Ultradeep Carbonate Gas Reservoirs: Reservoir Characteristics and Percolation Mechanism

335 Pages·2023·13.691 MB·English

by  Lu Wang

Lu Wang
Ultradeep
Carbonate
Gas Reservoirs
Reservoir Characteristics and
Percolation Mechanism
Ultradeep Carbonate Gas Reservoirs
Lu Wang
Ultradeep Carbonate Gas
Reservoirs
Reservoir Characteristics and Percolation
Mechanism
Lu Wang
Department of Petroleum Engineering
College of Energy
Chengdu University of Technology
Chengdu, Sichuan, China
ISBN 978-981-19-9707-5 ISBN 978-981-19-9708-2 (eBook)
https://doi.org/10.1007/978-981-19-9708-2
© The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature
Singapore Pte Ltd. 2023
This work is subject to copyright. All rights are solely and exclusively licensed by the Publisher, whether
the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse
of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and
transmission or information storage and retrieval, electronic adaptation, computer software, or by similar
or dissimilar methodology now known or hereafter developed.
The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication
does not imply, even in the absence of a specific statement, that such names are exempt from the relevant
protective laws and regulations and therefore free for general use.
The publisher, the authors, and the editors are safe to assume that the advice and information in this book
are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or
the editors give a warranty, expressed or implied, with respect to the material contained herein or for any
errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional
claims in published maps and institutional affiliations.
This Springer imprint is published by the registered company Springer Nature Singapore Pte Ltd.
The registered company address is: 152 Beach Road, #21-01/04 Gateway East, Singapore 189721,
Singapore
Preface
Carbonate gas reservoirs play an important role in the world energy pattern,
accounting for 26% of the total 370 large natural gas fields discovered in the world.
In addition, the recoverable reserves of carbonate gas reservoirs are 72.4 × 1012 m3,
accounting for 46% of the recoverable reserves of all gas reservoirs. With the devel-
opment and progress of hydrocarbon theory and technology, ultradeep carbonate
gas reservoirs have become the key areas of fossil fuel exploration and develop-
ment. The annual gas production of conventional natural gas in Sichuan Basin, the
cradle of China’s modern natural gas industry, is 350 × 108 m3, of which the annual
production of natural gas in the ultradeep carbonate gas reservoir accounts for more
than 83%, indicating that the ultradeep carbonate gas reservoir is the most potential
hydrocarbon resource field in China and even in the world.
The ultradeep carbonate gas reservoir has experienced a geological history of
more than 100 million years, as well as multistage tectonic movement and diagenetic
transformation, thereby forming a coexistence pattern of multiple media, including
microscopic pores, macroscopic pores, dissolution cavities and fractures. Therefore,
this type of gas reservoir is characterized by extremely strong reservoir hetero-
geneity, extremely high temperature and pressure, special percolation mechanism,
complex gas–water relationship, difficult reserve evaluation, and large difference in
gas well productivity. A systematic and comprehensive investigation of the reservoir
characteristics and percolation mechanism of ultradeep carbonate gas reservoirs is
a prerequisite for scientific and efficient development and is also the main content
of this monograph. At present, there is a lack of theoretical research on ultradeep
carbonate gas reservoirs because of the limitations of experimental techniques
and analytical methods. Our team has preliminarily formed a variety of research
techniques through 6 years of technical breakthrough and practice accumulation on
the ultradeep carbonate gas reservoirs of Sinian Dengying Formation and Cambrian
Longwangmiao Formation in Sichuan Basin, namely comprehensive evaluation
technique of reservoir characteristics and storage-percolation capacity, ultra-high
temperature and pressure physical simulation experiment technique, microscopic
visualization technique based on CT scanning and microelectronics lithography,
and heterogeneous reservoir development physical simulation technique. The key
v
vi Preface
techniques and methods introduced in this monograph can meet the needs of efficient
development of ultradeep carbonate gas reservoirs at this stage and are expected
to provide theoretical basis and technical reference for readers to conduct relevant
research on similar gas reservoirs.
The monograph is comprised of five chapters. Chapter 1 gives a detailed introduc-
tion to the reservoir characteristics and fluid properties of the ultradeep carbonate gas
reservoir based on a variety of testing techniques, and a analysis of the storage and
percolation capacity of various types reservoirs according to the established reservoir-
type classification standards. The ultra-high temperature and pressure physical
simulation experiment technique and equipment are introduced in Chap. 2, and the
gas-phase and gas–water two-phase percolation mechanism and percolation capacity
of different types of reservoirs in ultradeep carbonate gas reservoirs under actual
formation conditions are revealed. In Chap. 3, the microscopic visualization tech-
nique of fluid percolation based on CT scanning and microelectronic lithography is
presented. Then, the complex gas–water relationship and the formation mechanism of
residual water and trapped gas of different types of reservoirs during the hydrocarbon
accumulation and water encroachment processes are qualitatively and quantitatively
studied. Chapter 4 focuses on the sensitivity characteristics and formation damage
mechanisms of water, salinity, velocity, acid, and alkali of different types of reser-
voirs in ultradeep carbonate gas reservoirs. Furthermore, both the permeability and
porosity stress sensitivity degree and characteristics of different types of reservoirs
are determined. The monograph ends with Chap. 5 which reveals the gas production
characteristics and gas supply capacity of differential types of reservoirs in ultradeep
carbonate gas reservoirs with interlayer heterogeneity and horizontal heterogeneity,
and analyzes the effects of reservoir heterogeneity, permeability difference, deple-
tion pressure differential, initial water saturation, and water encroachment on the gas
production capacity of the two types of heterogeneous gas reservoirs. In addition,
the suggestions for efficient development of gas reservoirs are put forward according
to the reservoir characteristics and percolation mechanism of ultradeep carbonate
gas reservoirs. I hope this systematic monograph will be valuable to academics and
engineers working in the related area.
I would like to sincerely thank my former Ph.D. advisor, Prof. Shenglai Yang at
the China University of Petroleum (Beijing), who introduced me to the interesting
field of ultradeep carbonate gas reservoirs in 2015. I would also like to thank the
leaders and engineers of PetroChina Southwest Oil and Gas Field Company for their
technical support to my monograph. Furthermore, I would like to thank my wife,
Dr. Xingli Xu, for her consideration in my life during my monograph edition. Last
but not least, I am grateful for the financial support provided by the National Science
and Technology Major Projects of China (2016ZX05015-003), the National Natural
Science Foundation of China (51774300), the Natural Science Foundation of Sichuan
Province (2022NSFSC0205), and the Open Fund of State Key Laboratory of Oil and
Gas Reservoir Geology and Exploitation (PLC2020007).
Preface vii
Many research contents introduced in this monograph are still in the exploratory
stage, because the exploration and development of ultradeep carbonate gas reservoirs
is a new research field. Owing to my limited knowledge, there might be some mistakes
and flaws in this monograph. Please don’t hesitate to correct me.
Chengdu, China Dr. Lu Wang
Contents
1 Reservoir Characteristics of the Ultradeep Carbonate Gas
Reservoir ...................................................... 1
1.1 Geological Setting of the Ultradeep Carbonate Gas Reservoir ..... 2
1.1.1 Tectonic Setting ..................................... 2
1.1.2 Sedimentary Setting .................................. 4
1.2 Comprehensive Evaluation Method for Ultradeep Carbonate
Gas Reservoirs ............................................. 6
1.2.1 Samples and Testing Process .......................... 6
1.2.2 Conventional Petrophysical Measurements ............... 7
1.2.3 Casting Thin Sections ................................ 7
1.2.4 SEM Testing ........................................ 8
1.2.5 HPMI Testing ....................................... 8
1.2.6 Multiscale CT Scanning .............................. 9
1.3 Reservoir Characteristics of Ultradeep Carbonate Gas
Reservoirs ................................................. 13
1.3.1 Lithology and Mineral Composition of Reservoir Rocks ... 13
1.3.2 Petrophysical Properties .............................. 14
1.3.3 Reservoir Space Types and Characteristics ............... 19
1.3.4 Throat Types and Characteristics ....................... 24
1.3.5 Reservoir Classification Based on HPMI Testing ......... 24
1.3.6 Two-Dimension CT Scanning Analysis .................. 29
1.3.7 Reservoir Temperature and Pressure Conditions .......... 32
1.3.8 Fluids Properties and Compositions ..................... 35
1.3.9 Reservoir Thickness Distribution Characteristics ......... 36
1.4 Storage and Percolation Capacities of Ultradeep Carbonate
Gas Reservoirs ............................................. 37
1.4.1 Effect of Cavities and Fractures on Storage
and Percolation Capacities ............................ 37
1.4.2 Pore and Throat Size Distribution and Connectivity
Characteristics ....................................... 38
ix
x Contents
1.4.3 Analysis of Pore Throat Network Models ................ 51
1.4.4 Analysis of the Pore Throat Connectivity ................ 54
1.4.5 Proportion of Various Types of Reservoir Spaces ......... 59
1.5 Characteristics and Classification Standard of Various Types
of Ultradeep Carbonate Gas Reservoirs ........................ 60
1.6 Summary .................................................. 61
References ..................................................... 67
2 Special Percolation Mechanism of the Ultradeep Carbonate
Gas Reservoir .................................................. 71
2.1 Ultra-High Temperature and Pressure Physical Simulation
Experiment Technique ...................................... 72
2.1.1 Difficulties and Countermeasures in Physical
Simulation Experiment of Ultra-High Temperature
and Pressure ......................................... 72
2.1.2 Introduction of Ultra-High Temperature and Pressure
Physical Simulation Experiment System ................. 78
2.2 Nonlinear Percolation Mechanism of Single-Phase Gas .......... 86
2.2.1 Experimental Objective ............................... 86
2.2.2 Experimental Samples and Conditions .................. 86
2.2.3 Experimental Scheme ................................ 91
2.2.4 Experimental Procedure ............................... 93
2.2.5 Gas-Phase Percolation Mechanism Under Irreducible
Water Condition ..................................... 94
2.2.6 Gas-Phase Percolation Mechanism Under Different
Water Saturation Conditions ........................... 106
2.3 Mathematical Model of Gas-Phase Nonlinear Percolation ........ 118
2.3.1 Reservoir and Percolation Characteristics of Ultradeep
Carbonate Gas Reservoirs ............................. 119
2.3.2 Trinomial Percolation Mathematical Modeling ........... 122
2.3.3 Analysis of Influencing Factors of Gas-Phase
Percolation Capacity ................................. 129
2.4 Gas–Water Two-Phase Percolation Mechanism ................. 134
2.4.1 Experimental Samples and Conditions .................. 136
2.4.2 Experimental Scheme ................................ 139
2.4.3 Experimental Method ................................. 139
2.4.4 Experimental Procedure ............................... 142
2.4.5 Characteristics of Gas–Water Two-Phase Percolation
in Different Types of Carbonate Reservoirs .............. 143
2.4.6 Effect of Reservoir Type on Gas–Water Two-Phase
Percolation Characteristics ............................ 149
2.4.7 Effect of Temperature and Pressure Conditions
on Gas–Water Two-Phase Percolation Characteristics ..... 151
Contents xi
2.4.8 Characteristics of Gas–Water Two-Phase Percolation
in Full-Diameter Cores ............................... 153
2.5 Summary .................................................. 156
References ..................................................... 159
3 Complex Gas–Water Relationship of the Ultradeep Carbonate
Gas Reservoir .................................................. 163
3.1 Microscopic Visualization Technique of Fluid Percolation
Based on CT Scanning and Microelectronic Lithography ......... 164
3.1.1 Mask Design and Creation Based on Typical CT Scan
Images ............................................. 168
3.1.2 Visual Model Fabrication Based on Microelectronic
Photolithography ..................................... 170
3.1.3 Advantages of Microscopic Visual Models ............... 172
3.1.4 Quantitative Methods for Microscopic Visualization
Experimental Results ................................. 174
3.2 Microscopic Visualization of Gas–Water Relationship During
Accumulation Process ....................................... 175
3.2.1 Similarity Principles for Microscopic Visualization
Experiments ......................................... 176
3.2.2 Experimental Apparatus .............................. 177
3.2.3 Experimental Fluids .................................. 177
3.2.4 Experimental Procedure ............................... 177
3.2.5 Experimental Scheme ................................ 181
3.2.6 Formation Mechanism of Residual Water in Different
Types of Reservoirs .................................. 181
3.2.7 Occurrence Patterns of Residual Water and Its Effect
on Gas Percolation ................................... 185
3.2.8 Quantitative Characterization of Gas Flooding Water
Visualization Experiments ............................. 188
3.3 Microscopic Visualization of Gas–Water Relationship During
Water Encroachment Process ................................. 193
3.3.1 Experimental Procedure ............................... 194
3.3.2 Experimental Scheme ................................ 195
3.3.3 Characteristics of Gas–Water Two-Phase Percolation
During Water Encroachment ........................... 195
3.3.4 Formation Mechanism of Different Types of Trapped
Gas ................................................ 198
3.3.5 Quantitative Characterization of Different Types
of Trapped Gas ...................................... 208
3.3.6 Quantitative Characterization of Saturation
and Recovery Factor .................................. 209
3.4 Summary .................................................. 214
References ..................................................... 217