Multi-component thermal fluids stimulation is a feasible way to recover offshore heavy oil reservoir. As a new technology, its mechanism of enhanced oil recovery should be understood through systematic simulation experiments and quantitative analysis. Laboratory experiments were carried out to investigate the effects of temperature, natural gas, and various gases (N 2 , CO 2 , or N 2 +CO 2 ) on the viscosity of heavy oil from Nanbao block of Bohai offshore oilfield. The results show that in the range of 56 • C (reservoir temperature) to 120 • C, natural gas saturated and degassed oils are all very sensitive to temperature, and the viscosity is reduced by more than 90% when heated to 120 • C; under lower temperature condition, injection of 5MPa N 2 , N 2 +CO 2 , or CO 2 can significantly reduce the viscosity of natural gas saturated heavy oil, with a viscosity reduction ratio of about 20%, 50%, and 80%, respectively, at 56 • C. Therefore, heavy oil production by viscosity reduction can be achieved by raising temperature or through gas injection. Taking into account the equipment, heat loss, and cost of steam injection, the technology of moderate heating, auxiliary gas injection is very promising for the recovery of Nanbao heavy oil.
Guizhou Province which located in the southwest China is one of China's least developed but fastest growing provinces, has large reserve potential for Coal Bed Methane (CBM) but yet, the natural gas utilization is among the lowest in China. The exploitation of CBM resources in the province started since early 90's, but no substantial breakthrough has been achieved. Among all the challenges encountered in the attempt to develop the resources, one key challenge is on how to frac stimulate the coal seams effectively. The high coal-rank CBM reservoirs commonly contain low permeability multiple thin coal seams that require frac stimulation to flow. However, conventional blanket-type frac treatment via pumping down casing at high rate has been shown to leave some coal seams untreated and not contributing. Pin-point fracturing using coiled-tubing allows multiple precisely targeted coal seams to be treated, which can increase gas flow rate and reserve, and significantly shorten time cycle as compare to conventional casing frac method. Three CBM wells in the north-west Guizhou province in China have been pin-point stimulated using coiled-tubing producing gas at an encouraging rate compared with conventional method. This paper discusses how the pin-point fracturing technique been introduced for the very first time to Guizhou CBM wells, the details of the concept, fracturing process, operational methods, treatment outcome of the field trial, and how the technology could shape the future of CBM exploitation strategy in Guizhou Province.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.