| What is called "substrata" is always single sand or single sand layer and belongs to the lowest reservoir unit. The division and correlation of substrata is the most important for the research of oil and gas exploitation, its credibility relates the distribution of oil and gas layers in portrait and landscape orientation. This research will try to resolve the distribution and controlling factors of gas layers by the study of division of substrata in Bawu gas field.The main reservoir of Bawu gas field are the sand layers in the formation of K1sh, K1y,K1d, K2q, sediment delta plane, delta frontier, plait delta developing distributary riverway sand, bayou sand dam, far sand dam and river sand of plait. Its sands tend to be laterally inextensive in the plane. This research know distribution and connectivity of the sand layer by the study of division and correlation of substrata, and effective analyze the distribution of gas pool, disciplinarian of gas and water, heterogeneity, condition of reservoir, making hydrocarbon, caprock and the type of trap in the whole field. On the direction of sequence stratigraphy theory, Writer sets down unit framework in this gas field on the basis of analysis of logging data of 42 wells, seism synthesize and API of 17 wells and 155.5m core data of 8 wells. Four key interface, fifteen three stage sequence interface are been set off in the research strata. The substrata are been divided and contrasted in controlling grade with low circle model. It can be dispart 137 sand layers in the droop of 15 sand groups and adds up to 1191single sand layers, summarizes 7 types of correlation: steady, spite, pinch, stack, stack-pinch, stack-spite, complex in the work. The relation between the distribution types of substrata with reservoir levels are four types of reservoir, and I, II are good reservoir of gas in Bawu gas field. By the study of logging result of 31 wells, it can be known that the development of gas layers are different in every well area, disperse in the portrait, and the relation of gas and water so complicates, the distribution of pure gas area is small, bound of connect is limited. The gas layers are controlled by the faults in the direction east and west in the plane, and in the direction of north and south the connectivity is somewhat better, the wells of connection become more and the gas layers stand in the high place of structure. The character of this gas field are more gas layers, distribution concatenation in the portrait, and instability in the landscape orientation. They are separated by the faults in the direction of east and west, restricted by the lithology in the direction of south and north. The separation of gas and oil and water only limits to small system of gas pool and there are not separation of gas and water in the large bound. The border water is not active, the system of gas and water is small and driving power of water is poor. The degree of mineralization of strata water is lower, the type of water is sodium carbonate andrespects the character of closing transition in the continent circumstance. Taking all the parameters character of the gas pool into account, it can be result that fullness of gas pool is lacking and gas layers are more blocks by the influence of faults, and thereout the model of making pool can be done. |
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