Regular Article

Influence of salinity on the properties of the different HPAM/Al³⁺ systems

¹ Department of Petroleum Engineering, China University of Geosciences, Wuhan 430074, China
² Department of Petroleum and Gas Engineering, Balochistan University of Information Technology, Engineering & Management Sciences (BUITEMS), Quetta 87300, Pakistan
³ Institute of Petroleum Engineering, China University of Petroleum (East China), Qingdao 266580, China

^* Corresponding author: chshpu_tx@126.com

Received: 25 September 2018
Accepted: 15 February 2019

Abstract

In order to achieve oil increment and water cut reduction in the heterogeneous oil reservoirs, a conformance control technology by using HPAM/Al³⁺ systems has been widely used due to the low price and environmental friendliness. However, the complex structure and state of high-valent metal ions in brine water can directly affect the properties of the different HPAM/Al³⁺ systems, which may lead to unreasonable applications. Therefore, in order to better utilize the HPAM/Al³⁺ systems, the characteristics of gelation of HPAM and the three types of aluminum citrate under different salinities are systematically studied. Experimental results show that an important reason for the cross-linking reaction of HPAM/Al³⁺ being affected by salinity is that the morphology and structure of the aluminum citrate complex is different under the different salinities. Although the change of characteristics of the reaction time and the cross-linking degree of the three HPAM/Al³⁺ systems are different, the process of the cross-linking reactions of the three HPAM/Al³⁺ systems are the same. Besides, the thermal stability of the HPAM/Al³⁺ gels is weakened with the increasing of salinity regardless of the ratio of citrate ligands to Al³⁺. According to the matching relationship between salinity and HPAM/Al³⁺ systems, the reaction time can be controlled to achieve the requirements of on-site construction operation for the conformance control of a given heterogeneous oil reservoir.