| Gas injection flooding as an important method of EOR has been researched and applied on a large scale in both laboratory and field. Nowadays, several methods for screening out which one is best for gas injection among great number of reservoir have been presented in literature. Among these methods, most all of them adopted fuzzy integration assessment method. Although it has splendid processing capability for uncertainty assessment element systems that characterized by fuzzy number, the fuzzy integration assessment is inability for dealing with element of assessment represented by interval number (closed interval). If we simply consider that the value of evaluation index in every scheme has been accurately matched, the result will have no help but lost its due scientific and practical purport, and probably lead to do a wrong determination.In order to reduce the risk of gas injection reservoir screening that caused by the uncertainty of the layer factor and the influence of anthropogenic factor. Based on gas injection miscible flooding as well as immiscible flooding mechanism, this paper has systematically analyzed various influencing factors on gas injection effect, screened out several important reservoir parameters, and established the system of appraising and screening indexes. According to investigating a large number of domestic and international gas injection reservoir data, estimated the limitation of each index, corroborated the index's extent, established screen model of gas injection reservoir for different conditions. We make key research for such screening model of double uncertain terms that the reservoir evaluation index and evaluating index weight of gas injection reservoir are interval number. Case study indicates this method can reflect the truth of the stratum even more than other methods, and has more rationality and validity. This method has extensive practicability and wide prospect in other fields of oil development. |
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