Experimental study on threshold pressure gradient of CO2 flooding in low permeability reservoir

2015 ◽  
pp. 1121-1125 ◽  
Author(s):  
Zhaojie Xue
Keyword(s):  
Experimental Study ◽  
Pressure Gradient ◽  
Low Permeability ◽  
Threshold Pressure ◽  
Co2 Flooding ◽  
Threshold Pressure Gradient ◽  
Low Permeability Reservoir

The Research Progress of Threshold Pressure Gradient

2014 ◽  
Vol 700 ◽  
pp. 612-616
Author(s):  
Xian Kang Xin ◽  
Gao Ming Yu ◽  
Zhou Fang
Keyword(s):  
Experimental Study ◽  
Pressure Gradient ◽  
Research Progress ◽  
Low Permeability ◽  
Oil Reservoir ◽  
Threshold Pressure ◽  
Threshold Pressure Gradient ◽  
Fluid Seepage ◽  
Seepage Theory ◽  
Heavy Oil Reservoir

Fluid seepage needs to overcome threshold pressure gradient in low permeability reservoir and heavy oil reservoir. A conclusion about the research progress of threshold pressure gradient was made by summarizing the literatures, which includes: the existence and experimental study of threshold pressure gradient, research of seepage theory considering threshold pressure gradient and applications. These can supply reference for the researching and engineering staffs engaged in related work.

Numerical Simulation of Pressure Distribution between Injection and Production Well in Low Permeability Reservoir

2013 ◽  
Vol 807-809 ◽  
pp. 2554-2557
Author(s):  
Qi Han Zhang ◽  
Zi Yi Guo ◽  
Ji Peng ◽  
Ting Song Xiong ◽  
Shi Feng Xue
Keyword(s):  
Numerical Simulation ◽  
Pressure Gradient ◽  
Pressure Distribution ◽  
Low Permeability ◽  
Threshold Pressure ◽  
Production Well ◽  
Pressure System ◽  
Threshold Pressure Gradient ◽  
Low Permeability Reservoir ◽  
Pressure Sensitive

Considering the pressure-sensitive effect and threshold pressure gradient in low permeability reservoirs, a new mathematical model of the variable permeability for reservoir between injection and production well is established. The Garlerkin method is used to set up the finite element computation equations, and corresponding numerical simulation program is developed. The influence of Injection-production pressure, well spacing and hydraulic fracture are quantitative evaluation. The simulation results show that the pressure-sensitive effect and threshold pressure gradient has a strong influence on pressure distribution between injection and production wells. Establishing the effective driving pressure system is the key to improve well production of low permeability reservoir.

Study on the Optimal Design Methodology of Fracture Spacing in Low-Permeability Reservoir Horizontal Well

2013 ◽  
Vol 868 ◽  
pp. 487-496
Author(s):  
Guo Cheng Zhang ◽  
Yang Liu ◽  
Zhao Hui Zhang
Keyword(s):  
Pressure Gradient ◽  
Low Permeability ◽  
Threshold Pressure ◽  
Threshold Pressure Gradient ◽  
Fracture Spacing ◽  
Hole Pressure ◽  
Low Permeability Reservoir ◽  
Bottom Hole Pressure ◽  
Bottom Hole ◽  
Reservoir Permeability

Threshold pressure gradient for extra-low permeability reservoir is studied experimentally. A production model is established which couples wellbore pipe flow, fracture linear flow and reservoir non-Darcy flow. The influence of bottom-hole pressure and reservoir permeability on threshold distance is performed based on the model. A fracture spacing design method is provided for different bottom-hole pressure and reservoir permeability. Results show that threshold pressure gradient increases considerably as permeability decreases when permeability is below 0.02 mD; threshold pressure gradient is relatively lower when permeability is greater than 0.1 mD; threshold pressure gradient decreases gradually and flattens when permeability lies between 0.02 mD and 0.1 mD. Simulated threshold pressure gradient of formation water is as one-third as that of crude oil. While permeability is between 0.01-0.05 mD, 0.05-0.1 mD, 0.1-0.5 mD and 0.5-1.0 mD, the optimal fracture spacing is about 9 m, 16 m; 36 m and 50 m.

scholarly journals Analysis and Calculation of Threshold Pressure Gradient Based on Capillary Bundle

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Shuangshuang Ren ◽  
Fei Shen ◽  
Shenglai Yang ◽  
Xiangyang Zhang ◽  
Hongwu Luo ◽  
...  
Keyword(s):  
Pressure Gradient ◽  
Water Injection ◽  
Low Permeability ◽  
Threshold Pressure ◽  
Threshold Pressure Gradient ◽  
Low Permeability Reservoir ◽  
Start Up ◽  
Seepage Law ◽  
Oilfield Development ◽  
Starting Pressure Gradient

Oilfield water injection is one of the important means to supplement energy to the formation and enhance oil recovery in the process of oilfield development. The level of water injection technology determines the effect of oilfield development and also determines the length of oilfield development life. Research on seepage law of water injection development in low-permeability reservoir is the basis and important technical means of low-permeability reservoir development, and the key point of seepage law is to analyze the starting pressure gradient law. In previous studies, either static test or dynamic experimental value is used, so the error of pseudo starting pressure gradient derived from experimental value is too large, which makes people expand the starting pressure value in low-permeability reservoir in practical engineering application, and the starting pressure gradient obtained from laboratory test cannot be applied in actual reservoir. To accurately calculate the threshold pressure gradient for low-permeability reservoirs, the threshold permeability is proposed through the study of the seepage law and laboratory experiments. It is recognized that the threshold pressure gradient and the threshold permeability had been changing during the seepage. Through steady-state “flow rate-pressure difference” displacement experiment, with natural cores from a low-permeability reservoir, based on a capillary bundle model, the method for calculating the gradient is innovatively proposed. The experimental data show that the whole low-permeability seepage flow is nonlinear, divided into three stages according to the physical stages with obvious changes. Through processing and analyzing of the experimental results, first, it is showed that both threshold pressure gradient and threshold permeability increase with the rise of flow rate and the increasing amplitude is gradually decreasing. Second, the study proposes the permeability is the main controlling reason of the threshold pressure gradient, and the flow velocity is an important reason. Third, we obtain the formulas of the minimum threshold pressure gradient, the threshold pressure gradient, and the corresponding threshold permeability of different cores and the power function relationship between the threshold pressure gradient and the core permeability is obtained. And further, the one-dimensional experimental results are applied to the radial fluid flow, and the recognition that the threshold pressure gradient decreases with increasing distance and the ratio of the threshold pressure to the total displacement pressure difference are obtained. The ratio of starting pressure to total pressure drop is about 0.5, and the higher the permeability is, the lower the ratio is lower under 0.5. These findings significantly help in understanding how to effectively develop low-permeability reservoir by water injection. Through the dynamic macro experiment and microcapillary bundle principle, the experiment can be divided into several sections for analysis, which can be more accurate. The minimum start-up pressure gradient can not only guide the later development of the oilfield, but also enrich the theoretical study of non-Darcy low-velocity seepage. At the same time, the law of flow velocity and start-up pressure gradient indirectly proves the boundary layer theory of the generation mechanism of start-up pressure gradient and supports and guides the effective development of various development methods of low-permeability reservoir.

Study on the Theory of Effective Displacement in Low Permeability Reservoir

2013 ◽  
Vol 868 ◽  
pp. 551-555
Author(s):  
Feng Jiao Wang ◽  
Yi Kun Liu ◽  
Yong Ping Wang ◽  
Chao Yang Hu
Keyword(s):  
Pressure Gradient ◽  
Injection Pressure ◽  
Optimal Choice ◽  
Oil Field ◽  
Experimental Result ◽  
Low Permeability ◽  
Threshold Pressure ◽  
Threshold Pressure Gradient ◽  
Low Permeability Reservoir ◽  
Well Spacing

Taking displacing pressure gradient and threshold pressure gradient into account, we have carried on a research of effective displacement theory in low permeability formation. Based on displacing pressure gradient expression of different production diverging/converging, we get displacing pressure gradient engraving when formational pressure, injection pressure, bottom hole producing pressure, and inter well distance is changing. And analyze its regular as well. On the basis of experimental result, establishing the relationship between threshold pressure gradient and displacing pressure gradient, and analyze the critical value of different pay zones for effective displacement. Study has shown that if we want to drive low permeability formation it is necessary that the displacing pressure gradient is larger than the threshold pressure gradient. It is the optimal choice for low permeability formations effective displacement that the well spacing should be smaller. It can achieve a goal that effective driving low permeability reservoir by the adjustment of taking measures and the injection-production pressure systems modulation. The study has important guiding significance for the development of low permeability formation, and it has got effective verification in oil field test.

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