Prediction Methods About Development Condition
of Horizontal Well Section
Fengkai Zhao, Yanyu Zhang and Dongdong Li
School of Petroleum Engineering, China University of Petroleum,qingdao,shandong
Keywords: Well testing, numerical well testing, reservoir engineering method, development condition.
Abstract: With the advancement of drilling technology, in order to meet the demand of special oil reservoirs,
horizontal well has become an advanced and important technology to develop oil and gas fields and
improve recovery. However, in the process of the development of oil and gas fields with horizontal wells,
the unbalanced development condition of horizontal wells severely restricts the exploitation results of
horizontal well. At present, optical fiber testing is carried out in the field to obtain the development
condition of the horizontal well section. However, this method leads to costly expense and requires prefect
well statues. Therefore, this paper presents a prediction method about the horizontal well section
development condition. The way of the well testing and reservoir engineering method were adopted. This
method makes the most of the dynamic data and static data to ensure the correctness of the result. And this
method is low-cost and high-precision, which can provides a basis for large-scale the evaluation of the
potential, the next development and deployment of the oilfield.
1 INTRODUCTION
Horizontal well development technology has been
widely adopted in various kinds of reservoirs. It
plays an effective role in the construction of new oil
fields and the adjustment of old oil fields. According
to the actual data of oil field, the development
condition of horizontal well section has great
influence on reservoir development. At present, the
analysis of the horizontal section development
condition is only limited to heavy oil reservoirs,
since it obtains the development condition of
horizontal well section by temperature distribution
along the wellbore, in the process of thermal
recovery for heavy oil reservoir. Therefore,
providing a set of effective methods to obtain the
development condition of horizontal well section is
necessary（Joshi,1991）.
First of all, well testing method is adopted in this
method to obtain the effective development length,
geological parameters of horizontal wells and
dynamic development parameters. Subsequently, to
verify the correctness of the well testing, the
horizontal well productivity formula is applied to
calculate the effective development length. Finally,
the numerical well testing model is proposed to
establish the geologic model of the well
circumference which is used to simulate the
development of the block where the target well is
located. By combining well testing method with
reservoir engineering methods, the development
condition of horizontal well section of the target
well is obtained.
2 ANALYSIS
A horizontal well (called well A) in edge water
reservoir is studied in this paper. The development
condition of this horizontal well is obtained. The
basic data of the well is shown in Table 1.
Table 1 Parameters of the well A
Porosity
（%）
30.0 volume factor 1.060
Thickness
（m）
4.5 Viscosity（cp） 9.46
Wellbore
radius（m
）
0.062
Compressibility
(psi-1)
1.283*10
-
5
72
Zhao, F., Zhang, Y. and Li, D.
Prediction Methods About Development Condition of Horizontal Well Section.
In 3rd International Conference on Electromechanical Control Technology and Transportation (ICECTT 2018), pages 72-76
ISBN: 978-989-758-312-4
Copyright © 2018 by SCITEPRESS – Science and Technology Publications, Lda. All rights reserved

2.1 Conventional well testing
Two sets of well test data from well A in August
2008 and June 2016 are analysed by the
conventional well testing methods. The results of
well testing including initial formation pressure, well
storage coefficient, skin coefficient, effective
permeability, the ratio of vertical permeability and
radial permeability, effective development length are
shown in Table 2. The curve fitting of conventional
well testing are shown in Fig 1,and Fig 2. By
conventional well testing, the horizontal section
effective development length of well A are 178 m
and 180.4 m, respectively.
Table 2 Results of well test about well A
August
2008
June
2016
initial formation pressure（MPa
）
11.3621 9.4533
well storage coefficient（m
3
/MPa
）
11.1 2.31
skin coefficient -6.73 -6.08
k
Z
/
k
r
0.342 0.011
effective
p
ermeabilit
y
(
md
)
240 56.4
effective utilization len
g
th
(
m
)
178 180.4
Analysis of the well test data from August 2008
Figure 1 Log-Log plot：pressure and pressure derivative
curve
Analysis of the well test data from June 2016
Figure 2 Log-Log plot：pressure and pressure derivative
curve
2.2 Reservoir engineering method
2.2.1 Borisov
In 1964, the Soviet scholar Borisov system studied
the seepage principle of horizontal well. He divides
the three dimensional seepage field around the
horizontal well into internal seepage field and
external seepage field. Assuming that the horizontal
well is located in the middle of the top-bottom
closed oil layer, the fluid flow is steady-state and the
fluid is incompressible in the formation. The
pressure drop in the wellbore was ignored in this
formula. According to the quasi-3D method obtain
the horizontal well yield formula, Laid the
foundation for two-dimensional steady-state analysis
of horizontal well productivity（Joshi, 1988）.
eh
oo
w
0.543
4
ln ln
2
Kh P
q
r
hh
B
LL r
μ
π
Δ
=
+
eh
A
r
π
=
(1)
2.2.2 Giger
In 1984, Giger applied the equivalent radius instead
of the semi-major axis of the horizontal elliptic area.
And derive the production formula for homogeneous
isotropic reservoir under the steady-state （ Giger,
1985）（Giger， Reiss and Jourdan, 1984）.
2
oo
eh
w
eh
0.543
0.5L
1+ 1+
ln ln
0.5L
2
Kh P
q
B
r
hh
Lr
r
μ
π
Δ
=
⎡⎤
⎛⎞
⎢⎥
⎜⎟
⎝⎠
⎢⎥
+
⎢⎥
⎢⎥
⎢⎥
⎣⎦
(2)
2.2.3 Guo Baoxi
Assuming that the reservoir is a circular, closed,
anisotropic and top-bottom closed formation. The
horizontal well section is 2L.The reservoir thickness
is h. The horizontal wellbore radius is r
w.
The
horizontal well section is located at the distance z
w
from the bottom of the reservoir. The horizontal well
is located horizontally in the center of the
reservoir .Setting the amount of liquid production q,
derived horizontal well productivity formula from
the edge water reservoir.(
Guo, Wang and Luo,
2007.)
Prediction Methods About Development Condition of Horizontal Well Section
73

h
oosse
=
1.842
Kh P
q
B
F μ
Δ
(3)
The reservoir engineering method is used to
calculate the effective development length of the
horizontal section of well A in September 2016. The
results of the three formulas are 164m, 165m and
177m respectively, as shown in Table 3. The results
match conventional well testing. By comparing
conventional test method and reservoir engineering
method, the effective length of the well is about
170m, and the total length of the horizontal well is
279m. Therefore, the length of the undeveloped
horizontal well section is about 100m. The
comparison of traditional well test method and
reservoir engineering method is shown in Table 3.
The reservoir engineering method is applied to
verify the accuracy of well testing method. But the
effective development length of the horizontal
section is high sensitivity for multiple parameters in
the productivity formulas. Such as, yield,
permeability and reservoir thickness. Reservoir
engineering method can only be used as a validation
method, therefore, cannot be directly used to
calculate the development condition of horizontal
well section.
Table 3 Results of conventional well testing and reservoir
engineering
conventional
well testin
g
Borisov Giger
Guo
Baoxi
June
2016
180.45m 164.38m 165.17m 176.69m
2.3 Numerical well testing
Numerical well testing method is a new well testing
interpretation technique developed in recent years.
The technology has absorbed the mature technology
of reservoir numerical simulation to describe the
properties of complex reservoir. Such as describing
the change of formation fluid properties, reservoir
thickness distribution, seepage condition hetero-
geneity and reservoir special outer boundary shape,
etc. The high precision pressure gauges were
adopted in the field, which provides an effective
technical support for the dynamic description of well
testing in heterogeneous reservoirs（Ding, Onur and
Reynolds, 1989）（Al-Zayer, Mesdour, Al-Faleh,
Basri and Utaibi, 2013）.
In fact, the numerical well testing is a fine
numerical simulation of a well group or a flow unit
of injection and production. Compared with the
conventional well testing, it has the characteristics of
small hypothesis, large scale and the influence of the
neighboring well. Therefore this technology is more
suitable for the seepage of the actual reservoir
development characteristics. It can better solve
problem of the multiphase flow, multi-well inter-
ference, complicated boundary and heterogeneity
which can’t be solved by the conventional well
testing. Numerical well testing can determine
formation pressure, reservoir parameters and under
multi-well system, which can provide the basis for
the adjustment of injection-production structure and
the measures for the excavation（Frick, Brand, and
Schlager, 1996）（Al-Mohannadi, Ozkan, Kazemi
H, 2007 ）（Al-Thawad ， Issaka and Aramco,
2003）.
In order to obtain the development position of
the horizontal well, numerical well testing method is
applied to obtain the pressure distribution and the
saturation distribution in the block where the target
well is located. Firstly, based on the formation
parameters and fluid parameters of well A, the
Saphir was applied to establish three-dimensional
geological model. The geological model was loaded
with production data to establish a production model.
Then, the model was used to simulate the production
status from the well put into production to August
2008. Adjust the model parameters by fitting the
log-log curve of reservoir pressure and pressure
derivative which obtained from the well test data
simulated by the model and the field test well data.
Pressure fitting curve is shown in Fig 2, and Log-
Log fitting curve is shown in Fig 3.
Figure 2 Pressure fitting curve
ICECTT 2018 - 3rd International Conference on Electromechanical Control Technology and Transportation
74

Figure 3 Log-Log fitting curve：pressure and pressure
derivative curve
The adjusted model was used to simulate
reservoir development performance from the well
put into production to June 2016. The pressure
distribution and the saturation distribution obtained
by numerical well testing method were shown in Fig
4 and Fig 5, respectively. The water saturation
distribution is shown in Fig 6. The water saturation
across well A section is shown in Fig 7.
Figure 4 Pressure distribution
Figure 5 Oil saturation distribution
Figure 6 Water saturation distribution
Figure 7 Water saturation across well A section
The simulation results of the numerical well
testing show that the energy supplements of well A
is mainly from the water injection on the right and
the edge water. Water breakthrough has happened in
the finger tip of horizontal section.
3 CONCLUSIONS
(1) Compared with the results of conventional well
testing and reservoir engineering method, the
effective use length of the well is about 170m. The
total length of horizontal well is 279 m. Therefore,
the horizontal section of the well about 100m has not
been utilized.
(2) Numerical well testing simulation shows that
the water breakthrough in the finger tip of horizontal
section. It is the main segment of producing.
Well A
Prediction Methods About Development Condition of Horizontal Well Section
75

(3) Combining the two methods, it can be seen
that the heel of the horizontal well section is poorly
developed.
REFERENCES
Joshi, S. D., 1991. Horizontal well technology, Pennwell
Corp.
Joshi S D., 1988. Augmentation of well productivity with
slant and horizontal wells, Journal of Petroleum
Technology.
Giger, F. M., 1985. Horizontal Wells Production
Techniques in Heterogeneous Reservoirs, Middle East
Oil Technical Conference and Exhibition Society of
Petroleum Engineers.
Giger, F. M., Reiss, L. H., & Jourdan, A. P., 1984. The
Reservoir Engineering Aspects of Horizontal Drilling,
SPE-13024-MS.
Guo Baoxi, Wang Xiaodong, Luo Wanjing, 2007.
A New
Method of the Productivity Evaluation for Horizontal
Wells with Edge Water Drive, Geoscience.
Ding, W., Onur, M., & Reynolds, A. C., 1989. Analysis of
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25(5), 472.
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Utaibi, A., 2013.
The book, Practical Well Testing
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92041-PA.
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