Numerical Simulation of Low Salinity Water Flooding on Core Samples for an Oil Reservoir in the Nam Con Son Basin, Vietnam

Doanhuy Hien,Bui Viet Dung,Nguyen Minh Quy,Hoang Long,Pham Quy Ngoc,Pham Truong Giang,Pham Huy Giao,Dinh Duc Huy

doi:10.3390/en14092658

Abstract

Low-salinity water flooding (LSWF) is environment-friendly and operates similarly to conventional waterflooding without the need for synthetic chemical materials. The application of LSWF makes sense in Vietnam as HC production has steadily declined since 2002, and the majority of main oil fields have become near mature and mature fields. In the next years, Enhanced Oil Recovery (EOR) should be a top priority for Petro Vietnam to boost its oil production, for which the key issue is how to select a suitable EOR technology. In this study, LSWF of the Lower Miocene sand using low salinity water from Lower Oligocene sand was investigated. Previously at the Ruby field in the Cuu Long Basin, an LSWF feasibility study was carried out based on a conventional core flooding experiment, which is time-consuming and costly. This study targets the Chim Sao field in the Nam Con Son Basin, for which a cheaper and faster assessing method is required. As a result, a numerical code written in Matlab was developed and successfully validated with the core flooding experiment results obtained at the Ruby field. The LSWF simulation was conducted using the multiple ion-exchange mechanisms (MIE), and the results obtained showed an increase in the oil recovery factor by 2.19% for the Lower Miocene Sand. Another important outcome of this study is the innovative proposal and successful simulation to use the abundant low salinity water from the underlying Lower Oligocene sand as a natural LSW source to inject into the Lower Miocene oil reservoir that can be a decisive factor to help apply LSWF in practice on a wide scale not only for Chim Sao but also other similar oil fields in southern offshore Vietnam.

Highlights

For a long period since 1987, the main oil production of Vietnam has come from the famous White Tiger fractured granite reservoir in the Cuu Long Basin, which peaked in 2006 and started to decrease gradually
The simulation in this study focused, only on the multiple ion exchange (MIE) mechanism so that the simulation results can be compared and validated by the laboratory core flooding experiment results obtained at the Ruby oil field in the Cuu Long Basin [8]
As the coreflooding experiment for Low-salinity water flooding (LSWF) is quite expensive and time-consuming in general, and for the Chim Sao field in particular, we have investigated the feasibility of LSWF using a numerical simulation approach in this study

Summary

Introduction

For a long period since 1987, the main oil production of Vietnam has come from the famous White Tiger fractured granite reservoir in the Cuu Long Basin, which peaked in 2006 and started to decrease gradually. While the petroleum production from the Miocene sands is second to that from the fractured granite basement reservoirs since. As a matter of fact, most major oil fields in Vietnam are in a declining phase, which requires an intensive study on Improved Oil Recovery (IOR) or Enhanced Oil. Recovery (EOR) [1]. Thang et al (2021) in [1] reported that many major oil fields in Vietnam are in the declining phase and can be classified as mature or near-mature fields, which need the application of IOR/EOR to sustain their production life. An EOR master plan was proposed based on a recent comprehensive study by Quy et al 2020 [7], in which LSWF is considered as one of the viable methods, as shown in Figure 2 below:

Objectives

Results

Conclusion