Volume 33: CCUS Technologies for the Carbon Neutrality: Part I

Study on Laboratory Performance Evaluation of Anti-gas Invasion and Solid-free Killing Fluid for Carbon Dioxide Flooding WANG Li, LI Qingsong, CHEN Wenjiang, LI Guo, KANG Yan

Abstract

Gas prodution in the CO2 flooded production wells of low permeability reservoirs in Daqing Oilfield is increasing year by year, which makes conventional pump inspection operation impossible, and leads to the high cost of the operation with pressure. A new type of solid-free killing fluid is developed to balance formation pressure and ensure the safe field operation. The killing fluid is mainly composed of weighting agent, corrosion inhibitor, anti-gas invasion synergist and filtrate reducer. Laboratory performance evaluation results show that the density of the kill fluid can be adjusted in the range of 1.0~2.0g/cm3, the corrosion rate is less than 0.070mm/a, the anti-swelling rate can reach 95.9%, the API water filtration loss is less than 10mL/30min, and the water loss at high temperature and high pressure (4.1MPa, 85℃) is less than 10mL/30min after CO2 gas invasion. It has the characteristics of solid-free, low corrosion, low filtration loss, strong anti-swelling, and anti-gas invasion, etc., which can meet the requirement of well killing for CO2 flooding in peripheral low permeability reservoir.

Keywords CO2 flooding, Anti-gas invasion, Density, Solid-free, Well killing fluid, Performance evaluation, Low filtration