The Energy Company of Choice Integration of Seismic Inversion, Pore Pressure Prediction, and TOC Prediction in Preliminary Study of Shale Gas Exploration Andika Perbawa (1) , Bayu Kusuma (1) , Sonny Winardhi (2) PIT HAGI 2012 - 216 (1) Medco E&P Indonesia (2) Institute of Technology Bandung
30
Embed
Integration of Seismic Inversion, Pore Pressure Prediction, and TOC Prediction in Preliminary Study of Shale Gas Exploration
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
The Energy Company of Choice
Integration of Seismic Inversion, Pore Pressure Prediction, and TOC Prediction in Preliminary Study of Shale Gas Exploration
(1) Medco E&P Indonesia (2) Institute of Technology Bandung
Halaman 2Halaman 2
• Introduction
• Basic theory
• Data Availability and Method
• Result
• Conclusions and Recommendations
Outline
Halaman 3Halaman 3
Unconventional Gas ?
Introduction
“Natural gas that cannot be produced at economic flow rates or in
economic volumes of natural gas unless the well is stimulated by a
large hydraulic fracture treatment, a horizontal wellbore, or by using
multilateral wellbores or some other technique to expose more of the
reservoir to the wellbore”
Holditch, 2007
Halaman 4Halaman 4
What is Shale Gas ?
Source: US Energy Information Administration
American Century Investment, 2011
1,275 TCF862 TCF
774 TCF681 TCF
485 TCF
Halaman 6Halaman 6
Organic rich shale : TOC > 1.0%, HI > 100
Gas type : Free gas and absorb gas
Permeability : Low need fracture job
Maturation : Mature to over-mature zone window (> 1.3 %Ro)
Thickness : > 75 ft
Kerogen type : Type I and II generates more gas than type III.
Mineralogy : More quartz / less clay, brittle shale / more fracture.
Storage : Fractures and pores
Low recovery efficiency : 8-15%
Performance of production : Depend on natural fractures and artificial fracture
Characteristics
Introduction
Halaman 7
• Rock type, lithology, mineralogy and V-clay estimation• Kerogen estimation and distribution • Fracture orientation• Maturation distribution• Shale distribution• TOC distribution• Reservoir pressure distribution• Brittleness and ductile distribution• Porosity distribution• Permeability distribution• Depositional setting, direction and isopach of shale distribution• Gas saturation and composition estimation• Fluid sensitivity• Volume calculation
Key Parameter in Shale Gas Exploration
Introduction
Materials covered
Halaman 8Halaman 8
Delineate potential shale gas play using available
data, then recommend a drilling location to acquire a
complete set of new data and to be able to evaluate
shale gas resources more intensively
Objectives
Introduction
Halaman 9Halaman 9
1. Geochemistry• Total Organic Carbon: TOC• Maturation : %Ro , Tmax, LOM• Kerogen type : HI, S2/S3
Data needed to evaluate the potential of shale gas in exploration:
Data Availability
2. Petrophysics and Petrography• Mineralogy: XRD, SEM• Permeability• Fracture evaluation• Gas content and capacity (absorbed and free)• Pressure
Pore Pressure Prediction using velocity data from:1. DT log/Sonic (purple).2. Pseudo DT derived from
resistivity (red) using Faust (1953) equation. VR=a(Rdeep)c
3. Calibrated velocity stacking (black).
After all of velocity data are aligned, apply Eaton’s equation to calibrated velocity stack cube
Halaman 28
Potential Shale Gas Area
Result
Potential Area
Halaman 29
• Passey’s method shows a sweet spot interval in Upper Talang Akar Fm.
• The potential shale gas is about 100 feet thick and has more than 1% of TOC in Upper Talang Akar Fm.
• The Lower Talang Akar Fm. has less potential shale gas.
• The shale distribution covers a whole objective area (Upper Talang Akar Fm.)
• There are several spotty areas that have a medium pressure regime in the north, west and south-east relative to well- X. Drilling needs to be aware.
• The two interesting potential shale gas areas (TOC ≥ 1%) are located in the west, trending north-south, and in the east relative to well-X.
• Both locations can be recommended for the next pilot holes in order to acquire a complete set of new data and to be able to evaluate more intensively
Conclusions
Halaman 30
• Use actual shear wave data to reduce uncertainty.
• Use TOC data from Core or SWC for accurate depth location.
• Drill a pilot hole in order to acquire a complete set of new data and to be able to evaluate more intensively.
• Core Data• SEM• XRD• Geochemist analysis (TOC, Ro, HI, Rock eval, etc.)• Complete well log data (include shear wave data)• VSP
• Conduct a 3D data with small bin and narrow inline/xline interval. Perform anisotropic processing and analysis to determine young modulus and bulk modulus cube for brittleness identification.
• Conduct coherence, variance, dip-azimuth attribute to determine fracture orientation.
Recommendations
Halaman 31
• Argakoesoemah R.M.I., Raharja M., Winardhi S., Tarigan R., Maksum T.F., Aimar A., 2005, Telisa Shallow Marine sandstone As An Emerging Exploration Target In Palembang High, South Sumatra Basin, Proceedings Indonesian Petroleum Association, 30th Annual Convention, Jakarta.
• Bishop, Michele. G., 2001, South Sumatra Basin Province, Indonesia: The Lahat/Talang Akar-Cenozoic Total Petroleum System. USGS 99-50-S. USA.
• Dutta, N.C., ed, 1987, Geopressure: Society of Exploration Geophysicists Reprint Series 7, 365 p.
• Eaton, Ben A., 1975. The Equation For Geopressure Prediction From Well Logs. SPE 50th Annual Fall Meeting, Dallas, TX, September 28 – October 1, 1975. SPE paper # 5544, 11 pp.
• Fatti, J. L., P. J. Vail, G. C. Smith, P. J. Strauss, and P. R. Levitt, 1994. Detection of gas in sandstone reservoirs using AVO analysis: A 3D seismik case history using the Geostack technique . Geophysics, 59, 1362–1376.
• Faust, L. Y., 1953, A velocity function including lithologic variation, Geophysics, 18, 271-288.
• Finnegan, J., 2011, Is Shale Gas a Game Changer in the Global Energy Supply Outlook?, American Century Investment, In-Fly-72552 1107.
• Ginger, D., K. Fielding, 2005, The Petroleum Systems and Future Potential of the South Sumatra Basin. IPA05-G-039.
• Holditch, S.A., 2007, Unconventional Gas. NPC Global Oil and Gas Study, Texas.
• Lee. M.W., 2005, A simple method of predicting S-wave velocity. Geophysics 71, 161-164.
• Passey. Q. R., 1990, A Practical Model For Organic Richness from Porosity and Resistivity Logs , AAPG Bulletin V.74, No.12.