西江24-3-A20ERW大位移井钻井液技术

西江24－3－A20ERW大位移井钻井主要目的是开发相距8km的西江24－1边际油田。该井完钻井深为8987m，垂直井深为2851.23m，水平位移为7825.51m，尾管下至井深为8984m，该井根据A4井，A17井和A18井的成功经验，确定了适应不同井段的钻井液体系，即在φ609.6mm井眼使用海水高粘膨润土浆，在φ406．4mm井眼使用海水氯化钾部分水解聚丙烯酰胺水基钻井液，在φ311．1mm和φ215．9mm井眼使用低毒Versaclean油基钻井液体系，并优化了钻具组合和钻井液流变参数，确定了合适的钻井液密度范围，以改善井眼稳定性，现场应用表明，该套钻井液体系具有润滑性好，井眼稳定性强以及抗高温，抗污染和保护油层的特点，在低剪切速率下具有较高的粘度，成功地钻成了西江24－3A20ERW大位移井，固井质量优良。

Drilling fluid technology for the extended reach well Xijiang 24-3-A20ERW

Well Xijiang 24-3-A20ERW was an extended reach well drilled to develop the marginal oilfield of Block 24-1 8 km away. It had a total measured depth of 8987 m, a vertical depth of 2851. 24 m and horizontal displacement of 7825. 51 m, and the liner was run to 8984 m. Suitable drilling fluid systems for different intervals were selected based on the successful drilling practices in well A4, A17 and A18, i. e. , seawater highly viscous bentonite mud was used in the 609. 6 mm hole, partial hydrolyzed polyarylamide water based drilling fluid was used in the 406. 4 mm hole, and in the 311. 1mm and 215. 9 mm hole, low toxicity oil based drilling fluid system VersaClean was selected. At the same time, the bottom hole assembly and drilling fluid rheological properties were also optimized, and the suitable,drilling fluid densities were determined, so as to improve the borehole stability. Field using showed its advantages over better lubricity, stable borehole condition, high temperature tolerance, contamination resistance and reservoir protection. This technology ensured the success of well Xijiang 24-3A20ERW, and excellent cementing quality was achieved.