long-term safety of the technology.