水平井分段酸压工艺在大牛地气田的研究与应用

The Application and Research of Sectional Acidic Fracturing Technology in Horizontal Wells of Daniudi Gasfield

大牛地气田下古生界发育有裂缝-基质性碳酸盐岩气藏,气藏基质渗透率低,微裂缝发育。储层改造过程中存在储层段酸液滤失严重、实现深度酸压困难、直井效果差、建产难等问题。以大牛地气田下古生界碳酸盐岩储层地质特征为基础,开展了水平井分段酸压工艺技术研究,优选出多级管外封隔分段酸压工艺技术+转向酸液体系。在此基础上,采用"高排量、降阻、缓速、降滤、大规模、深穿透"的技术思路,对水平井分段酸压参数进行了优化,在大牛地气田水平井PG2井的现场试验中取得了良好的改造效果,为今后大牛地气田下古生界同类储层的酸压改造提供了借鉴意义。

Fractured-matrix carbonate gas reservoirs were developed in the lower Paleozoic system of Daniudi Gasfield,which was characterized by low matrix permeability and micro fractures.There existed the problems of serious acid filtration and difficulty of deep acidic fracturing with poor effect in straight wells and difficult production.Besides,the poor production result of vertical well caused difficult industrial production.Based on the geologic features of carbonate reservoirs of the lower Paleozoic in Daniudi Gasfield,a multistage external packer section of acid fracturing was optimized in combination with diverting acid system by studying sectional acidic fracturing in horizontal wells.On the basis stated above,the idea of high displacement,drag reduction,low speed,fluid-loss reduction,large scale and deep penetration technology is used for optimizing the sectional fracturing parameters of the horizontal wells,and better reconstruction effect is obtained in the field application in Horizontal Well-PG2,it provides reference for acidic fracturing in similar reservoirs in the lower Paleozoic in Daniudi Gasfield.