This study concentrates on the modelling of three phase flow and miscible CO2 flooding in pore networks that captures the natural porous medium of a reservoir. That is to say, the network, that is a Matlab code, consists of different sided triangles which are located randomly through the grids. The throats that connect the pores are also created by the model. Hence, the lengths and the radii of the throats are varying. The network used in this research is assumed to be representative of mixed-wet carbonates in 2-D. Mixed wettability arises in real porous media when oil renders surfaces it comes into prolonged contact with oil-wet while water-filled nooks and crannies remain water-wet. The model developed is quasi-static approach to simulate two phase and three phase flows. By this, capillary pressures, relative permeabilities, saturations, flow paths are determined for primary drainage, secondary imbibition, and CO2 injection cases. To calculate the relative permeability, capillary entry pressures are first determined. Then, hydraulic conductances and flow rates of the network for each grid are obtained. Phase areas and saturations are also determined. It is accepted that the displacement mechanism in drainage and CO2 injection is piston-like whereas in imbibition it is either piston-like or snap-off.
The results of the model are compared with the experimental data from the literature. Although, the pore size distribution and the contact angle of the model are inconsistent with the experimental data, the agreement of the relative permeabilities is promising.
The effect of contact angle in the same network for three phase flow where immiscible CO2 is injected as a third phase at supercritical temperature (32 ° / C) is investigated. And it is found that, the increase in the intrinsic angles causes decrease in relative permeability values.
As another scenario, two phase model is developed in which miscible CO2 & / #8211 / water is flooded after the primary drainage of the same 2-D network at supercritical temperature (32 ° / C). This case is compared with the previous case and the effects of miscibility are investigated such that it causes the relative permeability values to increase.
Adsorption is another concern of which its effects are analyzed in a single pore model. The model is compared with the reported experimental data at high temperature and pressures. A reasonable fit is obtained.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/2/12606876/index.pdf |
| Date | 01 December 2005 |
| Creators | Uzun, Ilkay |
| Contributors | Akin, Serhat |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | M.S. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for METU campus |
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