伊朗TBK气田严重漏失与严重坍塌地层钻井液技术

TABNAK气田是伊朗南部位于波斯湾近海岸的一个出露背斜，地层岩性主要是碳酸盐岩和页岩。该气田地层裂缝发育，钻井过程中井漏和井塌问题非常严重，钻井作业十分困难。一开采用微泡沫钻井粗泡沫堵漏工艺；二开采用稳定泡沫钻井液；三开采聚磺钻井液；四开采硬胶泡沫钻井液；五开和六开采用随钻堵漏技术与低密度水包油钻井液相结合的方法。钻井过程中防漏堵漏效果好。现场应用表明，该套钻井液体系密度低，防漏，防塌效果好，抗盐，抗钙和携砂能力强，机械钻速快，钻井施工顺利，成本低，基本解决了TBK气田表层钻井和固井漏失问题，据TBK-2井，TBK-3井和TBK-6井完井统计，实际钻井液材料费用比预算分别降低了67.4%,81.0%和76.3%。

The drilling fluid technology in TBK gas field, Iran

TABNAK gas field is located in the south of Iran and its formation type is mainly carbonate rock and shale. Very severe problems during drilling were circulation loss and borehole collapse because of formation fracture growing, and drilling operation was very difficult. Therefore, different drilling fluid systems were selected for different sections. In the surface 914 mm hole, micro-foam drilling fluid and coarse-foam plugging technology were used; stable foam drilling fluid was used in the 660 mm hole; polysulfonate drilling fluid was used in the 444 mm hole; ebonite foam drilling fluid was selected in the 311 mm hole; plugging-while-drilling technology and low density oil-in-wa-ter drilling fluid were used in the 216 mm and 152 mm holes. Field application showed that the drilling fluid systems have such excellent characteristics as low density, lost circulation control,sloughing control,slat resistance, calcium resistance, good cuttings suspension, high penetration rate and low cost. The circulation loss problems during drilling and cementing have been solved in the gas field. According to the completion counts of wells TBK-2, TBK-3 and TBK-6, the actual drilling costs have decreased by 67. 4%, 81. 0% and 76. 3%.