Petrophysics

Steve Cannon is a geologist by profession, a petrophysicist by inclination and a reservoir modeller by design.  Graduating in 1977, Steve has worked as a geologist and petrophysicist in all sectors of the oil and gas industry, including government, major and independent oil companies, the service sector and consultancy.  Having had the opportunity to work offshore and in a core analysis laboratory, as well as a reservoir geologist has helped to shape his appreciation of petrophysics constrained by geology.  Steve is a Past-President of the London Petrophysical Society.

• Preface xi1 Introduction 11.1 The basics 41.1.1 Units and abbreviations 61.1.2 Cores and logs 61.1.3 Lithology identification 81.1.4 Rock properties 101.1.5 Physics of a reservoir 101.1.6 Porosity 101.1.7 Water saturation 111.1.8 Permeability 131.1.9 Capillary pressure 141.1.10 Wettability 141.2 The results 151.2.1 Hydrocarbon pay 151.2.2 Simple volumetrics 151.2.3 3D static models 171.2.4 Value of information 171.3 Summary 182 Data Acquisition 192.1 Drilling data 192.2 Coring and core analysis 212.3 Wireline logging 242.4 Well test data 282.5 Borehole environment 292.6 Summary 333 Rock and Fluid Properties 353.1 Controls on rock properties 353.2 Lithology 393.2.1 Spontaneous potential 393.2.2 Gamma ray 423.3 Porosity 463.3.1 Core porosity 463.3.2 Log porosity 483.4 Water saturation 553.4.1 Core]derived water saturation 573.4.2 Wettability 593.4.3 Electrical measurements 603.4.4 Log]derived water saturation 613.5 Permeability 643.5.1 Core permeability 663.5.2 Log permeability 673.5.3 Porosity–permeability relationship 683.5.4 Overburden correction and Klinkenberg effect 703.6 Summary 714 Quality Control of Raw Data 734.1 Validation of log data 734.1.1 Labelling 744.1.2 Parametric ranges 764.1.3 Repeatability 764.1.4 Tension 764.1.5 Borehole conditions 764.1.6 Noise spikes and cycle skipping 774.1.7 Editing log data 774.1.8 Creation of pseudologs 774.2 Depth merging 784.3 Tool corrections 784.3.1 Environmental corrections 794.3.2 Invasion corrections 794.4 Core analysis data 804.5 Merging core and log data 804.6 Converting measured depth to true vertical depth 824.7 Summary 825 Characteristic Log Responses 835.1 Characteristic shale response 835.2 Matrix characteristics 895.3 Fluid characteristics 905.4 Hydrocarbon corrections 905.5 Shale corrections 915.6 Summary 916 Evaluation of Lithology, Porosity and Water Saturation 936.1 Evaluation of lithology 936.1.1 Histograms 956.1.2 Scatter plots 956.1.3 Lithology interpretation 1006.2 Evaluation of porosity 1016.2.1 Sonic porosity 1016.2.2 Density porosity 1036.2.3 Neutron porosity 1036.2.4 Selection of reservoir porosity 1046.2.5 Total and effective systems 1056.3 Evaluation of water resistivity 1066.3.1 SP method 1066.3.2 Resistivity cross]plot method 1076.3.3 Pickett plot 1096.3.4 Apparent Rw method (Rwa) 1106.4 Estimation of water saturation 1106.4.1 Clean sands 1116.4.2 Shaly sands 1126.5 Summary 1147 Petrophysical Workflows 1157.1 Data management 1157.2 Quick]look interpretation 1167.3 Full petrophysical interpretation 1187.3.1 Permeability estimation 1227.3.2 Evaluation of cut]off parameters 1237.3.3 Determination of zone averages 1247.3.4 Reporting 1268 Beyond Log Analysis 1278.1 Pressure measurements, gradients and contacts 1278.2 Saturation]height functions 1318.2.1 Single]predictor algorithms 1338.2.2 Multi]predictor algorithms 1348.2.3 Normalized functions 1348.3 Electrofacies and facies analysis 1358.4 Rock typing 1388.5 Integration with seismic 1418.5.1 Depth conversion 1428.5.2 Fluid substitution 1438.6 Production logging 1458.6.1 Pulsed neutron logging 1458.7 Geo]steering 1468.8 Petrophysics of unconventional reservoirs 1478.8.1 Total organic content 1488.8.2 Porosity estimation 1508.8.3 Gas in place 1509 Carbonate Reservoir Evaluation 1519.1 Rock fabric classification 1519.2 Petrophysical interpretation 1539.2.1 Porosity 1539.2.2 Water saturation 15410 Petrophysics for Reservoir Modelling 15710.1 Multi]scale modelling 15810.2 Petrophysical issues 15810.3 Blocking logs 16010.4 Geological issues 16210.5 Engineering issues 16410.6 Volumetrics 16510.7 Uncertainty 16510.8 Epilog 167Appendix 1 Petrophysical Report 169Appendix 2 Data Collection and Management 179Appendix 3 Oilfield Glossary 189References 197Index 201