Title

Acid-Alternating-Base (AAB) Technology for Blockage Removal and Enhanced Oil Recovery in Sandstone Reservoirs

Abstract

An acid-alternating-base (AAB) system was evaluated based on ability to generate CO2 in a reservoir for blockage removal and oil recovery improvement. CO2 generation processes were measured in both the containers and the porous media for comparison. Optimal CO2 production and generating efficiency were obtained by adjusting the acid molar concentration ratio and system mass concentration. The AAB system had a good displacement efficiency in both homogeneous and heterogeneous porous media. Enhanced oil recovery (EOR) mechanisms of the acid-alternating-base (AAB) technology were then investigated. The basic solution of the AAB system can lower interfacial tension (IFT) between crude oil and displacing fluid; the CO2 generated in formation can swell oil and reduce oil viscosity; the heat released by the acid-base reaction can dissolve organics and increase oil recovery, and the pressure fluctuation caused by CO2 generation process and inorganic dissolution can also contribute to the improvement of oil recovery. This technology has been successfully applied in the offshore Bohai Bay Field approximately 200 km east of Beijing.

Department(s)

Geosciences and Geological and Petroleum Engineering

Comments

This work was supported by the National Science and Technology Major Project ( 2017ZX05009-004 ), the China National Offshore Oil Corporation ( YSB15YF002 ), the Science Foundation of China University of Petroleum-Beijing At Karamay (No. RCYJ2017A-01-001), and the China Scholarship Council ( 201606440051 ).

Keywords and Phrases

Acid-alternating-base technology; Blockage removal; Enhanced oil recovery; In situ CO2 generation; Sandstone reservoir

International Standard Serial Number (ISSN)

0016-2361

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2018 Elsevier Ltd, All rights reserved.

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