Evaluation of Prediction Models for the Physical Properties in Fire-Flooding Exhaust Reinjection Process

Yong Wang,Shihao Fan,Long Chen,Dongyang Hua,Shouxi Wang,Mingliang Chang

doi:10.3390/en15020562

Abstract

The reinjection of the fire-flooding exhaust is a novel disposal process for handling the exhaust produced by the in-situ combustion technology. For reasonable process design and safe operation, it is of great significance to select an optimum property calculation method for the fire-flooding exhaust. However, due to the compositional particularity and the wide range of operating parameters during reinjection, the state equations in predicting the exhaust properties over the wide range of operating parameters have not been studied clearly yet. Hence, this paper investigates the applicability of several commonly-used equations of state, including the Soave–Redlich–Kwong equation, Peng–Robinson equation, Lee–Kesler–Plocker equation, Benedict–Webb–Rubin–Starling equation, and GERG-2008 equations. Employing Aspen Plus software, the gas densities, compressibility factors, volumetric coefficients, and dew points for five exhaust compositions are calculated. In comparison with the experimental data comprehensively, the result indicates that the Soave–Redlich–Kwong equation shows the highest precision over a wide range of temperature and pressure. The mean absolute percentage error for the above four parameters is 3.84%, 5.17%, 5.53%, and 4.33%, respectively. This study provides a reference for the accurate calculation of the physical properties of fire-flooding exhausts when designing and managing a reinjection system of fire-flooding exhaust.

Highlights

The LKP equation has the highest precision in forecasting the dew points, but it is not accurate enough in calculating the compressibility factors and volume coefficients with the mean absolute percentage error (MAPE) of beyond 6%
It is revealed that the GERG-2008 equation is considered as the international standard model for the natural gas, it is not entirely suitable for the fire-flooding exhaust
Accurate prediction of the physical properties with the change of working conditions is of significant importance for the design and simulation of the reinjection processes of fire-flooding exhaust

Summary

Introduction

To improve the production of heavy oil reservoirs, some enhanced oil recovery (EOR) methods [1,2] have been adopted, such as steam flooding [3], high-pressure nitrogen flooding [4], CO2 flooding [5], fire flooding [6], microbial technology [7], and so on. Among them, taking the technical advantages of efficient oil displacement, low unit thermal cost, and wide applicability, the fire flooding technology is one of the most effective and promising ways to improve the thermal recovery of heavy-oil resources [8]. By combusting the air underground, the heat and mixed gas generated push the heavy oil from the gas injection well to the production well to realize short-distance displacement of heavy oil [9]

Objectives

Methods

Results

Conclusion