浅层疏松砂岩稠油油藏聚合物驱矿场试验效果评价

哈萨克斯坦CB油田具有埋藏浅、胶结疏松、地下原油黏度大、地层水矿化度高、储层高孔高渗的特点,经过多年的注水开发后,地层非均质性加剧、注水波及效率低、采出程度低、综合含水高,油水关系日趋复杂,开发效果亟待改善。开展聚合物驱试验的目的是通过优选适合CB油田特征的抗盐聚合物体系,实现封堵高渗流通道、改善吸水剖面、增大水驱波及体积,达到深度调驱、提高采收率的目的。通过在油田4个井组应用聚合物复合弱凝胶实施聚合物驱试验,结果表明聚合物复合弱凝胶有较强的适应性,注聚施工后井组平均日产油量增加了21. 7 t,平均含水下降了7. 7%,降水增油效果显著,累计增油超过2×104t。建议在该油田针对不同区块的地质油藏特点精选注聚井组,通过推广应用逐步扩大注聚规模、形成集中效应,不断提升油田的开发效果。

Effect Evaluation on the Industrial Experiment with Polymer Flooding in the Shallow Unconsolidated Sandstone Heavy Oil Reservoir

CB oilfield in Kazakhstan is characterized by shallow-buried, loose cementation, high viscosity of underground crude oil, high salinity of formation water and high porosity and permeability of reservoir. After years of waterflooding development, formation heterogeneity becomes stronger, waterflooding sweep efficiency is low, recovery degree is low, water cut is high, oil-water relationship is becoming more and more complex, development effect needs to be improved urgently. The purpose of polymer flooding experiment is to plug crossflow channel with high permeability, improve water injection profile, increase the sweep volume of water flooding, realize deep profile control and flooding, and enhance oil recovery by optimizing salt-resistant polymer system, which is suitable for CB oilfield characteristics. By using polymer composite weak gel in the 4 well groups of the oil field to carry out the polymer flooding experiment, the results showed that the polymer composite weak gel had strong adaptability. After the polymer injection, the average daily oil production of well group increased by 21.7t, the average water cut decreased by 7.7%, the effect of oil increasing and water cut decreasing was significant, and the cumulative oil increased more than 20 thousand tons. It is suggested that polymer injection wells should be selected carefully according to the characteristics of different geological areas in the oilfield, and the injection scale should be gradually enlarged by popularizing application to form a concentrated effect, so as to continuously improve the development effect of CB oilfield.