This paper is the result of oil and gas exploration engineering.
Objective The low-permeability reservoirs of the Kexia Formation in the X zone of the Karamay Oilfield have problems such as poor physical properties and low waterflooding development and recovery, which affect the sustainable development of the oilfield. CO2 is the main component of global warming, every country in the world is trying to reduce its content in the atmosphere. This research attempts to use CO2 to drive oil and gas to increase the oil production rate in this reservoir and turn bane into a boon.
Methods According to the core samples of the Lower Karamay formation from more than 60 coring wells in the test area, combined with the data of SEM and mercury injection test, the reservoir characteristics are systematically studied, and the pore structure characteristics of low-permeability sandstone reservoir are clearly studied. Using reservoir numerical simulation technology, the injection and production parameters of CO2 water-gas alternating flooding (CO2-WAG) and CO2 continuous gas flooding were optimized, and on this basis, the two development modes were compared.
Results The optimum technical scheme is obtained: using CO2 water-gas alternating flooding technology, 15 wells are injected with water-gas alternately after 4 years of continuous gas injection. The gas-water ratio is 2:1, the gas-water ratio is 1:1 after 10 years. The numerical simulation predicts that the final recovery rate is increased by more than 30% after 15 years of gas injection development.
Conclusions Experiments show that the oil production after gas injection is 1.85 times that of water injection. The output is increased. It is of great significance to achieve stable production in the old oilfieldsand sustainable development of the oilfield.
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