Sensitivity of unsteady-state gas-water relative permeability to experimental artefacts and interpretation techniques; case study from a gas reservoir in south Iran

Farahani, Milad; Aghaei, Hamed; Asadolahpour, Syed Reza

doi:10.1016/j.jngse.2019.102998

Cited by 20 publications

(13 citation statements)

References 11 publications

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“…However, numerous influencing factors in relative permeability measurement, such as stress sensitivity, salt sensitivity, gas slippage effect, and low water saturation, are involved in the experiment [1,11,12]. High stress reduces the gas-water flow channels (Figure 1A).…”

Section: Introductionmentioning

confidence: 99%

“…Li reported that as the effective stress increased, the relative permeability of the gas decreased significantly. When the confining pressure was increased to 34 MPa (5, 511 psi), the porosity of the tight sandstone formation decreased by 5%, resulting in a decrease in permeability [11]. Hao Zhang found that core permeability decreased with increased confining pressure until the critical pressure was reached.…”

Section: Introductionmentioning

confidence: 99%

“…Beyond the critical pressure, the core permeability changed only slightly with the increase in confining pressure. In order to attain almost similar formation pressure conditions, it is necessary to conduct gas-water relative permeability experiments under the in situ stress conditions [8,11].…”

Section: Introductionmentioning

confidence: 99%

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Experimental study on the permeability jail range of tight gas reservoirs through the gas–water relative permeability curve

et al. 2022

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The permeability jail refers to a specific water saturation range in a tight gas reservoir, where almost no gas or water phase can flow effectively. In the process of drilling and fracturing, water saturation rises and falls into the permeability jail. To reduce or avoid falling into the permeability jail in the recovery process, a method for measuring gas–water relative permeability of tight sandstone is established here that considers salt sensitivity, gas slippage effect, stress sensitivity, and high bound water saturation. Then, the permeability jail range was determined to provide guidance and suggestions for field application. Considering a typical tight sandstone as an example, the proposed method was used to expand the measurement range of gas–water relative permeability and observe the permeability jail range, laying an experimental foundation for accurately determining the permeability jail range in a given formation. The Byrnes model can preliminarily predict the permeability jail range with accurate bound water saturation and residual gas saturation. When the permeability jail phenomenon occurs in the core, the larger the permeability is, the smaller the permeability jail range will be; and the larger the porosity is, the smaller the permeability jail range will be. When the permeability jail phenomenon occurs in the tight sandstone reservoir, the damage to the reservoir due to external fluid and solid phased particles should be strictly controlled. The damage is stronger, the permeability and porosity decline, and the permeability jail range is wider. Other gases or solvents can be used as fracturing fluids to minimize formation damage.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Experimental study on the permeability jail range of tight gas reservoirs through the gas–water relative permeability curve

et al. 2022

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“…The total ground production was about 44 × 10 8 m 3 in 2015 and 59.1 × 10 8 m 3 in 2019, with an average increase in ratio of 8.6% per year. The main problem of restricting the development of gas production is associated with strong adsorption of the methane in coal and low permeability of the coal bed. − A variety of stimulation techniques have been applied for many years to enhance the permeability of coal beds, including hydraulic fracturing, − CO 2 fracturing, − and steam injection. − All these stimulation techniques have a common feature; that is, some material must be injected into the coal bed for CBM recovery. − The injected material can be varied with different fracturing techniques, including fracturing water, superheated water with high temperature, and gases of carbon dioxide or nitrogen. − This material injection is an essential process of energy transport and transition. − …”

Section: Introductionmentioning

confidence: 99%

Review on Coal Bed Methane Recovery Theory and Technology: Recent Progress and Perspectives

Liang¹,

Yan

Zhang

et al. 2021

Energy Fuels

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Coal bed methane (CBM) is a primary clean energy source found in coal seams. The recovery ratio of CBM is very low, especially with ground extraction, due to the strong adsorption of CH 4 on the pores and fissures of coal and low permeability of the coal bed. On the basis of the theory of energy balance, a theory of enhanced CBM (ECBM) recovery by energy stimulation is proposed in this review. The desorption and transportation of CH 4 in coal beds are analyzed from the perspective of energy consumption. Two pacesetting stimulation technologies are proposed to increase the permeability of coal beds: supercritical CO 2 (SCCO 2 ) fracturing and thermal fracturing through steam injection. The experimental study and the related results of SCCO 2 -enhanced CBM recovery are presented and analyzed. The results demonstrate that the permeability of SCCO 2 in the tested four ranked coal specimens decreases in the form of a negative exponent function with the increase of effective stress. The transportation capacity of SCCO 2 in high ranked coal beds deep underground is inferior to that in low ranked coal beds at shallow depth. The experiment of the total permeability of CO 2 with CH 4 in coking coal shows that the permeability decreases in the form of a logarithmic function as the content of CO 2 increases. SCCO 2 has higher transportation capacity than gaseous CO 2 in coal beds, and the total permeability decreases with its content increasing in the synthetical system with CH 4 . The SCCO 2 -enhanced CBM recovery experiment demonstrates that the economic production time is different for the four ranked coal specimens given 50% of each content in production gas being defined as a threshold for economic production. The economic production for gas coal and anthracite takes a longer time than that in weakly caking coal of a lower ranked coal. The study demonstrates that different ranked coals have different inner structures and transportation properties. However, the original structures of different ranked coals can be modified by SCCO 2 by changing the void volume or the structure of the pores and fissures. The challenges and perspectives for the CBM recovery theory and technology are also presented. The study is of importance with the novel dual efficient approach for clean energy CBM recovery ratio improvement and greenhouse gas sequestration underground in deep coal beds.

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“…It is one of the most critical properties controlling multiphase flow and transport in porous media [2][3][4][5][6][7][8][9][10][11][12][13]. Studies have shown that the wettability of rocks has a direct impact on relative permeability [4,10,14,15], capillary pressure [3,16], and performance of secondary and tertiary oil recovery methods [5,17,18]. A lack of knowledge of rock wetting behavior may lead to substantial uncertainties in the estimation of a reservoir's accessible oil and recovery rate [18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Wettability of Carbonate Reservoir Rocks: A Comparative Analysis

et al. 2021

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Various methods have been proposed for the evaluation of reservoir rock wettability. Among them, Amott–Harvey and USBM are the most commonly used approaches in industry. Some other methods, such as the Lak and modified Lak indices, the normalized water fractional flow curve, Craig’s triple rules of thumb, and the modified Craig’s second rule are based on relative permeability data. In this study, a set of capillary pressure curves and relative permeability experiments was conducted on 19 core plug samples from a carbonate reservoir to evaluate and compare different quantitative and qualitative wettability indicators. We found that the results of relative permeability-based approaches were consistent with those of Amott–Harvey and USBM methods. We also investigated the relationship between wettability indices and rock quality indicators RQI, FZI, and Winland R35. Results showed that as the rock quality indicators increased, the samples became more oil-wet.

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Sensitivity of unsteady-state gas-water relative permeability to experimental artefacts and interpretation techniques; case study from a gas reservoir in south Iran

Cited by 20 publications

References 11 publications

Experimental study on the permeability jail range of tight gas reservoirs through the gas–water relative permeability curve

Experimental study on the permeability jail range of tight gas reservoirs through the gas–water relative permeability curve

Review on Coal Bed Methane Recovery Theory and Technology: Recent Progress and Perspectives

Wettability of Carbonate Reservoir Rocks: A Comparative Analysis

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