Geology _ Geophysics in Oil Exploration

Increasing in diameter of borehole indicates about

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Unformatted text preview: imated. Amount of oil still in pores by Capillary pressure In this case, Recovery Factor is used to solve this problem. In this case, the OOIP is calculated by: OOIP=k*Thickness*A*Φ*(1‐Sw)*(Net/Gross)*FVF*Recovery Factor NOTES: • The Unit Convergent Factor (K) is used to avoid the problem of difference in units between Area & Depth • The area of reservoir (closure for example) is determined in map then measured by software (Planimeter). • This type of calculation is called Rough Calculation because it is not 100% accurate (we consider that the reservoir layer is flat & it is not always true). Original Gas in Place (OGIP): The steps for calculating OGIP is exactly like OOIP except: • Beta Oil (Bo) will be Beta Gas (BG) • Recovery factor will have different values (Gas can move & extract more easily than oil). 51 Geology & Geophysics in Oil Exploration Mahmoud Sroor Geology & Geophysics in Oil Exploration Lead Evaluation: It is an evaluation for structure or closure after studying & before drilling. The Lead is called Prospect after calculations. The evaluation depends on studying where the source, Migration path, traps. This figure shows an evaluation for 22 Leads. Lead: is column for number of structures or closures which are interested Preliminary Risk: Are the results for the closure or structure evaluation. • • • • • Column1 (Structure): is a general evaluation for structure (Size for example). Column2 (Migration & Source): if the area has a source rock or not, the migration also passes to structure or not. Column3 (Sealing): if the structure is sealed by a cap rock or not (both Vertical Sealing & Horizontal Sealing). Column4 (Reservoir): evaluation depends on Porosity, Permeability, fractures (for Limestone & basement reservoir). Column5 (Opportunity of Success): is percentage of reservoir success (multiplying columns 1, 2, 3 & 4). OOIP MMBLS: is Origina2l Oil in Place in million Barrels. • Column1 (un risked): is the OO...
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This note was uploaded on 01/05/2011 for the course GEOL 1 taught by Professor Jenniferalford during the Spring '10 term at Indian Institute of Technology, Roorkee.

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