三相可循环微泡沫钻井液的研究及其在彩南油田的应用

Study on three-phase circular micro-foam drilling fluid technology and its application in Cainan oilfield.

根据新疆准噶尔盆地彩南油田 96口开发井资料统计 ,发生不同程度漏失的井为 70口 ,漏失率达 72 .9%。主要漏失井段为 4 0 0～ 70 0m ,次要漏失井段为 180 0～ 2 0 0 0m。漏失现象为随钻有进无出。随钻井漏严重影响了钻井速度 ,使钻井综合成本增加。针对上部井段低压裂缝地层严重漏失问题 ,研究出了三相可循环微泡沫钻井液体系。该体系主要采用起泡剂、稳泡剂、固泡剂配制而成 ,能反复循环使用 ,无需特殊脱气和充气设备 ,同时保留了普通泡沫钻井液的部分优点。室内对微泡沫钻井液体系组成、微观形态分析、稳定性评价、当量密度计算等方面进行了研究 ,形成了三相可循环微泡沫钻井液技术。现场应用效果表明 ,该钻井液体系具有稳定性高、现场配制简单、性能优良、抗污染能力强和防漏堵漏效果好等优点。

According to investigative data of 96 developing wells in Cainan oilfield of Xinjiang, there were 70 absorption wells, i.e., 72.9% of the wells investigated were absorption wells. The primary lost circulation zone is from 400 m to 700 m and the secondary zone is from 1800 m to 2000 m. While lost circulation occurred, no any drilling fluid returned. Due to lost circulation while drilling hampers severely ROP and makes drilling cost up, three phase circular micro foam drilling fluid system was developed to cope with severe lost circulation existing in low pressure fracture type reservoir of the upper section. The system consists of foaming agent, stabilizing agent and curing agent. It can be recycled without special degassing and aeration equipments while remains part advantages of common foam drilling fluid. Based on studies of composing, micro conformation, stability and equivalent density of micro foam drilling fluid, three phase circular micro foam drilling fluid technology was developed and was used in the field. The results showed that the drilling fluid has properties of high stability, easily preparing in site, good performance, strong resistance to fouling, as well as leak resistance and plugging effect.