What does a water cut (thievage) measure?

What does a water cut (thievage) measure?

• A. Oil density
• B. Temperature
• C. Water in cargo tank
• D. Pressure

Answer: (C)

Water cut, or thievage, measures the amount of water present in the cargo liquid, expressed as the percentage of water by volume (often in the cargo tank). The test is done by taking a representative sample from the cargo through a thief pipe, letting the sample separate into oil and water, and then quantifying how much of the sample is water (or by using a water-cut meter that detects the water fraction). This measurement is crucial because free water in cargo can cause corrosion, microbial growth, emulsions, or instability during loading and unloading, and it helps determine whether the cargo meets quality and safety limits. It’s not about oil density, which relates to API gravity; nor is it about temperature or pressure.

Water cut, or thievage, measures the amount of water present in the cargo liquid, expressed as the percentage of water by volume (often in the cargo tank). The test is done by taking a representative sample from the cargo through a thief pipe, letting the sample separate into oil and water, and then quantifying how much of the sample is water (or by using a water-cut meter that detects the water fraction). This measurement is crucial because free water in cargo can cause corrosion, microbial growth, emulsions, or instability during loading and unloading, and it helps determine whether the cargo meets quality and safety limits. It’s not about oil density, which relates to API gravity; nor is it about temperature or pressure.