Petrophysics: solving the jigsaw to get the reservoir description together

1. Petrophysics: solving the jigsaw to get the reservoir description together Elisabeth Furst Tuesday 21st August 2007 Longyarbyen Svalex 2007

2. Agenda • Challenges of reservoir description • What is Petrophysics? • The link to the different pieces of the jigsaw of reservoir description • Integration is the key • History

3. Introduction • Key questions where the petrophysicist is involved from exploration to production and IOR. • What have we got? • Lithology, fluids, reservoir geometry • How much? • Input for reserves calculations • How can we produce it? • Well planning, permeability, contacts • How certain are we? • Uncertainty analysis The goal: 3D visualisation of the reservoir

4. GEOPHYSICS DRILLING GEOLOGY PETROPHYSICS RESERVOIR ENGINEERING The jigsaw: a few challenges to the disciplines work together • We can rarely measure and see all the reservoir parameters • To start with we have seismic (2D 3D), geological ideas/analogs but what is the geological model/ make sense to seismic? • Well data 1D , seismic 2D/3D • geology depth, seismic in time • Well data is looking a few inches to a few feet into the formation, seismic: meters to kilometers • How do we link the static and dynamic aspects of the reservoir?

5. PETROPHYSICS What is Petrophysics? • Petrophysics is about describing the fluids distributions and interactions in the porous system of the reservoirs and estimate the production flow capacity This is done by integrating well data (mechanic, dynamic, static, log..) to help the multi-disciplinary teams to get a understanding of the reservoir and its behaviour • This can range from the identification of Netpay in exploration wells, to the optimum exploitation of reservoirs with complex lithologies and pore geometry or other unusual features Beyond the logs

6. Geological models and analogs GEOLOGY • Verify models and calibrate analogs: link between them and reality is core and logs • Petrophysical tools responses are lithology related • Examples: fluvial coarsening upwards, wells correlation Analog

7. Reservoir structure GEOLOGY • Bedding direction: supporting geological structure- 3D view of the borehole • Identify faults and describe them (inc, az, open..) linking them to seismic Bedding direction Fault incl/azimuth

8. Core Core SCAL FMI Reservoir properties Wireline log curves GEOLOGY • Model population with properties of models • Upscaling • Reserves calculations input: Por, sat, fluids…. • Uncertainty analysis Facies Upscaling/ Populating Volumes

9. Calibrate seismic to well Predict seismic response Identify seismic facies Seismic attribute maps: porosity… Key in exploration Predicting and calibrating seismic response Geophysics Modelling Facies for seismic attributes Seismic facies /rock properties Porosity map Syntool Synthetic 1D seismic from accoustic logs

10. Predicting and identifying fluids and contacts Input to dynamic models, permeability- test data Relative permeability Constant updating: monitoring production effects (RST+4D) Well X 3190 m Crest RESERVOIR ENGINEERING Sand B Sand C ODT-3430 m 19 m oil P01 3438 m Water- up-to OWC(P50) 3545 m P50 OWC(mdt)-3630 m P90 Reservoir dynamics Fluids interactions and reserves Relative permeability is used to predict flow and breakthrough Pressure profiles: gradients and contacts

11. Well Planning/drilling support DRILLING • Correlation of well properties allow to plan wells and target the best reservoir more efficiently • Optimization of reservoir drilling: pore pressure estimate, rock mechanics • Real time stirring wells using real-time interpretation and new technology for maximum reservoir penetration Well positioning to target best reservoir Real time evaluation for well stirring

12. PETROPHYSICS Petrophysics: integration tool • The integration of all the aspects of the reservoir is the key to achieve the 3D visualisation Well test Formation tester sampling seismic INTEGRATION SCAL SEM The goal: 3D visualisation of the reservoir Well logging: density, neutron, resistivity, NMR, Sonic, spectrometry ….

13. GEOLOGY GEOPHYSICS PETROPHYSICS RESERVOIR DRILLING ENGINEERING Solving the jigsaw - Facies characterization - Structural - Sand bodies distribution - Seismic facies - Rock Physics - Synthetic seismic/Tie-in Model Maps Volumes Where what to drill compartments Model update (4D) - Rock mechanics - Data Acquisition - Real time drilling optimization - Fluids /contatcs - Pressure/Compartments - Relative permeability Targetting hydrocarbons, P&T

14. Petrophysics has come a long way • This has come a long way from the time when petrophysics was papers logs, now we have imaging, magnetic tools, signal processing to see more • Reservoir description is built around integration packages • Technology allows us to see at smaller scale (thin beds) and bring it to a 3D visualisation Present day: digital data and packages built to integrate while drilling 80 years ago: paper logs

15. What does it take to be a petrophysicist? • Numeracy, solid scientific/physics skills • Skills to follow innovation: technology • 3D subsurface visualisation ability: G&G • Aptitude for solving puzzles: get all reservoir aspects together • Communication skills : key team integrator