Origin and Prediction of Abnormal Formation Pressures

Preface. List of Contributors. 1. Introduction to Abnormally Pressured Formations. (E.C. Donaldson et al.). Introduction. Abnormal pressures. Subpressures. Surpressures. Origin of vertical barriers resulting in abnormal formation pressures. Undercompaction. Tectonic compression. Faulting. Diapirism. Geothermal temperature. Phase changes that produce abnormal pressures. Osmosis as a factor for generation of abnormal pressure. Salinity of interstitial water. Reservoir engineering concepts in abnormal pressure environments 13
Economics in overpressure environments. Summary. Bibliography. 2. Origin of Abnormal Formation Pressures (G.V. Chilingar et. al.). Introduction. Definitions. Compaction process. Hydrostatic pressure. Formation or interstitial fluid pressure.
Sediment consolidation. State of stress in compacting shales. Resolution of the total stress field. Hydrostatic stress state. Deviatoric stress state. Total stress tensor. Spring models of compaction. Hooke's law. Load transfer. Porosity-density variations with depth. Compaction models. Athy's compaction model. Hedberg's compaction model. Weller's compaction model. Powers' compaction model. Teodorovich and Chernov's compaction model. Burst's compaction model. Beall's compaction model. Overton and Zanier's compaction model. Creation and maintenance of abnormal pressures. Mechanisms generating abnormal formation pressures. Undercompaction. Tectonics. Growth faults. Transference. Effect of temperature increase on formation pressure (aquathermal pressuring). Decomposition of organic matter. Gas migration. Osmosis. Density contrast. Conclusions. Bibliography. 3. Origin of Formation Fluid Pressure Distributions (A. Gurevich et al.). Introduction. Factors causing fluid flow and pressure distributions. Factors of fluid flow and pressure distribution and changes. Free convection of ground fluids. Forced convection of ground fluids. Role and distribution of formation permeability. Presentation of pressure as the additive sum of two components. Some major factors of underground fluid forced convection and characteristics for correlation. Compaction of granular sediments. Upward fluid migration. Correlation between porosity and pressure. Methods used in Azerbaijan to determine abnormal pressures. Distributions of abnormal pressures. Definitions of terms as used in this chapter. Conclusions. Bibliography. 4. Smectite-Illite Transformations during Diagenesis and Catagenesis as Related to Overpressures (L.A. Buryakovsky et al.). Introduction. Burst's compaction model. Origin of abnormally high formation pressure. Clay-mineral transformation. Effect of thermobaric conditions. Effect of hydrochemical factors. Discussion. Summary. Conclusions. Bibliography. 5. Methods of Estimating and Predicting Abnormal Formation Pressures
(G.V. Chilingar et al.). Introduction. Prediction of abnormally high pressure in regions with nonequilibrium compaction. Abnormal pressure due to temperature variations. Estimation and prediction of abnormally low pressures in basins in permafrost regions. Formation pressure in regions with upthrown and downthrown blocks (uplift and subsidence of sedimentary rocks). Calculation of abnormal pore pressure during drilling. Method of equivalent depth. Method of normal compaction trend. Method of compressional curves. Radioactivity study of zones with abnormally high formation pressure. Pulsed neutron capture logs. Quantitative pressure evaluation. Technique A: empirical calibration charts. Method B: equivalent depth method. Shalewater influx - driving mechanism. Various geophysical well logging methods - a summary. Conclusions. Bibliography. 6. Drilling Parameters (W.H. Fertl et al.). Drilling rate (penetration). Normalized rate of penetration (d-exponent). Effect of drilling hydraulics. Effect of drill bits. Overbalance. Drilling rate equations. Porosity and formation pressure logs. Logging while drilling. Torque. Drag. Drilling mud parameters. Mud-gas cutting. Flowline specific weight of drilling fluids. Pressure kicks. Flowline temperature. Resistivity, chloride ion content, and other methods. Pit level and total pit volume. Hole fill-up. Mud flow rate. Shale cuttings parameters. Shale bulk specific weight. Shale factor. Volume of shale cuttings. Shape and size of shale cuttings. Other pressure indicator methods. Drilling concepts in overpressured environments. Bibliography. 7. Seismic Methods of Pressure Prediction (F. Aminzadeh et al.). Introduction. Prediction of abnormal pressure from geophysical data. Empirical relationships. Eaton's exponent of pore pressure determination from sonic data. Eaton's exponent for pore pressure determination from resistivity logs. Eaton's fracture pressure gradient equation. Dutta's method. Fillippone formula. Modified Fillippone formula. Practical applications. South Caspian Basin. AVO effects of overpressure. Real time pressure analysis. Lithology. Empirical relationships based on laboratory measurements. Velocity and acoustic impedance inversion of seismic data. Pore pressure and seismic amplitude versus offset (AVO). Pore pressure estimation from seismic velocities. Deep-water prospects. Mapping reservoir fluid movement and dynamic changes of reservoir pressure using time lapse (4-D seismic). Estimation of sonic velocity from resistivity logs. Bibliography. 8. Tectonics and Overpressured Formations (G.V. Chilingar et al.). Introduction. Faulting as a cause of overpressured formations. Shale diapirism (mud lumps, mud volcanoes). Prediction of tectonically caused overpressures by using resistivity and density measurements of associated shales. Origin and distribution of overpressures in carbonate reservoirs. Conclusions. Bibliography. 9. Prediction of Abnormally High Pressures in Petroliferous Salt-Bearing Sections (V.I. Zilberman et al.). Introduction. Indicators of approaching the overpressured zones. Locating the areal positions of AHFP zones. Quantitative AHFP forecast. Conclusions. Bibliography. 10. Pore Water Compaction Chemistry as Related to Overpressures (H.H. Rieke et al.). Introduction. Overview and constraints. Thermodynamic and reaction models. Evolution of seawater into porewater. Reliability of water sampling. Palmer and Sulin water classifications. Palmer's classification. Sulin's classification.
Chemical composition of subsurface brines. Salinity variations in compacting sandstones and associated shales. Field case studies. Hackberry and Manchester fields, Louisiana, U.S.A. Global reconnaissance. Bengal and Kutch basins, India. Songliao Basin, China. South Caspian Basin. Laboratory experiments. Early laboratory experiments. Effect of rate of loading (experiments).
Smectite to illite transformation. Experiments involving mixtures of oil and seawater. Fluid chemistry compaction models. Non-thermodynamic approaches. Warner's double-layer model. Kotova and Pavlov's empirical model. Pol'ster's capillary model. Thermodynamic approach. Bolt's pressure filtrate model. Appelo's Donnan equilibrium model. Smith's Gibbs equilibrium model. Isotope studies of interstitial fluids. Geological observations and evaluation. Isotope studies of shales in the Gulf Coast.
Summary and conclusions. Bibliography. 11. Abnormally Low Formation Pressures (V.A. Serebryakov et al.). Introduction. Origin of abnormal pressures. Estimation of the effects of temperature change and erosion on pore pressure. Summary. Bibliography. 12. Mathematical Modeling of Abnormally High Formation Pressures (M.R. Islam et al.). Introduction. Methodology of simulation of dynamic systems. Analytical approach. Analytical models. Simulation of pore-fluid (formation) pressure. Numerical models. Tectonic and lithological modeling. Numerical criterion and sensitivity analysis for time-dependent formation pressure in a sealed layer. Modeling of mean value for time-dependent formation pressure. Formation pressure in the case of constant fluid flow through the lower boundary of the formation. Criterion for the type of time-dependent variation of formation pressure. Box-type fluid flow. Sensitivity analysis for the mean value of the formation pressure in the sealed permeable layer. Criterion B = A and relaxation coefficient for the Western Kuban region in the southern part of Russia 336
Examples of formation pressure development. Discussion. Identification of conductivity function for petroleum reservoirs. Basic mathematical model of the pressure distribution in petroleum reservoirs. Indirect evaluation of the conductivity function. Determination of the piezoconductivity coefficient layer by layer. Model example of determining the conductivity function. Discussion. Framework of a comprehensive model. Overpressurization due to rapid loading. Shear deformations aided by overpressures. Fluid generation at depth. Diagenesis. Conclusions. Nomenclature used in this chapter. Bibliography. 13. Interrelationship among Fluid Production, Subsidence and Reservoir Pressure (V.A. Serebryakov et al.).
Introduction. Compaction of rocks. Conclusions. Bibliography. Author Index. Subject Index.