Research And Application Of Foam Fracturing Technology In Low-pressure Gas Reservoirs In Western Sichuan

Chuanxi gas reservoir, the medium-shallow pay of which is with both low ermeability and porosity, now arrive at its last exploitation period while the formation pressure is getting lower and lower. For formation with both low pressure and permeability is highly sensitive to fluids injected into wellbore, common fracturing fluids and acids applying to such reservoir often leads to great leak-off, low flowback velocity and rate, ect.. Meanwhile, the retention of treatment fluids always brings serious damage to the formation.Aiming at these problems, based on statistical analysis of the implementation effect of nitrogen ejecting, evaluation of the foam fracturing adaptability on Chuanxi low pressure gas reservoir was conducted. Using of relevant knowledge, through laboratory experime, Carried out the following research:(1) Evaluation of the feasibility and adaptability of foam fracturing process, based on the mechanism of foam fracturing technology research, research on the optimal combination of foam fracturing test blocks Block geological characteristics; by foam fracturing equipment, fracturing materials and fracturing economy other aspects of the analysis of different types of foam fracturing process to evaluate the feasibility and adaptability, preferably suitable foam fracturing technology type.(2) Development of foam fracturing fluid system. Foam system by evaluating the foam volume and half-life, preferably foaming agent with excellent foaming ability. Impact study fracturing fluid additives which performance foaming system, and further preferably optimal foaming system. Effect of fracturing fluid performance evaluation as temperature, pressure, foam quality and other parameters.(3)Foam fracturing technology research, including foam fracturing parameter optimization, foam fracturing equipment and processes.(4)Foam fracturing field test, field tests were analyzed to assess the effect of the foam fracturing the formation.Through the above research, the site implementation shows that the foam racturing technology can effectively improve the fracturing fluid flowback rate, reduce the time of the formation of the fracturing fluid, thus relieve the damage fracturing fluids bring about, at the same time shorten the time for producing gas. It proves that this technology has good potential on application in low pressure gas reservoir for improving well production and recovery efficiency.