Features of formation of the temperature field in a well with a multilayer system during oil degassing

Abstract

As is known, well thermometry is one of the main methods for diagnosing the condition of a well and formation while monitoring the development of oil and gas fields. Despite the widespread use of thermometry in the oil and gas industry, today the question of the formation of the temperature field in a well with a multilayer system under conditions of oil degassing remains poorly understood. Therefore, it is relevant to study thermohydrodynamic processes that form the temperature field in the well-reservoir system based on a mathematical model of the movement of a two-phase flow of oil and gas, taking into account oil degassing. Based on a numerical model describing the non-isothermal movement of a two-phase fluid in a well with a multi-layer system, the article discusses the problem of selecting soda oil from a well that operates two layers. The formation of the temperature field is due to the influence of the adiabatic and Joule-Thomson effects, as well as the heat of gas degassing. The system of differential equations is solved numerically, and discretization by the control volume method. The resulting system of nonlinear equations is linearized by the Newton-Raphson method, the roots of which are found by the Gauss method from the LAPACK library. The paper considers the features of temperature effects in a well with a two-layer system for various durations of pressure reduction at the wellhead, oil saturation pressure with gas, as well as the functional dependences of the relative phase permeabilities of phases on saturation. It is shown that a sharp decrease in pressure at the wellhead leads to significant cooling in the first hour of well operation. The results can be used in the planning of field geophysical studies and interpretation of the results of temperature studies of wells in the production of gas-cut oil.