| Popis: |
Fracturing with slickwater has been widely adopted over the past couple of decades in the development of shale and tight formations. Horizontal wells utilize 0.5 to 1 million gallons of water per stage for upward of 40 stages per well. Reducing water usage in hydraulic fracturing treatments is of global interest due to various motives including water scarcity, government regulations, environmental concerns, and optimizing flowback and well productivity. The objective of this paper is to explore foamed slickwater as a potential alternative fluid to slickwater. A circulating-loop foam rheometer having a helically coiled, 10 ft long tube was utilized in this study to compare the rheological behavior of slickwater and CO2-foamed slickwater at varying foam qualities. The rheological behavior of water and linear gel at varying foam qualities was also investigated. These fluids were tested under a wide range of conditions including pressures up to 5000 psi, temperatures up to 300°F, and shear rates up to 1500 1/s. In addition, SEM imaging and geomechanical testing on tight carbonate rock specimens were performed to investigate the effect of slickwater and supercritical CO2 on rock texture and tensile strength. A growing body of literature has recently proven that injection of supercritical CO2 generates much more complex fracture network compared to slickwater-induced fractures in unconventional formations. CO2 alone has poor proppant carrying capacity. This paper presents a novel demonstration of carbonated slickwater as a potential fluid that maintains good proppant carrying capacity while achieving less fresh water consumption, faster and efficient flowback recovery, improved hydrocarbon recovery due to CO2 miscibility with reservoir fluids, and potentially a more extensive stimulated reservoir volume. |
