Laboratory Studies of Producing Hydrogen and Incremental Oil From Light Oil Reservoirs Using Downhole Gasification
- M. Greaves (University of Bath, England) | T.X. Xia (University of Bath, England)
- Document ID
- Society of Petroleum Engineers
- Journal of Canadian Petroleum Technology
- Publication Date
- March 2010
- Document Type
- Journal Paper
- 65 - 70
- 2010. Society of Petroleum Engineers
- 5.5.2 Core Analysis, 5.5 Reservoir Simulation, 4.3.4 Scale, 5.4 Enhanced Recovery, 4.2 Pipelines, Flowlines and Risers, 5.4.2 Gas Injection Methods, 4.1.5 Processing Equipment, 4.1.2 Separation and Treating
- downhole gasification (DHG)
- 2 in the last 30 days
- 290 since 2007
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The idea of gasifying (reforming) a fraction of a light crude oil in the reservoir, was conceived originally by Davidson and Yule(1). This involved "stringing?? a series of downhole gasification (DHG) units along either a horizontal producer well or vertical producer well, or along some other suitable well arrangement.
Although catalytic steam reforming of naphtha practiced on a large scale has been extensively researched, such understanding is largely restricted to much lower pressures than those investigated in the present study. We present results obtained using a small, "pilot-scale?? DHG unit, or reforming reactor, operated at up to 100 bar pressure. The feed to this unit was a light naphtha fraction cut from Statfjord crude oil. The effect of pressure, catalyst loading, steam to hydrocarbon ratio and gasifier temperature were investigated.
Essentially, the conversion to inert gases, principally hydrogen and carbon dioxide, at high pressure was sufficiently high to make the process technically feasible in depleted light oil reservoirs. Furthermore, the economics of this novel enhanced oil recovery process, which also produces (and stores) hydrogen, appear to be very favourable. However, the experiments, which were conducted under pilot-scale conditions using a single-tube reactor unit, were not of sufficient duration time to test the long-term effects on catalyst activity owing to carbon fouling and sulphur poisoning. These factors (at least carbon deposition) can be controlled as demonstrated in the experiments by adjusting the steam-to-hydrocarbon ratio and the depth of naphtha-cut taken from the crude oil. These aspects of the process are to be further investigated in a Phase 2 project.
Davidson and Yule(1) originally conceived the idea of a self-contained, downhole gasification (DHG) unit as a safer, "greener?? method for transporting oil out of environmentally sensitive areas, such as the Everglades, as gas. Subsequently, the focus was directed towards applying DHG in depleted light oil reservoirs. The inert gases generated by a downhole DHG unit(s) are directed into a gas cap, or used to create a gas cap (Figure 1). This would then allow gravity stabilized displacement (GSGI), WAG, or another assisted gas injection technique, to be implemented for the purpose of improved oil recovery. This is still a high priority, especially in such areas as the North Sea, and the many hundreds of depleted light oil fields in the US, where output continues to fall. The main IOR problem is the availability of a suitable gas to inject into the reservoir, especially offshore. Although the displacement dynamics are likely to be complex because of the hydrogen in the generated gas, it is estimated that valuable incremental oil can be gained using the DHG process.
|File Size||1 MB||Number of Pages||6|
1. Davidson, I.F. and Yule, A.G. 2001. Enhanced Oil Recovery by In SituGasification. International Patent (IPC) No. WO/2001/81723.
2. Greaves, M., Xia, T.X., Rathbone, R.R., and Bentaher, A.H. 2005. DownholeGasification for Improved Oil Recovery. Prog. Oilfield Chem. 6(Managing Mature Fields and Wells): 1-12.
3. Greaves, M., Xia, T.X., Rathbone, R.R., and Bentaher, A.H. 2006.Producing Hydrogen and Incremental Oil from Light Oil Reservoirs Using DownholeGasification. J Can Pet Techol 45 (8): 41-47.
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