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is a virtual moving boundary at the flow edge, and these percolation models of fractured wells with Darcy formula are no longer applicable.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 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.

A Novel Model for Well Production Performance Estimate in Low-Permeability and Tight Reservoirs Considering Stress Sensitivity

2020 ◽  
Vol 142 (9) ◽  
Author(s):  
Mingda Dong ◽  
Xuedong Shi ◽  
Jie bai ◽  
Zhilong Yang ◽  
Zhilin Qi
Keyword(s):  
Pressure Gradient ◽  
Effective Stress ◽  
Stress Sensitivity ◽  
Production Performance ◽  
Low Permeability ◽  
Threshold Pressure ◽  
Threshold Pressure Gradient ◽  
Vertical Well ◽  
Tight Reservoirs ◽  
Rock Compressibility

Abstract Stress sensitivity phenomenon is an important property in low-permeability and tight reservoirs and has a large impact on the productivity of production wells, which is defined as the effect of effective stress on the reservoir parameters such as permeability, threshold pressure gradient, and rock compressibility change accordingly. Most of the previous works are focused on the effect of effective stress on permeability and threshold pressure gradient, while rock compressibility is critical of stress sensitivity but rarely noticed. A series of rock compressibility measurement experiments have been conducted, and the quantitative relationship between effective stress and rock compressibility is accurately described in this paper. In the experiment, the defects in previous experiments were eliminated by using a new-type core holder. The results show that as the effective stress increases, the rock compressibility becomes lower. Then, a stress sensitivity model that considers the effect of effective stress on rock compressibility is established due to the experimental results. The well performance of a vertical well estimated by this model shows when considering the effect of effective stress on the rock compressibility, the production rate and recovery factor are larger than those without considering it. Moreover, the effect of porosity and confining pressure on the productivity of a vertical well is also studied and discussed in this paper. The results show that the productivity of a vertical well decreases with the increase in overburden pressure, and increases with the increase in the porosity.

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