Abstract Using the principles of seepage mechanics, this paper analyzes the interrelationship between formation pressure and injection-production ratio and the influential factors. On the basis of a mechanical study, it quantitatively analyzes the pressure history of each area by means of a mathematical statistic method and the controlling factors, and the effect of every factor on formation pressure. It furnishes a scientific basis for the effective and rational control of the Southern development area of the Saertu Reservoir and each sub-area.
Introduction Injection-production ratio is a composite index, which reflects the balance condition of injection and production, characterizing the relation between fluid-withdrawal rate, water injection rate and formation pressure during waterflooding in an oilfield. It is also an important index to program and design the water injection rate. Reasonable injection production ratio can maintain formation pressure, so that the oilfield can have vigorous ability to produce fluid and oil, reduce ineffective energy consumption and improve oil recovery. Therefore, injection-production ratio should be regulated in accordance with the geological features of the oilfield and the development conditions, such as the active control of the formation pressure level, which is important in the optimization of the whole injection-production system, and is of great significance to the scientific development of the oilfield. The development principle of waterflooding at the early stage is to maintain formation pressure. However, with the development of deep reservoirs and taking various measures to tap oil potentials, especially successive development of different types of reservoirs, injection-production ratio of the oilfield has greatly changed. The previous procedure of keeping the injection-production ratio around 1.0 has been unable to maintain the desired formation pressure. The control of the injection-production ratio of the oilfield, and the relation between the injection-production ratio and formation pressure has problems to be resolved during further production in southern development area of Saertu Reservoir. Practical performance knowledge of the field, and history matching by means of a mathematical statistical method have shown the quantitative relations between the influential factors of the Southern development area of Saertu Reservoir and each sub-area.
Establishment Of Mathematical Model Between The Formation Pressure And Injection-Production Ratio Of the Oil Wells The formation pressure usually used in the material balance equation is the average formation pressure of the whole reservoir system. It is different from the oil well formation pressure usually used in the development performance analysis.