Impact of permeability heterogeneity on production characteristics in water-bearing tight gas reservoirs with threshold pressure gradient

2015 ◽  
Vol 22 ◽  
pp. 172-181 ◽  
Author(s):  
Hongqing Song ◽  
Yang Cao ◽  
Mingxu Yu ◽  
Yuhe Wang ◽  
John E. Killough ◽  
...  
Keyword(s):  
Pressure Gradient ◽  
Threshold Pressure ◽  
Tight Gas ◽  
Gas Reservoirs ◽  
Threshold Pressure Gradient ◽  
Tight Gas Reservoirs ◽  
Permeability Heterogeneity ◽  
Production Characteristics

A Model for Predicting Productivity of Multi-Staged Fractured Horizontal Wells in Ultra-Low Permeability Tight Gas Reservoirs

2014 ◽  
Vol 934 ◽  
pp. 143-149
Author(s):  
Chun Cheng Yang ◽  
Hong Jun Yin ◽  
Tang Qian Zhu ◽  
Lei Wang
Keyword(s):  
Pressure Gradient ◽  
Pressure Loss ◽  
Horizontal Wells ◽  
Low Permeability ◽  
Threshold Pressure ◽  
Tight Gas ◽  
Gas Reservoirs ◽  
Threshold Pressure Gradient ◽  
Tight Gas Reservoirs ◽  
Fractured Horizontal Wells

Based on the equivalent radius model and superposition potential, a productivity model for ultra-low permeability tight gas reservoirs was developed, which considered the influence of the threshold pressure gradient and the variable mass flow in fractures, and pressure loss inside the wellbore. With examples for capacity sensitive factors are analyzed. The results show that the threshold pressure gradient must be accounted to evaluate the productivity in ultra-low permeability tight gas reservoirs; after considering wellbore pressure loss; close toe fractures inflow velocity segment has been reduced; the larger matrix permeability, the greater the optimum fracture conductivity; When the number of fracture is more, the greater the impact on the capacity of the fracture angle. The research results provide a scientific basis for the design of multi-fractured horizontal wells in the ultra-low permeability tight gas reservoirs.

scholarly journals Gas-Water Flow Behavior in Water-Bearing Tight Gas Reservoirs

Geofluids ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-16 ◽  
Author(s):  
Renyi Cao ◽  
Liyou Ye ◽  
Qihong Lei ◽  
Xinhua Chen ◽  
Y. Zee Ma ◽  
...  
Keyword(s):  
Water Saturation ◽  
Flow Behavior ◽  
Stress Sensitivity ◽  
Gas Production ◽  
Tight Gas ◽  
Gas Reservoirs ◽  
Threshold Pressure Gradient ◽  
Tight Gas Reservoirs ◽  
Gas Recovery ◽  
Mobile Water

Some tight sandstone gas reservoirs contain mobile water, and the mobile water generally has a significant impact on the gas flowing in tight pores. The flow behavior of gas and water in tight pores is different than in conventional formations, yet there is a lack of adequate models to predict the gas production and describe the gas-water flow behaviors in water-bearing tight gas reservoirs. Based on the experimental results, this paper presents mathematical models to describe flow behaviors of gas and water in tight gas formations; the threshold pressure gradient, stress sensitivity, and relative permeability are all considered in our models. A numerical simulator using these models has been developed to improve the flow simulation accuracy for water-bearing tight gas reservoirs. The results show that the effect of stress sensitivity becomes larger as water saturation increases, leading to a fast decline of gas production; in addition, the nonlinear flow of gas phase is aggravated with the increase of water saturation and the decrease of permeability. The gas recovery decreases when the threshold pressure gradient (TPG) and stress sensitivity are taken into account. Therefore, a reasonable drawdown pressure should be set to minimize the damage of nonlinear factors to gas recovery.

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