Opportunities in Oil and Gas Fields Questions TABLE OF CONTENTS

Transcription

1 TABLE OF CONTENTS A. Asset What is the size of the opportunity (size the prize)? Volumetric Evaluation Probabilistic Volume Estimates Material Balance Application Is the Opportunity Spread Out between multiple reservoirs or alone? In what stage of field life does the opportunity lay? (Infant No or limited depletion recovery; youth; adolescent; young adult; middle age; mature; elderly) How many wells does it lie within?... 3 B. Local Well Observations Development What is the average well spacing within the opportunity? What are the Wellbore Geometries? What are the Formation tops? Is the reservoir Faulted? Has the opportunity been tested? Well Logs over opportunity... 3 C. Areal View by Seismic Data Development Are 2D Geophysical Data available? How about 3D Geophysical Data? Coverage of Seismic Data? Can Seismic be used to define the opportunity, or has it been used?... 4 D. What Other Field Data can aid Development of Opportunity Surface Mapping Outcrop Samples Source rock maturity analyses Other Surface Samples Faults Are there Analogs?... 4 E. How rapidly can the Opportunity be Expanded or be closed if un-successful? What are the project gates? F. What are the Project Economic Factors and Risks? In Production? In Costs? In the reservoir? Where Uncertainties exist will we need new data or can new processing be applied to old data?... 4 G. What are the storage and flow Risks from Petrophysical Analysis? Determination of full-field petrophysical cut-offs Generate summations, log displays, and other reports Interpretation of wireline formation testing results Saturation Functions Determine fluid contacts... 5 H. What are the Structural Framework Mapping Issues? Seismic Interpretations Structure Mapping on Key Geologic Surfaces Gross Reservoir Interval Isochore Mapping Fault Interpretations... 5 Page 1 of 8

2 5. Fold Geometries... 5 I. What are the Reservoir Zones Uncertainties? Net Reservoir Isochore Net:Gross Ratio Determination Net Reservoir Petrophysical Properties... 5 J. Fluid Properties Determination Uncertainties? Reservoir Parameters... 5 K. What is the Quality of the Dynamic Data Pressure Survey Data? Existing Pressure Data Flowing Surveys Static Surveys Productivity Index Gas Well Surveys Pressure Testing... 6 L. What is the Quality of the Multiphase Flow Properties? Wettability studies Capillary Pressure Relative Permeability Residual saturations... 6 M. What is the Quality of the Production, Pressure, and Secondary Product Data? Production Data Reservoir Allocation Decline curve analysis and interpretation Map Displays Interval tests and workovers Volumetric average pressure data Reservoir surveillance sections Mechanical status review... 6 N. Are other Engineering Data for Water or EOR Injection Available? Well Patterns... 7 O. Fractured Reservoir Characterization Fracture Identification Fracture Origin Fracture Morphology Fracture Characterization Identify and map fractures from seismic attribute analysis where possible Fracture Modeling Fracture Stimulation Effects... 7 P. Other Generalized Data? Mobility Ratio of displacement process? Vertical Equilibrium or no cross-flow and the following? Can k be derived from Petrophysical Data? Miscellaneous Data Geostatistical Evaluation Property Distribution Volumetric Analysis... 8 Page 2 of 8

3 A. Asset 1. What is the size of the opportunity (size the prize)? 2. Volumetric Evaluation a. Oil Volumes i. Original oil in place ii. OOIP and STOIP iii. OOIP comparisons to historical estimates b. Gas Volumes i. Original free gas in place ii. Original solution gas in place c. Transition Zone Volumes i. OW transition volumes ii. Swept zones and saturation estimates 3. Probabilistic Volume Estimates a. Assignment of uncertainty in volumetric estimates b. Results of Monte Carlo estimation methods 4. Material Balance Application a. Drive Mechanisms b. Pressure History c. Volume Estimates i. In place volume estimates (see Volumetric Evaluation) d. Aquifer Strength i. Aquifer size ii. Aquifer properties 5. Is the Opportunity Spread Out between multiple reservoirs or alone? 6. In what stage of field life does the opportunity lay? (Infant No or limited depletion recovery; youth; adolescent; young adult; middle age; mature; elderly) 7. How many wells does it lie within? B. Local Well Observations Development 1. What is the average well spacing within the opportunity? 2. What are the Wellbore Geometries? 3. What are the Formation tops? a. Chronostratigraphic tops b. Lithostratigraphic tops 4. Is the reservoir Faulted? a. Have Fault cuts been observed in wells? b. What other evidence of faulting exists from performance date 5. Has the opportunity been tested? a. Wireline formation testing b. Drillstem testing c. Production testing 6. Well Logs over opportunity Page 3 of 8

4 a. Conventional open-hole wireline logs b. Cased hole logging services c. Image logs and other special surveys d. Dipmeter logs C. Areal View by Seismic Data Development 1. Are 2D Geophysical Data available?. 2. How about 3D Geophysical Data? 3. Coverage of Seismic Data? 4. Can Seismic be used to define the opportunity, or has it been used? D. What Other Field Data can aid Development of Opportunity 1. Surface Mapping a. Geological b. Geochemical data c. Special Studies / Maps 2. Outcrop Samples a. General description and classification b. Petrographic thin sections, descriptions, and classifications c. SEM studies d. Chemical and mineralogical analyses 3. Source rock maturity analyses a. Thermal maturation analyses b. VR data c. Basin modeling i. Basin modeling studies in 2D and 3D ii. Maturation profiles iii. Migration studies 4. Other Surface Samples a. Groundwater samples and analyses b. Surface seep samples and analyses c. Geochemical surveys and analyses 5. Faults 6. Are there Analogs? E. How rapidly can the Opportunity be Expanded or be closed if un-successful? 1. What are the project gates? 2. F. What are the Project Economic Factors and Risks? 1. In Production? 2. In Costs? 3. In the reservoir? 4. Where Uncertainties exist will we need new data or can new processing be applied to old data? G. What are the storage and flow Risks from Petrophysical Analysis? Page 4 of 8

5 1. Determination of full-field petrophysical cut-offs 2. Generate summations, log displays, and other reports 3. Interpretation of wireline formation testing results 4. Saturation Functions a. Leverett J functions b. Other fluid saturation parameters (Thomeer, etc.) 5. Determine fluid contacts a. Free water level b. Oil-water contact c. Gas-oil contact d. HPW, LKO, etc. H. What are the Structural Framework Mapping Issues? 1. Seismic Interpretations a. Attribute Analysis 2. Structure Mapping on Key Geologic Surfaces 3. Gross Reservoir Interval Isochore Mapping 4. Fault Interpretations a. Fault Plane Mapping b. Fault Cuts in Wells c. Fault Displacement Analysis 5. Fold Geometries a. SCAT Analysis I. What are the Reservoir Zones Uncertainties? 1. Net Reservoir Isochore 2. Net:Gross Ratio Determination 3. Net Reservoir Petrophysical Properties J. Fluid Properties Determination Uncertainties? 1. Reservoir Parameters a. Oil and gas volume factors for volumetric reserves determination i. Boi and Sg b. Recovery factors i. Variable by zone or facies? K. What is the Quality of the Dynamic Data Pressure Survey Data? 1. Existing Pressure Data a. Fault block isolation indication i. Tracer test results b. Support for determination of fluid contacts i. Pressure profile analysis c. Formation pressure testing results and analyses 2. Flowing Surveys a. Tubing head pressure surveys b. Bottomhole pressure surveys 3. Static Surveys a. Tubing head pressure surveys Page 5 of 8

6 b. Bottomhole pressure surveys 4. Productivity Index 5. Gas Well Surveys a. Multi-rate test results and interpretations 6. Pressure Testing a. Pressure Buildup Tests b. Stimulation Activities c. Drawdown Tests d. Fall-off tests e. Injectivity tests f. Parting pressure tests L. What is the Quality of the Multiphase Flow Properties? 1. Wettability studies 2. Capillary Pressure a. Drainage capillary pressure b. Imbibition capillary pressure 3. Relative Permeability a. Water-oil relative permeability b. Gas-oil relative permeability c. Gas-condensate relative permeability d. Relative permeability hysteresis 4. Residual saturations a. Residual oil saturation b. Residual gas saturation M. What is the Quality of the Production, Pressure, and Secondary Product Data? 1. Production Data a. PLT and Injection Log Visualization in 3D b. Bubble Maps i. Compare historical production to simulation results and predictions c. Vertical Lift Data i. Needed to calculate FTHP for simulation 2. Reservoir Allocation a. Production allocation b. Injection allocation 3. Decline curve analysis and interpretation 4. Map Displays a. EUR maps b. Drainage radius maps c. Cumulative fluids maps d. Field status maps e. Water and/or gas advance maps (time-dependent) 5. Interval tests and workovers 6. Volumetric average pressure data 7. Reservoir surveillance sections 8. Mechanical status review Page 6 of 8

7 N. Are other Engineering Data for Water or EOR Injection Available? 1. Well Patterns a. Pattern Performance b. Volumetrics c. Injection/Flood design and performance appraisal O. Fractured Reservoir Characterization 1. Fracture Identification 2. Fracture Origin a. Determine stress field directions 3. Fracture Morphology 4. Fracture Characterization a. Orientation b. Density and intensity c. Porosity and Permeability effects 5. Identify and map fractures from seismic attribute analysis where possible 6. Fracture Modeling a. Construct DFN models i. Validate fracture permeability in DFN model b. Calculate dual porosity and/or dual permeability model parameters 7. Fracture Stimulation Effects P. Other Generalized Data? 1. Mobility Ratio of displacement process? 2. Vertical Equilibrium or no cross-flow and the following? a. Sequence and Areal Distribution i. If there is any deviation from the stratigraphic sequence defined above, we will need to have those exception defined. b. Key Surfaces i. Any key surfaces (geophysical markers, unconformity surfaces, etc.) need to be identified. c. Layering Constraints d. Edge Effects i. How should erosional and non-depositional limits be handled (if any are present)? 3. Can k be derived from Petrophysical Data? 4. Miscellaneous Data a. Boundary Conditions / Limits i. Are there geographic limits to the study area? b. Contacts i. Oil-Water 1) Highest proven water ii. 2) Lowest proven oil Gas-Oil 1) Highest proven oil 2) Lowest proven gas c. Special Data 5. Geostatistical Evaluation a. Data analysis and quality control Page 7 of 8

8 i. Use geostatistical tools to evaluate data quality, screen unrealistic data outliers, isolate individual wells that have spurious data, etc. b. Variogram analysis i. Use facies distribution summary to build variograms for each facies type 6. Property Distribution a. Porosity b. Permeability c. Fluid Saturations d. Facies Distribution i. Use SIS or object-modeling to distribute facies e. Flow Zone Indicators 7. Volumetric Analysis a. Determine petrophysical parameters to be used in volumetric reserves determination b. Quality control i. Check for zero-volume or negative volume cells in grid c. Determine original in-place volumes i. Gross reservoir volume ii. Net reservoir volume iii. Net hydrocarbon volume (OOIP and OGIP) iv. Recoverable reserves (if recovery factors are available) d. Monte Carlo Simulation i. Create multiple realizations to capture uncertainty in: 1) Fluid contacts 2) Saturation profiles 3) Pore volume and pore distribution 4) Other uncertainty ii. Perforations, liners, open-hole completions iii. Recompletions iv. Plug-backs v. Other Page 8 of 8