韩城区块煤层气钻井堵漏技术措施的探讨

通过对韩城区块5口煤层气钻井漏失情况的分析,发现主要漏失层位为上部的孙家沟组和上、下石盒子组,漏失层的岩性以砂岩为主,且大都发生在岩性变化处。该区井漏形式主要为砂泥岩层段漏失及纵向裂隙漏失,据此提出了相应的堵漏措施：在渗透、纵向裂隙发育的砂泥岩中加入丹封、锯末及复合材料进行堵漏;在纵向裂隙发育的砂岩,漏失量较大时,采用大颗粒材料加水泥封堵,必要时用水泥固井进行堵漏。并针对该区的地层特性漏失原因,提出了相应的井漏预防措施。

Discussion on CBM Drilling Leak Plugging Technical Measures in Hancheng Region

Through analysis of leakage situation in 5 CBM boreholes in Hancheng area, found that main leak horizons are in the upper part of Sunjiagou Formation and upper and lower Shihezi formations, lithologic characters of leak layers are mainly sandstone, and mostly in lithologic changing sectors. The leak forms are mainly alternating sandstone and mudstone longitudinal fracture leakage, hereby, corresponding leak plugging measures put forward. During drilling in penetrating, longitudinal fracture developed sandstone and mudstone should add in sawdust and other composite materials; in longitudinal fracture developed sandstone with larger leakage, and then large-grained material and cement are used in plugging, and cementing off when necessary. Aimed at strata characteristics and leak causation, corresponding leak preventive measures put forward.