5 - Log Correlation Techniques

5 - Log Correlation Techniques - PETE 3053 – SUBSURFACE...

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Unformatted text preview: PETE 3053 – SUBSURFACE ASPECTS OF PETE 3053 – SUBSURFACE ASPECTS OF PETROLEUM ENGINEERING Log Correlation Techniques PETE 3053 – SUBSURFACE ASPECTS OF PETE 3053 – SUBSURFACE ASPECTS OF PETROLEUM ENGINEERING Correlation The Determination of Structural or Stratigraphic Units That Are Equivalent in Time, Age, or Stratigraphic Position. In the Subsurface the two Sources of Information are: 1. Geophysical Well Logs 2. Seismic Sections PETE 3053 – SUBSURFACE ASPECTS OF PETE 3053 – SUBSURFACE ASPECTS OF PETROLEUM ENGINEERING Electric log correlation is pattern recognition. PETE 3053 – SUBSURFACE ASPECTS OF PETE 3053 – SUBSURFACE ASPECTS OF PETROLEUM ENGINEERING 1. 1. 1. 2. Correlation Type Log A Log That Exhibits A Complete Stratigraphic Section In A Field or Area of Study. Stratigraphic Type Log A Log That Depicts Depositional Environments In A Field or Area of Study. Composite Sand Type Log A Log That Illustrates Potential Sands In A Field or Area of Study. AKA Pay Logs and Show Logs From Tearpock et al 1991 From Tearpock et al 1991 PETE 3053 – SUBSURFACE ASPECTS OF PETE 3053 – SUBSURFACE ASPECTS OF PETROLEUM ENGINEERING 1. 2. 3. 4. 5. 6. 7. 8. Log Correlation Procedures Align depth scale and look for patterns. Quick Look Correlation ­ Use Major Sands and GR or SP Curves. Detailed Correlations ­ Use Shale Sections. Initial Correlations in Shales ­ Use the Shallow Resistivity Curve (Short Normal, SFL, or LL8). Use Colored Pencils (Erasable). Start at the TOP! Be Gentle ­ Don't Force the Correlation. Correlate Down Then Correlate Up. PETE 3053 – SUBSURFACE ASPECTS OF PETE 3053 – SUBSURFACE ASPECTS OF PETROLEUM ENGINEERING Log Correlation ­ Vertical Wells 1. Prepare A Correlation Type Log. 2. Correlate Each Well With At Least Two Other Wells. 3. Correlate Wells With The Most Complete Section First. 4. Work From Down Structure To Up Structure. 5. Correlate Wells That Are Close To Each Other. 6. Correlate Wells That Have The Same Stratigraphic Thickness. PETE 3053 – SUBSURFACE ASPECTS OF PETE 3053 – SUBSURFACE ASPECTS OF PETROLEUM ENGINEERING Log Correlation ­ Directional Wells 1. Prepare A Correlation Type Log. 2. Correlate Each Vertical Well As Before. 3. Classify Deviated Wells as Either Down­Dip, Along Strike, or Up­Dip. 4. Correlate Down­Dip Wells First Starting With Least Deviation First. 5. Continue With Higher Deviation Wells. 6. Next Work With Wells Drilled Along Strike. 7. Correlate the Up­Dip Wells Last Since They Are The Most Complicated. PETE 3053 – SUBSURFACE ASPECTS OF PETE 3053 – SUBSURFACE ASPECTS OF PETROLEUM ENGINEERING Correlation of Vertical & Directional Wells 1. Mark Deviation Angle Every 100 Feet On The Log. 2. Slide the Vertical Log. 3. Use Thickness Ratios To Determine Thinning, Faulting, or Deviation. 4. Use The Copy Machine! 5. If The Beds Are Horizontal Convert The Directional Well To A TVD Log. 6. For Steeply Dipping Beds Use TVT Log. PETE 3053 – SUBSURFACE ASPECTS OF PETE 3053 – SUBSURFACE ASPECTS OF PETROLEUM ENGINEERING Faults and Fault Cuts Fault Types 1. Normal 2. Reverse 3. Thrust Fault Size The Vertical Thickness of Missing or Repeated Section. PETE 3053 – SUBSURFACE ASPECTS OF PETE 3053 – SUBSURFACE ASPECTS OF PETROLEUM ENGINEERING Unconformities – How to identify 1. Structural dip is different above and below an angular unconformity. 2. When missing section appears at the same depth in two or more wells. 3. Missing section increasing upstructure. 4. Truncation in younger sequences down structure. 5. For onlap, missing section increases above and below in the upstructure direction. From Tearpock et al 1991 From Tearpock et al 1991 From Tearpock et al 1991 From Tearpock et al 1991 From Tearpock et al 1991 From Tearpock et al 1991 From Tearpock et al 1991 From Tearpock et al 1991 From Tearpock et al 1991 From Tearpock et al 1991 From Syed, Gulf Science & Technology, HTSC Report No. 442A1032, 1977 From Syed, Gulf Science & Technology, HTSC Report No. 442A1032, 1977 From Syed, Gulf Science & Technology, HTSC Report No. 442A1032, 1977 From Syed, Gulf Science & Technology, HTSC Report No. 442A1032, 1977 From Syed, Gulf Science & Technology, HTSC Report No. 442A1032, 1977 From Syed, Gulf Science & Technology, HTSC Report No. 442A1032, 1977 From Syed, Gulf Science & Technology, HTSC Report No. 442A1032, 1977 From Syed, Gulf Science & Technology, HTSC Report No. 442A1032, 1977 From Syed, Gulf Science & Technology, HTSC Report No. 442A1032, 1977 From Syed, Gulf Science & Technology, HTSC Report No. 442A1032, 1977 An unconformity between parallel strata A depositional break of minor extent presumed to represent a hiatus of minor duration From Syed, Gulf Science & Technology, HTSC Report No. 442A1032, 1977 From Syed, Gulf Science & Technology, HTSC Report No. 442A1032, 1977 From Syed, Gulf Science & Technology, HTSC Report No. 442A1032, 1977 From Syed, Gulf Science & Technology, HTSC Report No. 442A1032, 1977 From Syed, Gulf Science & Technology, HTSC Report No. 442A1032, 1977 From Syed, Gulf Science & Technology, HTSC Report No. 442A1032, 1977 From Syed, Gulf Science & Technology, HTSC Report No. 442A1032, 1977 From Syed, Gulf Science & Technology, HTSC Report No. 442A1032, 1977 ...
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This note was uploaded on 02/01/2011 for the course PETE 3053 taught by Professor L during the Spring '11 term at LSU.

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