New Technique for Condensate Banking Removal in Gas Reservoirs

摘要

In unconventional and tight-gas reservoirs, hydraulic fracturing treatments are widely performed to recover significant amounts of hydrocarbon, thus establishing unconventional plays as commercially viable. However, in gas reservoirs, formation damage and various unfavorable conditions, such as condensate banking, phase trapping, water-blocking, etc., can cause production that is less than expected. This paper introduces a new fracturing fluid additive that aims to help increase production following a hydraulic fracturing treatment and helps control fracture face damage. The new surfactant in the fracturing fluid system can allow faster production at higher rates. It can also provide a better regained permeability after hydraulic fracturing because it reduces formation damage caused by phase trapping and improves mobilization of liquid hydrocarbons, including condensate. The product has been typically designed for unconventional reservoirs, including tight gas, tight sandstone, shale, and coalbed methane. Coreflooding experiments were conducted to demonstrate the performance and efficiency of this new additive in fracturing fluid and to optimize its concentration. Favorable results were obtained from the experiments that indicated good formation damage control in terms of regained permeability along with significant condensate production after the fracturing fluid treatment. The additive, when used in specific concentrations, has physical and chemical properties that contribute to improving hydrocarbon production by enhancing the mobilization of liquid hydrocarbons. It tends to reduce the capillary pressure and surface tension of the treating fluid to allow higher fluid mobility in the treated reservoir zone. This effective new fracturing fluid system is environmentally friendly and exhibits excellent performance under high-temperature/high-pressure conditions. The fracturing fluid additive presented here helps overcome a condensate banking problem and unfavorable conditions, such as wells coming online slowly and low production rates resulting from formation damage following hydraulic fracturing treatments. Experiments validate the performance of the fracturing fluid additive, and significant condensate production for optimum additive concentration was observed during experimental treatments.