玛18井区压裂支撑剂适应性研究

FracturingProppant Adaptability in the Wellblock Ma18

为了研究玛18井区压裂支撑剂的适应性,在不同铺置方式和不同闭合压力下,对不同压裂支撑剂的导流能力与压裂后效果进行分析评价,根据小型压裂测试、闭合后分析等解释结果,进行储层压裂后特性分析,并对石英砂部分代替陶粒效果进行论证。结果表明:当高闭合应力时,增大铺砂浓度可有效提高裂缝导流能力,但分段式铺砂不能提高裂缝导流能力;混合支撑剂和全陶粒支撑剂的改造井地层能量与裂缝类型均类似,但混合支撑剂井的地层系数、动态储量均不如全陶粒井,且日均压降高于全陶粒井。研究认为,石英砂替代陶粒效果较差,主要原因在于:在裂缝改造类型相同时,由于储层埋深较大,地应力较高,混合支撑剂无法满足所处深度的地应力。通过计算动态储量可知,长期开采时陶粒支撑剂比石英砂支撑剂更有利于节省成本,建议在玛18区块继续采用全陶粒支撑剂。

In order to determine the fracturing proppant adaptability in the Wellblock Ma18,the conductivities and post-fracturing performances of different proppant categories were analyzed under different proppant placing patterns and closing pressures.The post-fracturing reservoir properties were analyzed according to the mini-frac test and post-closing analysis.In addition,it also presents the fracturing performance of partially replacing ceramsite with quartz sand.Result indicates that high sand placing concentration could effectively enhance the fracture conductivity under high closing stress condition,but subsection sand placing is incapable of enhancing fracture conductivity.The formation coefficient and dynamic reserve of the well with mixed proppant are all lower than that of well with all-ceramsite under similar formation pressure and fracture category,and the corresponding daily pressure drop is higher than that of well with all-ceramsite.Research illustrates that replacing ceramsite with quartz sand shows a relatively poor fracturing performance.The major reason is that under the similar fracture category,the mixed proppant is unable to meet the in-site geo-stress due to the greater reservoir depth and higher in-situ geo-stress.According to the dynamic reserve calculation,it can be concluded that ceramsiteproppant is more cost-effective than quartz sand proppant in long-term production.Full ceramsiteproppant is recommended in the Wellblock Ma18.