新型抗高温聚胺抑制剂在大庆致密油水平井中的应用

APPLICATION OF A NEW HIGH-TEMPERATURE POLYAMINE INHIBITOR IN HORIZONTAL WELLS IN TIGHT OIL RESERVOIRS IN DAQING

目前钻井液中常用的聚胺抑制剂,对提高井壁稳定性起到了较大作用,但由于分子链上存在醚键,导致稳定性和抗温性较差。针对这种情况,对第一代抑制剂DHIB-1的分子结构进行了重新设计,选用含不饱和键的醇类单体M和抗高温单体N,自主合成出一种抗高温、耐盐的低分子量抑制剂DHIB-2。红外光谱等检测表明,DHIB-2分子结构与设计相符,含有适量胺基基团,分子量适中,不含易断裂的醚键。室内实验表明,DHIB-2抗温高于200℃,抑制性与国外聚胺相当,比国内常用聚胺强,且长效抑制性好;与钻井液配伍性良好。以DHIB-2为核心处理剂的水基钻井液体系在大庆致密油区块Long 2井进行了应用,该井水平段长达1 557.2 m,成功解决了姚家组大段泥岩地层易水化和青山口组易剥落的难题,机械钻速为7.32 m/h,平均井径扩大率仅为9.26%。研究结果表明,DHIB-2抑制性突出、稳定性好,能够应用于高水敏、易水化泥页岩地层。

The polyamine inhibitor is commonly used in drilling fluids,very effective in improving borehole stability. But its stability and high temperature performance are rather poor due to the ether bond in its molecular structure. So the molecular structure of the first-generation polyamine DHIB-1 was redesigned,alcohols M containing unsaturated bonds was used to compound with high-temperature monomer N to synthesize a high-temperature low-molecular salt-tolerant inhibitor DHIB-2.The infrared spectroscopy analysis shows that DHIB-2 molecular structure is as designed,containing reasonable amino groups and non-breakable ether bonds,with moderate molecular weight. Inhibition evaluation and compatibility studies in laboratory show DHIB-2 inhibitor is equivalent to foreign polyamine in inhibition,better than those commonly used in china,especially with superior long-time inhibition performance. Its stability is good at240℃ and it has good compatibility with drilling fluids. It was successfully applied in Well Long26-Ping43 of Tight oil Reservoirs at Daqing,with horizontal interval 1557. 2m long,having solved the problems of hydration at Yaojiazu shale and scaling at Qingshankou formation,ROP reaching 7. 32m/h,average borehole enlargement only 9. 26%. The field results prove that DHIB-2 has outstanding inhibition and high stability,can be used in highly water-sensitive and easily hydrated shale or silt formations with and.