| As we know,with the rapid development of Chinese economy is accompanied by the rapid growth of energy demand.Natural gas,as one of important clean energy,has increased it's proportions in Chinese energy structuction year by year.Sulige gas field is a typical representative of Chinese early Paleozoic continental tight sandstone gas resources and natural gas accounted for 15% of the total demestic gas production.There are exist irrational exploitation and waste of resources at present in the process of development because of the lack of a deep understanding of the region.In order to ensure the rational,efficient and stable development of the Sulige gas field and maintain the domestic natural gas market supply.It is necessary to combine advanced technologies to conduct more in-depth and detailed research on the region.Su 20 well area is located in the central area of Sulige gas field,there are two main reservoirs are the Shan1,He8 which is the typical tight sandstone reservoir.The horizontal distribution of sand bodies is limited,the connecting channels are mostly isolated and distributed and the relationship between gas and water is complex those have become the limiting factors for the further development of the wells in the later period.In order to avoid the risk of development and reduce the cost of production.The article is based on the previous research of using geological data,core observation,logging curve of stratigraphy and sedimentary in this region are reformed.The reservoir parameters were used to study the physical properties and heterogeneity of the reservoirs.The test data and comprehensive logging interpretation maps are used to obtain the lower limits of reservoir properties,electrical properties and gas inclusions.Finally,on the basis of the above,3D geological modeling technology is used to present the reservoir 3D in accuratly and the gas reserves are estimated.This study has achieved the following conclusions and recognitions:(1)According to the contrast division of the marker layer,the thickness comparison of the strata and the characteristics of sedimentary cycles,the He8 is divided into four small layers and the Shan1 is divided into 3 small layers.(2)He8 upper period and Shan1 are meandering river phases,and the edge beach and crevasse fan are in micro-phase development.He8 lower period is the sedimentary facies of the fluvial river.The mass of the beach is abundant and it is an advantageous reservoir sand body.The sand body in He8 lower period is the thickest,the sand body on He8 upper period is the best,and the sand body thickness of the Shan 1 section of the mountain is greatly changed.(3)The reservoir lithic quartz sandstone and lithic sandstone.The type of pores is mainly rock debris and intergranular pores.The pore throat combination type is mainly low-hole-fine throat and low-hole-micro throat types.It has the characteristics of small pore throat and poor sorting is a set of low and low permeability reservoir.He8 and Shan 1 showed strong heterogeneity which He 8 lower periodshowed strong heterogeneity.(4)According to the relationship between gas and water,there are three types of aquifers,gas reservoirs and water and gas layers.Most of the reservoirs in this area are mainly gas reservoirs and the gas water is the same layer and the water level is hardly to find.Under the background of low shale content and high natural potential anomaly,the high value zone is the gas reservoir with the test gas data and the low value zone is the same layer of gas water or water layer.(5)Accurately restore reservoir characteristics using petrofacies model and attribute model obtained from 3D geological modeling technology.We based on the modeling to calculate the gas bearing area and effective thickness and porosity of the reservoir and finally calculate the geological gas reserves of Su 20 well is 520.61 x 108 m~3. |
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