Method for determination of sandstone oil reservoir oil-water relative permeability under different temperature gradients

Abstract

A method for determination of a curve of sandstone oil reservoir oil-water relative permeability under different temperature gradients comprises the following steps: 1) according to displacement experimental data of different temperature gradients under normal temperature conditions, determining curves of oil-water relative permeability at different experimental temperatures, and building a relationship formula for the variation rule of oil-water viscosity and endpoint saturation along with the experimental temperatures; 2) normalizing data of the curves of oil-water relative permeability under different temperature gradients, and determining values of A1, A2, n and m and a relationship formula for the values and the temperatures; and 3) building a relationship formula for oil phase relative permeability Kro and water phase relative permeability Krw with the temperature t. The method can quantitatively describe the influence of the experimental temperature on the curves of oil-water relative permeability, converts the curves of oil-water relative permeability under different temperature conditions, provides a more reliable reference for oil reservoir numerical value simulation, subsequent development program prediction and on-site construction works, and can effectively reduce costs and save time due to no need for performing of a lot of core displacement experiments.

Description

technical field [0001] The invention relates to the technical field of petroleum development reservoir engineering, in particular to a method for determining the relative permeability of oil and water in sandstone reservoirs under different temperature gradients. Background technique [0002] The relative permeability curve is one of the most important basic data in the development of oil and gas reservoirs. It is used in many aspects such as numerical simulation of oil and gas reservoirs, dynamic analysis of water flooding oil and planning schemes. [0003] The influence of temperature on the relative permeability of oil and water is crucial to the study of the seepage and displacement process of thermal oil recovery, and the morphological characteristics of the relative permeability curve reflect the properties of the reservoir. In the application of numerical simulation, reasonable and accurate relative permeability curves have a great influence on the fitting of historic...

AI Technical Summary

Problems solved by technology

The relative permeability test process is simple and time-consuming under normal temperature conditions, but the relative permeability curve tested cannot truly reflect the actual seepage characteristics of the reservoir

However, the phase permeability test process under high temperature and high pressure conditions is complicated, there are many considerations, and it takes a long time. It is difficult to implement when there are many samples in the oil field.

In recent decades, scholars at home and abroad have carried out many experiments to study the influence of temperature on the relative permeability curve. The results all show that the temperature rise has a significant impact on the relative permeability curve, but there is no method to characterize this effect at present.

[0005] At present, the conventional relative permeability curve test in the laboratory often does not meet the temperature and pressure conditions of the formation. How to correctly obtain the relative permeability curve under the actual reservoir temperature conditions is still controversial.

Based on this problem, Bennion et al. used the regression equation method to establish the relationship between water saturation, endpoint saturation, oil-water two-phase relative permeability and temperature of unconsolidated sandstone reservoirs in western Canada under low-temperature and high-temperature conditions. This method is based on a large number of experiments. Based on the data, the applicability is not strong for reservoirs with a small number of samples; Sola et al. performed curve fitting on parameters such as injection / production rate, injection / production pressure, and water / oil production data based on the black oil model, and obtained The oil-water relative permeability curves at different experimental temperatures were compared with the Johnson-Bossler-Neumann (JBN) method, which is commonly used in unsteady state data processing methods. The results show that the relative permeability curves obtained by JBN method and fitting method have certain deviation

The above methods are all aimed at specific oilfield blocks, and the methods are complex and not widely applicable

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