Organization
Tianjin Bohai Vocational Technology College, Tianjin 300221, China
Oilfield Chemistry Division, China Oilfield Services Limited, Sanhe 065201, China
Drilling Fluid Technology Service Company of Chuanqing Drilling Engineering Co., Ltd., PetroChina, Chengdu 610051, China
摘要
针对四川盆地龙马溪组页岩孔隙、微裂缝较发育，导致油基钻井液漏失频发的问题，研发了抗高温油基钻井液堵漏剂。该堵漏剂以丙烯酸异辛酯（EHA）和4￣甲基苯乙烯（MPE）为单体，二乙烯基苯（DB）为交联剂，偶氮二异丁腈为引发剂，通过乳液聚合法制备得到。合成反应的最佳条件为：反应单体配比EHA与MPE的摩尔质量比为8∶2，单体总质量分数20%，交联剂质量分数为0.10%，反应温度为80 ℃，反应时间为8 h。合成的堵漏剂颗粒粒径分布在3～30 μm，粒径中值为11.2 ?滋m，可以有效封堵页岩地层漏失。热重分析表明：合成的堵漏剂分解温度为270 ℃，热稳定好；在钻井液中加入3%制备的堵漏剂，180 ℃热滚16 h后，黏度变化不大，累计漏失量由16.2 mL降至4.8 mL。在W204H井的应用结果表明：该堵漏剂在油基钻井液中的堵漏效果明显，平均井径扩大率低于3%，油基钻井液损耗量低于0.3 m3/h，造斜段作业顺利，为安全钻进和钻完井工程质量提供了保障。
Abstract
12Aiming at the problem of frequent leakage of oil-based drilling fluid due to the development of shale pores and micro-fractures in the Longmaxi Formation in the Sichuan Basin, a high-temperature resistant oil-based drilling fluid plugging agent was developed. The plugging agent was prepared by emulsion polymerization with isooctyl acrylate (EHA) and 4-methylstyrene (MPE) as monomers, divinylbenzene (DB) as crosslinking agent and azobisisobutyronitrile as initiator. The optimal conditions for the synthesis reaction were as follows: the molar mass ratio of the reaction monomer of EHA and MPE was 8∶2, the total monomer content was 20%, the crosslinking agent content was 0.10%, the reaction temperature was 80 ℃, and the reaction time was 8 h. The particle size distribution of the synthetic plugging agent particles was between 3 and 30 μm, and the median diameter was 11.2 μm, which can effectively seal the shale formation loss. Thermogravimetric analysis showed that the decomposition temperature of the synthetic plugging agent was 270 ℃. Adding 3% of the plugging agent prepared into the drilling fluid, after hot rolling at 180 ℃ for 16 h, the viscosity did not changed much, and the cumulative loss was reduced from 16.2 to 4.8 mL. W204H shows that the plugging agent has excellent plugging performance in oil-based drilling fluids. The average well diameter expansion rate is less than 3%, and the oil-based drilling fluid loss is less than 0.3 m3/h. The operation of the inclined section is smooth, which provides a guarantee for the quality of safe drilling and completion.
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