川西地区蓬莱镇组开发水平井固井难点及对策

DIFFICULTIES AND COUNTERMEASURES OF HORIZONTAL WELL CEMENTING TECHNOLOGY IN CHUANXI PENGLAIZHEN FORMATION

川西地区蓬莱镇组气藏储量丰富,勘探开发前景巨大,因气藏为致密砂岩气藏,直井采收率低,采用水平井开发技术。针对前期水平井固井技术不成熟,固井质量较差,重点分析了蓬莱镇组水平井固井技术难点。提出应重视钻井与注水泥过程中的沉床岩屑的清除;旋流扶正器和双弓弹性扶正器交替组合使用,实现螺旋流顶替;在套管居中度得到保证的前提下,加大施工排量;合理使用固井液浆柱结构,优化水泥浆性能;使用膨胀水泥浆体系与防气窜水泥浆体系,减小水泥石的收缩率,增强水泥石的应力胶结;延缓水泥浆的"失重",提高其防气窜效果。通过在川西蓬莱镇组几口水平井固井中实践验证上述技术的综合应用是可行的。

Gas reserves are rich in the tight sandstone gas reservoir of Chuanxi Penglaizhen formation,the exploration and development prospects are huge.In order to improve recovery ratio,the horizontal well development technology was adopted.Because the early horizontal well cementing technology wasn' t mature,the cementing quality was poor,the technical difficulties of horizontal well cementing were analyzed in Penglaizhen formation.Some measures which improve cementing quality were proposed,such as paying attention to removal cuttings during drilling and cementing;alternating use cyclone centralizer and double bow elastic centralizer to realize spiral flow displacement;increasing construction discharge capacity under the condition of the casing centralization;using rational cementing fluid column structure and optimizing the cement slurry performance;adopting dilatant cement slurry system and gas-check cement system to reduce the shrinkage of cementstone and enhance the cementation stress of cementstone;delaying the ' weightlessness ' of the cement slurry to improve the effect of anti-gas channeling.These measures have been applied successfully in horizontal well cementing of Chuanxi Penglaizhen reservoir,the results were proved these measures were feasible.