CHDT
Cased hole dynamics tester
Conduct multiple pressure measurements and collects fluid samples behind the casing in a well.
LFA
Live fluid analyzer
How it works: Optical absorption spectrometry
The miscibility of oil-based muds with formation hydrocarbons poses significant challenges for determining contamination by oil-based mud filtrate during downhole fluid analysis (DFA) and sample acquisition.
The LFA analyzer module’s absorption spectrometer uses visible and near-infrared light transmission to reliably detect water and oil by their unique absorption spectra. Because methane is present in all naturally occurring hydrocarbons and absent from drilling fluids, any methane detected is due to reservoir hydrocarbons and not filtrate and can be used to monitor contamination.
The LFA analyzer uses light in the visible and near infrared range to characterize the fluid flowing through the flowline. The refractometer provides discrimination between the liquid phase and the gas phase.
The increased sensitivity of the LFA analyzer to free gas ensures that a single-phase sample is collected downhole.
Single-phase assurance by bubblepoint monitoring
The LFA analyzer’s second sensor is a gas refractometer for differentiating between gas and liquid. By monitoring the bubblepoint of the produced fluid to ensure it is below the flowing pressure, representative single-phase fluid is acquired.
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