17 Questions
What is the 'Delaware Effect' seen in laterologs?
A gradual increase in apparent resistivity due to a thick non-conductive bed like salt or anhydrite
What type of mud is ideal for laterologs to give their truest resistivity?
Mud with low resistivity
Why do highly resistive muds adversely affect laterologs?
Decrease the apparent resistivity
How does the Groningen Effect differ from the Delaware Effect in laterologs?
Groningen Effect causes a larger negative potential in the N electrode even with electrodes at the surface
What thickness of mud is required for LL7 to be unaffected by adjacent beds?
At least 5 feet
How does the invasion depth affect the accuracy of laterolog readings?
Shallow invasion gives truest resistivity readings
What is the purpose of accurate estimates of lithology and porosity in reservoir evaluation?
To determine the saturation and volume of hydrocarbons in a reservoir
Why is Rw often not a simple parameter to understand or characterize?
It varies both horizontally and vertically in formation water
In the Archie equation, how does an increase in Rw affect calculated Sw?
Increases Sw
What effect does a rise in Rw have on calculated Sw according to the Archie equation?
Increases Sw linearly
Why might reservoirs in SE Asia have widely different salinity in the hydrocarbon leg compared to underlying water?
Due to the presence of meteoric water invasion
What role does Rw play in the Archie equation and its variants?
It directly multiplies a parameter in the numerator
What is the significance of measuring Rw accurately as the formation water freshens?
Rw is more sensitive at fresher water conditions
Why is measuring Rw from recovered formation water samples not always ideal?
Iron contamination is often present in recovered samples
How does a small change in salinity at low concentrations affect Rw compared to a similar change at high concentrations?
Small changes in salinity at low concentrations have more influence on Rw
What is the key drawback of establishing Rw from previously measured values in a basin?
Dependence on this parameter affects analysis precision
How can Rw be derived from a static spontaneous potential (SSP)?
Derive Rwe using chart SP-1
Explore how borehole mud, invaded zone, and adjacent beds impact laterologs. Learn about correction charts for different tools and the 'Delaware Effect' observed in laterologs when a zone is covered by non-conductive beds like anhydrite or salt.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
