The Study About The Feature And Genetic Mechanism Of Gas/Water Distribution Of Xujiahe Formation Of Xinchang

The well field of Xinchang is situated in the interior of Deyang of Sichuan province.The local structure of Xinchang gas field locates the middle part of large uplift zone of NEE direction of Mianzhu-Yanting of middle part of West Sichuan Depression,and the Pengxian syncline and the zitong syncline locate selectively its south and the north.The Xinchang structure is a nosing structure which plunge to the east,and the west neighbourhood is the Xiaoquan anticline,and it joint the SN direction structure of Qinggangzui and Hexingchang at its east. According to the research result,we find that the gas pools of Xujiahe formation of Xinchang has the features including tight reservoir,general gas,favorable seal and save condition,superior generating-accumulating-caping collocation,vegetal traps,large resource amount.So,its exploration activity occurs the phase that simulcasts high profit and high hazard.With constant exploratory development research,we find the Xujiahe formation of Upper Triassic of Xinchang of West Sichuan Depression has conditions developing large and medium size gas field.In 2000,the well of X851 made a breakthrough in Xinchang structure,and disclosured there would be a tremendous foreground of exploration in the gas reservoirs of Xinchang.Henceforth,the high production well of X2 and so on discovered give us firm belief about the resource of Xichang.During the formation of oil and gas accumulation,as the displacing force and carrier,the groundwater plays an important role. The groundwater of Xujiahe formation is mainly the calcium chloride-type of gas field water.The type of Xu 4's groundwater is relatively homogeneous,but The types of Xu 2's groundwater are relatively diverse,including not only the type of closed and burial groundwater with high salinity,but also the low-salinity condensate water and the mixed water between the two.The Xu 2's natural gas is mainly the dry gas which is high maturity-post maturity mixed gas;but the natural gas of Xu 4 is mainly the humid gas which has the lower maturity than Xu 2's and is the typical coal-formed gas.With the study of feature and regular pattern of gas/water distribution of the region,the exploratory development of its oil and gas would be directed well.The long-term study of exploration activity of Xinchang indicates:The Xujiahe formation of Xinchang has favorable bear-storage-cap conditions,and well developed traps,and it presents the feature of general gas storage of reservoirs.but thanks to the feature of"deep buried depth,extra tight reservoirs,high aeolotropy"of gas pools of Xujiahe formation of Xinchang,and presenting water content of many stratigraphic positions of Xu 2 and Xu 4,there is the"complex relationship,indistinct regular pattern"feature with gas/water distribution of Xujiahe formation of Xinchang.Through the research of basic distribution features of gas/water distribution plane and profile of Xu 4,Xu2;we find the upper member of Xu 4 has the feature that contain water universally,and the under member only display it has water locally At present,and its sandbodies are dense universally,and the proportion of Gas-bearing sandstone is not high in it.Through the character of water content of sand body,we find that the sets of sand body has the feature that the lower parts have high water saturation and the higher parts have high gas saturation;But Xu 2 has the feature of universal gas,and the distribution of water layers which are in the same permeable reservoir are controlled by the location of the level of the structure,and There is no uniform gas-water interface with the whole gas reservoirs of Xu 2.According to analysis of connectivity,we can find the sandbodies of Xu 4 and Xu 2 are very development,and it has the features of the same set of sandbody with great connectivity and having bad connectivity between the different sandbodies.Xu 2 has the features that the sandbodies are connected and the gas bearing reservoirs are not connected,but if they have the great conditions of existence of fractures and the dredge effect of cracks,the gas/water formation of the region could be in a good connectivity status.Based on the significance and complexity of gas/water distribution of Xujiahe formation of Xinchang,many scholars have been putting their hands to research the gas/water distribution of gas pools of Xujiahe formation of this region.Based on the research outcome of predecessors,and with the measures of seism and logging in this research,I will generally understand the relationship between the key elements including structure and sediment and so on and the gas/water distribution,and do my best to discover the master control elements and the genetic mechanisms of the gas/water distribution of gas pools of Xujiahe formation of this region,and point out the relationship of gas and water distribution and distribution law nowadays,and establish gas and water distribution pattern of Xu 2 and Xu 4 of the area and predict the distribution of gas and water in the plane of upper Xu 4 and middle Xu 2,and then offer references to evaluate the potentiality of exploration of deep zone of this region further and realize the concentration situation of natural gas of Xujiahe formation of Xinchang.