Main Controlling Elements Of Oil Gas Production Capacity In The Car Bonate Reservoir Of Tazhong?zone

Increasing exploration activities in the Tazhong area has discovered high yield flow from the Ordovician and Carboniferous in the high position of the Tazhong area,Tazhong I anticline as well as the Tazhong No.10 anticline in the north slope belt.Currently,carbonate reservoirs in the Tazhong I gas field has regarded as an important target in the Tarim oilfield.However,different from the initial stage,yield decreases significantly in the studying area,e.g.,Tazhong 62,Tazhong 82,Tazhong26 and Tazhong 83 block.Therefore,based on the hydrocarbon distribution,hydrocarbon generation and expulsion history,reservoir characteristics,this study analyzed the key elements of oil and gas production capacity,and proposed carbonatite oil and gas reservoir development technical strategy for the Tazhong area.Result shows that,the Ordovician crude oil of the Tazhong area is generally high-over mature,increasing from east to west.Natural gas in the Yingshan Formation is characterized by high methane content.Natural gas dry coefficient varies greatly,e.g.,dry coefficient in the east is laterally higher than that in the west,and value in the Ordovician Yingshan formation is vertically higher than the Lianglitage Formation.The Ordovician reservoir in the Tazhong?zone primarily comprises the Upper Ordovician Lianglitage reef-bank complex and Lower Ordovician Yingshan karst reservoir with averaged porosity and permeability of 1.51%and 1.1902×10^-3?m².The primary storage space includes pores,fractures and fracture-pores,specifically,fracture-pores are type I reservoir,while fractures and pores are type II and type?respectively.Dolomitization improved reservoir quality significantly.A series of evidences from rock property analysis,log interpretation and seismic prediction prove the reservoir heterogeneity that was suggested to be caused by the micro pore structure.Oil and gas distribution in the Tazhong?area is primarily controlled by the structure with efficient wells mainly in the high position of the anticlinal zone along the platform margin.Also,reservoir plays an important role in the oil and gas production.Type I reservoir has highest gas production per day with strong bottom hole supply capacity.Type II reservoir show a fast-decreasing oil pressure at the early stage,indicating low bottom hole supply capacity.Parameters,including injection media,injection timing,injection volume and shut-in time,can exert huge impact on the oil recovery in the condensate gas reservoir.Some measures,including improving the proportion of the efficient wells and effective wells,controlling phase transformation to improve oil and gas recovery,using a reasonable water injection plan,can improve oil and gas production.