FACTORS AFFECTING THE GAS RECOVERY COEFFICIENT AT GAS CONDENSATE FIELDS WITH ABNORMALLY HIGH RESERVOIR PRESSURE

Abstract

The results of numerical experiments to assess the influence of abnormally high reservoir pressure on the dynamics of pressure reduction at the bottom and the supply circuit, flow rate and life of wells are presented. It is shown that the growth of the anomaly coefficient of reservoir pressure has a positive effect on the dynamics of the considered indicators. It has been established that in hydrocarbon deposits with abnormally high reservoir pressures, the rock pressure of up to 75% is balanced by the pressure of saturating hydrocarbons. High rates of gas extraction, achieved due to large depressions on the reservoir in producing wells, lead to reservoir deformation, which in fractured and fractured-pore reservoirs leads to the closure of hydrocarbon filtration channels. Using the example of the Severny Nishan gas condensate field, it is shown that the deformation of the reservoir is the main reason for the low efficiency of development and the abandonment of half of the gas reserves in the reservoir. Hydraulic fracturing technology is recommended for the extraction of residual gas reserves. With an increase in the depth of the productive horizons, the proportion of hydrocarbon deposits with abnormally high reservoir pressures is steadily increasing. As it is known, the energy potential of productive layers is largely determined by the activity of the legal aquifer area. There are elision and infiltration natural water pressure systems. The experience of developing hydrocarbon deposits with AVPD shows that this factor, depending on the geological and physical conditions of the deposits, can affect the oil and gas recovery coefficient as a positive (increasing) and negative (decreasing) factor. At the same time, as positive factors, there is a higher concentration of reserves in the specific volume of the deposit, relatively high well flow rates, ensuring the gushing of wells for a long time, maintaining high reservoir properties of reservoir rocks, and as a negative factor, a decrease in stability and susceptibility of oil and gas saturated reservoirs to deformation processes.