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Learn about the global landscape of shale gas resources, including exploration stages, key characteristics, evaluation criteria, and geologic parameters. Discover the economic potential and environmental considerations associated with shale gas extraction.
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Energy Experts Believe • Oil is Finite • Demand is not
E&P Business: Oil Price, Margin, Size & Value Low Oil Price High Margin Asset = high tide high operating costs *Low Margin Asset = low tide High Oil Price low operating costs
Despite Early Stages of Exploration Huge Amounts of Shale Gas is estimated in different parts of world Global Shale Gas Volumes GIP TCF Source: Rogner 1997 • Over 32,500 TCF of gas identified worldwide from Unconventional Reservoirs
Shale Gas Tight Gas Basin Centered gas
Attractive, Hottest Business OpportunityAcross Globe Shale Gas is key to USA Energy Basket • US 2008 ytd. production of Shale Gas is 3.23 TCF • 17% of total US gas production from Shale Gas • India’s total annual Conventional Gas production is only 26% of US Shale Gas production (Schlumberger)
What is shale Gas? Continuous type regionally pervasive self contained natural gas plays in Shale/Shaly Formations • Shale gas is natural gas contained within shale sequences. The gas is stored in shale in two major ways: • As adsorbed gas on kerogen (insoluble organic matter). In this respect, it is similar to natural gas from coals. • The adsorbed gas portion range between 20% (Barnett Shale) and 85% (Lewis Shale). UTICA SHALES, NEW YORK
Play Type Identification is Critical For Assessment and Exploration Thermogenic Biogenic Mix Type
…..Contd. • Gas Shales contain significant portions of both adsorbed gas and interstitial pore gas
NO TWO SHALES ARE ALIKE But look for right combination of shale characteristics SHALE TYPING IS ESSENTIAL
PLAY CHARACTERISTICS • Continuous type plays • Cover large arial extent • Large net thickness (on average) • Traits which differ from coals
*Gas Saturations Adsorbed and Free Gas* PRINCIPAL TYPES OF GAS STORAGE PHENOMENA
Dual Permeability System • Natural Fracture Systems often Control the Success or Failure of Stimulation Attempts • Natural Fracture Geometry can Change Laterally and Vertically with Lithology related Mechanical Properties and Stress Changes
The Fundamental Aspects for Evaluation • Generation Potential (source) • Storage Potential (reservoir) • Production Potential (Productivity)
EVALUATION CRITERIA • GEOSCIENTIFIC Geological Geochemical Petrophysical Reservoir • TECHNOLOGICAL • Gas assessment related • Drilling and completion related • Stimulation and production related • COMMERCIAL & ECONOMIC
Geological Parameters • Shale Thickness (>100M) • Shale Depth (<2500M) • Areal extent • Shale Type (silty) • Shale brittleness (low Poissons ratio & high Youngs Modulus)
What makes the shale a good SOURCE for gas plays TR TOC Vro Thickness Kerogen type HI/O2 Biogenic-Thermogenic ratio
Organic Matter Type Effect • Sapropelic Kerogens generate twice the volume of gas as do Humic Kerogens but oil interfere with release of gas until >1.0Vro • Humic Kerogens (III) generates mainly gas starting at 0.5 Vro • Type I Kerogen starts gas generation at higher maturity than type II and Type III Kerogens