Ultradeep Carbonate Gas Reservoirs: Reservoir Characteristics and Percolation Mechanism

Preface
Contents
About the Author
1 Reservoir Characteristics of the Ultradeep Carbonate Gas Reservoir
	1.1 Geological Setting of the Ultradeep Carbonate Gas Reservoir
		1.1.1 Tectonic Setting
		1.1.2 Sedimentary Setting
	1.2 Comprehensive Evaluation Method for Ultradeep Carbonate Gas Reservoirs
		1.2.1 Samples and Testing Process
		1.2.2 Conventional Petrophysical Measurements
		1.2.3 Casting Thin Sections
		1.2.4 SEM Testing
		1.2.5 HPMI Testing
		1.2.6 Multiscale CT Scanning
	1.3 Reservoir Characteristics of Ultradeep Carbonate Gas Reservoirs
		1.3.1 Lithology and Mineral Composition of Reservoir Rocks
		1.3.2 Petrophysical Properties
		1.3.3 Reservoir Space Types and Characteristics
		1.3.4 Throat Types and Characteristics
		1.3.5 Reservoir Classification Based on HPMI Testing
		1.3.6 Two-Dimension CT Scanning Analysis
		1.3.7 Reservoir Temperature and Pressure Conditions
		1.3.8 Fluids Properties and Compositions
		1.3.9 Reservoir Thickness Distribution Characteristics
	1.4 Storage and Percolation Capacities of Ultradeep Carbonate Gas Reservoirs
		1.4.1 Effect of Cavities and Fractures on Storage and Percolation Capacities
		1.4.2 Pore and Throat Size Distribution and Connectivity Characteristics
		1.4.3 Analysis of Pore Throat Network Models
		1.4.4 Analysis of the Pore Throat Connectivity
		1.4.5 Proportion of Various Types of Reservoir Spaces
	1.5 Characteristics and Classification Standard of Various Types of Ultradeep Carbonate Gas Reservoirs
	1.6 Summary
	References
2 Special Percolation Mechanism of the Ultradeep Carbonate Gas Reservoir
	2.1 Ultra-High Temperature and Pressure Physical Simulation Experiment Technique
		2.1.1 Difficulties and Countermeasures in Physical Simulation Experiment of Ultra-High Temperature and Pressure
		2.1.2 Introduction of Ultra-High Temperature and Pressure Physical Simulation Experiment System
	2.2 Nonlinear Percolation Mechanism of Single-Phase Gas
		2.2.1 Experimental Objective
		2.2.2 Experimental Samples and Conditions
		2.2.3 Experimental Scheme
		2.2.4 Experimental Procedure
		2.2.5 Gas-Phase Percolation Mechanism Under Irreducible Water Condition
		2.2.6 Gas-Phase Percolation Mechanism Under Different Water Saturation Conditions
	2.3 Mathematical Model of Gas-Phase Nonlinear Percolation
		2.3.1 Reservoir and Percolation Characteristics of Ultradeep Carbonate Gas Reservoirs
		2.3.2 Trinomial Percolation Mathematical Modeling
		2.3.3 Analysis of Influencing Factors of Gas-Phase Percolation Capacity
	2.4 Gas–Water Two-Phase Percolation Mechanism
		2.4.1 Experimental Samples and Conditions
		2.4.2 Experimental Scheme
		2.4.3 Experimental Method
		2.4.4 Experimental Procedure
		2.4.5 Characteristics of Gas–Water Two-Phase Percolation in Different Types of Carbonate Reservoirs
		2.4.6 Effect of Reservoir Type on Gas–Water Two-Phase Percolation Characteristics
		2.4.7 Effect of Temperature and Pressure Conditions on Gas–Water Two-Phase Percolation Characteristics
		2.4.8 Characteristics of Gas–Water Two-Phase Percolation in Full-Diameter Cores
	2.5 Summary
	References
3 Complex Gas–Water Relationship of the Ultradeep Carbonate Gas Reservoir
	3.1 Microscopic Visualization Technique of Fluid Percolation Based on CT Scanning and Microelectronic Lithography
		3.1.1 Mask Design and Creation Based on Typical CT Scan Images
		3.1.2 Visual Model Fabrication Based on Microelectronic Photolithography
		3.1.3 Advantages of Microscopic Visual Models
		3.1.4 Quantitative Methods for Microscopic Visualization Experimental Results
	3.2 Microscopic Visualization of Gas–Water Relationship During Accumulation Process
		3.2.1 Similarity Principles for Microscopic Visualization Experiments
		3.2.2 Experimental Apparatus
		3.2.3 Experimental Fluids
		3.2.4 Experimental Procedure
		3.2.5 Experimental Scheme
		3.2.6 Formation Mechanism of Residual Water in Different Types of Reservoirs
		3.2.7 Occurrence Patterns of Residual Water and Its Effect on Gas Percolation
		3.2.8 Quantitative Characterization of Gas Flooding Water Visualization Experiments
	3.3 Microscopic Visualization of Gas–Water Relationship During Water Encroachment Process
		3.3.1 Experimental Procedure
		3.3.2 Experimental Scheme
		3.3.3 Characteristics of Gas–Water Two-Phase Percolation During Water Encroachment
		3.3.4 Formation Mechanism of Different Types of Trapped Gas
		3.3.5 Quantitative Characterization of Different Types of Trapped Gas
		3.3.6 Quantitative Characterization of Saturation and Recovery Factor
	3.4 Summary
	References
4 Sensitivity Characteristics of the Ultradeep Carbonate Gas Reservoir
	4.1 Conventional Reservoir Sensitivity Characteristics
		4.1.1 Formation Damage Types and Mechanisms of Carbonate Reservoirs
		4.1.2 Velocity Sensitivity Evaluation
		4.1.3 Water Sensitivity Evaluation
		4.1.4 Salinity Sensitivity Evaluation
		4.1.5 Alkali Sensitivity Evaluation
		4.1.6 Acid Sensitivity Evaluation
		4.1.7 Summary of Conventional Reservoir Sensitivity Characteristics
	4.2 Reservoir Stress Sensitivity Characteristics
		4.2.1 Experimental Samples and Conditions
		4.2.2 Experimental Apparatus
		4.2.3 Experimental Scheme
		4.2.4 Experimental Method
		4.2.5 Experimental Procedure
		4.2.6 Improvements in Stress Sensitive Experiments
		4.2.7 Permeability Stress Sensitivity of Different Types of Carbonate Reservoirs
		4.2.8 Porosity Stress Sensitivity of Different Types of Carbonate Reservoirs
		4.2.9 Effect of Reservoir Type on Permeability Stress Sensitivity
	4.3 Summary
	References
5 Gas Production Characteristics of the Heterogeneous Ultradeep Carbonate Gas Reservoir
	5.1 Gas Production Characteristics of Interlayer Heterogeneous Gas Reservoirs
		5.1.1 Experimental Objective
		5.1.2 Similarity Principle
		5.1.3 Experimental Samples and Conditions
		5.1.4 Experimental Apparatus
		5.1.5 Experimental Scheme
		5.1.6 Experimental Procedure
		5.1.7 Effect of Interlayer Heterogeneity on Gas Production Characteristics
		5.1.8 Effect of Permeability Differences on Gas Production Characteristics
		5.1.9 Effect of Depletion Pressure Differential on Gas Production Characteristics
	5.2 Gas Production Characteristics of Horizontal Heterogeneous Gas Reservoirs
		5.2.1 Experimental Objective
		5.2.2 Similarity Principle
		5.2.3 Experimental Samples, Conditions and Apparatus
		5.2.4 Experimental Scheme
		5.2.5 Experimental Procedure
		5.2.6 Effect of Horizontal Heterogeneous on Gas Production Characteristics
		5.2.7 Effect of Permeability Differences on Gas Production Characteristics
		5.2.8 Effect of Depletion Pressure Differential on Gas Production Characteristics
		5.2.9 Effect of Initial Water Saturation on Gas Production Characteristics
	5.3 Suggestions for the Exploration and Development of Ultradeep Carbonate Gas Reservoirs
	5.4 Summary
	References