致密砂岩储层可动流体分布特征及主控因素  

Distribution Characteristics and Main Controlling Factors of Movable Fluid in Tight Sandstone Reservoir

作　　者：李亚婷[1] 童长兵 韩进[1] 师良 钟高润 赵帮胜 Li Yating;Tong Changbing;Han Jin;Shi Liang;Zhong Gaorun;Zhao Bangsheng(Yan′an University,Yan′an,Shaanxi 716000,China;Yan Chang Petroleum Group Coporation BaoTa Oil Production Plant,Yan′an,Shaanxi 716000,China)

机构地区：[1]延安大学,陕西延安716000 [2]延长石油股份有限公司宝塔采油厂,陕西延安716000

出　　处：《特种油气藏》2024年第4期44-53,共10页Special Oil & Gas Reservoirs

基　　金：国家自然科学基金“矿物脉体示踪富有机质页岩中烃类流体形成与演化:以大巴山构造带下寒武统为例”(42362021);延安市2023年科技计划项目“鄂尔多斯盆地中南部致密砂岩储层微观孔隙结构特征对可动流体赋存影响”(2023-CYL-151);陕西省2024年自然科学基础研究计划项目“CCS过程原位CO 2溶解核磁共振表征模型研究”(2024JC-YBQN-0341)。

摘　　要：针对鄂尔多斯盆地富县地区长8储层流体分布差异显著、孔隙结构复杂、渗流能力相对薄弱等问题,选取研究区5块典型岩样开展测试分析,利用铸体薄片、扫描电镜(SEM)、X衍射黏土矿物分析(XRD)、恒速压汞实验,对可动流体主控因素进行分析。研究表明:致密砂岩储层中可动流体饱和度为26.31%~50.61%,平均值为35.15%;可动流体孔喉半径为0.10~0.50μm;T_(2)截止值为6.69~49.90 ms,可动流体最小孔喉半径为0.16~0.36μm。储层渗透率较孔隙度对可动流体的控制更强;中值半径、最大孔喉半径、平均孔喉半径与可动流体均具有正相关性,中值半径影响较大;长石含量越高,越容易形成长石溶孔,可动流体饱和度越大;I类和Ⅱ类储层中高岭石含量较高,呈分散质点式填充孔隙,Ⅲ类储层中伊利石和伊蒙混层含量较高,呈搭桥式分割孔隙,是堵塞孔喉的主要原因。该研究成果可为提高致密油藏采收率提供参考和借鉴。Due to the significant variation in fluid distribution,complex pore structure,and relatively low percolation capacity of the Chang 8 reservoir in the Fuxian Area of the Ordos Basin,five representative rock samples from the study area were selected for testing and analysis.The primary controlling factors affecting fluid mobility were analyzed using thin section casting,scanning electron microscopy(SEM),X-ray diffraction clay mineral analysis(XRD),and constant velocity mercury injection experiments.The results indicate that the movable fluid saturation in tight sandstone reservoirs ranges from 26.31%to 50.61%,with an average of 35.15%.The pore throat radius for movable fluid is between 0.10μm and 0.50μm;the T_(2)cutoff value falls within the range of 6.69 ms to 49.90 ms,and the minimum pore throat radius for movable fluid is between 0.16μm and 0.36μm.The permeability of a reservoir exerts greater control over the mobility of fluids than porosity.The median radius,maximum pore throat radius,and average pore throat radius exhibit a positive correlation with movable fluid,with the median radius exerting a greater influence.Higher feldspar content facilitates the formation of feldspar dissolution pores,resulting in greater movable fluid saturation.TypeⅠand TypeⅡreservoirs exhibit high kaolinite content,with pores filled with dispersed particles.TypeⅢreservoirs exhibit high illite and mixed-layer illite content,with pores bridged and segmented,leading to pore throat plugging.These research findings provide valuable insights for enhancing the recovery of tight oil reservoirs.

关 键 词：微观孔喉 可动流体 核磁共振 致密砂岩 主控因素 鄂尔多地盆地 

分 类 号：TE122.1[石油与天然气工程—油气勘探]