Oil-based mud contamination estimate from physical properties

• Main Authors: Rocco Difoggio, Hermanus J. Nieuwoudt
• Format: Patent
• Language: English
• Published: 06.04.2022
• Subjects: EARTH DRILLING; EARTH DRILLING, e.g. DEEP DRILLING; FIXED CONSTRUCTIONS; INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIRCHEMICAL OR PHYSICAL PROPERTIES; MEASURING; MINING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR ASLURRY OF MINERALS FROM WELLS; PHYSICS; TESTING

Methods and apparatus for estimating a presence of oil-based mud (OBM) in a downhole fluid. Methods include generating measurement values by measuring one or more gross physical properties of the downhole fluid with at least one sensor, the measurement values comprising at least one measurement value representative of each gross physical property; and estimating with at least one processor a relative concentration of OBM with respect to the downhole fluid by using a model correlating the measurement values with the relative concentration. Methods may include taking measurements from the downhole fluid in situ and/or estimating the relative concentration in real-time with respect to generating the measurement values. The model may comprise a correlation prediction function mapping the measurement values to the relative concentration, which may use the measurement values as input to predict the relative concentration.