A Feasibility Research Of Exploitation Of Chang2+3Formation In Yingwang Oil Field

Reservoir Characteristics of Chang2+3formation in Yingwang oil field(including Sedimentary microfacies, physical property, heterogeneity,sensitivity,pore structure, seepage characteristics,etc.) was researched in the paper using various experimental methods,such as casting sheet,SEM, sensitivity experiments, permeability experiments, high pressure mereury intrusion, fluid displacement,etc. Main controlling factors of high quality reservoirs were discussed and the advantageous regions were predicted. Based on the researches above, The feasibility of exploitation of Chang2+3formation heavy oil reservoirs was analysed. Main achievements are summarized as follows:Sedimentary facies of the area is delta plain intrafacies and rock type is mainly arkose. Cementation type is pore-film cementation primarily and inlayer heterogeneity is weak.Interlayer heterogeneity of Chang22and Chang31formation are strong.Interlayer in this area developed well.Pore type in the area is mainly intergranular pore and pore combination type mainly dissolved-intergranular pore.Throat type is punctual throat primarily. The capillary pressure curves in the area was divided into3types(Ⅰ,Ⅰ,Ⅲ).Reservoirs are mainly lithological-structural reservoirs in the area.The reason for the high viscosity oil in Chang2+3formation is the low formation temperature primarily. Reservoirs in the area was divided into3types. Type I and Type II reservoirs in each formation could be recognized as favorable zones.Chang2+3formation belongs to ordinary2-class heavy oil reservoir. Analysed from the technical measures(huff and puff, gas mixture exploitation, hot-water injection,etc.) that were used in the area formly and compared the oil reservoir parameter of Yingwang oil field with the selecting criteria of exploitation technology for heavy oil reservoir domestic and overseas,we draw a conclusion that thermal recovery is unsuited for Yingwang oil field and the only suitable method is chemical visbreaking cold production technology.Indoor displacement experiment showed that displacement efficiency is noly35.7%even the viscosity reducer was added and it could not reach the lower limit of industrial exploitation.We suggested that the reservoir should not enter the large scale exploitation phase at the existing economic and technological conditions and chose type I favorable zones to carry on field trial at the same time of enhancing indoor research about displacement experiment which viscosity reducer was added.