Productivity model with mechanisms of multiple seepage in tight gas reservoir

Fu, Jingang; Su, Yuliang; Li, Lei; Wang, Wendong; Li, Dongsheng

doi:10.1016/j.petrol.2021.109825

Cited by 18 publications

(14 citation statements)

References 35 publications

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“…Once the pressure of the tight gas reservoir decays to a certain value, CO 2 injection is implemented. When the differential pressure between the injection well and the production well is larger than the threshold pressure; that is, the differential pressure gradient at any position in the reservoir is greater than or equal to the TPG, then the fluid starts to flow. , This condition may be expressed as where v is the gas flow rate (m/s), d p /d l is the differential pressure gradient (MPa/m), Δ P thresh is the TPG (MPa/m), K g is the gas permeability (×10 –3 , μm 2 ), and μ is the gas viscosity (mPa s).…”

Section: Resultsmentioning

confidence: 99%

Quantifying Controls on Threshold Pressure during CO₂ Injection in Tight Gas Reservoir Rocks

et al. 2022

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The simultaneous flow of gas and water is controlled by a threshold pressure gradient (TPG) effect during CO 2 injection of tight gas reservoirs. The TPG effect is dynamic because it varies with both the effective stress and the water saturation. The sensitivity of TPG to effective stress and mobile water is affected by the porethroat microstructure. In this paper, we report the results of dynamic TPG tests on six cores with similar permeability. The influence of the pore-throat microstructure on the sensitivity of the TPG to stress and to mobile water was also quantitatively studied using a fractal method, and the distribution of the threshold pressure and corresponding gas production loss were calculated during CO 2 injection in tight gas reservoirs. The test results show that TPG decreases logarithmically with the increase of the pore fluid pressure during CO 2 injection, a change of 0.1−50 MPa in the pore fluid pressure corresponding to a 1.8−3.5 times increase of the TPG variation. The TPG increases exponentially by 3.5−6.7 times from irreducible water saturation to a mobile water saturation of 30%. The fractal dimension (D) of the heterogeneity of the rock pore-throat microstructure has a linear relationship with both the stress sensitivity coefficient (λ) and mobile water sensitivity coefficient (η), with the larger values of λ and η being associated with more heterogeneous pore-throat microstructures. The reservoir threshold pressure showed a significant nonlinear distribution in near-well reservoirs at low bottom-hole flow pressures of the production well during CO 2 injection. The calculated gas well production loss as a result of a dynamic threshold pressure is 7−16% higher than that of the fixed threshold pressure, and the difference is larger at low pressures.

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Section: Resultsmentioning

confidence: 99%

Quantifying Controls on Threshold Pressure during CO₂ Injection in Tight Gas Reservoir Rocks

et al. 2022

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“…They obtained typical pressure and flow rate transient responses in tight reservoirs. Fu et al 33 proposed a productivity model for fractured horizontal wells that considers stress sensitivity, TPG, and other factors. The model was solved using an equivalent method, but the determination of the equivalent radius for each fracture remains a challenge.…”

Section: Introductionmentioning

confidence: 99%

Productivity Analysis of Fractured Horizontal Wells in Tight Gas Reservoirs Using a Gas–Water Two-Phase Flow Model with Consideration of a Threshold Pressure Gradient

Ding

Fan

et al. 2023

Energy Fuels

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Tight gas reservoirs are valuable yet challenging unconventional resources as a result of their complex flow mechanisms. Typical challenges are characterized by gas−water two-phase flows with a threshold pressure gradient (TPG). In this work, experimental studies are initially conducted to investigate and quantify the influence of water saturation on the TPG. A gas− water two-phase flow model is then established for a fractured horizontal well considering the influence of water saturation on gas− water permeability and TPG, along with the dynamic changes in the water−gas ratio. Sensitive studies are performed to investigate the impact of various parameters on the productivity of a horizontal well. The results demonstrate that, as water saturation increases, the TPG increases and the relative permeability of the gas phase decreases, resulting in the gas well productivity decrease. As the permeability decreases, the changes in the TPG become more prominent, leading to a greater impact on productivity. In comparison to a constant TPG, the changes with water saturation in the TPG have a more significant effect on productivity. Hence, it is beneficial to regulate the rate of the water cut increase to enhance production in tight gas reservoirs.

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“…Traditional capacity forecasting models can be divided into two categories: (1) Mechanism model Capacity forecasting model 1 . (2) Capacity prediction model of decline curve 2 .…”

Section: Introductionmentioning

confidence: 99%

Oil well productivity prediction in tight reservoirs based on machine learning

Zhu¹,

Wang²,

Tuo³

et al. 2023

International Conference on Computer Graphics, Artificial Intelligence, and Data Processing (ICCAID 2022)

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The complex seepage laws and high production costs in tight oil reservoirs have prompted scholars to apply machine learning methods to optimize construction plans and predict development results. The machine learning method uses artificial intelligence algorithm to make data "speak" to reveal the internal relationship and change rule among parameters in the process of system operation. In this paper, principal component analysis, k-means clustering, time series and other methods are used to predict the production capacity of tight oil reservoirs, reveal the development law of tight oil reservoirs, and guide the efficient and rapid development of unconventional resources in China.

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Productivity model with mechanisms of multiple seepage in tight gas reservoir

Cited by 18 publications

References 35 publications

Quantifying Controls on Threshold Pressure during CO₂ Injection in Tight Gas Reservoir Rocks

Quantifying Controls on Threshold Pressure during CO₂ Injection in Tight Gas Reservoir Rocks

Productivity Analysis of Fractured Horizontal Wells in Tight Gas Reservoirs Using a Gas–Water Two-Phase Flow Model with Consideration of a Threshold Pressure Gradient

Oil well productivity prediction in tight reservoirs based on machine learning

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Productivity model with mechanisms of multiple seepage in tight gas reservoir

Cited by 18 publications

References 35 publications

Quantifying Controls on Threshold Pressure during CO2 Injection in Tight Gas Reservoir Rocks

Quantifying Controls on Threshold Pressure during CO2 Injection in Tight Gas Reservoir Rocks

Productivity Analysis of Fractured Horizontal Wells in Tight Gas Reservoirs Using a Gas–Water Two-Phase Flow Model with Consideration of a Threshold Pressure Gradient

Oil well productivity prediction in tight reservoirs based on machine learning

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Quantifying Controls on Threshold Pressure during CO₂ Injection in Tight Gas Reservoir Rocks

Quantifying Controls on Threshold Pressure during CO₂ Injection in Tight Gas Reservoir Rocks