Rate Decline Behavior of Selectively Completed Horizontal Wells in Naturally Fractured Oil Reservoirs

Selectively completed horizontal wells (SCHWs) can significantly reduce cost of completing wells and delay water breakthrough and prevent wellbore collapse in weak formations. Thus, SCHWs have been widely used in petroleum development industry. SCHWs can shorten the effective length of horizontal we...

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Bibliographic Details
Published in:Mathematical problems in engineering 2019-01, Vol.2019 (2019), p.1-13
Main Authors: Ji, An-zhao, Li, Long-xin, Xu, You-jie, Liu, Qiguo
Format: Article
Language:English
Subjects:
Boundary conditions
Collapse
Conservation equations
Cross flow
Derivatives
Differential equations
Equations of motion
Equations of state
Exact solutions
Fairs & exhibitions
Flow coefficients
Fluids
Fourier transforms
Fractured reservoirs
Horizontal wells
Industrial development
Integrals
Laplace transforms
Mathematical models
Mathematical problems
Natural gas
Permeability
Productivity
Reservoirs
Seepage
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Summary:Selectively completed horizontal wells (SCHWs) can significantly reduce cost of completing wells and delay water breakthrough and prevent wellbore collapse in weak formations. Thus, SCHWs have been widely used in petroleum development industry. SCHWs can shorten the effective length of horizontal wells and thus have a vital effect on production. It is significant for SCHWs to study their rate decline and flux distribution in naturally fractured reservoirs. In this paper, by employing motion equation, state equation, and mass conservation equation, three-dimension seepage differential equation is established and corresponding analytical solution is obtained by Laplace transform and finite cosine Fourier transform. According to the relationship of constant production and wellbore pressure in Laplace domain, dimensionless rate solution is gotten under constant wellbore pressure in Laplace domain. Dimensionless pressure and pressure derivate curves and rate decline curves are drawn in log-log plot and seven flow regimes are identified by Stehfest numerical inversion. We compared the simplified results of this paper with the results calculated by Saphir for horizontal wells in naturally fractured reservoirs. The results showed excellent agreement. Some parameters, such as outer boundary radius, storativity ratio, cross-flow coefficient, number and length of open segments, can obviously affect the rate integral and rate integral derivative log-log curves of the SCHWs. The proposed model in this paper can help better understand the flow regime characteristics of the SCHWs and provide more accurate rate decline analysis of the SCHWs data to evaluate formation.
ISSN:1024-123X
1563-5147
DOI:10.1155/2019/7281090