陕北下古生界低渗储层酸压改造技术研究

Reservoir Reconstruction by Acidization of Low-permeability Reservoirs of Lower Palaeozoic System in Northern Shaanxi Area

针对陕北下古生界奥陶系马家沟组碳酸盐岩储层低孔、低渗、非均质的特性,通过室内实验和现场施工实践,研究出适于陕北下古生界储层的酸压前置液和胶凝酸主体配方体系。该体系具有较低的表面张力,有利于压后残液快速返排,减少对地层的伤害。3口井的现场试验均采用多级注入酸压+闭合酸化工艺技术,实践证明其施工工艺是可行的;最后对陕北富县探区今后的酸压工作提出了具体的建议。

It was demonstrated by internal and external oilfield operation that acid fracturing was an effective stimulation often used in low permeability and hard to be produced carbonate reservoirs. In allusion to the characters of low porosity, low permeability and heterogeneity in carbonate reservoirs of Majiagou Formation in lower Palaeozoic Ordovician system, by laboratory and field tests a formula system suitable for pre-pad and gelling fluid was developed for lower Palaeozoic reservoirs, it had low surface tension and was beneficial for rapid flow back of residual fluid, reduced formation damage. It is used in 3 wells by using the method of acid fracturing with multi-stage injection + closed acidization, it is demonstrated that the technique is feasible and proposal is provided for the acid operation in the future.