油基钻井液用耐高温碳酸钙-聚氨酯核壳型微球井壁强化剂

Calcium Carbonate-polyurethane Core-shell Microspheres Well Wall Reinforce with High Temperature Resistance for Oil-based Drilling Fluids

孙方龙 李瑞刚 宋元成 焦延安 詹富斌 唐华

SUN Fanglong LI Ruigang SONG Yuancheng JIAO Yan’an ZHAN Fubin TANG Hua

为了提高油基钻井液的封堵性能，以氯化钙、碳酸钠、谷氨酸、2，4-甲苯二异氰酸酯、二月桂酸二丁基锡等 为原料，通过水热法制备了刚柔并济的核壳型碳酸钙-聚氨酯井壁强化剂。通过测定流变参数、破乳电压、滤失 量和侵入深度等，考察井壁强化剂加量对基浆流变性、稳定性和封堵性的影响。将井壁强化剂与钛酸钾纤维、海 泡石、硅藻土和氧化沥青等材料复配，研究了复配井壁强化剂对油基钻井液润湿性、流变性、稳定性、封堵性和耐 温性等的影响。结果表明，井壁强化剂以耐高温且具备一定形变能力的聚氨酯为壳、碳酸钙球为核，微球粒径约 2 μm；对基浆流变性和稳定性的影响较小，可显著提高基浆的封堵性能；加量为2.5%～3.0%时可实现良好的封 堵效果，破乳电压为525～542 V、侵入深度为0.6 cm。最优配方的复配井壁强化剂可显著提高油基钻井液的润 湿性；对基浆流变性的影响较小，有利于基浆稳定性的提升，破乳电压提高至637 V。复配井壁强化剂各组分发 挥协同效应，可以针对不同孔隙的裂缝进行有效封堵，表现出较好的降滤失性能。在常温下的滤失量和侵入深 度分别为1.0 mL和0.2 cm。在经过180 ℃高温老化8 h 后，复配井壁强化剂依旧保持较好的降滤失性能，滤失量 和侵入深度分别为3.3 mL和0.3 cm，抗高温性能较好。核壳型井壁强化剂的聚氨酯软壳利于微球进入诱导裂缝 的最前端，碳酸钙硬核能促进应力的分散，防止裂缝的进一步延伸，实现对井壁裂缝的有效封堵，同时能与钻井 液保持良好的配伍性，封堵性能优异。

In order to enhance the plugging performance of oil-based drilling fluids， a hybrid core-shell calcium carbonate-polyurethane well wall reinforcer was prepared via hydrothermal synthesis using calcium chloride，sodium carbonate， glutamic acid，2，4-toluene diisocyanate and dibutyltin dilaurate as raw materials. The effects of well wall reinforcer dosage on the rheological properties，stability and plugging performance of base slurry were investigated by measuring rheological parameters， demulsification voltage，filtration loss and invasion depth. The well wall reinforcer was compounded with some materials such as potassium titanium oxide fibers，sepiolite，diatomite and asphalt oxide. The effects of the compounded well wall reinforcer on the wetting properties，rheological properties，stability，plugging performance，and temperature resistance of the oil-based drilling fluids were studied. The results showed that the well wall reinforcer，with polyurethane as the shell and calcium carbonate microsphere as the core，had a microsphere diameter about 2 μm，exhibited minimal influence on the rheological properties and stability of base slurry，and significantly improved the plugging performance of base slurry. A dosage of 2.5%—3.0% achieved good plugging effects，with a demulsification voltage of 525—542 V and an invasion depth of 0.6 cm. The compounded well wall reinforcer with optimum formula significantly improved the wetting properties of oil-based drilling fluids，had little influence on the rheological properties of base slurry，and helped enhance stability. The demulsification voltage increased to 637 V. The various components of the compounded well wall reinforcer exerted synergistic effects，effectively plugging cracks with different pore sizes，and then exhibited good filtration loss performance. The filtration loss and invasion depth at room temperature were 1.0 mL and 0.2 cm，respectively. After aging at 180 ℃ for 8 hours，the compounded well wall reinforcer still maintained good filtration loss performance. The filtration loss and invasion depth were 3.3 mL and 0.3 cm，respectively，indicating good temperature resistance. The polyurethane soft shell of the well wall reinforcer facilitated the microspheres entry into the leading edge of induced fractures，while the calcium carbonate hard core dispersed stress and prevented further crack extension，effectively plugging the wellbore cracks. Additionally，it exhibited good compatibility with drilling fluids and excellent plugging performance.

10.19346/j.cnki.1000-4092.2024.02.002