EOR application of CO2 injection for small fault block reservoirs in Subei Basin

CHEN Zuhua¹, WU Gongyi², QIAN Weiming², WANG Jun¹, MA Tao³, WANG Haimei¹, ZHENG Yongwang¹, XIONG Xinya¹

1. Research Institute of Exploration and Development, East China Oil and Gas Company, SINOPEC, Nanjing 210011, Jiangsu Province, China;

2. Taizhou Oil Production Plant, East China Oil and Gas Company, SINOPEC, Taizhou 225300, Jiangsu Province, China;

3. Petroleum Exploration & Production Research Institute, SINOPEC, Beijing 100083, China

Abstract: Based on the geological characteristics which are “broken, small, low, thin, and deep” and the development characteristics of “three low (low recovery factor, low oil production rate, and low average daily oil production), and three high (high recovery degree, high composite water cut, highly scattered remaining oil distribution)” of the small complex fault block reservoirs in Northern Jiangsu Basin (Subei Basin), five development technologies are formed in the East China Oil and Gas Field, including laboratory experiment, suitability evaluation, scheme design and timely optimization and adjustment, miscibility identification, and development evaluation. In addition, six supporting technologies of collection, purification, gathering and transportation, injection, oil production, and recovery are also formed. In the situation of low oil price and with the focus on the two key factors of cost and benefit, the CO₂–EOR technology applied in low permeability reservoirs is extended to the medium-high permeability reservoirs, and also developed from single flooding/stimulation to combined flooding/stimulation, which provides strong technical support for stable and increasing production and effective development in the old fields of Subei Basin.