A semi-analytical model for investigating the productivity of fractured horizontal wells in tight oil reservoirs with micro-fractures

Sun, Ruofan; Hu, Jinghong; Zhang, Yuan; Li, Zhiping

doi:10.1016/j.petrol.2019.106781

Cited by 17 publications

(14 citation statements)

References 36 publications

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“…Tight oil flows through the reservoir matrix, microfractures, artificial fractures, and finally into the wellbore and lifts to the ground in tight oil reservoirs with stimulated reservoir volume development. ,, The difference scales in the flow media formed the characteristics of multiscale flow. Among them, nanopores are widely distributed in tight sandstone reservoirs.…”

Section: Multiscale Flow Characteristicsmentioning

confidence: 99%

“…Therefore, the multiscale complex flow field structure of the reservoir matrix (nanometer level), fracture network (micron level), and hydraulic fracture (millimeter level) is formed. It is necessary to establish a mathematical model to characterize the multiscale nonlinear flow. ,,,, …”

Section: Mathematical Model Of Multiregion Coupling Flowmentioning

confidence: 99%

“…However, the numerical method is limited by the model and computing equipment. On the other hand, many scholars established a semianalytical model for predicting the productivity of fractured well. − In view of characteristics of the unconventional reservoir, Zhu et al , developed a mathematical model to study pressure propagation by using steady-state replacement method and material balance law, which can describe the problem more accurately and grasp the essence of the problem better.…”

Section: Introductionmentioning

confidence: 99%

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Study on Pressure Propagation in Tight Oil Reservoirs with Stimulated Reservoir Volume Development

Zhu

Liu

Li³

et al. 2021

ACS Omega

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The stimulated reservoir volume fracturing development in tight oil reservoirs is characterized by multiscale flow of the reservoir matrix, fracture network, and hydraulic fracture. Therefore, the flow field structure is extremely complex. Multiscale flow characteristics have been revealed through the systematical experiments including the threshold pressure gradient and the stress sensitivity. Based on the theory of elliptical flow, a comprehensive and practical mathematical model of multiregion coupling flow is established to characterize the multiscale flow, and the pressure distribution equation is derived. The calculation method of moving boundary is established to simulate the dynamic supply boundary and the dynamic pressure distribution by using the steady-state sequential replacement method. The characteristics of multiscale flow, multistage development state, and stress sensitivity are considered, especially the different stress sensitivity characteristics in different regions. Finally, the pressure propagation in tight reservoirs is clarified and the influence of matrix permeability, stress sensitivity characteristics, and drawdown pressure on the distance at the dynamic supply boundary are revealed. The research results provide theoretical basis for the development effect evaluation.

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Section: Multiscale Flow Characteristicsmentioning

confidence: 99%

Section: Mathematical Model Of Multiregion Coupling Flowmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Study on Pressure Propagation in Tight Oil Reservoirs with Stimulated Reservoir Volume Development

Zhu

Liu

Li³

et al. 2021

ACS Omega

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“…The model can be employed to simulate tight reservoirs with a large-scale complex fracture network system. Sun ruofan et al [20] established an elliptical seepage model for fractured horizontal wells and obtained a semi-analytical solution to the problem of micro-fractures in tight reservoirs affecting the fluid flow and oil well production. These models have limitations in describing the morphology of complex fracture networks.…”

Section: Introductionmentioning

confidence: 99%

Study on Deliverability Evaluation of Staged Fractured Horizontal Wells in Tight Oil Reservoirs

et al. 2021

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At present, the existing deliverability evaluation models mainly consider the impact of specific factors on production, and the description of the complex fracture network structure primarily remains at the stage of an ideal dual-pore medium with uniform distribution. However, this cannot reflect the actual fracture network structure and fluid flow law of fractured horizontal wells. Thus, in this paper, a non-uniform fracture network structure is proposed considering the influence of the threshold pressure gradient and stress sensitivity characteristics on the production performance of horizontal wells. The stress sensitivity and the fractal theory are combined to characterize the permeability of the complex fracture network, and a three-zone compound unsteady deliverability model for staged fractured horizontal wells in tight oil reservoirs is successfully developed. Laplace transformation, perturbation theory, and numerical inversion are applied to obtain the semi-analytical solution of the proposed deliverability model. The reliability and accuracy of the analytical solution are verified by the classical tri-linear flow model and an oil field example. The effects of related influential parameters on the production of horizontal wells are analyzed. The deliverability evaluation method proposed in this paper can provide a theoretical basis for formulating rational development technology policies for tight oil reservoirs.

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“…They can directly transport oil into the large fractures, which has a continuous impact on the productivity of the oil wells and can increase production. However, as reservoir's permeability increases, this promotion effect will slow down [11,12]. The capillary force is mainly manifested as imbibition and the Jamin effect in tight oil reservoirs.…”

Section: Introductionmentioning

confidence: 99%

Division Method and Seepage Law of Seepage Channels in a Tight Reservoir

Fang

et al. 2021

Geofluids

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Tight oil reservoirs are characterized by a low porosity, low permeability, and strong heterogeneity. The macropores, throats, and microcracks in reservoirs are the main seepage channels, which affect the seepage law in the reservoirs. In particular, oil-water two-phase flow in different types of pores requires further study. In this study, two groups of online NMR displacement experiments were designed to study the seepage characteristics of tight oil reservoirs. It was found that the main seepage channels for oil-water two-phase flow are the microcracks, large pores, and throats in the reservoir. The large pores are mainly micron and submicron scale in size. The oil in the small pores is only transferred to the large pores through imbibition to participate in the flow, and there is no two-phase flow. Based on the influence of different pore structures on the seepage law of a tight reservoir, the pores were divided into seepage zones, and a multistage seepage model for tight reservoirs was established. Based on this model, the effects of the imbibition, stress sensitivity, threshold pressure gradient, and Jamin effect on model’s yield were studied. The results show that imbibition is no longer effective after a while. Owing to the stress sensitivity, the threshold pressure gradient, and the Jamin effect, oil production will be reduced. As the parameter value increases, the oil production decreases. The production decreases rapidly in the early stage of mining while decreases slowly in the later stage, exhibiting a trend of high yield in the early stage and stable yield in the later stage.

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A semi-analytical model for investigating the productivity of fractured horizontal wells in tight oil reservoirs with micro-fractures

Cited by 17 publications

References 36 publications

Study on Pressure Propagation in Tight Oil Reservoirs with Stimulated Reservoir Volume Development

Study on Pressure Propagation in Tight Oil Reservoirs with Stimulated Reservoir Volume Development

Study on Deliverability Evaluation of Staged Fractured Horizontal Wells in Tight Oil Reservoirs

Division Method and Seepage Law of Seepage Channels in a Tight Reservoir

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