摘要
顺北油气田二区断控体油气藏储层埋深在8 200~9 300 m，岩性复杂，断裂带与裂缝多，气油比达3 000~24 000，温度达165~210 ℃，钻井中遭遇坍塌、井漏、气侵以及钻井周期长等难题。为此，通过应用井震联合刻画技术，优选必封点与修正三压力值，优化2套四级井身结构；基于致密封堵裂缝原理，优选2套随钻防漏堵漏钻井液配方，将二叠系与志留系裂缝地层承压能力提高0.08 g/cm3以上；优选预弯曲钻具组合替代垂钻系统，实现防斜打快；设计四段制井眼剖面，实现低温井段造斜与高温井段稳斜，满足超高温定向钻井要求；优选差异化控压工艺，降低气侵与井漏问题的发生，实现长距离斜穿主干或次级断裂带。上述井身结构设计及配套技术应用于12口井，平均钻井周期比优化前缩短119.2 d，并创造了亚洲陆上水平井钻井最深纪录——9 300 m，为顺北油气田二区断控体油气藏高效开发提供了技术支撑。
Abstract
The buried depth of fault-controlled reservoir of No.2 Block in Shunbei oil-gas field is more than 8,200￣9,300 m, with complex lithology, many fracture zones and fractures, gas-oil ratio up to 3,000￣24,000, and temperature exceeding 165￣210 ℃. There are many problems such as collapse, lost circulation, gas invasion and long drilling period during the drilling. Therefore, by applying the well-seismic combination technique, the required sealing points were selected and the three-pressure values were corrected, and the two four-stage well structures were optimized. Based on the principle of tight fracture plugging, two drilling fluid formulations of anti-leakage and plugging while drilling were selected, and the pressure bearing capacity of Permian and Silurian fractured formations was increased by more than 0.08 g/cm3. The pre-bending bottom hole assembly is selected to replace the vertical drilling system so as to realize the deviation control and fast drilling. Four-stage borehole profile is designed to realize deviation in low-temperature well section and deviation stabilization in high-temperature well section, so as to meet ultra-high temperature directional drilling. The differential pressure control process is optimized to reduce gas intrusion and lost circulation so as to realize long distance oblique penetrating of the main or secondary fault zone. The above well structure design and supporting technology were applied to 12 wells, shortting the average period by 119.2 days, setting the deepest record of 9,300 m for onshore directional drilling in Asia, and providing technical support for the efficient development of fault-controlled reservoir of No.2 Block in Shunbei oil-gas field.
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