Novel apparatus to measure the low-permeability and porosity in tight gas reservoir

Jang, Hochang; Lee, Won Suk; Kim, Junggyun; Lee, Jeonghwan

doi:10.1016/j.petrol.2016.01.037

Cited by 18 publications

(7 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…By analyzing the changes in the upstream and downstream pressures over time, the permeability of the core can be obtained. Modifications are also made to the primary testing method in order to improve the accuracy and the flexibility, and to decrease the testing time [6,7]. All of these analysis methods are based upon the homogeneous model.…”

Section: Mathematical Models and The Numerical Methodsmentioning

confidence: 99%

Investigation of Analysis Methods for Pulse Decay Tests Considering Gas Adsorption

2019

View full text Add to dashboard Cite

The pulse decay test is the main method employed to determine permeability for tight rocks, and is widely used. The testing gas can be strongly adsorbed on the pore surface of unconventional reservoir cores, such as shale and coal rock. However, gas adsorption has not been well considered in analysis pulse decay tests. In this study, the conventional flow model of adsorbed gas in porous media was modified by considering the volume of the adsorbed phase. Then, pulse decay tests of equilibrium sorption, unsteady state and pseudo-steady-state non-equilibrium sorption models, were analyzed by simulations. For equilibrium sorption, it is found that the Cui-correction method is excessive when the adsorbed phase volume is considered. This method is good at very low pressure, and is worse than the non-correction method at high pressure. When the testing pressure and Langmuir volume are large and the vessel volumes are small, a non-negligible error exists when using the Cui-correction method. If the vessel volumes are very large, gas adsorption can be ignored. For non-equilibrium sorption, the pulse decay characteristics of unsteady state and pseudo-steady-state non-equilibrium sorption models are similar to those of unsteady state and pseudo-steady-state dual-porosity models, respectively. When the upstream and downstream pressures become equal, they continue to decay until all of the pressures reach equilibrium. The Langmuir volume and pressure, the testing pressure and the porosity, affect the pseudo-storativity ratio and the pseudo-interporosity flow coefficient. Their impacts on non-equilibrium sorption models are similar to those of the storativity ratio and the interporosity flow coefficient in dual-porosity models. Like dual-porosity models, the pseudo-pressure derivative can be used to identify equilibrium and non-equilibrium sorption models at the early stage, and also the unsteady state and pseudo-steady-state non-equilibrium sorption models at the late stage. To identify models using the pseudo-pressure derivative at the early stage, the suitable vessel volumes should be chosen according to the core adsorption property, porosity and the testing pressure. Finally, experimental data are analyzed using the method proposed in this study, and the results are sufficient.

show abstract

Section: Mathematical Models and The Numerical Methodsmentioning

confidence: 99%

Investigation of Analysis Methods for Pulse Decay Tests Considering Gas Adsorption

2019

View full text Add to dashboard Cite

show abstract

“…The highly scattered distribution of the lenticular reservoir determines the production characteristics of the gas reservoirs: due to the small scale of the effective sand body, the single well production is low, the stable production capacity is poor, and the single well control reserves and the final accumulated yield are low. Generally, the dynamic reservoir controlled by a single well is less than 30 million cubic meters, and the gas production rate can keep 10,000 cubic meters for three years, then the production rate will keep decline for about 7–10 years until the reservoir pressure is too low to produce (Fan et al., 2016; Jang et al., 2016; Zhao et al., 2016).…”

Section: Basic Geological Characteristics Of the Tight Gas Reservoir mentioning

confidence: 99%

Modeling and analyzing gas supply characteristics and development mode in sweet spots of Sulige tight gas reservoir, Ordos Basin, China

Zhang

et al. 2018

Energy Exploration & Exploitation

View full text Add to dashboard Cite

In order to study the characteristics of the gas supply and development mode in sweet spots of Sulige tight gas reservoir in Ordos Basin, China, a mathematical model was developed for the typical lenticular reservoirs in tight gas reservoirs, and its analytical solution was obtained. The ideal model was calculated by using the analytical solution. Analysis of the production data indicated a clear boundary between the high-and low-permeability regions of the lenticular reservoir, and the boundary will supply gas to the low-permeability region. The reliability of this finding was validated by real production data. The development mode of the lenticular reservoir was obtained, that is the high-permeability area was first used during the initial production; when the pressure wave reached the boundary in the high-permeability region, the production showed a pseudo-steady state; further increase of the production pressure exceeding the threshold of the surrounding low-permeability region triggered the utilization of the low-porosity and low-permeability regions. The established model can provide useful guidance for the development of similar tight gas reservoirs.

show abstract

“…To correct the compressive storage, Jones 18 introduced a correction factor “ f 1 ” into the original analytical permeability solution to improve the efficiency and accuracy of the measured permeability. Although the effect of gas compressive storage can be somewhat corrected, the results are still less reliable because the porosity of the sample cannot be estimated precisely 17,21‐23 . Following Jones's work, Cui et al 24 modified “ f 1 ” to account for the effect of gas sorption by incorporating Langmuir constants into the analytical solution, which further extends the applicability of the pulse decay method in permeability measurements of rock reservoirs with gas sorption.…”

Section: Introductionmentioning

confidence: 99%

A simplified transient technique for porosity and permeability determination in tight formations: Numerical simulation and experimental validation

Feng

et al. 2020

Energy Science & Engineering

View full text Add to dashboard Cite

A simplified pulse decay method (PDM) with only a single downstream reservoir is proposed to replicate the in situ conditions for reservoir fluid flow, where the pore pressure at any location declines as production continues. The proposed PDM also allows determining the effective porosity and permeability for the core sample under replicated in situ conditions. A mathematical model is firstly established to closely represent the experimental design and verify the feasibility of the method. The analytical solutions of the model are derived to calculate the effective sample porosity and permeability. A series of experiments are then conducted under triaxial stress condition, and a detailed comparison is also made between the PDMs with a single upstream reservoir and a single downstream reservoir. The experimental results showed that accurate measurements on effective sample porosity and permeability can be achieved by the single downstream reservoir PDM due to its capability of better replicating the in situ fluid flow behavior, which extends the application of the transient technique. It is also found that the pore pressure along the sample changes linearly, and its gradient varies with time, indicating the applicability of the single‐reservoir PDMs in permeability determination. This method also lays a foundation for studying flow behavior when a second fluid phase evolves during pressure decline, which occurs in many reservoirs.

show abstract

Novel apparatus to measure the low-permeability and porosity in tight gas reservoir

Cited by 18 publications

References 11 publications

Investigation of Analysis Methods for Pulse Decay Tests Considering Gas Adsorption

Investigation of Analysis Methods for Pulse Decay Tests Considering Gas Adsorption

Modeling and analyzing gas supply characteristics and development mode in sweet spots of Sulige tight gas reservoir, Ordos Basin, China

A simplified transient technique for porosity and permeability determination in tight formations: Numerical simulation and experimental validation

Contact Info

Product

Resources

About