Dynamic Well Testing in Petroleum Exploration and Development

Cover
DYNAMIC WELL
TESTING IN
PETROLEUM
EXPLORATION AND
DEVELOPMENT
Copyright
Preface
About the author
1
Introduction
	The purpose of this book
		Well test: A kind of system engineering
		Well test: Multilateral cooperation
		Writing approaches of this book
	Role of well test in gas field exploration and development
		Role of well test in exploration
			Drill stem test of exploration wells
			Exploration well completing test
			Reserves estimation
				Several issues worth noting in reserves estimation
				Role of well test method in reserves estimation
		Role of well test in predevelopment
			Deliverability test of development appraisal wells
			Transient well test of development appraisal wells
			Well test of pilot production test wells
			Selection and evaluation of stimulation treatment
			Verifying reserves and creating the development plan
		Role of well test in development
	Keys of well test analysis
		Direct and inverse problems in well test research
		How to understand direct problems
			Analyzing the formation where the oil/gas well locates and classifying it geologically
			Classifying, simulating, and reproducing formation from the viewpoint of flow mechanics
			Constructing the well test interpretation model and resolving the related problem
			Expression forms of resolving direct problems in well test
		Describing gas reservoirs with well test analysis: Resolving inverse problem
			Well test design
			Acquiring pressure and flow rate data onsite
			Graphical analysis in well test interpretation
			Well test interpretation combining actual formation conditions
			Recommend knowledge obtained from well test interpretation to be applied in gas field development
		Computer aided well test analysis
	Characteristics of modern well test technology
		One of the three key technologies of reservoir characterizations
			The distinct information here includes the following
			Deficiencies of well test technology
		Methods of gas reservoir dynamic description
			Dynamic reservoir description with deliverability of gas wells at the core
			New thoughts in gas reservoir dynamic description
				Evaluation and prediction of gas well deliverability: The core of gas reservoir dynamic description
				Study of gas reservoir dynamic model
				Study of pressure distribution
				Understand the effect of geologic conditions on gas flow
2
Basic concepts and gas flow equations
	Basic concepts
		Steady well test and transient well test
			Steady well test
			Transient well test
		Well test interpretation models and type curves
		Dimensionless quantities and pressure derivative curve in well test interpretation type curves
		Wellbore storage effect and its characteristics on type curves
			Implications of wellbore storage effect
			Order of magnitude of wellbore storage coefficient
			Characteristics of wellbore storage effect on well test interpretation type curves
		Several typical flow patterns of natural gas and their characteristics on type curves
			Radial flow
			Steady flow
			Pseudo steady flow
			Spherical flow and hemispherical flow
			Linear flow
				Linear flow caused by parallel impermeable boundaries
				Linear flow caused by hydraulically created fracture
				Linear flow caused by horizontal well
			Pseudo radial flow
			Flow condition in formation becomes smooth or blocked
		Skin effect, skin factor, and equivalent wellbore radius
		Radius of influence
		Laminar flow and turbulent flow
	Gas flow equations
		Definition of reservoir as a continuous medium
		Flow equations
			Deriving flow equations based on three basic equations
			Average flowing velocity and flow velocity of unit cell
			Darcys law applied for flow of viscous fluid
			Continuity equation
			State equation of gas
			Subsurface flow equations of natural gas
				Flow equation of liquid and that of gas under high-pressure conditions
				Gas flow equations under normal conditions
				Fundamental assumptions for gas flow equations
				More assumptions regarding gas flow conditions and further simplification of flow equation
				Another assumption for gas flow conditions and the expression of flow equation with p2
				Expression of flow equation with pseudo pressure
			Dimensionless expressions of gas flow equations
			Boundary conditions and initial conditions for solving gas flow equations
				Initial condition
				Inner boundary condition
				Outer boundary conditions
	Summary
3
Gas well deliverability test and field examples
	Gas well deliverability and AOFP
		Meanings of gas well deliverability
		Gas well deliverability indices
			Deliverability of a gas well
			Absolute open flow potential of gas wells
			Validity of AOFP
			Initial and dynamic AOFP
		Initial deliverability, extended deliverability, and allocated production of gas well
			Initial deliverability index
			Extended deliverability index
			Allocating flow rate index
	Three classical deliverability test methods
		Back pressure test method
		Isochronal test method
		Modified isochronal test method
		Simplified single point test
			Stable point LIT deliverability equation
			AOFP calculation with single point test method
		Schematic diagram of calculating pressure differential for various test methods
	Treatment of deliverability test data
		Two deliverability equations
			Exponential deliverability equation
			LIT equation
		Difference between two deliverability equations
			If gas flow rate of tested well during testing is higher than 50% of AOFP, calculation results of two deliverabi ...
			Greater error is generated from exponential deliverability equation if pressure drawdown are small at all test p ...
		Three different pressure expressions of deliverability equation
	Parameter factors influencing gas well deliverability
		Expressions of coefficients A and B in deliverability equation of a well in infinite homogeneous reservoir
			Analysis of expression of A (Eq. 3.22)
			Analysis of expression of B (Eq. 3.23)
		Deliverability equation when gas flow enters into pseudo steady state
	Short term production test combined with modified isochronal test in gas wells
		Pressure simulation of tested wells
		Improvement of AOFP calculation methods in modified isochronal test
			Classical method
			Improved calculation method
			Comparison of two calculation methods
				Special attention to improved deliverability calculation method
	Stable point LIT deliverability equation
		Background of bringing forward stable point LIT deliverability equation
			Puzzles in determining gas well deliverability by classical methods
			Existing problems of classical methods
				Abnormal conditions of B1 in deliverability equation
				Flowing pressures have not yet been stabilized or intervals of flowing at different rates are not equal in back pressure de ...
				Inverse peak of flowing pressure curve appears due to liquid loading in testing wells
				AOFPs calculated with different deliverability test methods and/or different analysis methods are very different
				Low implementation rate of classical deliverability test onsite in production wells
		Stable point LIT deliverability equation
			Characteristics of new type deliverability equation
			The new method is a supplement and improvement to the classical deliverability test method
		Theoretical deduction and establishment of stable point LIT deliverability equation
			Classification of parameters influencing coefficients A and B
				Formation pressure pR
				Formation physical properties, Tf, μg, and Z
				Apparent skin factor of gas wells Sa
				There are three effective methods to determine D value currently
			Determination of kh and establishment of initial deliverability equation
		Field examples
			Application of initial stable point LIT equation in Well KL-205
			LIT equation established in SLG gas field
				Analysis of standard modified isochronal tests
				Stable point LIT equation
		Methods of establishing dynamic deliverability equation
			Initial stable point LIT equation is established first
			Establishment of dynamic deliverability equation
			Deliverability decline process in gas wells
		Stable point LIT equation of horizontal wells
			Theoretical deduction of stable point LIT equation for horizontal wells
			Establishment the initial stable point LIT deliverability equation for horizontal wells
				Readings of initial steady production point
				Selection of the parameters of the representative well
				Calculation of deliverability equation coefficients of horizontal wells
				Establishment of initial stable point LIT equation of the representative well
			Method of establishing dynamic deliverability equation
				Calculation of physical property parameters
				Calculation of the coefficients of dynamic deliverability equation Ah and Bh and the formation pressure pR
				Deliverability depletion of the representative well
	Production prediction in development program design of gas fields
		Deliverability prediction of wells with available well test data
			Determining gas well flow rate with reasonable pressure drawdown
			Gas flow rate is determined by intersection of the IPR and outflow performance relationship curves
			Determining deliverability during the process of formation pressure depletion
			Other limitations on gas flow rate
		Deliverability prediction of production wells in development program designing
			Establishing the deliverability equation of the whole gas field
				Establishing the deliverability equation of a gas field by calculation
				Establishing the deliverability equation of a gas field by regression of deliverability test data
				Establishing the deliverability equation of a gas field by typical well analogy method
				Exponential deliverability equation
			Plotting distribution map of kh value over the whole gas field and determination of kh value at well point
			Calculating rational flow rate of planned wells in the development program by deliverability equation
				AOFP method
				Pressure drawdown method
				IPR curve and OPR curve intersection method
				Other flowing velocity control methods
	Discussion on several key problems in deliverability test
		Design of deliverability test points
			Design of flow rate sequence
			Stabilization of gas flow rate
			Selection of duration for each test point
		Why calculated AOFP sometimes is lower than measured wellhead flow rate
		Existing problems in calculating AOFP by back pressure test method
			Backpressure test for homogeneous formations
			Back pressure test for fractured wells in channel homogeneous formation
		Method and analysis of single point deliverability test and its error
			Single point deliverability test
			Two examples of AOFP calculation formulas for single point test in development areas of gas field
			Some examples of AOFP calculation formulas for single point test method for exploration wells
			Errors analysis of single point deliverability test method
				Homogeneous formation
				Fractured wells in channel homogeneous formation
		Deliverability test without any stable flow points
		Discussion on wellhead deliverability
		Manually calculating the coefficients A and B in deliverability equation and AOFP
			Data acquisition
			Establishment of transient deliverability equation
			Establishment of stabilized deliverability equation
			Calculating AOFP
	Summary
4
Analyzing gas reservoir characteristics with pressure gradient method
	Pressure gradient analysis of exploration wells in the early stage and some field examples
		Collection and processing of pressure data
		Pressure gradient analysis
	Calculation of gas density and pressure gradient under formation conditions
	Pressure gradient analysis during development of a gas field
	Some key points in pressure gradient analysis
	Accuracy of acquired pressure data
	Pressure gradient analysis should be combined closely with geologic research
		The area division of the reservoir provided by pressure gradient analysis should be supported by the relevant ge ...
		Analysis of pressure gradient characteristics provides supporting information for validating reserves calculatio ...
		Analysis of pressure gradient provides basic parameters for the designing of development program
	Acquisition of dynamic formation pressure after a gas field has been put into development
		Dynamic production indices during production of a gas field
		Several formation pressures with different meanings
			Measured average formation pressure
			Formation pressure determined by deduction based on dynamic model
			Calculation of formation pressure at gas drainage boundary pe
			Other frequently used formation pressure concepts
		Performance analysis with dynamic formation pressures
			Research on reservoir division
			Dynamic variation analysis of pressure gradient line
5
Gas reservoir dynamic model and well test
	Introduction
		Static and dynamic models of gas reservoir
			Geological modeling of gas reservoirs
				Uncertainty of sealing of faults marked on structural map
				There are some lithologic buffers in homogeneously distributed sandstone reservoirs
				Reserves and physical properties distribution of buried hill fissured limestone reservoirs are uncertain
				Configuration description of unusual lithologic reservoirs such as volcanic rock
			Dynamic model of gas reservoirs and gas wells
				Pressure history and related production history of gas field
				Well test model of reservoir based on pressure analysis
				Reservoir dynamic model formed by integrating individual well models
		Pressure history of a gas well symbolizes its life history
			Different pressure histories exist under different reservoirs and/or different well completion conditions
				In Fig. 5.6, pressure history curves of three production testing wells reflect three different kinds of formation and well  ...
					Case I
					Case II
					Case III
				Seen from Fig. 5.6
			Pressure history trend of gas well is determined by reservoir conditions
			Main approach to confirm reservoir dynamic model is pressure history match verification
				Main approach to establish reservoir dynamic model is mainly transient well test analysis
				Type curve match analysis is major approach of transient well test analysis
				Ambiguity of type curve match analysis
				Pressure history match is the final verification for removing ambiguity
		Study characteristics of reservoir dynamic model based on characteristics of transient well test curves
			Different portions of transient pressure curve reflect characteristics of different zones of the reservoir
				Early wellbore storage flow period I
				Near wellbore formation influence period II
				Reservoir influencing period III (radial flow regime)
				Boundary influence period IV
			Pressure derivative curve is the main basis in identifying reservoir characteristics
			Graphics analytical method used to identify reservoir dynamic model
				Principles of graphics analysis
				Some simple graphical analysis methods
	Pressure Cartesian plot-pressure history plot
		Content and drawing of gas well pressure history plot
			Preprocessing and data examination of gas well pressure history records
			Pressure history plot of gas well
		Information about formation and well shown in pressure history plot
			Pressure history plot during DST of natural flow gas well
			Pressure history plot during DST of low production rate gas well
	Pressure semilog plot
		Several semilog plots
			Pressure drawdown analysis plot
			Horner plot
			MDH plot
			Superposition function plot
		Semilog plot used in analysis by well test interpretation software
			Model diagnosis in early interpretation process
			Verification of match analysis results of well test model
	Log-log plot and model graph of pressure and its derivative
		Log-log plots and type curves for modern well test interpretation
			Type curve analysis is the core of modern well test interpretation
				Features of type curves may fully reflect characteristics of the reservoir dynamic model
				Type curve match analysis method
			Some common log-log type curves
				Dimensionless parameters in various type curves
				Introduction of commonly used type curves for gas well test interpretation
				Some infrequently used type curves in gas well test analysis
				Some new type curves
		Typical characteristic curves-Model graphs for well test analyses
	Characteristic diagram and field examples of transient well test in different types of reservoirs
		Characteristic diagram (model graph M-1) and field examples of homogeneous formations
			Homogeneous formations in gas fields
				Various types of reservoirs in China
				Concept of ``homogeneous formation´´
				Examples of homogeneous formations
			Positioning analysis
			Classified model graphs for positioning analysis of homogeneous formations
			Field examples
				Large area homogeneous sandstone formation
				Carbonate formation displayed as homogeneous reservoir
				Condensate gas wells during initial flowing periods
		Characteristic graph of double porosity system (model graphs M-2 and M-3) and field examples
			Composition and flow characteristics of double porosity system
				Composition of formation with double porosity system
				Fluid flow in formation with double porosity system
				Flow characteristic graph of the formation with double porosity system
				Difference of formation with double porosity system and common homogeneous formation
			Several influencing factors in acquiring parameters of double porosity system
				Pressure buildup test must last sufficiently long
				Effect of wellbore storage coefficient on test data
				Disturbance of complex fissure system to double porosity system characteristic
				Pressure buildup curve cannot show characteristics of the transition flow regime due to short flowing duration before shutt ...
				Effect of reservoir boundary
				Effect of pressure measurement precision
			Conditions for high quality data acquisition and some field examples
				Conditions of acquiring high quality pressure buildup curves in double porosity system
				Field examples
		Characteristic graph of homogeneous formation with hydraulic fractures (model graphs M-4 and M-5) and field examples
			Creation and retention mechanism of hydraulic fracture
			Curve characteristics of well connecting with a high conductivity vertical fracture
				Curve characteristics
				Field examples
			Flow characteristics in fracture with uniform flow
			Vertical fracture with finite conductivity
				Curve shape for low conductivity fracture
				Curve shape in the case of large conductivity
			Fracture skin factor and its effect
				Damage mechanism of fracture skin zone
				Type curves and field examples of existence of fracture skin
		Characteristic diagram of wells with partial perforation (model graph M-6) and field examples
			Geological background of well completion with partial perforation
				Partial perforation for gas well completion
				Partial perforation for oil well completion
			Flow model in cases of partial perforation
			Field examples
				Well KL-201
				Well KL-2
				Well KL-204
		Characteristic diagram and field examples of composite formation (model graphs M-7 and M-8)
			Principles for evaluation of type of reservoir boundary
				On the basis of geological conditions
				Model graphs obtained from transient well test analysis are the main analysis basis
				Performance of gas wells will verify the correctness of the model
			Geological conditions of composite formations
			Model graph of composite formation
				Two parameters defined for composite formation model
				Geologic condition and model graph for pressure buildup curves
			Analysis of field examples
				Field example of composite formation in JB gas field
				KL-2 gas field: Well KL-205
		Characteristic graph of formations with no flow boundaries (model graphs M-9-M-13) and field examples
			Geological background
			Flow model graph of a well with no flow outer boundary
				Angular no flow boundaries (M-9, M-10)
					Field example: Well S8
				No flow boundaries shaped approximately like a circle
					Field example: Well S6
				Band shaped no flow boundary
					Field example: Well Hu2
				Fractured gas wells in band shaped formation
					Field examples
		Characteristic graph and field examples of fissured zone with boundaries (model graphs M-14 and M-15)
			Strip like fissured zone with directional permeability
				Geological background
				Flow modal graph
				Field examples
			Beaded fissured bands
				Geological background
				Well test model graphs
					Field examples: Wells BS-8 and BS-7
					Field examples
					Field example: Well BS-6
			Complex fissured zone
		Characteristic graph and field examples of condensate gas wells
			Geological background and focused problems
				Phase diagram of condensate gas
				``Hump´´ occurrence due to phase change behavior inside the wellbore during shut in periods
				Conversion of gas flow rate during well test in condensate gas wells
				Well test analysis problems brought about by accumulation belt of condensate oil in formation
				Two ideas for solving problems in condensate gas well tests
			Model graphs and field examples of transient test in condensate gas well
				Hump caused by wellbore phase change behavior
				Normal test data acquired before condensation happens in formation
				Test data obtained from well in near bottom hole area with a local retrograde condensation zone
					Field example: Well YH3
		Characteristic graph of horizontal wells (model graph M-16) and field examples
			Geological and engineering background
			Typical well test model graph
				Field examples
	Summary
6
Interference test and pulse test
	Application and development history of multiple well test
		Application of multiple well test
			To identify formation connectivity between wells
			To confirm the sealing of faults
			To estimate interwell connectivity parameters
			To identify the vertical connectivity of reservoir
			To study formation anisotropy
			To study the reservoir areal distribution and to confirm the results of reserves estimation
		Historical development of multiple well test
			Multiple well test development
			Development of multiple well test in China
		How to conduct and analyze the interference test and pulse test
			Factors affecting interference pressure acquisition
				The value of the interference pressure is of a very small order
				Background bottom hole pressure of the observation well should be sufficiently steady
				The test duration is not long enough so that the accumulated interference pressure is not enough at all for Identification  ...
				Active well and observation well are not connected at all
			Dialectic consideration for performing multiple well test research in a region
				Operators should avoid dilemmas
				The test research should be grouped and classified according to different situations
	Principle of interference test and pulse test
		Interference test
			Test methods
			Parameter factors affecting interference pressure response value
				Interference pressure response estimation
				Influence of formation fluid mobility k/μ
				Influence of distance between wells r on interference pressure transmission
				Influence of stimulation amount per unit thickness qg/h on interference pressure response
			Type curve interpretation method for interference test data
				Interpretation type curves for interference test in homogeneous formations
				Separation of pure interference pressure
				Type curve match analysis and parameter calculation
				Pressure history match verification of interpretation results
				Other interpretation type curves for interference test analysis
			Characteristic point interpretation method for interference test
		Pulse test
			Pulse test method
			Kamals analysis method for pulse test
				Some Definitions
				Eight type curves
				Parameter calculation
			Pulse test analysis by conventional interference test type curve methods
		Multiple well test design
			Principle of multiple well test design
			Multiple well test simulated design
				Interference test
				Pulse test
			Make multiple well test field implementation plan
	Field examples of multiple well test in oil and gas field research
		Interference test research in JB gas field
			Geological conditions of JB gas field
			Well test design and operation
			Test results
			Parameter calculation
		SLG gas field interference test research
			Overall geological conditions of well group of interference test
			Interference test well group design and implementation
				Dynamic monitoring and analysis results of well S6
				Static pressure analysis when the second group of infilling wells was put into production
				Determination of interference test well group
				Simulation and Design of Interference Test
			Interpretation of interference test data
				Results of interference tests
				Interpretation of interference test data
				Pressure monitoring results of other observation wells
			To identify rational well spacing in SLG gas field by interference test results
		Gas well interference test study in fault block Y8 of SL oil field
		Test research on connectivity between injector and producer in fault block
			Research of connectivity between injector and producer in ST block 3, SL oil field
			Research on isolation of the fault in well Y18 area of SL oil field
			Efficiency analysis of injection in fault block B96
		Comprehensive evaluation of multiple well tests in KL Palaeo Burial Hill oil field
			Overall geological condition of KL oil region
			Test arrangement and achieved results
				Test results of period I
				Test results of period II
				Test results of periods III and IV
				Test results of period V
				Test results of period VI
			Analyzing the characteristics of formation dynamic model with multiple well test results
	Summary
7
Coalbed methane well test analysis
	Coalbed methane well test
		Function of coalbed methane well test in coalbed methane reservoir
			To obtain effective permeability of fissures or cleats in coalbed
			To obtain average reservoir pressure
			To analyze damage and improvement in coalbeds
			To evaluate fracturing effects
			To identify coalbed connectivity and calculate connectivity parameters
			To determine the coalbed pore volume
			To analyzed the development direction of fissures
			To detect the coalbed flow boundaries
		Differences between coalbed methane well test and common gas well test
			Fluid seen during coalbed methane well testing is often water
			The behavior of the double porosity medium can not observed
			Purpose and analysis methods depend on production stages
	Flow mechanism and well testing models in a coalbed
		Structural characteristics of a coalbed and flow of coalbed methane
			Structure of coalbed and reserve of methane
			Flow process in coalbed methane production
		Typical dynamic models of coalbed methane well test
		Water single phase flow characteristics and data interpretation methods
		Single phase flow of methane desorption and well test analysis method
			Coalbed conditions
			Flow equation
			Analyzing coalbed methane well test data by conventional method
			Characteristics of well test curves when desorption happens
	Injection/falloff well test method for coalbed methane wells
		Equipment and technology for injection/falloff well testing
			Test string
			Measuring instruments
			Water injection pump
			Testing process
		Well test design of injection/falloff
			Selection of shut in mode
			Calculation of injection pressure
			Calculation of water injection rate
			Determination of water injection volume
			Determination of influence radius and injection duration
			Effect of coalbed elastoplasticity
		Data examination and analysis methods for injection/falloff well testing
			Variable wellbore storage effect in injection/falloff test process
			Inspection of abnormal changes of test curves
				Example 1: Data examination and analysis of the injection/falloff test of Well WS-1
				Example 2: Data examination and analysis of injection/falloff test of Well WS-2
			Comments on data examination and analysis
	Analysis and interpretation of injection/falloff test data
		Interpretation methods
			Model types
			Interpretation procedure
		Field example
			Well Ex 1-A coalbed methane well completed with fracturing
			Well Ex 2-A perforated completion coalbed methane well
	Summary
8
Gas field pilot production test and dynamic description of gas reservoir
	Pilot production test in unusual lithologic gas fields in China
		Unusual lithologic gas field in China
		Pilot production test: An effective way to solve problems in development of unusual lithologic gas reservoirs
			Problems in development of unusual lithologic gas fields
			Pilot production test is the only effective approach of gas reservoir research
				New connotation of gas field pilot production test
				Dynamic gas reservoir description focusing on gas well deliverability
		Procedure of pilot production test in gas wells
			Arrangement for production rate of gas test wells in different periods
			A typical pressure history of gas pilot production test wells in field
				Modified isochronal test period
				Pressure buildup test period
				Long term production test period
		Dynamic reservoir description based on pilot production test data of gas wells
	Dynamic description in development preparatory stage of JB gas field
		Geological conditions of JB gas field
		Focuses of the problems
		Dynamic study at the preparatory stage of gas field development
			Short term production test integrating deliverability and pressure buildup tests
				Deliverability analysis
				Analysis of deliverability stability
				Features of reservoir model
			Interference test analysis
			Dynamic reserves test in well block S45
			Hydrostatic pressure gradient analysis of JB gas field
	Short term production test and evaluation of gas reservoir characteristics in KL-2 gas field
		Geological conditions
		Procedure and results of well test analysis
			Test of Well KL-2
				Understanding gained from testing Well KL-2
				Deficiency in the testing of Well KL-2
			Test of Well KL-201
			Test of Well KL-203
				Test technology
				Arrangement of production proration and acquisition of pressure data during the test
				Abnormal phenomena and analysis of pressure data
				Validation of interpretation results of pressure buildup curves and the dynamic reservoir model
				Deliverability analysis
				Understandings gained in dynamic test of Well KL-203
			Well test analysis of Well KL-205
				Improvement of test technology
				Well test analysis results
				Test operation
				Pressure data acquisition
				Deliverability evaluation
				Reservoir model parameters obtained from pressure buildup analysis
		Gas reservoir description of KL-2 gas field
			Dynamic model of gas wells established primarily through short term production test
			The established dynamic model of gas wells and reservoir is not yet perfect
	Tracing study on gas reservoir dynamic description of SLG gas field
		Overview of SLG gas field
		Geological situation of SLG gas field
			Structural characteristics and production zones
			Sedimentary microfacies of the formation
		Dynamic description process of SLG gas field
			Preliminary knowledge obtained in 2001 and 2002
			Tracing study of long term pilot production test in 2003
			Enhancement of tracing study in 2005
		Dynamic description result of typical wells
			Primarily establish the dynamic model by short term pilot production test
				Model I of Well S6 established by results of the type curve match analysis of pressure buildup test data
				Improved model II of Well S6 obtained by adjusting model Parameters of model I
				Model III of Well S6 modified with test data acquired in 2003
				Continuing improvement of model III by adjusting parameters with test data in 2005
			Calculation of average reservoir pressure and dynamic reserves of Well S6
		Knowledge obtained from the dynamic description of SLG gas field
	Dynamic description of YL gas field
		Overview of YL gas field
			Geographical location and geological situation of YL gas field
			Pilot production test of YL gas field
			Process of dynamic description for the gas reservoir
				Gas well deliverability study
				Establish dynamic analysis models for gas wells
				Numerical well test study
				Pressure gradient analysis
		Deliverability analysis for production wells in main gas production area
			Initial stable point LIT deliverability equation
			Dynamic deliverability equation and dynamic deliverability
		Establishing the dynamic models of gas wells and carrying on the tracing study
			Establish archives for gas well production history
				Method of establishing gas well pressure history
				Process and verification of converting wellhead casing pressure to bottom hole pressure
			Establish dynamic models of the gas wells
			Tracing studies
		Analysis of reservoir pressure gradient of YL gas field
			Analysis of the initial hydrostatic pressure gradient
			Dynamic formation pressures of gas wells and reservoir
		Comparison of reservoir characteristics between YL gas field and SLG gas field
	Dynamic description of DF offshore gas field
		Overview of DF gas field
			Characteristics and difficulties in development of DF gas field
				All production wells are horizontal wells
				Monitoring of bottom hole pressure history with high precision permanent pressure gauges
				Complicated follow up production allocation
				Uncertainties in transient test analysis of horizontal wells
			Innovations in performance study of DF gas field
		Evaluation of initial deliverability and dynamic deliverability
			Backpressure tests and analyses
			Establishment of ``initial stable point LIT equation´´ to reevaluate the initial deliverability of gas wells
			Derivation of dynamic deliverability equation
			Deliverability test design under dynamic monitoring conditions
		Dynamic description of gas wells and gas reservoirs
			Establishment of gas well dynamic model with pressure buildup test data
			Model reliability verification through pressure history match
			Knowledge obtained from dynamic description
		Long term performance analysis in DF gas field
		Comprehensive knowledge of DF gas field
	Dynamic description of Longwangmiao-Carbonate gas reservoir in Moxi block of Anyue gas field, Sichuan Basin
		Overview
		Static geological characteristics
			Sediments and shoal bodies
			Accumulation space
			Physical properties and heterogeneities
		Concept of dynamic reservoir description
			Focuses
			Approach
		Recognitions of productivity-dominating factors in the appraisal stage
			Reservoir flow characteristics based on transient well test
			Physical properties and heterogeneity based on dynamic description
			Main controlling factors for productivity
		Description of shoal distribution through tracing study of well testing analysis
			Apparent homogeneity type-Well group W21
				Determination of well drainage area of Well W21 during production test stage
				Shoal distribution in well groups according to later pressure test of offset wells
			Compartmentalized type-Well group W19-H2
		Conclusions
	Dynamic description of fractured tight sandstone gas reservoir with ultra high pressure in Keshen gas field, Tarim Basin
		Overview
		Basic reservoir characteristics
			Geological characteristics
			Development characteristics
		Concept of dynamic reservoir description
			Challenges
			Approach
		Dynamic description of gas wells and gas reservoirs
			Downhole tool-conveying test technique
			Application examples
				Test in August 2014
				Test in May 2015
				Test in August 2015
				Test in May 2016
				Experience and lessons
				Well test design for the Keshen-2 gas reservoir
			Performance-based reserves estimation methods for high pressure and ultra high pressure gas reservoirs
				Material balance reserves calculation method for high pressure and ultra high pressure gas reservoirs
				Approximate relationship between reserves and cumulative effective compressibility
				Key inflection points of apparent reservoir pressure depletion
				Relationship between performance-based reserves and apparent OGIP
				Case study
		Recognitions from dynamic description of gas wells and gas reservoirs
			Dynamic reservoir characteristics
			Matrix gas supply capacity
			Performance based reserves
		Conclusions
	Dynamic description of Tazhong No.1 fractured vuggy carbonate gas reservoir
		Overview
		Basic characteristics of gas reservoir
			Geological characteristics
			Typical development characteristics
		Concept of dynamic reservoir description
			Challenges
			Approach
		Dynamic description of gas wells and gas reservoirs
			Dynamic description based on well test analysis
			OGIP estimation of individual well
			Development index prediction of individual well
		Understandings from dynamic description of gas wells and gas reservoirs
			Reservoir dynamic evaluation
			OGIP of individual well
		Discussion on double porosity media
			Double porosity media concept for geologists
			Double porosity media concept in well test and seepage mechanics
		Conclusions
	Dynamic description of Xushen volcanic gas reservoir
		Overview
		Basic geologic and development characteristics of Xushen gas field
		Dynamic description for main block
			XS1 well block
				Dynamic description of Well XS1-1
				Dynamic description of Well XS1
				Dynamic description of other wells
			SS2-1 well block
		Conclusions, implications, and perceptions
	Summary
9
Well test design
	Procedure of well test design and data acquisition
		Procedure of well test design
			Collect relational geologic data and casing program of the tested well
				Basic data of tested well
				Basic geologic data of tested well
				Well test data of tested well
			Objectives of the test
			Simulation of pressure variation trend and log-log plot for well test design with well test interpretation software
			Putting forward the geological design report of well test project
			Detailed operation design of well test
				Accuracy and resolution of pressure gauges
				Location where pressure gauges are installed in tested well
				To acquire pressure buildup data with downhole shut in tools as far as possible
		Essential requirements for data acquisition
	Key points of simulation design of transient well test for different geologic objectives
		Well test design for wells in homogeneous formations
		Well test design for wells in double porosity formations
		Well test design for fractured well in homogeneous formation
		Well test design for wells in formation with flow barrier
		Deliverability test design for gas wells
		Multiple well test design
		Duties and principles of well test designers
Nomenclature [with China statutory units (CSU)]
Appendix A
Commonly used units in different unit systems
Appendix B
Unit conversion from China statutory unit (CSU) system to other unit systems
Appendix C
Formulas commonly used in a well test under the China statutory unit system
	Formulas in log-log plot analysis
	Formulas in semilog pressure analysis
	Gas flow rate formulas
	Gas well deliverability equations
	Pulse test formulas (by Kamal)
	Other common formulas of gas wells
Appendix D
Method for conversion of coefficients in a formula from one unit system to another
	Conversion of gas flow rate formula
	Conversion of dimensionless time formula
References
Index
	A
	B
	C
	D
	E
	F
	G
	H
	I
	J
	K
	L
	M
	N
	O
	P
	Q
	R
	S
	T
	U
	V
	W
	X
	Y
	Z
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