The Research Of Reservoir Geological Characteristic And Waterflood Development Plan In Huaziping Zhangcha Region

Huaziping Zhangcha oil region is located in the middle of the slope of Ordos in northern Shaanxi, the Chang6 oil-bearing layers is a major development in this area strata. After many years of practice has proved that the Chang 6 reservoir formations turnout low energy, low development efficiency, therefore it need to replenish the formation energy, enhanced oil recovery efficiency. The study area tried to start infusion in small-scale in 2010, and received some success, but in the development process, due to a ambiguity understanding of the geological conditions, the development program unreasonable, resulting in many problems. Based on the original basis of the geological understanding, together with re-examine the geological features and classify the developed strata and make reasonable adjustments for well network and resolve the injected water quality problems, we attempt to make a reasonable choice of waterflood timing, establish a rational water flooding pressures regime.On the basis of understanding of regional geology and combination of lithology and logging discipline theory, we divide and correlate stratigraphic of the study area, prepare the top surface structure map, analyze its structure characteristics, the study area only exist local nose-like uplift caused by different coMPaction. In addition, according to the outcrop and core data, combined with logging response characteristics, sedimentary facies analysis carried out, Chang 6 are thought to reflect delta front facies, including underwater distributary channel, mouth bar, front sheet sands, natural levee, interdistributary bay, five kinds of sedimentary microfacies. Then through the sand flat distribution characteristics, we analysis sedimentary micro facies and evolutionary characteristics, and make a research on reservoir and petroleum deposit characteristics. The casting thin sections and scanning electron microscopy analysis results show that the Chang 6 are mainly composed of arkose, and pore types are dissolution intergranular pore and intragranular dissolved pore, reservoir physical property is bad. Reservoir sensitivity analysis test results show that are mainly weak water sensitivity, velocity sensitive, weak alkali sensitivity and medium acid sensitivity. Chang6 reservoir trap types are mainly lithologic trap.Based on the above research results, Chang 6 in region are thought to divide into a development series of strata more reasonable. In addition, by means of the contrastive analysis of gas injection and waterflooding of the two types of energy development, we confirm the Chang 6 feasibility of waterflooding in region.The research results show that Chang 6 reasonable well pattern form is rhombus pattern at 9 o’clock, reasonable well spacing density is 14/km2,and wells line direction and fracture direction is NE510-NE68.70. Furthermore, to analyze the injection-production pressure system, determine the maximum bottom hole injection pressure is 19.28 MPa, the biggest wellhead injection pressure is 11.5 MPa, the reasonable formation pressure is 6.21 MPa< P< 8 MPa, the reasonable flowing pressure is 1.7 MPa to 2.26 MPa, and production pressure difference is from 4.7 MPa to 4.7 MPa. Finally, on the basis of geological research and water flooding technology research, we adjust the study area deployment and predict the development effect.