低含量KCl钻井液在苏里格气田的应用

苏里格气田石千峰组和石盒子组泥岩地层易发生严重井壁垮塌,井塌划眼、卡钻、填眼侧钻等复杂情况频繁发生。针对苏里格气田的地层岩性特点,开展了低含量KCl钻井液研究,通过保持聚磺钻井液中0.8%~1.0%的KCl含量,提高体系的抑制防塌性能。2口井的现场应用表明,该体系抑制性强,砂样清晰,无垮塌现象,起下钻通井无阻卡;封堵造壁和流变性能良好,滤饼光滑致密,性能稳定,钻井液无排放,较好地满足了井下施工需要,为安全高效开发苏里格气田积累了经验。

Application of low content KCl drilling fluid in Sulige Gas Field

Severe borehole collapse occur easily in mudstone formations of Shiqianfeng Formation and Shihezi Formation of Sulige Gas Field, and troubles like hole collapse reaming, sticking, filling the hole and sidetracking often occur also. In view of the formation rock properties and characteristics of Sulige Gas Field, study was conducted on low content KCl drilling fluid; the inhibition and anti-collapse performance of the drilling fluid system is improved by maintaining 0.8%-1.0% of KCl in polysulfonate drilling fluid. Its application in two wells shows that this system has generated strong inhibition and clear sand specimen with no collapse and no obstructions in wiper trips; it has favorable performance in plugging and side-wall building and rheological property; the filter cake is smooth and tight and has stable performance; there is no discharge of drilling fluid; all of these properties satisfactorily meet the downhole service requirements and provide experiences for safe and efficient development of Sulige Gas Field.