| Sichuan basin is a large and ancient basin,which is also a basin of petroleum structure in western China.The exploration area of oil and gas in Sichuan basin is achieved 18.8km2,here the natural gas is abundant,the natural gas resources of Sichuan basin are reached 10.6×1012m3.Based on the existing proven reserves in the basin,the proved rate is just that 19.5%.The total resource of exploration in Sichuan basin is 4063.5 ×108m3,which have found that is 293.06×108m3,The resource discovery rate and the detection rate are very low,only is 7.21%and 4.3%,The prospect of oil and gas exploration is very promising.In east Sichuan,surface condition is very complicated,landform undulates terribly,and the cropped anticline mostly consists of Permian and Triassic carbonate rocks.Its limb beds were folded severely to become very steep,vertical and even reverse,so that there occur many over thrust faults.There are quite heavy acoustic wave,surface wave,side wave and other noise waves in raw seismic data in this area.Influenced by both lateral velocity variation and some noise waves(bow tie,side wave,diffraction wave,etc.),which is in the wubaiti the stacked seismic sections have quite poor im-age quality to cause some distorted geological structures.At present,In the eastern of the Sichuan basin,the wubaiti buried structure which has been explored for many years.Combined with drilling situation of sixty-one well which have been completed,it is mainly produced by carboniferous.Among them,there are twenty-two wells produce the natural gas,there are only one well produce the mixture of natural gas and water,there are three wells just produce water,and also there have one well has not been tested.According to the comprehensive analysis of drilling geology,logging,logging and seismic data,in the southwest and the Northeast of wubaiti there exist a large area of low permeability area,its area is reached 103.86km2,ratio of total area 66.23%,its reserves are 160.87×108m3,the total amount of natural gas reserves is 48,06%.And there are two high permeable areas in the section.In summary,it is shown that the exploration potential of the gas reservoir in the wubaiti is still huge.Combining the requirements of national energy strategy development and deployment,and taking into account the oil and gas reserves in the region,in the west of tiandong-22 well which Carboniferous system has a certain potential for rolling exploration.In 2011,on the basis of the wushankan 3D seismic exploration project,the wubaiti tectonic stratigraphic complex trap reach 229.5km2,the wushankan tectonic stratigraphic complex trap reach 59.2km2.In 2009,the western boundary of the Carboniferous tectonic-stratigraphic complex trap is not as clear as the wushankan,in order to further implement the position of the Carboniferous point extinguishing line,carrying out the scale of the Carboniferous stratigraphic structure complex trap and the distribution of the thickness of the Carboniferous Reservoir,it is decided to reprocess and explain the 3D projects in the west of the five hundred ladder.Moreover,for the analysis of the well which is located in the west of wubaiti,the block in the lower Paleozoic and Proterozoic has good exploration prospects.Based on the comprehensive evaluation of stratigraphic and structural traps in the whole area,we will provide some theoretical support for further exploration and development of Carboniferous gas reservoirs in the wubaiti and wushankan area. |
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