白云岩储层酸蚀裂缝导流能力实验研究  

Experimental study on conductivity of acid etched fractures in dolomite reservoirs

作　　者：李宪文[1] 侯雨庭 古永红[1] 张存旺 牟春国[1] 齐宁[3] 潘林 LI Xianwen;HOU Yuting;GU Yonghong;ZHANG Cunwang;MOU Chunguo;QI Ning;PAN Lin(Oil and Gas Technology Research Institute,Changqing Oilfield Company,PetroChina,Xi’an City,Shaanxi Province,710018,China;Exploration Department,Changqing Oilfield Company,PetroChina,Xi’an City,Shaanxi Province,710018,China;School of Petroleum Engineering,China University of Petroleum(East China),Qingdao City,Shandong Province,266580,China)

机构地区：[1]中国石油长庆油田分公司油气工艺研究院,陕西西安710018 [2]中国石油长庆油田分公司勘探事业部,陕西西安710018 [3]中国石油大学(华东)石油工程学院,山东青岛266580

出　　处：《油气地质与采收率》2021年第1期88-94,共7页Petroleum Geology and Recovery Efficiency

基　　金：国家科技重大专项“中亚和中东地区复杂碳酸盐岩油气藏采油采气关键技术研究与应用”(2017ZX005030005)。

摘　　要：酸蚀裂缝导流能力是评价酸压效果的关键参数之一,目前碳酸盐岩油藏裂缝酸蚀实验研究多集中在灰岩储层,对白云岩储层的相关研究鲜有报道。灰岩与白云岩储层的酸岩反应特征差异明显,为了对白云岩储层裂缝酸蚀形态和微观反应机理进行研究,以长庆油田取心白云岩储层岩心为例,开展酸蚀裂缝导流能力实验研究,并通过3D激光扫描对比分析灰岩与白云岩岩板酸蚀微观形态。通过短期导流能力实验,分析储层物性、酸液浓度等条件影响下酸蚀裂缝导流能力的变化规律。结果表明,白云岩相对于灰岩而言,其表面反应速度低,酸岩反应速度慢,酸岩反应速度数值相差一个数量级;白云岩酸液刻蚀程度低,溶蚀主要沿节理面进行,高酸液浓度有利于深入酸蚀节理面,从而沟通基质与裂缝;另外高浓度酸液能更为充分地刻蚀酸压裂缝壁面,提高非均匀刻蚀程度,获得更高导流能力的裂缝;通过数值模拟研究发现,酸液交替注入可以有效地提高白云岩岩板的非均匀刻蚀程度,提高酸蚀裂缝导流能力,改善酸压改造效果。The conductivity of the acid etched fractures is one of the key parameters to evaluate the acid fracturing effect.At present,the experimental research on acid etch of fractures in carbonate reservoirs focuses mainly on limestone reser⁃voirs,and the related research on dolomite reservoirs is rarely reported.The acid-rock reaction characteristics of limestone and dolomite reservoirs are obviously different.In order to study the acid etch morphology and microscopic reaction mecha⁃nism of dolomite reservoir fractures,we carried out experimental study on the acid etch conductivity of fractures with the core of dolomite reservoir in a block as the object and comparatively analyzed the micro-morphology of acid etch of lime⁃stone and dolomite slates by 3D laser scanning.Through the short-term conductivity experiment,the trend in conductivity of acid etched fractures under the influence of physical properties of the reservoir and acid concentration was analyzed.Compared with limestone,dolomite has a lower surface reaction rate.Moreover,its acid-rock reaction rate is an order of magnitude less than that of limestone.The acid solution of dolomite leads to less etch and its dissolution is mainly along the joint surface.High acid concentration is conducive to the solutions’deep permeation through the acid etched joint surface,so as to connect matrix and fracture.In addition,the acid solution of a high concentration can more fully etch the wall sur⁃faces of acid fractures to improve the non-uniform etch degree and obtain fractures of greater conductivity.Through numeri⁃cal simulation,it was found that alternating acid injection could effectively improve the non-uniform etch degree of dolomite slates,the conductivity of acid etched fractures,and the acid fracturing effect.

关 键 词：酸压 酸蚀裂缝 白云岩 导流能力 非均匀刻蚀 长庆油田 

分 类 号：TE357.2[石油与天然气工程—油气田开发工程]