Forecast of hydrocarbon losses in deposits during the development of gas condensate fields

Abstract

The design and forecast of the development of gas condensate fields, accompanied by the construction of hydrodynamic models (HM), is based on the PVT model of a reservoir multicomponent system. To create such a model, a technique based on equations of state and an algorithm for modeling vapor-liquid transitions of hydrocarbon mixtures is used. The studies performed in the framework of the work by the contact and differential method on the reservoir fluid model (MPF) with imitation of the process of natural depletion of the deposit proved that low condensate content leads to lower losses in the reservoir. Thus, using the example of a reservoir mixture of the Kovyktinskoye field, it was revealed that this condensate content in the gas shifts the pressure of maximum condensation to the region of lower reservoir pressures. The productive horizon P is the basic object of concentration of industrial gas reserves and its constituent components. In the upper part of the terrigenous complex of the Chorskaya formation, it is represented by medium-fine-grained sandstones with subordinate layers of siltstones and mudstones. According to the ratio in the section of sandstone interlayers and siltclay deposits, the Parthenovsky horizon is divided into two separate layers (from top to bottom: P₁ and P₂), where there is no clay bridge between them in many wells. The results of the forecast of hydrocarbon losses in the P1 reservoir, that were performed using algorithms for modeling vapor-liquid equilibrium on a reservoir fluid model, allowed us to determine the pressure of the beginning of condensation, which was 25.40 MPa and the maximum condensation pressure equal to 7.50 MPa. The data of the conducted studies allow us to formulate predictive recommendations on changes in the properties of fluids and the condensate recovery coefficient.