petrophysical data acquisition...
TRANSCRIPT
Mud Logging – A Combination of Direct and Indirect Measurements
Petrophysical Data Acquisition Basics
Learning Objectives
By the end of this lesson, you will be able to:
Understand the process of mudlogging including hydrocarbon shows and lithology determination.
Identify the components of the drilling mud system and describe where cuttings samples and gas samples are collected.
Identify lithology and hydrocarbon type (oil or gas) from Mudlog in a hydrocarbon bearing zone.
Mud Logging
Diluted gas drawn from Gas Trap agitator in mud returns Chromatograph and hot wire analyze stream for hydrocarbons
• Total combustible gas using hot wire• Chromatograph with FID for specific hydrocarbons (C1 -C6)
Drill cuttings collected from shale shaker• Washed, described by mud logging engineer• Lithology, oil shows, fluorescence, compared to gas data
Sample and gas lag times must be measured or calculated Interpreted log combines ROP, lithology, HC gas readings, and
detailed cuttings descriptions, all plotted vs. depth
Lithology determination Formation fluid typing Well positioning within stratigraphy
• Selection of casing and/or coring points
Detection of geo-pressures Drilling Optimization
• Bit selection; hydraulics
Mud Logging Applications
Notes: • Cuttings lithology when intervals drilled with PCD
bits
• Fluid typing, ROP, pressure, bit runs still useful
The Drilling Mud System
Where are drilling mud
samples collected?
Drill Cuttings Samples Collected at the Shale Shaker
Mud Log – Processing Flow
Sampledat theshaker
Agitator/ Gas Trap in Possum Belly
Hot Wire (Total Combustible)
Gas Detector
Chromatograph(Gas Components
by FID + GC)
InterpretiveMudlog Output (ASCII/LAS) or
graphic formats
Drill Cuttings Interpretation
Drilling Engineering Data
Log
Mud Logging Wellsite Units
Combination Digital, Analog Unit Digital Unit
Logging Unit
Geology Side
Mud Logging: Evaluation
ROP log used for well-well correlation Cuttings lithology Gas Analysis Oil staining on cuttings (e.g., chlorothene solvent cut):
• water zone: no staining• oil zone: more heavy components• gas zone: only light components
• Color of fluorescence when sample wetted with solvent, viewed in UV light is excellent clue
Mud Logging Components
Sample, gas for analysis• Samples each
5-30 feet as requested• Continual total gas• Components each 12-15
minutes
Data output is graphic, digital
• Spreadsheet• ASCII• LAS
Analysis of Total Gas − ComponentsHydrogen generator
PC withIChrom
Igniter Glow Plug 24 volt
Oiler
FID Detector BlockHeated to 250C
Jet
Metal Tube tocatch Ions – 240 volts(Collector)
Balston Filter
Possum belly or ditch• Gas trap• Agitator motor• Gas lines• Condensate bottle
Pneumatics panel• Vacuum pump• Moisture Filters• Flow regulators
HP6890 Gas Chromatograph• Total gas• Gas chromatography
Courtesy of BakerInteq
Lithology Determination Takes Practice!
Large cuttings are cavings Fine cuttings of Woodford shale with no cavings
Measuring Time – Depth Sample Lag
Drilling Rate/Porosity Relationship
Hydrocarbon Tests on Cuttings
Staining, bleeding, odor, gas, iridescence (color) (Pos., Neg., Quest.)
Natural fluorescence (UV): Distribution, intensity, color 5 = strong... 0 = nil
Solvent cut test (Chlorothene): Minerals will not produce cut fluorescence
Acetone test (light oil): Hydrocarbons cause milky white solution
Acid test: Bouncing motion of cutting if HC present
Pyrolysis test (“burn it”)
Hot water test: Oil film at surface
Graphical Mud Log Exercise
Hydrocarbon Fluorescence
API°
(45°) blue-white to violet
(35-45°) white
(25-35°) yellow to cream
(15-25°) orange
(below 15°) brown
Sample fluorescence (approximate)
Now… Is this a Good Show?
Learning Objectives
Understand the process of mudlogging including hydrocarbon shows and lithology determination.
Identify the components of the drilling mud system and describe where cuttings samples and gas samples are collected.
Identify lithology and hydrocarbon type (oil or gas) from Mudlog in a hydrocarbon bearing zone.