Dear Label_Name,

Greetings! I hope you are well.

I am writing on behalf of an international publishing house, Science and Education Publishing, USA (http://www.sciepub.com).

Science and Education Publishing (SciEP) is a multidisciplinary open access publisher of Journals covering the fields of Science, Technology and Medicine. All SciEP publications are subject to high-quality peer review, editorial and production processes and are freely available online.

Welcome to the April, 2013 edition of SciEP newsletter, providing monthly summaries of articles on science & education related topics of interest to scientist and professionals. The mission of our journals is to provide an open access forum for publishing new findings on issues pertinent to scientific and academic field. We also invite you to submit original research papers, review articles, short reports, or case studies are considered for publication in our Multidisciplinary Journals.

American Journal of Public Health Research
DOI: 10.12691/ajphr-1-1-3

The Implementation of a Tele-Homecare System with Service Oriented Architecture and HL7 Message Transmission Standard
Ching-Sung Wang

American Journal of Medical and Biological Research
DOI: 10.12691/ajmbr-1-1-2

The Influence of Ethanol on Pyruvate Kinases Activity in Vivo, in Vitro, in Silico
Lelevich Sergey Vladimirovich, Khrustalev Vladislav Victorovich, Barkovsky Eugene Victorovich, Shedogubova Tatyana Aleksandrovna

American Journal of Medical Sciences and Medicine
DOI: 10.12691/ajmsm-1-1-1

Clinical and Histological Features in Wegener Granulomatosis
Li Cavoli Gioacchino, Passantino Rita, Bono Luisa, Tortorici Calogera, Ferrantelli Angelo, Giammarresi Carlo, Rotolo Ugo

American Journal of Infectious Diseases and Microbiology
DOI: 10.12691/ajidm-1-1-2

The Curse of Lymphatic Filariasis: Would the Continual Use of Diethylcarbamazine Eliminate this Scourge in Papua New Guinea?
Anne Lanham, Lillian Mwanri

We have released issues of some journals on February 2013.
American Journal of Public Health Research
American Journal of Medical Sciences and Medicine
American Journal of Medical and Biological Research
American Journal of Pharmacological Sciences
American Journal of Clinical Medicine Research
American Journal of Nursing Research
American Journal of Cancer Prevention
American Journal of Medicine Studies
American Journal of Infectious Diseases and Microbiology
American Journal of Cardiovascular Disease Research
American Journal of Biomedical Research
American Journal of Mechanical Engineering
American Journal of Microbiological Research
Journal of Preventive Medicine
American Journal of Food and Nutrition
American Journal of Hypertension Research
American Journal of Sports Science and Medicine
Journal of Cancer Research and Treatment
American Journal of Zoological Research
Journal of Biomedical Engineering and Technology
American Journal of Microbiological Research
Biomedical Science and Engineering

We are pleased to announce that submissions are now being accepted for peer review for all the journals across all our subject areas in SciEP.

Please submit your manuscript via our online submission system:
http://www.sciepub.com/author/signin

To unsubscribe from our mailing list, please click on the following link: unsubscribe

I am looking forward to hearing from you.

Kind regards,

David Rain
Email:join@sciepub.com
Science and Education Publishing (http://www.sciepub.com)

The Similar Structure Method for Solving the Radial Seepage Model of Fractal Composite Reservoir with Double-porosity

Wen-wen Xia, Shun-chu Li*, Dong-dong Gui

Institute of Applied Mathematics of XiHua University, Chengdu, China

Abstract: This paper introduces the fractal theory into composite reservoir with double-porosity, and establishes the radial seepage model of fractal composite reservoir with double-porosity. Based on the similar structure theory of solutions for the boundary value problem of differential equation, the similar structure expression of solutions can be obtained in Laplace space. The similar structure theory of solution which avoids the complex calculation is used to solve the model, meanwhile, the similar structure expression of solution reflects the influence of different parameters for the bottom pressure.

Keywords: radial seepage, composite reservoir with double-porosity, laplace transformation, similarity kernel function, similar structure

Received March 27, 2015; Revised April 10, 2015; Accepted April 19, 2015

Citation: Wen-wen Xia, Shun-chu Li, Dong-dong Gui, The Similar Structure Method for Solving the Radial Seepage Model of Fractal Composite Reservoir with Double-porosity. American Journal of Applied Mathematics and Statistics, 3 (2). 80-85. January 2015. doi:10.12691/ajams-3-2-7

1. Introduction

Fractal theory was born in the field of mathematics, and it is a good tool to describe irregular objects. Chang and Yortsos [1] introduced the fractal theory into the study of reservoir seepage in 1990 for the first time, producing many studies about the application of the fractal theory in well test model. Li [2,3,4] introduced the fractal theory into the dual-porosity reservoir model in well test analysis under three outer boundary condition(infinite, closed, constant pressure), and obtained the solution of dimensionless reservoir’s pressure and dimensionless well-bore’s pressure in Laplace space. Deng and Li [5,6,7] used the fractal dimension and the fractal index to describe features of the fractured medium and the rock matrix in the fractal composite reservoirs, and established an analysis mathematical model of well test with the well-born storage and the skin effects, and obtained a formula of Laplace space solution on dimensionless reservoir’s pressure and dimensionless well-bore’s pressure.

In this paper, the fractal theory is introduced into the composite reservoir with double-porosity, establishing the radial seepage model of fractal composite reservoir with double-porosity, and obtaining the solution of the model in Laplace space.

2. SSM the Boundary Value Problem for Composite Modified Bessel Equations

In order to solve the reservoir model, this paper introduces SSM [8] (The Similar Structure Method) for solving the modified composite Bessel equations’ boundary value problem:

[picture] | (1)

[picture] | (2)

[picture] | (3)

[picture] | (4)

[picture] | (5)

[picture] | (6)

Where,,,,,,,,,,, and are all known as real numbers and satisfy , , , , .

The SSM steps are presented as follow.

Step 1. Find two linearly independent solutions of , as follows [9]:

[picture] | (7)

Where , , , , and , are modified Bessel functions of order [10].

Step 2. Guide function is defined by and :

[picture] | (8)

If we define

[picture] | (9)

where are real numbers, can be rewritten as

[picture] | (10)

Then, calculate respectively the partial derivative of for ,:

[picture] | (11)

[picture] | (12)

[picture] | (13)

Step 3. The similar kernel function of right region is defined, as follows:

[picture] | (14)

The similar kernel function of left region is defined, as follows:

[picture] | (15)

Step 4. Obtaining the similar structure formula of solutions, they are

[picture] | (16)

[picture] | (17)

3. The SSM for Solving the Radial Seepage Model of Fractal Composite Reservoir with Double-porosity.

The dimensionless mathematical model of fractal composite with double-porosity with radial seepage in Appendix A. Taking the Laplace transform for the dimensionless mathematical model as follow:

We can write the model in Laplace space as follows:

The basic seepage equations:

[picture] | (18)

[picture] | (19)

[picture] | (20)

[picture] | (21)

[picture] | (22)

[picture] | (23)

[picture] | (24)

Where:

[picture] | (25)

[picture] | (26)

Equations (18), (20), (22), (23) and (24) comparing with (1)~(6) result in

,, or ,, or ,,representing there types of outer boundaries, respectively. So we can construct similar structure formula of dimensionless reservoir’s pressure in Laplace space, as follows:

[picture] | (27)

[picture] | (28)

From (19) and (21), we can obtain

[picture] | (29)

[picture] | (30)

Taking the Laplace transform about for (A.4), and using (27), the dimensionless well-bore’s pressure can be obtained in Laplace space, as follow:

[picture] | (31)

Where is outer region similar kernel function, andis inner region similar kernel function. They are the following.

For , using the properties of modified Bessel function, ,(14) and (15), we can obtain the similar kernel function as follows:

[picture] | (32)

[picture] | (33)

For ,

[picture] | (34)

[picture] | (35)

For ,

[picture] | (36)

[picture] | (37)

Where

4. Conclusions

For the radial seepage model of fractal composite reservoir with double-porosity, introducing dimensionless variables, using the Laplace transform, structuring similarity kernel functions (32)~(37). Then we can obtain the model’s solutions by using SSM, and know the solutions of dimensionless reservoir’s pressure (27)~(30), dimensionless well-bore’s pressure (31) under three outer boundary conditions (infinite, closed, constant pressure) have similar formula in Laplace space. The formulas can clearly shows that well-bore storage coefficient and skin factor generated influence for reservoir pressure and bottom hole pressure.

Appendices

A. Mathematical Model of Fractal Composite Reservoir with Double-porosity with Radial Seepage.

In order to study the radial seepage model of fractal composite reservoir with double-porosity, the main assumptions for fluid flow in porous media as follows: Ignoring the influence of quadratic pressure gradient term, gravity and capillary pressure; Fluids are of low compressibility and single-phase; The flow follows Darcy's law; Radial seepage which has one production; Both consider the well-bore storage and the skin factor.

The distributions of the porosity and permeability of inner and outer region of reservoir are defined as follows [1]:

where and are fractal dimension, Euclidean dimension, fractal index, radial distance, and well radius respectively.

The radial seepage model of fractal composite reservoir with double-porosity is obtained:

The basic seepage equation:

Initial condition:

Inner boundary condition:

Convergence condition:

Outer boundary condition:

1). Infinite pressure outer boundary condition:

2). Closed pressure outer boundary condition:

3). Constant pressure outer boundary condition:

The following dimensionless parameters can be defined to simplify the formulation:

The dimensionless radial seepage model of fractal composite reservoir with double-porosity is obtained:

The basic seepage equations:

[picture] | (A.1)

Initial conditions:

[picture] | (A.2)

Inner boundary conditions:

[picture] | (A.3)

[picture] | (A.4)

Convergence conditions:

[picture] | (A.5)

Outer boundary conditions:

1). Infinite outer boundary conditions:

[picture] | (A.6)

2). Closed outer boundary conditions:

[picture] | (A.7)

3). Constant pressure outer boundary conditions:

[picture] | (A.8)

Nomenclature

:Reservoir pressure,; :Initial reservoir pressure,; :Well-bore storage coefficient,; :Skin factor; :Total compressibility, ;:Formation volume factor,; : Permeability,;:Porosity,; : Viscosity, ; :Radial distance, ; :Radial distance of the outer boundary,; :Production rate or injection rate, ; :Time,; :The internal and external interface radius; :Fractal dimension; :Euclid dimension; :Fractal index; : Laplace space variable.

Superscript

: Laplace domain.

Subscript

:Inner region; :Outer region; :Fissure media; :Matrix block; :Well-bore; :Well-bore effective; :Dimensionless.

Acknowledgment

This work is supported the by the Scientific Research Fund of the Sichuan Provincial Education Department of China (Grant No. 12ZA164).

References

[1]   | Xiang-yan Kong. Higher seepage mechanics [M]. Hefei: China University of Science and Technology Press, 1999.
[2]   | Shun-chu Li. A solution of fractal dual porosity reservoir model in well testing analysis (in Chinese)[J]. Progress in Exploration Geophysics, vol.25(5), p.60-62, 2002.
[3]   | Shun-chu Li.Well test model for fractal dual porosity closed reservoir (in Chinese)[J].Xinjiang Petroleum Geology, vol.24(2), p. 149-151, 2003.
[4]   | Shun-chu Li. A model solution of testing analysis in fractal dual porosity reservoirs with constant pressure outer boundary (in Chinese) [J]. Petroleum Drilling Techniques, vol.31(1), p.51-52,2003.
[5]   | Shun-chu Li, Tian-pu Zheng. A model solution of testing analysis in fractal composite reservoir (in Chinese)[J]. Journal of Jilin University (Engineering and Technology Edition), vol.34, p.104-107, 2004.
[6]   | Xue-ru Deng, Shun-chu Li. Solution to the well testing model for fractal composite reservoirs (in Chinese)[J]. Journal of Xihua University (Natural Science Edition), vol. 24(2), p.4-7, 2005.
[7]   | Tian-pu Zheng, Shun-chu Li, Ying Xu. A model solution of testing analysis in fractal composite reservoir with constant pressure outer boundary (in Chinese)[J]. Journal of Northeast Normal University (Natural Science Edition), vol.35(Supp.), p.46-49(to13), 2003.
[8]   | Shun-chu Li. The Similarity Structuring Method of Boundary Value Problems of the Composite Differential Equations (in Chinese) [J]. Journal of Xihua University (Natural Science Edition),vol.32(4), p. 27-31,2013.
[9]   | Cui-Cui Sheng, Jin-Zhou Zhao, Yong-Ming Li, Shun-Chu Li and Hu Jia. Similar construction method of solution for solving the mathematical model of fractal reservoir with spherical flow[J]. Journal of Applied Mathematics, vol. 2013, Article ID 219218, 8 pages, 2013.
[10]   | Shun-chu Li, Bing-guang Huang. Laplace transform and Bessel functions and the theoretical basis of well test analysis [M].Beijing: Petroleum Industry Press, 2000.
[11]   | Li-ya Chen, Shun-chu Li, Xia Lai. Solution analysis of bottom hole pressure distribution in the dual porosity composite reservoir (in Chinese)[J]. Drilling & Production Technology, vol.33(5), p. 52-54(to61), 2010.
[12]   | Wei Li, Xiao-ping Li, Shun-chu Li, Quan-yong Li.The Similar structure of solutions in fractal multilayer reservoir including a quadratic gradient term [J]. Journal of Hydrodynamics, vol. 24(3), p. 332-338, 2012.
[13]   | Xiao-xu Dong, Shun-chu Li, Dong-dong Gui, Jun Pu, Hui-chun Li. Similar constructing method for solving the boundary value problem of the composite first Weber system[J]. American Journal of Applied Mathematics and Statistics, vol.1(4), p.76-82, 2013.
[14]   | Cong-yin Fan, Shun-chu Li, Dong-dong Gui, Ming Hu, Hui-chun LI. Similar constructing method for solving the model of the plane radial flow of dual permeability reservoir [J]. Applied Mechanics and Materials, vol. 419, p.43-50, 2013.