Research Journal of Applied Sciences, Engineering and Technology 4(16): 2881-2889, 2012
ISSN: 2040-7467
© Maxwell Scientific Organization, 2012
Submitted: April 07, 2012 Accepted: April 23, 2012 Published: August 15, 2012
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Abstract: The motive of the study is to establish a seepage flow model of pinnate horizontal well in infinite reservoir according to the characteristics of 3D distribution of CBM pinnate horizontal well. Taking flow pressure drop along the main and branch boreholes into consideration, the fluid flow formulas of CBM pinnate horizontal well are proposed. The corresponding calculation program has been achieved based on C++ computer language to analyze the effects of branch symmetry, angle between main and branch boreholes, branch number on isobar distribution, inflow profiles of branch and main boreholes of CBM pinnate horizontal well. The results show that: the isobars present symmetry property by the main borehole when branches are symmetrical. At the same time, production per unit length of main borehole at branch node declines rapidly while the radial inflow curves of branch boreholes are almost the same. With the increasing of angle between branch and main boreholes, isobars transfer into trapezoid from slantwise triangle, meanwhile, the inflow rate of branch borehole increases gradually. Isobars transfer into irregular polygon with the increase of branch number. Moreover, the inflow rate of main and branch boreholes all decreases with the increasing of branch number.
Keywords: Branch parameter, CBM pinnate horizontal well, flow coupling, numerical simulation, seepage flow model
INTRODUCTION
As an abundant new clean energy, Coalbed Methane
(CBM) is a kind of unconventional natural gas with absorption state associated with coal seam (Clarkson et al.
, 2011; Yan et al.
, 2010; Wang et al.
, 2010a). The abundant supplies of CBM resources mainly distribute in the north and northwest of China. The CBM resources within 2000 m deep are about 36.81 trillion m 3 , which are equal to 45 billion tons of standard fuel or 35 billion tons of standard oil. At the same time, CBM is considered as important as the natural gas to ensure the energy sources safety of China (Wang et al.
, 2010b, 2010c; Wang et al.
,
2011a, 2011b). With the rapid growth of CBM demand, improving CBM output per well has become an urgent problem. The CBM pinnate horizontal well is a new type of well developed on the basis of conventional horizontal well and multilateral well. The multi-branch technology can increase the control area of the main borehole, while communicate the crack and pore systems of coal seam on larger scale. At the same time, it can exploit low permeability reservoirs of CBM which can’t be mined by conventional well, moreover increase the single well production and recovery (Thararoop et al.
, 2012; Wang et al.
, 2011a; Keim et al.
, 2011). However, during CBM pinnate horizontal well exploiting process, the change of branch parameters will influence the distribution of potential and seepage characteristics in coal seam because of complex wellbore structure (Maricic et al.
, 2008; Han et al.
, 2004). In the meantime, the fluid continuously flowing into the horizontal wellbore along flowing path, makes the flow become a variable mass flow with gradually increasing mass flow from toe to heel end
(Huang et al.
, 2009; Yan et al.
, 2009). Reflecting the dynamic inflow profile of CBM pinnate horizontal well accurately is an important foundation for production predicting. Archer and Roland (2001) solved the problem of outer boundary impaction in conventional oil a0nd gas reservoirs using the Green element method. Zhou et al.
(2003) figured out the theoretical issue of unstable flow well test in circular formation with numerical methods.
Salas (1996) built analytical model of single-phase flow
Corresponding Author: Xiujuan Yang, College of Pipeline and Civil Engineering, China University of Petroleum, Qingdao,
266580, Shandong, China, Tel.: +86 532 86981231; Fax: +86 532 86983097
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Res. J. Appl. Sci. Eng. Technol., 4(16): 2881-2889, 2012 of the multi-branch well, which divided each branch into a number of micro-segment along its length direction and obtained the linear equations of pressure and production without considering the interference between main and branch boreholes. Retnanto and Frick (1996) introduced the concept of “shape factor” in the pinnate horizontal well productivity prediction for the first time. Considering the permeability heterogeneity around a well and taking cumulative production and economic net present value as objective function, (Yeten and Louis, 2002) built the well type optimization model of the multi-branch well by genetic algorithms and artificial neural networks. The model could describe the impact of branch parameters on production precisely. Nevertheless, the model had the defects of solving complexity and great computing workload.
Therefore, the aims of the study are to establish a new model according to the characteristics of 3D distribution of CBM pinnate horizontal well and the potential superposition principle, which can predict the characteristics of CBM pressure distribution in infinite reservoir and CBM well production. Corresponding calculation program is achieved by C++ computer language and an actual CBM well of Qinshui basin is simulated as an example. Moreover, the effects of branch symmetry, angle between main and branch boreholes, branch number on isobar distribution, inflow profiles of branch and main boreholes of CBM pinnate horizontal well are analyzed.
MATHEMATICAL MODEL is A(x a
, y a
, z a
). The pinnate horizontal well has T branches constituted by several infinitesimal sections. The length of main borehole is L length of of the j
) x i
= th branch is L the length of is
2 j, z
.
)
) x x z z
which is divided into n parts with the
= L j
which is divided into m j, k
= angle between the j z
/n (1
) x j
# i # n). Meantime, the length
= L j
/m j
(1 j parts with
# j # T, 1 # k # m j
). The th branch and the main boreholes
Four assumptions are used in the model, namely (Liu et al.
, 2005):
C
The main and branch boreholes are in the same pressure system with potentials interfering each other
C The coal seam is heterogeneity with aeolotropism
C The angle between branch and main borehole is a constant
C
Take pressure drop along the main and branch boreholes into consideration
Based on potential superposition principle (Jiang et al.
, 2010), when the main borehole in separate production, the potential of any point W(x, y, z)in infinite strata can be expressed as follows:
Φ z
( )
= −
1
4
π ∆ x z
⋅ i
∑ n
=
1
⎢
⎣ ⎢
⎡
Q
Ri
⋅ ln
R
1 z i
R
1
+
+
R
2
R
2
+
−
∆ x z
∆ x z
⎥
⎤
⎦ ⎥
+
C where,
(1)
CBM pinnate horizontal well seepage model in infinite strata: In order to describe the distribution of pinnate horizontal well within the three-dimensional space accurately, a 3-D coordinate system is set up in Fig. 1.
The origin of coordinates o means the maximum vertical depth of the well, while the coordinate value of heel end
Z
R
1 ,
=
⎜
⎛
⎝ x a
+ ∆ x z i f
−
1
=
1
( sin ϕ cos
α
⎜
⎛
⎝ y a
+ ∆ x z
⋅ i
−
1 f
=
1
( sin ϕ sin
α
+
⎝
⎜
⎛ z a
+ ∆ x z i f
−
1
=
1 cos ϕ − z
⎞
⎟
⎠
2
)
− x
⎞ 2
⎠
⎟ +
)
− y
⎞
⎟
⎠
2
∆ x i
A
( x a
, y a
, z a
)
O
The j th branch
θ j , z
∆ x j , k
Fig. 1: 3D schematic diagram of CBM pinnate horizontal well
R
2
=
⎢
⎡
⎣ ⎢ x a
+
+ ⎢
⎡
⎣ ⎢ y a
∆ x z
+
⋅ ⎜
⎛
⎝
−
1 i f
=
1
( sin ϕ
∆ x z
⋅ ⎜
⎛
⎝ i
− f
1
=
1
( sin ϕ
+ ⎢
⎡
⎣ ⎢ z a
+ ∆ x z
⋅ ⎜
⎛
⎝
−
1 i f
=
1 cos ϕ cos
α sin
α
+ cos ϕ
)
+ sin ϕ cos
α
)
+ sin ϕ cos
α
⎞
⎠
⎟ − x
⎥
⎤
⎦ ⎥
2
⎞
⎠
⎟ − y
⎥
⎤
⎦ ⎥
2
⎞
⎠
⎟ − z
⎦ ⎥
⎥
⎤ 2 where, Q
Ri
stands for the flow flowing into the i th microsegment of main wellbore from coal seam, Q
Ri
= q gi
+q wi
, m 3 /d; n z, i
is deviation angle of the i th micro-segment of main wellbore, o ;
" z, i
represents azimuth angle of the i th micro-segment of main wellbore, o ; C stands for constant,
MPa.
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When the j th borehole in separate production, the potential of any point W(x, y, z) in infinite strata can be expressed as below:
Res. J. Appl. Sci. Eng. Technol., 4(16): 2881-2889, 2012 boreholes, m 3 /d; g represents acceleration of gravity, m/s 2 .
where, the expressions of R
1j,k
and R
2j,k
are similar to
R
1z,i
and R
2z,i
.
As the main and the j th branch boreholes all produce at the same time, the potential of any point in infinite strata can be expressed as follows:
Φ
Φ j
= −
1
4
π ∆ x j k
=
L j
1
⎢
⎡
⎣ ⎢
Q
⋅ ln
R
1
R
1
+
+
R
2
R
2
⋅
= Φ z
+ j
T
=
1
Φ j
+
−
∆ x j
∆ x j
⎥
⎤
⎦ ⎥
+
C
= −
−
1
4
π ∆ x z j
T
=
1
⎢
⎡
⎣ ⎢
1
4
π ∆ x j i n
=
1
⎢
⎡
⎣
Q
Ri k
L
j
=
1
⎢
⎡
⎣ ⎢
Q
⋅ ln
R
1 z i
R
1
⋅ ln
+
+
R
1
R
1
R
2
R
2
+
+
R
2
R
2
+
−
∆ x z
∆ x z
⎥
⎤
⎦
+
−
∆ x j
∆ x j
⎥
⎤
⎦ ⎥
⎥
⎤
⎦ ⎥
+
C
(2)
(3)
Flow analysis model of CBM pinnate horizontal well:
Flow analysis model along the main borehole: No branch in infinitesimal section, the flow pressure drop model along the main borehole production segment is:
Flow analysis model along the branch borehole: The flow pressure drop model along the j th branch borehole can be expressed as:
∆ p
+
=
j k f
,
∆ x
Q
+
Q
d
5 j gQ
Q
+
Q
2 4 d j
2
(6) j where, th
) p fj, k
stands for the k th micro-segment drop of the
branch borehole, MPa;
D j, k
is the k th micro-segment fluid density in the j th branch borehole, kg/m 3 ; f j, k is the friction coefficient of the k th micro-segment between fluid and tube wall along the j th branch wellbore; d j
represents the diameter of the j th branch borehole, m; Q j, k
is the flow rate flowing into the k th micro-segment of the j th branch borehole from neighboring upstream, m 3 /d;
Qrj, k
stands for the flow rate flowing into the k th micro-segment of the j th branch well bore from coal seam,
Qrj, k
= q gj, k
+q wj, k
, m 3 /d.
Multi-segments flow coupling model of CBM pinnate horizontal well: Each micro-segment flow rate of main wellbore is the sum of main and all branch boreholes flow flowing into the micro-segment:
∆ p
=
ρ i f i
∆ x i
(
2 Q i
+
Q
Ri
π
D
5
)
2
+
2
ρ i gQ
Ri
(
2 Q i
+
Q
Ri
π
2
D
4
)
(4)
Q i
∑ n
1
Q
Rl
∑ T
1 m k
∑ j
=
1
Q
(7)
In case of having branch in micro segment, the flow pressure drop model along the main borehole production segment can be expressed as:
∆ p
=
ρ i f i
∆ x i
( 2 Q i
+
Q
Ri
π
D
5
+
ρ i g cos
θ
Q
Ri
+
+
Q
Hi
π
Q
Hi
2
)
2
D
4
+
0 5
ρ i sin
θ
( Q i
+
Q
Ri
2 Q i
+
Q
Ri
+
π
Q
Hi
2
D
4
+
Q
Hi
)
2
(5) where, w is the quantity of branch within the range of micro-segment to heel end along the main borehole.
Flowing pressure of the main borehole in pinnate horizontal well can be expressed as below: p f, i
= p f, i-1
+0.5(
) p f, i
+
) p f, i-1
) (8)
Each micro-segment flow rate of the j th branch borehole is the sum flowing into all the micro-segments upstream from coal seam: where,
) p f, i
stands for the i borehole, MPa;
D th micro-segment drop of main i
is the mixed fluid density of the i th micro-segment along the main borehole, kg/m 3 ; f i
is the friction coefficient between fluid and tube wall of the i th micro-segment along main wellbore ; D is the diameter of main wellbore, m; Q i
is the flow rate flowing into the i th micro-segment of main wellbore from neighboring upstream, m 3 /d; Q
Hi
stands for the flow rate flowing into the i th micro-segment of main wellbore from branch
Q
= m
j
1
Q (9)
Flowing pressure of the j th branch borehole in pinnate horizontal well can be expressed as follows:
p fj, k
= p fj, k-1
+0.5(
) p fj, k
+
) p fj, k-1
) (10)
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Res. J. Appl. Sci. Eng. Technol., 4(16): 2881-2889, 2012 heel
160m
25
0m branch 1
30° main borehole
30°
320m branch 2
480m toe
Fig. 2: Branch distribution and size of B1 pinnate horizontal well in coal seam
Table 1: The basic parameters of coal seam
Coal seam thickness/m 5.40
Coal seam pressure/MPa
Coal porosity/% 4.50
4.19
Permeability of coal seam/mD 1.15
Langmuir pressure/MPa 3.42
Simulation time/d
Wellbore radius/m
400.00 Langmuir volume/(m 3 /t)
0.12
Desorption time/d 5.00
42.74
Due to pressure continuous principle, the fluid flow pressure within reservoir should be equal to that of wellbore fluid flow at the borehole in the mining process of CBM pinnate horizontal well. Based on the reason above, the models of CBM pinnate horizontal well seepage and fluid flow along the wellbore can be coupled.
(a)
300
0
-300
-600 -300
Pinnate horizontal well
0 (x/m) 300
APPLICATION ANALYSES
300
On the basis of the multi-segment flow coupling model above, the corresponding seepage calculation procedure near boreholes of CBM pinnate horizontal well is established. We have done numerical simulation on seepage of B1 CBM pinnate horizontal well in Qinshui basin by the procedure. The influences of branch symmetry, angle between branch and main boreholes, branch number on pressure field distribution have been analyzed. Simultaneously, the effects of branch parameters on flow rate per unit length of main and branch boreholes have been studied respectively. The branch distribution and size of B1 pinnate horizontal well are shown in Fig. 2. Meantime, Table 1 provides the basic parameters of coal seam.
Isopiestic distribution chart of B1 CBM pinnate horizontal well is shown in Fig. 3a. Due to the existence of two branches, isopiestic distribution presents characteristic. In the regions away from B1 pinnate horizontal well, the isobars present regular oval. At the same time, the closer to the pinnate horizontal well, the more severe the pressing line shape changing. Outside the
1 st branch, isobars bend towards to the branch borehole;
(b)
0
-300
-600 -300 0 (x/m) 300
Conventional horizontal well
600
/MPa
4.1
3.9
3.7
3.5
3.3
3.1
2.9
2.7
2.5
2.3
2.1
1.9
1.7
1.5
600
/MPa
4.1
3.9
3.7
3.5
3.3
3.1
2.9
2.7
2.5
2.3
2.1
1.9
1.7
1.5
Fig. 3: Comparison diagrams on isobar distribution of pinnate and conventional horizontal wells while inside the area between the 1 st branch and the main borehole, isobars bend towards to the branch point. The variation discipline of isobars near the 2 nd branch is similar to the 1 st branch. Figure 3b shows isopiestic distribution chart of conventional horizontal well near wellbore. Without the interference of branch boreholes, the shapes of isobars present regular oval. The farther from the borehole, the sparser the isobars are.
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Res. J. Appl. Sci. Eng. Technol., 4(16): 2881-2889, 2012
40
35
30
25
20
Pinnate horizontal well with two branches
15
10
5
0
0 50 100 150 200 250 300 350 400 350 500
Length/m
Fig. 4: Inflow profile along main borehole of pinnate horizontal well
40
35
30
25
20
15
10
5
0
0
Branch 1
Branch 2
50 100 150
Length/m
200 250
Fig. 5: Inflow profile along branch boreholes of pinnate horizontal well
Radial inflow graph along the main borehole of CBM pinnate horizontal well is shown in Fig. 4. The maximum value of inflow appears at the heel end of the main borehole, followed by the toe end; meanwhile, fluid radial inflow within the middle horizontal segment is smaller.
The flow rate firstly decreases obviously near the first branch point and then it declines again at the second branch point. Although the flow rate improves gradually within the range from the second branch point to toe end, it is still much lower than that of the heel end.
As is shown in Fig. 5, the inflow distribution along the branch borehole is completely different from the main borehole. Because of the interference between main and branch boreholes, the inflow rate of the branch borehole is the lowest at heel end; furthermore, it increases gradually in the middle and reaches the peak at the toe end.
The characteristic differences of isobar distribution between CBM pinnate horizontal well and conventional horizontal well are mainly due to the complex casing structure of pinnate horizontal well. In this study, we take branch parameters as branch symmetry, angle between branch and main boreholes, branch number into consideration to analyze the effects on isobar
(a) Symmetrical branches
300
0
-300
-600 -300 0 (x/m) 300 600
/MPa
4.1
2.1
1.9
1.7
1.5
3.9
3.7
3.5
3.3
3.1
2.9
2.7
2.5
2.3
(b) Asymmetrical branches
Fig. 6: Comparison diagrams on isobar distribution of pinnate horizontal well under the condition of different branch symmetry distribution and inflow rate distribution of main and branch boreholes in pinnate horizontal well.
Branch symmetry: Based on different branch symmetry conditions, the isobar distribution charts of CBM pinnate horizontal well are shown in Fig. 6. On the condition of branch symmetry (the branch point is 240 m away from the heel end), isobars present oval shape in the regions far away from the wellbore, while the isobar shape appears melon seed near wellbore area. In the meantime, isobars present symmetry with the symmetric axle of main borehole. Under the condition of branch asymmetry, the shapes of isobars near the wellbore look like triangles.
Figure 7 shows the inflow distribution charts of main and branch boreholes of CBM pinnate horizontal well.
When branches are symmetrical, the inflow rate per unit length along the main borehole reduces apparently at the branch point because of the serious interference between main and branch boreholes. The radial inflow curves of two branches are almost the same. The rules of radial inflow profiles of branch boreholes are nearly the same when branch asymmetrical. However, the 2 nd branch has higher inflow rate which is away from the heel end of the main borehole.
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Res. J. Appl. Sci. Eng. Technol., 4(16): 2881-2889, 2012
40
35
30
25
20
15
10
5
0
0 50
Branch symmetrical
Branch asymmetrical
100 150 200 250 300
Length/m
350 400 450 500
(a) Inflow profile of main borehole
40
35
15
10
5
30
25
20
0
0
Branch 1 branch symmetrical
Branch 2 branch symmetrical
Branch 1 branch asymmetrical
Branch 2 branch asymmetrical
50 100 150
Length/m
(b) Inflow profile of branch borehole
200 250
Fig. 7: Inflow profiles along main and branch boreholes of pinnate horizontal well under the condition of different branch symmetry
Angle between branch and main boreholes: Figure 8 shows the isobar distribution charts of CBM pinnate horizontal well on the condition of different angles between main and branch boreholes. With the increasing of angle, the isobars change gradually from triangle to ladder near wellbore area. According to increasing the angle, it can reduce the interference between main and branch boreholes. In the meantime, it can also improve gas area of pinnate horizontal well to increase the production of CBM.
The inflow profiles of main and branch boreholes on the condition of different angles are shown in Fig. 9. Two branch points divide the main borehole into three sections from heel end to toe end. With the increasing of angle, the inflow rates within the three regions are reducing, unchanged and increasing respectively. The radial inflow profile law of the two branches is substantially the same.
Taking the 1 st branch for example, the impact of main and branch boreholes is weakened gradually with the increasing of angle, which increases the inflow rate along the branch borehole.
(a) 30 degree
300
0
0 (x/m) 300 600
/MPa
4.1
3.9
3.7
3.5
3.3
3.1
2.9
2.7
2.5
2.3
2.1
1.9
1.7
1.5
-300
-600
(b) 45 degree
- 300
300
0
-300
-600 - 300 0 (x/m) 300 600
3.1
2.9
2.7
2.5
2.3
2.1
1.9
1.7
1.5
/MPa
4.1
3.9
3.7
3.5
3.3
(c) 60 degree
Fig. 8: Comparison diagrams on isobar distribution of pinnate horizontal well under the condition of different branch angles
Branch number: Taking the pinnate horizontal well in
Fig. 2 as a foundation, the schematic diagrams of pinnate horizontal well with three or four branches are shown in
Fig. 10. Figure 11 shows the isobar distribution charts of
CBM pinnate horizontal on the condition of different branch number.
With the increasing of branch number, the shape of isobars near wellbore zone changes from sloping triangle to irregular pentagon gradually. By improving branch number, we can enlarge the communication channel between wellbore and coal seam, and expand the gas area of pinnate horizontal well to improve productivity.
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Res. J. Appl. Sci. Eng. Technol., 4(16): 2881-2889, 2012
40
35
30
25
20
15
10
5
0
0 50
30 degree
45 degree
60 degree
100 150 200 250 300
Length/m
350 400 450 500
30
25
20
15
45
40
35
10
5
0
0
30 degree
45 degree
60 degree
50 100 150
Length/m
200 250
(a) Inflow profile of main borehole (b) Inflow profile of branch borehole
Fig. 9: Inflow profiles along main and branch boreholes of pinnate horizontal well under the condition of different branch angles heel
120m
25
0m branch 1
30° main borehole
30°
240m
360m
480m
30° branch 2 toe branch 3
(a) Three branches
25
0m branch 1 heel
30° main borehole
96m
192m
288m
384m
480m branch 2 branch 3 toe branch 4
(b) Four branches
Fig. 10: Structure and size of multi-branch pinnate horizontal wells
The interference of main and branch boreholes increases gradually with the increasing of branch number, which can be seen from Fig. 12. Due to this reason, the radial inflow rate of main borehole decreases a lot. Taking the 1 st branch for example to analyze the effects on inflow rate, the inflow profile laws are nearly the same, however, the flow rate declines gradually with the increase of branch number. The diminution range
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Res. J. Appl. Sci. Eng. Technol., 4(16): 2881-2889, 2012
3 00
0
-300
-60 0
(a) Two branches
- 300 0 (x/m )
3 00
0
-3 00
-6 0 0
3 00
- 3 0 0
60 0
/MPa
4.1
3 .9
3.7
3 .5
3 .3
3.1
2. 9
2. 7
2. 5
2. 3
2. 1
1. 9
1. 7
1. 5
3 00
0
-3 00
-6 00 - 30 0 0 (x/m )
0 (x/m )
(b) Three branches
3 0 0 60 0
/MPa
4.1
3.9
3.7
3.5
3.3
3.1
2.9
2.7
2.5
2.3
2.1
1.9
1.7
1.5
30 0 6 00
/MPa
4.1
3.9
3.7
3.5
3.3
3.1
2.9
2.7
2.5
2.3
2.1
1.9
1.7
1.5
(c) Four branches
Fig. 11: Comparison diagrams on isobar distribution of pinnate horizontal well under the condition of different branch number
40
35
30
25
20
15
10
5
0
0 50
Two branches
Three branches
Four branches
100 150 200 250 300
Length/m
350 400 450 500
35
30
25
20
15
10
5
0
0
Two branches
Three branches
Four branches
50 100 150
Length/m
200 250
(a) Inflow profile of main borehole (b) Inflow profile of branch borehole
Fig. 12: Inflow profiles along main and branch boreholes of pinnate horizontal well under the condition of different branch number decreases by degrees when the branch number increases from 2 to 4.
CONCLUSION
C
The isobar shapes near pinnate horizontal well are related to its own well structure. In the regions away from the well bore, isobars are approximately like ellipse with sparser form. The inflow profile of the main borehole shows the characteristics of high at both ends and low in the middle. Because of the interference between main and branch boreholes, the radial flow rate of main borehole declines at branch points. The characteristics of branch boreholes are low at heel, high at toe, increasing gradually in the middle.
C
When branches are symmetrical, isobars present the shape of melon seed near wellbore formation which present symmetry by the main borehole. With the increasing of branch angle, the isobars change
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gradually from triangle to ladder. At the same time, the isobars change from triangle to polygon near wellbore area gradually with the increasing of branch number. The increase of branch angle and branch number can improve the gas area of pinnate horizontal well, therefore enhance the CBM production.
C When branches are symmetrical, the inflow rate of main borehole declines rapidly at the branch point while inflow profiles of the two branches are almost the same. Two branch points divide the main borehole into three regions from heel to toe. With the increase of branch angle, the inflow rate of the three regions shows decrease, unchanged and increase, respectively. The radial flow rate along the branch borehole increases with the increasing of branch angle. The inflow rate along the main and branch boreholes all decreases with the increase of branch number.
ACKNOWLEDGMENT
The authors wish to acknowledge the financial support of the Important National Science & Technology
Specific Projects (Contract No. 2011ZX05037 and
2011ZX05036).
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