适于西非深水油田的水基钻井液室内评价

通过分析西非深水油田钻井液技术难点,针对钻井液低温流变性调控与井眼清洗问题、气体水合物的生成与控制以及活性泥页岩井壁失稳问题,提出了相应的技术对策,构建了新型深水高性能水基钻井液体系。实验评价表明,该钻井液具有较低的黏度和较高的动切力,φ6读数保持在7~10,有利于井眼清洗;钻井液流变性受低温影响较小,2℃和25℃的表观黏度比和动切力比分别为1.28和1.10。该钻井液在不同层位的泥页岩岩样回收率均在90%以上,抑制性明显优于以往使用的KClPHPA钻井液体系,且在动态和静态条件下均具有优良的水合物抑制效果,抗污染能力强,满足西非深水油田钻井液技术需求。

Laboratory evaluation on water-based drilling fluid suitable for deepwater oil field in West Africa

Via the analysis on technical difficulties of drilling fluid for deepwater oil field in the West Africa, in the light of the low-temperature rheological property regulation of drilling fluid, borehole cleaning, gas hydrate generation and control, and borehole instability of active mud shale, corresponding technical countermeasures have been raised, and a new deepwater high-performance water-based drilling fluid system has been established. According to the experimental evaluation, the drilling fluid has relatively low viscosity and relatively high dynamic shear force, and φ6 reading is maintained at 7 to 10, which is beneficial for the borehole cleaning; the rheological property of drilling fluid is slightly affected by low temperature; the apparent viscosity ratio at 2 ℃ and the dynamic shear force ratio at 25 ℃ are respectively 1.28 and 1.10. The drilling fluid recovery rate of mud-shale rock sample at different positions is more than 90%. The inhibition of drilling fluid is obviously superior to that of previously-used KCl-PHPA drilling fluid system, and has excellent hydrate inhibition effects under dynamic or static conditions. It still has strong anti-pollution capacity, and basically meets the technical requirements of drilling fluid for deepwater oil field in the West Africa.