川东北地区泡沫钻井井壁稳定技术

在分析川东北地区上部陆相地层井壁失稳原因的基础上,提出了提高空气可循环泡沫钻井液井壁稳定能力的3种技术,即选用自行研制的两性离子表面活性剂AC-2作为发泡剂,当其浓度为0.5%以上即可满足气体泡沫钻井携液要求;增加析液能力,经过析液的泡沫可将60%～70%的多余液相分离;选用自主研发的井壁稳定剂YJB-1,提高泡沫基液的抑制性.通过7口井的现场应用,在提高井壁稳定方面取得了比较理想的效果,为空气泡沫钻井技术在川东北地区应用提供了广阔前景.解决了川东北陆相地层钻遇水层后的钻进问题和井壁稳定问题,缩短了钻井周期,降低了综合成本.

Study on Improving Borehole Stability of Gas Foam Drilling in Northeast Sichuan

Analyzing the main factors of caving in upper terrestrial formations of Northeast Sichuan, three technologies of improving borehole stability of air foam drilling are discussed in this paper. Optimizing the zwitterionic surfactant AC-2(concentration>0.5%)to meet requirement of carrying fluid of foam drilling; improving the separation capability to separate excess fluid; choosing borehole stabilizer YJB-I to enhance the inhibition.The applications in 7 wells show that borehole stability has been strengthened...