The Research Of Logging Recognition Method Of Effective Reservoir On Layer 9 For Hang 219 Zone In Jiyuan Area

Jiyuan area is located in the territory of Ningxia, Yanchi County, the East Mafang oilfield, the westarrived in Hong jingzi oilfield. The main oil-bearing bed is the Triassic yanchang formation and Jurassic yan’an formation. Jiyuan oilfield is typical of the low permeability tight sandstone reservoirs, reservoir property is bad, anisotropy is strong and the relationship between oil and water is complicate of the reservoir. The difference of diagenesis and pore configuration seriously impacted the ability which takes well logging data to accurately identify and evaluate reservoir. We research the Chang9 reservoir of Jiyuan area in the Ordos Basin from the complex pore structure of low permeability reservoir, the electrical and lithology characteristics, logging interpretation model, low permeability formation with rapid identification and logging, capacity prediction and other aspects.The depositional system of the Chang9 reservoir in Jiyuan area belongs to the delta plain environment, main microfacies types are distributary channel, inter distributary bay and channel flank. The main rock types are lithic arkose, feldspathic sandstone, the content of feldspar and quartz are higher, debris is lower, and mainly metamorphic rock debris. The average porosity of Chang9 reservoir is 12.92%, average permeability is 1.91×10-3μm2, reservoir property is bad, the characteristics perform low porosity, low permeability. The pore types of Chang9 reservoir in H219 of Jiyuan area are mainly intergranular pores, followed by feldspar dissolution porosity and other pore types are relatively small. The average displacement pressure is 0.23 Mpa, median pressure 4.36 MPa, median throat radius is 0.17μm, Chang 9 reservoir develops small pore and it’s pore structure is not good. Diagenesis is the main factor to control reservoir developing, our study area has a strong diagenesis, complex type, compaction plays a major role in the destruction of primary porosity, while developing the cementation; Metasomatism and dissolution play a major role to form secondary porosity, and play a very important role to improve the reservoir properties of the area. Study of H219 reservoir heterogeneity is mainly from three angles ofinner layer, interlayer and plane heterogeneity of reservoir. The coefficient of variation of Chang 9 reservoir is medium; the on rush coefficient is weak; poor coefficient of medium. the entire layer of Chang 9 continuous superposition of occurrence in thick sandstone composition and interlayer heterogeneity is medium to weak. On the basis of fine interpretation model of reservoir parameters and the lower limit of reservoir properties, the paper established reservoir parameter limit value method, invasive characteristics analysis method, acoustic time overlap with the resistivity diagram method, lithology-electrical crossplot method, differential analysis method, horizontal contrast method and other comprehensive technologies for judging oil-water bed quantitative and qualitative to improve the coincidence rate.