塔里木油田大尺寸超深井干法固井技术研究

空气钻井后常将空气转换为钻井液,但这容易出现井壁不稳定、垮塌、漏失等现象,井壁易形成巨厚虚滤饼致下套管困难和固井质量差,此外,大尺寸套管常规固井还存在顶替效率较差的情况,以上因素最终导致固井准备时间长和固井质量难以保证。为此,空气钻井后采用了干法固井工艺,并根据塔里木油田套管尺寸大、井深的技术难点,建立了干法固井水泥浆实验评价方法,对干法固井井下水泥浆性能进行了评价和优选,最终取得成功,下套管质量达572×10^3kg,固井深度达3602m,同时减少了现场排污,有利于环境保护。

Dry Cementing Technology of The Large Size and Ultra-deep Wells in Tarim Oilfield

After air drilling, the air is transformed into drilling fluid, but it probably results in phenomena of the instability and collapse of the borehole wall, leakage of drilling fluid, and so on. A very thick filter cake is easy to be formed on the borehole wall so as to result in difficulty in running casing and poor cementing quality. In addition, poor mud displacement efficiency exists in the conventional cementing with large-size casings. The above factors ultimately lead to long preparation time for cementing and difficulty to guarantee the cementing quality. Therefore, the dry wellbore cementing process was adopted after air drilling. And a method of experimental evaluation of cement paste for the dry wellbore cementing process was established according to the technological difficulties of the large size casings and deep wells in the Tarim Oilfield. The performance of the downhole cement slurry for the dry cementing is evaluated and optimized. At last, the dry wellbore cementing has succeeded, with a mass of running casings of 572×10^3kg, and the depth of cementing of 3602m. The on-site sewage has been reduced, conducive to environment protection.