利用扩孔方法提高侧钻小眼井的固井质量

IMPROVE THE CEMENTING QUALITY OF SIDETRACKING SLIM HOLE BY REAMING

研究了造成侧钻小井眼井固井质量低、寿命短的主要原因 ,介绍了所采取的措施和扩孔施工工艺。现场实践证明 ,侧钻后对小井眼进行扩孔 ,可以迅速去掉钻井过程中形成的污染带 ,降低钻井液侵入油层的深度 ,减少对油层的污染 ,提高油井产量。扩孔后井壁上形成的滤饼薄且致密程度低 ,易于在固井时冲洗掉 ,可以有效地提高第 2界面的固井质量 ,减少后期的油气水窜。扩孔加大了环空间隙 ,固井后水泥环厚度和强度增大 ,可以延长侧钻小井眼油井寿命。

Reasons causing the poor cementing quality and short well life of the sidetracking slim hole were investigated, and the measures taken and reaming techniques were also illustrated. Field practices proved that by conducting the reaming operation after slim hole sidetracking could rapidly remove the contamination zone formed during drilling operation, and minimize the invasion depth of drilling fluid and reservoir contamination, thus improve the production rate. The mud cake on the hole wall formed after reaming was thin and incompact, and could be easily washed out during cementing, thus effectively improve the cementing quality at the second interface and minimize the chances of channeling afterwards. The annular clearance was also enlarged, thus the thickness and strength of the cement sheath was increased, and the oil well life of the sidetracked slim hole was also prolonged.