渤海海域Z油田水驱开发储层物性变化规律

为研究海上稠油砂岩油藏水驱开发储层物性变化规律,以渤海海域Z油田为目标,利用多口密闭取心井资料,结合油田生产实际,从储层的黏土矿物、孔隙结构、储集孔渗及渗流特征等方面系统开展了水驱开发前后储层物性变化规律及机理研究。结果表明,经长期水驱开发,储层中黏土矿物总量呈减少趋势,其中高岭石含量降低,伊/蒙混层含量增加;岩石平均孔隙半径增加,孔隙喉道和孔隙结构变好;平均孔隙度和渗透率都有不同程度增大,其中孔隙度增幅不大,渗透率增幅较为明显,储层储集物性变好,但非均质程度增强;润湿性表现为更强的亲水性,驱油效率也随之增高。该研究成果对Z油田高含水期剩余油挖潜和注采结构调整的措施制定有一定的指导意义。

RESEARCH ON RESERVOIR PHYSICAL PROPERTIES CHANGES DURING WATER FLOODING:A CASE FROM Z OILFIELD IN BOHAI SEA

In order to reveal the reservoir physical property changes in water flooding for offshore heavy oil sandstone reservoirs,systematically study has been carried out taking the Z Oilfield in Bohai Sea as an example.The data of clay minerals,pore structure,porosity,permeability and seepage characteristics are fully applied,in addition to multi-core wells analyses and actual production data.The researches show that after long-term water flooding,the total amount of clay minerals shows an obvious decreasing trend.The kaolinite content is decreased and the content of mixed layer illite/smectite increased.As the consequence,the average pore radius,the pore throat and pore structure increased,and the average porosity and permeability increased to varying degrees.The increase in porosity is little,but in permeability is obviously improved.The overall physical properties of reservoir become better,but the degree of heterogeneity is enhanced.Reservoir wettability is characterized by greater hydrophilicity and increased oil displacement efficiency.The research can effectively guide the adjustment of the development of remaining oil and injection-production structure in high-water-cut period of the Z Oilfield.