Understanding Oil and Gas Shows and Seals in the Search for Hydrocarbons

Introduction to the oil industry and oil show evaluation: a personal retrospective.- An introduction and vocabulary of oil and gas.- The art of exploration.- A history of drilling and exploration.- Generational challenges and evolving technology.- Some personal experiences in learning about seals and shows.- The art of exploration: plays versus prospects and getting proper experience early.- Creaming curves and new plays vs. prospect-challenging the 'peak oil' paradigm.- Looking at rocks, dealing with people and your learning curve.- Break from paradigms: believe in yourself and your data.- Pay attention to the fluids and the key well concept.- The value of teams, peer assists and risk assessment.- The need to get it right needs to be balanced by the need for speed.- Looking for the NULF (Nasty, Ugly, Little Fact) to break paradigms.- Pay attention to right rocks with oil and gas shows.- You never have enough data, but perseverance pays off.- Background on seismic.- New tools: advances in migration modelling and shows calibration.- Spider maps to 3D models.- The basics of traps, seals, reservoirs and shows.- The petroleum system: primary, secondary migration and unconventional exploration.- Traps, porosity, spill point and seals.- Assessing risk: think about seals, structure and reservoir quality.- Making the right maps.- Some thoughts on stratigraphic traps.- The basics of rock properties, free water levels, buoyancy pressure and hydrocarbon shows.- Porosity.- Buoyancy pressure (Pb), pressure verses depth plots, free water levels and water saturation.- Water and hydrocarbon saturations and height above free water plots.- Oil-water contacts, top of transition zones vs. FWL and relative permeability.- Permeability.- Waste zones.- Oil show types.- Kerogen-rich source rocks.- Thinking like a molecule.- Drilling, mud logging, wireline logs and cores.- Historical context around understanding shows and drilling wells.- Horizontal wells and multi-stage fracturing.- East vs. West: evolution of different evaluation techniques.- Seeps.- Drilling with mud.- Wellbore design, pressures and rig safety.- Background on muds, mud-weights and circulation time.- Mud logs, gasses and cuttings descriptions.- Analyzing mud gasses- wet to light gas ratio analysis.- Wellbore flushing and over and underbalanced drilling.- Cuttings and oil shows.- Residual shows.- Basics of well logs.- Well log formats: digital vs. raster.- The well header and common logs.- Common log displays and the basics of log interpretation.- Gamma ray (GR) and Spontaneous Potential (SP) logs.- Porosity logs, volume of shale calculations and total vs. effective porosity.- Quick look for gas effect and permeability from resistivity profiles.- Calculating lithology.- Capturing and interpreting core data.- Core data.- Saturation changes in coring.- How to miss good hydrocarbon shows and a case histories.- Ways to miss hydrocarbon shows.- Suppressed resistivity and 'hot gamma ray' reservoirs.- Case history 1: Russian River SE Field: "Hot" dolomite and by-passed pay, Williston Basin, Montana.- Case history 2: Using gas wetness mud log analysis to discover a new turbidite oil play fairway, Eocene Dharvi Dungar Formation, Barmer Basin, India.- Acknowledgements and introduction.- Regional setting.- Summary and impact.- Understanding seals, pressures and hydrodynamics.- Basic pressure terms, uses and pressure data collection.- Why look at seals from the standpoint of pressure and hydrodynamics?.- Some good references.- Pore pressure.- Recognizing seals on pressure-depth plots and understanding mud weights.- Tools and data capture for pressure analysis.- Data reporting formats.- Understanding facies and fault seals qualitatively.- Seals overview: facies and fault seals.- Seal quality, pressures and time.- Fault seals.- Fault traps, gouge and juxtaposition analysis.- Stress direction: borehole breakout.- Testing fault models with shows.- Building and interpreting pressure vs. depth plots and hydrodynamics flow.- The basics of pressure-depth plots and recognition of hydrodynamic flow.- Modeling hydrodynamic tilt and migration using potentiometric surface maps.- A practical example of hydrodynamic tilting using Trinity software.- Example of tilted contacts in an overpressured environment.- Building your own hydrodynamic maps: a bit more theory behind migration and hydrodynamics: the U-V-Z method.- A note on the value of Z in many petroleum systems software packages.- Hubbert's full equation with seal capacity added.- Perched water-another problem that can look hydrodynamic.- Ormen-Lange Field, Norway-perched or tilted?.- High pressure systems, pressure regressions and fracture seal breaching.- Maps of overpressure.- Deep overpressure and log and seismic methods of prediction.- Pressure regressions and fracture gradients-casing design, room for accumulations and enhanced seal capacity.- Bigger isn't always better-the role of pressures and centroids in fracture seal breach and exploration failure.- Case histories.- Temsah Field: 25 years to recognition of a tilted gas-water contact.- Deep Nile Delta play opener-pressures and shows identified the play.- Quantifying seals and saturations-capillary pressure, pseudo-capillary pressure and quantitative show assessment.- Fundamentals of capillary pressure.- The importance of understanding capillary pressure.- Fluid potential (entrapment) maps using capillary pressure seals.- Capillary pressure.- Mercury injection capillary pressure analysis.- Estimating height above free water from capillary pressure data.- Relative permeability, water cut and oil-water contacts.- Imbibition curves and residual saturations.- Flow units, Winland plots, pseudo-capillary pressure and mapping seals.- Flow units and Winland plots.- Pseudo-capillary pressure curves.- Making s seal capacity estimate when you do not have a pseudo-capillary pressure spreadsheet.- Weyburn Field example.- Migration with seals: examples from the Aneth Field are, Utah-Colorado.- Migration with both fault seals and hydrodynamics-Temsah Field, Egypt.- Show types and quantitative assessment.- Building and visualizing a shows database.- Case histories.- Cases 1-4: October Field, Egypt.- Underestimating field size-failure to get the free water level right, GS 184 Field, October Field complex, Egypt.- Cap pressure analysis finds a deeper oil-water contact, October Field, Egypt.- Capillary pressure and sample shows in a dry hole with by-passed pay lead to an updip oil discovery, October Field, Egypt.- "J" platform oil discovery: drilling updip of residual oil, October Field, Egypt.- Buzzard Field, United Kingdom-Missing a key oil show.- Hugoton Field: Giant re-migration along a residual migration pathway.- West Siberian Basin, Russia: perhaps the world's largest residual migration pathway. - Basic well log analysis, quick look techniques, pitfalls and volumetrics .- The Archie equation and finding Rw.- Archie equation limits due to shaliness.- Archie equation steps.- Finding Rw.- Porosity logs and calculation.- Sonic log porosity.- Density log porosity.- Porosity from combination neutron-density logs.- Some quick look techniques: Pickett and Buckles plots.- Pickett plots.- Buckles plots and Bulk Volume Water (BVW).- Pattern recognition of pay.- Residual shows on logs.- Pitfalls: Clays, shales, laminated pays.- Low resistivity-low contrast pays (LCLR).- Using Micro-resistivity and NMR logs in shaly and difficult pay zones.- NMR logs.- More pitfalls: Clays, conductive minerals and formation damage.- A note on calculating reserves.- Using fluid inclusion data in exploration.- The reality of migration: it is complicated!.- Conventional fluid inclusions analysis.- Using microthermometry data and identifying hydrocarbon types and salinities.- Bulk fluid inclusion analysis with FIS.- Proximity to pay.- Bacterial and thermal alteration.- A note on Drill Bit Metamorphism (DBM).- FIS interpretation examples.- Northwest coast of Australia.- Prospect ranking.- Barents sea.- Sogn graben.- Unconventional well performance-Mancos Shale, Utah.- Example of detecting oil shows missed on mud logs: Barmer Basin, India.- Shows and geochemistry: extracting more information from source rocks and hydrocarbons.- Source rock quality and maturation.- The language of source rocks.- Rock Eval pyrolysis.- Source rock quality.- Maturation and source rock type.- Maturation and Rock Eval numbers: what you see is not what you had.- Delta LogR and resistivity mapping.- Building maturation models and understanding heat flow.- Geothermal gradient heat flow.- Heat flow modelling.- An example of basement control on heat flow and maturation-Bakken Formation, Williston Basin.- 1-D burial models.- Rig data collection: Head space gas and mud isotubes.- Some source rock play screening criteria.- Sweet spots.- A note on calculating volumes of oil or gas in shale.- Oil to source rock correlations.- Example of utility of understanding basic oil and rock geochemistry correlations.- Nile Delta, Egypt.- Barmer Basin, India.- A case history of migration modelling using oil to source correlations: Cutbank Field, Montana.- Building and testing migration models.- The scale challenge in migration modelling.- Some migration concepts.- Building migration models and recognizing limits with risk maps.- Making migration risk index maps.- Appendices.- Common conversion equations and fluid classifications.- Constructing Winland pore throat graphs in Excel.- Equations in Excel to convert mercury-injection capillary pressure data to height above free water.- Equations in Excel to make pseudo-capillary pressure curves.- Converting paleogeographic maps or shapefiles in ARCGIS to grids.