Reserves are the basis of oilfield development, and determination of reserves accurately has great significance for future adjustment of oil fields development. Due to distinct characteristics of offshore oilfield development, it is difficult to obtain dynamic reserves accurately using conventional methods. To overcome the limitations of existing methods, in this paper, a new model for calculating dynamic reserves is established through theoretical derivation with innovative introduction of relative permeability ratio and the quadratic power function of water saturation based on Buckley-Leveret function and frontal movement equation. The result shows that this approach is simple to use and with good applicability, and only needs typical oil field dynamic data. The results of the study facilitates better recalculation of oil field reserves and implementation of oilfield adjustment well. More importantly, it has laid out a new methodology for increasing oil production and exploration in Bohai oil field and provided theoretical foundation for subsequent oilfields’ efficient development.
Based on STM32 microcontroller, the design scheme of the gear box shell drying device is proposed, and the design framework and software design flow of the device are given. On the basis of high-performance MCU, the device can automatically complete the intelligent drying of the gearbox shell, and can carry out the secondary recovery of cutting fluid. At the same time, the device is equipped with a monitoring system, which can monitor the internal influencing factors according to the specified requirements, so as to achieve the goal of safety and efficiency.
Reasonable formation pressure maintenance level is significant to high-efficient development of oilfields. In order to study the effects of overlying strata pressure on permeability, oil-water phase permeability curve, and oil displacement efficiency, a physical simulation experiment is designed. Based on the experimental results and the oil-water phase flow theory, the production equation and the mathematical model of oil displacement efficiency considering stress sensitivity are established. And the productivity changes with pressure drop under different permeability are plotted. Then, the permeability coefficients calculated by quantitative characterization of stress sensitivity under different formation pressures are introduced into the numerical simulation model to quantitatively determine the reasonable formation pressure maintenance level of different reservoir properties. Experimental and theoretical studies show that the permeability decreases continuously with the increase in effective overlying strata pressure. In a low permeability reservoir, the more permeability decrease is caused by the increase in effective overlying strata pressure. When reservoir pressure is restored by water injection, the permeability loss is irreversible. With the increase in effective overlying strata pressure, the producer productivity decreases obviously, and the effective seepage capacity and oil displacement efficiency decrease. For reservoirs with permeability below 100 mD and high stress sensitivity, high formation pressure level should be maintained. For reservoirs with permeability of more than 300 mD, lower formation pressure is acceptable in the initial stage. The results are consistent with the actual production characteristics, which effectively guide the establishing of reasonable oilfield development strategy. It has important guiding significance to the oilfield development plans and development of the middle-deep oilfields.
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