高温致密砂砾岩储层盐敏及盐析损害机理  

Formation Damage in High Temperature Dense Glutenite Reservoirs by Salt Sensitivity and Salt Precipitation

作　　者：何瑞兵 谭伟雄[3] 白瑞婷 康毅力 李鸿儒[3] 李鑫磊 游利军 HE Ruibing;TAN Weixiong;BAI Ruiting;KANG Yili;LI Hongru;LI Xinlei;YOU Lijun(CNOOC China Limited,Tianjin Branch,Tianjin 300459;State Key Laboratory of Offshore oil Exploitation,Tianjin 300459;CNOOC EnerTech-Drilling&Production Co.,Tianjin 300459;State Key Laboratory of Oil&Gas Reservoir Geology and Exploitation,Southwest Petroleum University,Chengdu,Sichuan 610500)

机构地区：[1]中海石油(中国)有限公司天津分公司,天津300459 [2]海洋石油高效开发国家重点实验室,天津300459 [3]中海油能源发展股份有限公司工程技术分公司,天津300459 [4]西南石油大学油气藏地质及开发工程国家重点实验室,成都610500

出　　处：《钻井液与完井液》2024年第2期155-165,共11页Drilling Fluid & Completion Fluid

基　　金：中海石油(中国)有限公司重大科技专项“渤海油田上产4000万吨新领域勘探关键技术”(CNOOC-KJ 135 ZDXM36 TJ 08 TJ)。

摘　　要：中国渤海湾盆地广泛分布特低渗致密砂砾岩油气藏,与常规砂岩储层相比,致密砂砾岩储层具有黏土矿物丰富,溶蚀孔隙及微裂缝发育且非均质性强等特点,注入流体侵入容易诱发储层损害,堵塞孔喉,降低储层渗流能力,阻碍油气井稳产。以BZ19-6井区砂砾岩储层井下岩心为例,分别依据行业标准法和高温高回压稳态法开展储层盐敏损害室内实验评价,基于扫描电镜分析了敏感性矿物和盐类矿物的类型及赋存特征。实验结果表明:储层盐敏程度为中等偏强~强;岩心渗透率越低,盐析对储层的孔隙度和渗透率的损害程度越大,建议对于渗透率小于0.1 mD、储层温度高于100℃的致密岩心,推荐应用高温高回压稳态法评价储层流体敏感性更具优势。研究区黏土矿物以丝片/丝缕状伊利石、蚀变高岭石及伊/蒙间层矿物为主,主要呈栉壳式、分散充填、搭桥等方式赋存于溶蚀孔隙,是储层盐敏的主要因素。高温环境地层水加速蒸发,易导致近井带盐析,盐类矿物主要为钾盐和石盐,赋存于矿物颗粒表面和孔隙壁面易堵塞微细孔喉;地层水静态蒸发可溶盐析出堵塞致密孔喉、动态驱替盐晶运移堵塞喉道及盐析弱化岩石力学强度,导致微粒运移是致密砂砾岩盐析损害的主要机理。推荐使用KCl-饱和盐水聚磺钻井液和两性离子聚合物钻井液技术,通过降低钻井液侵入和抑制盐类在钻井液中的结晶和成核,从而降低储层盐敏损害。Ultra-low permeability tight glutenite reservoirs are widely distributed in the Bohai Bay,China.Compared with conventional sandstone reservoirs,the tight glutenite reservoirs are rich in clay minerals,highly developed with dissolved pores and microfractures,and have strong heterogeneity.Invasion of injected fluids into the glutenite reservoirs easily induces formation damage and blocking of pore throats,thereby reducing the flow capacity and the production rates of oil and gas.Cores taken from the glutenite formation in the BZ19-6 block were evaluated for salt sensitivity damage according to the industrial standards and high temperature high back-pressure steady-state method.The types and in-situ characteristics of the sensitive minerals and salt minerals were analyzed using SEM.The experimental results show that the salt sensitivity of the Kongdian glutenite is moderately strong to strong.Since the lower the permeability of the core,the higher the damage to the porosity and permeability of the core by salt precipitation,it is thus recommended that for dense cores with permeability less than 0.1 mD and reservoirs temperature higher than 100℃,the high temperature high back pressure steady state evaluation method be used to evaluate the flow sensitivity of the reservoir rocks.The clay minerals in the Kongdian formation are mainly silky/filamentous illite,altered kalinite and mixed illite/montmorillonite which exist in the dissolution pores in the form of comb shell type,dispersed filling and bridging etc.,and are the main causes of salt sensitivity of the reservoirs.High temperature accelerates the evaporation of formation water,causing salt precipitation near the wellbore.The precipitated salts are mainly potassium salt and halite which exist on the surfaces of the mineral particles and walls of the pores,and cause the pore throats to be easily clogged.The main mechanisms of dense glutenite formation damage by salt precipitation include static evaporation of formation water which leads to clogging of the dense p

关 键 词：近源沉积 砂砾岩 流体敏感性 微粒运移 储层损害 评价方法 

分 类 号：TE258[石油与天然气工程—油气井工程]