提高均质致密碳酸盐岩储层酸蚀裂缝导流能力效果研究  

Improve the Effect of Acid Etching Fracture Conductivity in Homogeneous Tight Carbonate Reservoirs

作　　者：庄园[1] 王世彬[1] 郭建春[1] 

机构地区：[1]油气藏地质及开发工程国家重点实验室(西南石油大学),成都610500

出　　处：《科学技术与工程》2014年第20期35-38,共4页Science Technology and Engineering

基　　金：国家科技重大专项(2011ZX05045-03)资助

摘　　要：均质致密碳酸盐岩储层岩心经酸刻蚀后主要形成均匀刻蚀形态,裂缝主要通过少量凸起点支撑,岩性较软或在储层闭合应力时支撑点容易破碎或嵌入裂缝壁面使得裂缝大部分闭合,无法形成有效的自支撑渗流通道.通过向酸蚀裂缝内加入一定量的支撑剂能有效提高酸蚀裂缝导流能力.深入研究支撑剂粒径、铺砂浓度以及闭合应力等因素对酸蚀裂缝导流能力的改善情况.结果表明：自支撑裂缝随闭合压力增大下降迅速,在34.5 MPa时的导流能力已不足初始闭合压力下的2％,难以在储层闭合压力下有效保持,达不到长期增产的目的.增加额外支撑点的酸蚀裂缝,其导流能力在储层闭合压力下是自支撑裂缝导流能力的3～7倍.大粒径支撑剂能提供更高的裂缝导流能力,在酸压允许的情况下尽量选用大粒径支撑剂.现场对PG4井进行了加砂酸压改造技术,获得了6.314×104 m3/d的产量,证实了均质致密碳酸盐岩储层酸压改造中提供额外裂缝支撑剂的必要性.For homogenous tight carbonate reservoirs,the fracture surface mainly formed uniform etching pattern after acid etching and supported by a small amount of convex point.When rock is soft or in formation closre stress,those supporting points are easily broken or embedded into the fracture surface and consequently unable to form effective self-supporting flow channel.To better understand the improvement of conductivity after adding proppant in acid etching fracture,the influence of sanding concentration,proppant particle size,non-Darcy effects and closure stress on acid etching fracture conductivity were analyzed.The experimental results show that the conductivity of unpropped fracture drop rapidly with the increase of closure pressure,at a closure stress of 34.5 MPa,fracture conductivity is reduced less than 2％ of the initial conductivity and unable to meet the requirements of reservoir stimulation.Sand-adding fracture conductivity at formation closure stress is 3 to 7 times higher than self-supporting fracture conductivity.The bigger proppant can provide higher conductivity and should be selected if the acid fracturing conditions allow.Proppant-carrying acid fracturing technology was performed on well PG4 with a gas production rate of 6.314 × 104 m3/d,which confirms the necessity of adding additional support points in acid fracturing in homogeneous tight carbonate reservoirs.

关 键 词：均质致密碳酸盐岩储层 酸刻蚀 导流能力 支撑剂 非达西效应 

分 类 号：TE357.2[石油与天然气工程—油气田开发工程]