Organization
School of Petroleum and Natural Gas Engineering, Southwest Petroleum University, Chengdu 610500, China
State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Engineering, Southwest Petroleum University, Chengdu 610500, China
Xinchun Oil Production Plant, Shengli Oilfield Company, SINOPEC, Dongying 257000, China)
Abstract
In-situ polymerization plugging agent has been widely concerned due to the advantages of good injection property, controllable gelation time and strong gel strength. However, the gelation time and stability of high temperature and high salinity reservoirs need to be further improved. In this paper, the effects of different salinity types on the gelation performance have been researched experimentally and the infuence degree of Na+, Ca2+ and Mg2+ is compared. The results show that some cations in the formation water, to some extent, play a positive role in promoting the gelation time and gelation strength of system. The order of their effects on system gelation is as follows: Ca2+>Mg2+>Na+. Na+ has the greatest effect on the gelation time of plugging agent and has the minimum impact on the stability of colloid, which can keep the gel plugging agent from syneresis for a long time. As the concentration of each ion increases, the stability of colloid decreases.