头台油田茂503区块储层物性及增产措施研究

Reservoir physical property and stimulation treatment of block Mao-503 in Toutai oilfield

为进一步了解大庆油田外围低渗区块储层物性特征,为其开发措施调整提供理论依据。以头台油田茂503区块天然岩心为研究对象,采用压汞仪、X射线能谱仪、扫描电镜和驱替设备,在测定目标储层孔隙结构特征、矿物组成、润湿性和储层敏感性后,结合室内渗吸实验及矿场试验效果,提出了渗吸采油提高原油采收率的增产建议。头台油田茂503区块储层物性研究实验结果表明,储层岩石主要组成黏土矿物为伊利石、蒙脱石和高岭石,主要组成元素为氧(O)、硅(Si)、铝(Al),此外含有少量铁(Fe)、镁(Mg)、钠(Na)、钡(Ba)、碳(C)等元素。目标储层孔隙度范围为10%~17%,渗透率范围为(0.4~8.2)×10^(-3)μm^2,属于中等孔隙度、特低渗透砂岩储层,岩石孔喉尺寸相对较小,分选性和连通性较差;岩石表现出弱亲水性,毛管力在采油过程中可作为动力加以利用;储层岩石表现出较强流速敏感性、水敏感性和碱敏感性。室内实验及矿场试验均表明,类似物性区块适合开展渗吸采油,适当加入表面活性剂有利于提高渗吸采收率,改善开发效果。

The further understand of the reservoir characteristics of the peripheral low permeability blocks in Daqing oilfield pro- vides the theoretical basis for the adjustment of the development measures. Taking the block Mao-503 in Toutai oilfield as an exam- pie, and by using the equipment of the mercury injection apparatus, the X-ray energy dispersion spectrometer, the scanning elec- tron microscope and the displacement equipment, we provide the stimulation suggestions of the improving recovery ratio by the im- bibition oil recovery, according to the imbibition test and field experiment effects and based on the characters of the pore structure, mineral composition, wettability and reservoir sensitivity. The reservoir physical properties test of the block Mao-503 in Toutai oil- field shows that the main clay minerals of the reservoir rock are the illite, montmorillonite and kaolinite, the main component ele- ments are oxygen （O）, silicon （St） and aluminium （A1）, and the minor elements are ferrum （Fe）, magnesium （Mg）, natrium （Na）, barium（Ba） and carbon（C）. The target reservoir with the porosity between 10 % and 17 % and the permeability range of （0.40 N 8.2） ~ 10-3l.~m2 belongs to the medium porosity and ultra-low permeability sandstone reservoir. The pore throat size of the rocks is relatively small, and the sorting and connectivity are poor. Furthermore, the rocks show weak hydrophilicity, and the capillary force can be used as power in the process of the production. Meanwhile, the rocks have strong velocity sensitivity, water sensitivity and al- kaline sensitivity. The indoor experiment and mineral field experiment show that the similar physical block is suitable for the imbi- bition oil recovery, and adding the surfactant into the water solution is good for improving the imbibition recovery and enhancing the development effects.