Research on water plugging technology for water-producing gas wells in Tainan gas field

Author of the article:OU Baoming1, CHENG Changkun1, DU Jing1, HUANG Tianpeng2, NI Yong1, KANG Ruixin1, ZHANG Zhixuan1, LI Fangming3

Author's Workplace：1. Drilling & Production Technology Research Institute of Qinghai Oilfield, Dunhuang, Gansu, 736202, China; 2. Borehole Operation Company of Qinghai Oilfield, Dunhuang, Gansu, 736202, China; 3. PetroChina Qinghai Oil & Gasfield Development Office, Dunhuang, Gansu, 736202, China

Key Words：Water producing gas well; Water plugging technology; Screen pipe completion; Chemical plugging agent; Horizontal gas well; Tainan gas field

Abstract：This paper is presented to address the issue of undesired effects of“drainage gas recovery”technological measures in the high water-cut development stage of the loose sandstone gas field in Tainan and difficulties in the treatment of produced water. On the basis of the understanding of the heterogeneity of gas reservoirs and the breakthrough of high-permeability belts along the edge water, combined with complicated well conditions such as easy deformation of horizontal well completion screens, the technological countermeasures for water plugging with selective chemical plugging agents are proposed in accordance with the difference of reservoir physical properties. And a plugging agent formula suitable for high-salinity formation water with high gel strength was developed. The core displacement experiments show that the plugging rate of water-phase core is greater than 90%, and that of gas-phase core is less than 20%. The plugging agent enjoys good injectivity and selectivity. The field test of TH3-1 well verified that the precipitation rate reached 80%, achieving the expected effect.