Exploration and Application of Natural Gas Injection, Water Injection and Fracturing Technologies in Low-Permeability Reservoirs in China

This article provides an overview of low-permeability reservoir development technologies, including carbon dioxide injection, nitrogen injection, air injection, natural gas injection, water injection (unstable water injection, advanced water injection), water–gas alternating injection, and hydraulic fracturing (hydraulic fracturing, repeated fracturing). These technologies have their own strengths and weaknesses in improving crude oil recovery and are significantly constrained by reservoir characteristics. This article uses specific cases such as the increase in CO2 injection pressure in Yaoyingtai oilfield, which significantly improves recovery rate, nitrogen injection in Zhongyuan oilfield, which increases adjacent well production and single-well recovery rate, air injection in a certain block of Changqing oilfield, natural gas injection in Yushulin oilfield, which has the best effect under specific pressure, as well as the effects and problems of water injection technology, the increasing production effect, and potential risks of hydraulic fracturing, to deeply analyze the application effectiveness and influencing factors of various technologies. Through comparative analysis, it can be concluded that CO2 injection has corrosion and gas channeling problems, nitrogen injection is limited by solubility, oxygen consumption in air injection is affected by temperature and pressure, natural gas injection is constrained by reservoir structure, water injection technology is unstable and difficult to determine timings, and fracturing technology faces difficulties in energy replenishment and time determination. Therefore, optimizing and applying these technologies rationally is of great significance for the efficient development of low-permeability reservoirs.