克拉201井盐膏层钻井液技术

Drilling technology in the salt bed zones of well Kela201

克拉201井是塔里木盆地库车凹陷克拉苏构造克依构造中西段上的一口重点评价井,完钻井深4060 m。钻探目的是探明克拉2构造的油气分布和储量。该地区下第三系盐膏层厚度大,压力高,钻井过程中极易造成井塌、井漏、卡钻、划眼等井下复杂事故。克拉201井在盐膏地层采用高密度钻井液,该钻井液是在聚磺钻井液中加入护胶剂SPNH、SMP-Ⅱ和防塌剂FT-1。在钻井过程中使用Na_2CO_3和适量硅酸钾除钙,控制适当的pH值,膨润土含量保持在16—22 g/L,解决了高密度钻井液的流变性、润滑、防塌、抗温及抗盐膏污染能力难题,满足了施工要求。

Large sections of salt beds and high pressure exist in the lower Tertiary of Kuche sag in Tarim Basin, Drilling troubles as lost circulation, hole sloughing, and stuck pipe are likely to happen therefore. Well Kela 201 is an important exploration well located in this area, with total depth of 4,060m. Specific operation measures were taken on drilling fluid to control the rheology, solid content, thermal and contamination resistance in this well, such as adding colloid protecting agent and anti-sloughing agent, using Na2CO3 and potassium silicate, and controlling the pH value and bentonite content to a suitable level, etc.