Plugging is a prominent reason for production reduction in coalbed methane (CBM) wells. In order to solve this problem, authors conducted the feasibility analysis and optimal design of acidizing of CBM wells to remove the plugging in Hancheng block (H block) China. First, X-ray diffraction analysis shows that the plugging contains acid-soluble minerals and the field case indicates that acidizing effect is positively correlated with the content of acid-soluble minerals. Inspired by this, authors analyze determining factors of the content of acid-soluble minerals. Well logging parameters (DEN, AC, GR) are selected to establish a neural network model to predict the content of acid-soluble minerals. Furthermore, a feasibility criterion of acidizing of CBM wells is proposed. Then, a forward model and an inversion algorithm are proposed to diagnose the plugging. The multisolution problem of parameters inversion is solved by the Gauss–Marquardt (G-M) algorithm based on the stochastic initial value and maximum probability. Combining this method with the current numerical model of acidizing, authors present an optimal design in order to optimize the volume and injection rate of the acid. Meanwhile, by experimental study, authors propose a new acid formulation. Finally, results have been applied in the field to confirm the feasibility of the acidizing. It turns out that acidizing is an effective stimulation technology for some specific CBM wells, and the feasibility analysis and the optimal design can improve the effect of acidizing of CBM wells.

References

1.
Palmer
,
I. D.
,
Mavor
,
M. J.
,
Seidle
,
J. P.
,
Spitler
,
J. L.
, and
Voiz
,
R. F.
,
1993
, “
Openhole Cavity Completions in Coalbed Methane Wells in the San Juan Basin
,”
J. Pet. Technol.
,
45
(
11
), pp.
1072
1080
.
2.
Ni
,
X. M.
,
Zhu
,
M. Y.
,
Su
,
X. B.
, and Xu, T.,
2012
, “
Study on Methods of Repeated Hydraulic Fracturing Comprehensive Evaluation About CBM Vertical Wells
,”
J. Henan Polytech. Univ.
,
31
(1), pp.
39
43
.
3.
Keshavarz
,
A.
,
Badalyan
,
A.
,
Johnson
,
R.
, Jr., and Bedrikovetsky, P.,
2016
, “
Productivity Enhancement by Stimulation of Natural Fractures Around a Hydraulic Fracture Using Micro-Sized Proppant Placement
,”
J. Nat. Gas Sci. Eng.
,
33
, pp.
1010
1024
.
4.
Teng
,
T.
,
Wang
,
J. G.
,
Gao
,
F.
, and Ju, Y.,
2016
, “
Complex Thermal Coal-Gas Interactions in Heat Injection Enhanced CBM Recovery
,”
J. Nat. Gas Sci. Eng.
,
34
, pp.
1174
1190
.
5.
Xu
,
J. Z.
,
Zhai
,
C.
, and
Qin
,
L.
,
2017
, “
Mechanism and Application of Pulse Hydraulic Fracturing in Improving Drainage of Coalbed Methane
,”
J. Nat. Gas Sci. Eng.
,
40
, pp.
79
90
.
6.
Papi
,
A.
,
Mohebbi
,
A.
, and
Ehsan Eshraghi
,
S. S.
,
2019
, “
Numerical Simulation of the Impact of Natural Fracture on Fluid Composition Variation Through a Porous Medium
,”
ASME J. Energy Resour. Technol.
,
141
(
4
), p.
042901
.
7.
Harry
,
O.
, and
Mcleod
,
J.
,
1984
, “
Matrix Acidizing
,”
SPE J.
,
36
(12), pp.
2055
2069
.
8.
Fadele
,
O.
,
Zhu
,
D.
, and
Hill
,
A. D.
,
2000
, “
Matrix Acidizing in Gas Wells
,”
SEPCERI Gas Technology Symposium
, Calgary, AB, Canada, Apr. 3–5, Paper No.
SPE-59771-MS
.
9.
Zimmermann
,
G.
,
Blöcher
,
G.
,
Reinicke
,
A.
, and Brandt, W.,
2011
, “
Rock Specific Hydraulic Fracturing and Matrix Acidizing to Enhance a Geothermal System—Concepts and Field Results
,”
Tectonophysics
,
503
(
1–2
), pp.
146
154
.
10.
Shafiq
,
M. U.
, and
Mahmud
,
H. B.
,
2017
, “
Sandstone Matrix Acidizing Knowledge and Future Development
,”
J. Pet. Explor. Prod. Technol.
,
7
, pp.
1205
1216
.
11.
Zhang
,
D.
,
Kang
,
Y.
,
You
,
L.
, and
Li
,
J.
,
2019
, “
Investigation of Formation Damage Induced During Drill-In Process of Ultradeep Fractured Tight Sandstone Gas Reservoirs
,”
ASME J. Energy Resour. Technol.
,
141
(
7
), p.
072901
.
12.
Soliman
,
M. Y.
,
Daal
,
J.
, and
East
,
L.
,
2012
, “
Fracturing Unconventional Formations to Enhance Productivity
,”
J. Nat. Gas Sci. Eng.
,
8
, pp.
52
67
.
13.
Donghong
,
Z.
,
Xianpeng
,
J.
,
Hongyan
,
Z.
,
Chengyu
,
L.
,
Tao
,
W.
,
Haifei
,
W.
,
Zhongxiao
,
L.
,
Taizhen
,
Y.
, and
Wenjun
,
W.
,
2013
, “
Fracturing Technology of Coalbed Methane in Qinshui Basin
,”
SPE Unconventional Resources Conference and Exhibition-Asia Pacific
, Brisbane, Australia, Nov. 11–13, Paper No.
SPE-167108-MS
.
14.
Zhou
,
F.
,
Chen
,
Z.
, and
Rahman
,
S. S.
,
2015
, “
Effect of Hydraulic Fracture Extension Into Sandstone on Coalbed Methane Production
,”
J. Nat. Gas Sci. Eng.
,
22
, pp.
459
467
.
15.
Li
,
H. Y.
,
Lau
,
H. C.
, and
Huang
,
S.
,
2018
, “
Coalbed Methane Development in China: Engineering Challenges and Opportunities
,”
J. Pet. Sci. Eng.
,
166
, pp.
621
635
.
16.
Kalantariasl
,
A.
,
Schulze
,
K.
,
Storz
,
J.
,
Burmester
,
C.
,
Küenckeler
,
S.
,
You
,
Z.
,
Badalyan
,
A.
, and
Bedrikovetsky
,
P.
,
2019
, “
Produced Water Re-Injection and Disposal in Low Permeable Reservoirs
,”
ASME J. Energy Resour. Technol.
,
141
(
7
), p.
072905
.
17.
Kim
,
S.
,
Jung
,
H.
, and
Choe
,
J.
,
2019
, “
Enhanced History Matching of Gas Reservoirs With an Aquifer Using the Combination of Discrete Cosine Transform and Level Set Method in ES-MDA
,”
ASME J. Energy Resour. Technol.
,
141
(
7
), p.
072906
.
18.
Bhatt
,
A.
, and
Helle
,
H. B.
,
2002
, “
Committee Neural Networks for Porosity and Permeability Prediction From Well Logs
,”
Geophys. Prospecting
,
50
(
6
), pp.
645
660
.
19.
Burney
,
M. A.
,
Jilani
,
T. A.
, and
Ardil
,
C.
,
2004
, “
Levenderg–Marquarac Algorithm for Karachi Stock Exchange Share Rates Forecasting
,”
Trans. Eng. Comput. Technol.
,
3
, pp.
1305
1313
.http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.149.3923&rep=rep1&type=pdf
20.
Wang
,
S.
,
Cheng
,
L.
,
Huang
,
S.
,
Xue
,
Y.
,
Bai
,
M.
,
Wu
,
Y.
,
Jia
,
P.
,
Sun
,
J.
, and
Wang
,
J.
,
2019
, “
A Semi-Analytical Method for Modeling Two-Phase Flow Behavior in Fractured Carbonate Oil Reservoirs
,”
ASME J. Energy Resour. Technol.
,
141
(
7
), p.
072902
.
21.
Kang
,
P.
,
Hwang
,
J.
, and
Lim
,
J.
,
2019
, “
Flow Rate Effect on Wax Deposition Behavior in Single-Phase Laminar Flow
,”
ASME J. Energy Resour. Technol.
,
141
(
3
), p.
032903
.
22.
Stanislav
,
J. F.
,
Easwaran
,
C. V.
, and
Kokal
,
S. L.
,
1992
, “
Elliptical Flow in Composite Reservoirs
,”
SPE J.
,
31
(10), pp.
47
50
.
23.
Kuchuk
,
F. J.
, and
Tarek
,
H.
,
1997
, “
Pressure Behavior of Laterally Composite Reservoirs
,”
SPE Form. Eval.
,
12
(
1
), pp.
47
56
.
24.
Yang
,
J.
,
Yao
,
J.
, and
Wang
,
Z. S.
,
2005
, “
Study of Pressure-Transient Characteristic for Triple-Medium Composite Reservoirs
,”
J. Hydrodyn.
,
20
, pp.
418
425
.
25.
Rosa
,
A. J.
, and
Horne
,
R. N.
,
1983
, “
Automated Type-Curve Matching in Well Test Analysis Using Laplace Space Determination of Parameter Gradients
,” SPE Paper No.
SPE-12131-MS
.
26.
Nanba
,
T.
, and
Horne
,
R. N.
,
1992
, “
An Improved Regression Algorithm for Automated Well Test Analysis
,”
SPE Form. Eval.
,
7
(
1
), pp.
61
69
.
27.
Barua
,
J.
,
Horne
,
R. N.
,
Greenstadt
,
J. L.
, and Lopez, L.,
1988
, “
Improved Estimation Algorithms for Automated Type Curve Analysis of Well Test
,”
SPE Form. Eval.
,
3
(
1
), pp.
186
196
.
28.
Rosa
,
A. J.
, and
Horne
,
R. N.
,
1995
, “
Automated Well Test Analysis Using Robust (LAV) Nonlinear Parameter Estimation
,”
SPE Adv. Technol.
,
3
(
1
), pp.
95
102
.
29.
Da-li
,
G.
,
Xiao-hui
,
Z.
,
Jin-zhou
,
Z.
, and
Ci-qun
,
L.
,
2005
, “
Model and Method of Well Test Analysis for Wells With Vertical Fracture
,”
Appl. Math. Mech.
,
26
(5), pp.
571
578
.https://link.springer.com/article/10.1007/BF02466330
30.
Yin
,
H.
,
1999
, “
An Optimal Method of Well Test Analysis Based on Adaptive Genetic Algorithm
,”
Acta Petrolei Sin.
,
20
, pp.
51
56
.http://en.cnki.com.cn/Article_en/CJFDTOTAL-SYXB902.009.htm
31.
Liu
,
X.
,
Ormond
,
A.
,
Bartko
,
K.
, Ying, L., and Ortoleva, P.,
1997
, “
A Geochemical Reaction-Transport Simulator for Matrix Acidizing Analysis and Design
,”
J. Pet. Sci. Eng.
,
17
(
1–2
), pp.
181
196
.
32.
Chen
,
Y.
,
Fambrough
,
J.
,
Bartko
,
K.
,
Li
,
Y.
,
Montgomery
,
C.
, and
Ortoleva
,
P.
,
1997
, “
Reaction-Transport Simulation of Matrix Acidizing and Optimal Acidizing Strategies
,”
SPE International Symposium on Oilfield Chemistry, Houston
, TX, Feb 18–21, Paper No.
SPE-37282-MS
.
33.
Nitika
,
K.
, and
Gerard
,
G.
,
2010
, “
Fluid Temperature as a Design Parameter in Carbonate Matrix Acidizing
,”
SPE Production and Operations Conference and Exhibition
, Tunis, Tunisia, June 8–10, Paper No.
SPE-135654-MS
.
34.
Economides
,
M. J.
, and
Nolte
,
K. G.
,
2001
,
Reservoir Stimulation
, 3rd ed.,
Prentice Hall
,
Englewood Cliffs, NJ
.
35.
Leong
,
V. H.
, and
Mahmud
,
H. B.
,
2018
, “
A Preliminary Screening and Characterization of Suitable Acids for Sandstone Matrix Acidizing Technique: A Comprehensive Review
,”
J. Pet. Explor. Prod. Technol.
(epub).https://link.springer.com/article/10.1007/s13202-018-0496-6
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