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Using surfactants below their critical micelle concentrations, CCMC' to reduce gas mobility throughout a reservoir can be advantageous. When used in reservoir brines below their CCMC inexpensive anionic surfactants propagate through rock with little delay owing to adsorption. Yet gas mobility is reduced below that of a watertlood in either surfactant-water-altemating-gas (SWAG) or coinjection experiments. Moreover, oil recovery is higher than in processes without surfactant. In contrast, at concentrations above the CCMC, surfactant adsorption is much higher and the injected surfactant concentration can be greatly delayed. In addition, CO 2 mobility can be reduced so far below that of a watertlood that injectivity suffers. Moreover, oil recovery can be reduced because oil is emulsified and its mobility is lowered. This type of foam should be considered only for near-wellbore fluid diversions.

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Minimal Fab System Photolithography has been developed for wafer patterning process without the requirement of a cleanroom. It consists of minimal resist coater, minimal maskless UV exposure, minimal mask aligner and minimal resist developer. We have proved in practice that the spin coating using minimal resist coater for a 0.5-inch wafer gives the identical result of resist thickness compared with 4-inch wafers without changes to a higher rotational speed. The minimal maskless UV exposure using Digital Light Processing (DLP) confirms that only one LED light source with the light intensity of 150 mW/cm 2 can expose over a 0.5-inch wafer in a few minutes. The minimal mask aligner is developed for a high speed exposure within 5-20 seconds. The aligner also uses a LED light source that can produce the light intensity of 14 mW/cm 2. The present photoresist resolution for the maskless UV exposure and the mask aligner are 1 µm and 2 µm, respectively. The minimal developer has minimized its consumption of developing agents. Due to the surface tension, a volume of developing agent is kept on the wafer surface for slowly spinning to stimulate the developing process. The developing time is 20% saved from that of the conventional puddle development.