Enhanced Oil Recovery – EOR
Minimum Miscibility – Rising Bubble
Rising bubble apparatus (RBA) provides accurate, cost-effective measurement of minimum miscibility pressure. The most essential feature of the apparatus is a flat glass tube mounted vertically in a high pressure sight gauge in a temperature controlled oven. The glass tube is flat for better examination of bubbles rising in opaque oils and is approximately 20 cm long. The glass tube is back lit for visual observation of the tube contents. A hollow needle is mounted at the bottom of the of the sight gauge and protrudes into the rounded portion of the glass tube. The tip of the needle is kept about 3 – 5 centimeters below the flat portion of the tube. Initially the sight gauge and glass tube are pre-filled with deionized water at the initial test pressure and reservoir temperature. Reservoir oil is then injected downwards into the flat glass tube, displacing the water until only the lower circular portion of the glass tube contains any water. A small gas bubble is then formed at the tip of the hollow needle and eventually launched into the tube. The bubble rises through the water, through the water/oil interface and up through the column of oil. After two or three bubbles have risen through the oil the contaminated oil is replaced with a fresh batch of reservoir oil.
The behavior of the gas bubble is monitored using a motion tracking optical system consisting of a video camera mounted on a rail parallel to the path of the rising bubble. The magnified view of the bubble can be viewed on screen and is recorded as a small movie clip (mpeg).
Core Laboratories record the lifetime of each injected gas bubble in seconds (calculated from number of captured frames) at each test pressure and use this data to interpolate the MMP.