Study on the Unstable Seepage Flow Model and the Productivity Characteristics in Tight Gas Heterogeneity Reservoir

2013 ◽  
Vol 868 ◽  
pp. 465-472
Author(s):  
Jia Deng ◽  
Wei Yao Zhu ◽  
Qian Ma ◽  
Huai Jian Yi
Keyword(s):  
Pressure Gradient ◽  
Gas Flow ◽  
Flow Model ◽  
Seepage Flow ◽  
Threshold Pressure ◽  
Tight Gas ◽  
Low Velocity ◽  
Threshold Pressure Gradient ◽  
Tight Gas Reservoir ◽  
Matlab Programming

In this paper, considering on the real threshold pressure gradient (TPG), the mathematical model for low velocity non-Darcy unstable gas flow was established for the tight gas reservoir. Based on the low velocity non-Darcy unstable gas flow model, the gas flow model in heterogeneity formation was developed, and the analytical solution was obtained on the condition of constant production for inner boundary. Then we calculated the model numerically by Matlab programming. Its analyzed that the pressure distribution and the influencing factors such as production rate, producing time, reservoir thickness and the threshold pressure gradient. We compared the heterogeneity formation with the homogeneous formation by the heterogeneity low velocity non-Darcy unstable gas flow model, which shows great difference and illustrate the significance of research on heterogeneity.

The Moving Boundary Movement of Vertical Fractured Well in Tight Oil Reservoir

2013 ◽  
Vol 868 ◽  
pp. 633-637
Author(s):  
Li Feng Liu ◽  
Xin Wang
Keyword(s):  
Pressure Gradient ◽  
Flow Model ◽  
Moving Boundary ◽  
Flow Characteristics ◽  
Seepage Flow ◽  
Threshold Pressure ◽  
Threshold Pressure Gradient ◽  
Tight Reservoir ◽  
Tight Reservoirs ◽  
Fractured Well

Because of the obvious non-Darcy characteristic of fluid flowing in tight reservoirs, there is a virtual moving boundary at the flow edge, and these percolation models of fractured wells with Darcy formula are no longer applicable. Based on the threshold pressure gradient effect, the unsteady seepage flow model of vertical fractured well was established in the drain area by means of Source and Green's Functions. With the flow characteristics at the boundary of tight reservoir, the motion equation of axes of moving boundary was obtained. By Example analysis, its proved that the moving boundary is approximate circular in the far-field, and it will move slower with the increase of the threshold pressure gradient.

Study on Mechanism of Seepage Flow of S/P Flooding Fluid

2013 ◽  
Vol 421 ◽  
pp. 349-353
Author(s):  
Han Min Xiao ◽  
Su Nan Cong ◽  
Ling Hui Sun ◽  
Hai Qin Zhang ◽  
Lin Song Cheng
Keyword(s):  
Pressure Gradient ◽  
Influence Factor ◽  
Fluid Flows ◽  
Seepage Flow ◽  
Important Influence ◽  
Threshold Pressure ◽  
Low Velocity ◽  
Threshold Pressure Gradient ◽  
Linear Flow ◽  
The Core

Because plenty of polymers have been added in the surfactant/polymer (S/P) flooding fluid, its viscosity becomes higher. So when S/P flooding fluid flows in the stratum, its threshold pressure gradient is an important influence factor. According to study S/P flooding fluid with different viscosities that flows in different permeability cores, the variation laws of seepage curve have been obtained. The results of the study show that the seepage of S/P flooding exhibits nonlinear seepage in low velocity, and changes gradually to linear flow as the pressure gradient rises. As well, S/P flooding has obvious threshold pressure gradient when its speed is low. The threshold pressure gradient of S/P is related to the permeability of the core and its own viscosity. The higher the viscosity, the lower the permeability of the core, the threshold pressure gradient will be greater.

scholarly journals Mathematical Simulation about Gas Transport in a Dual-Porosity Tight Gas Reservoir considering Multiple Effects

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Jing Chen ◽  
Xinmin Song ◽  
Baozhu Li ◽  
Wuguang Li ◽  
Changlin Liao ◽  
...  
Keyword(s):  
Pressure Gradient ◽  
Stress Sensitivity ◽  
Gas Production ◽  
Dual Porosity ◽  
Threshold Pressure ◽  
Tight Gas ◽  
Gas Reservoir ◽  
Threshold Pressure Gradient ◽  
Gas Slippage ◽  
Tight Gas Reservoir

Threshold pressure gradient, gas slippage, and stress sensitivity have important effects on the production of a tight gas reservoir. But previous studies only focused on one or two of these effects. In this study, a mathematical model considering these three effects was established to describe gas transport in a dual-porosity tight gas reservoir. Threshold pressure gradient, gas slippage, and stress sensitivity are simultaneously considered in the velocity term of continuity equation which is mainly different from the previous research results. The partial differential equation and definite solution condition are discretized by a central difference method. A finite difference procedure was compiled and applied to solve this numerical model and predict the productivity of a production well in a dual-porosity tight gas reservoir. The difference between the predicted and tested cumulative production is less than 10%, which indicates that the proposed mathematical model can be used to describe the characteristics of gas flow in the dual-porosity tight gas reservoir. Then, gas productivity of five different scenarios considering these effects was compared. Results show that both stress sensitivity and threshold pressure gradient are negatively correlated with gas production, while gas slippage is positively correlated with gas production. Among them, stress sensitivity has the greatest impact on the production of a dual-porosity tight gas reservoir. Overall, these three effects have great influence on the development of the dual-porosity tight gas reservoir, which should be considered in the production prediction.

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