Fluid Saturations


Fluid saturation measurements are derived from Dean Stark and/or retort summation of fluids. Accurate fluid saturations are essential for proper reserves evaluation.

Fluid saturations help clients make informed decisions on which zones to complete, and obtain water-free production. Fluids extracted by the Dean Stark method are used to calculate the oil, water, and gas saturations present in plug, sidewall core, or whole core samples. Dean Stark fluid saturations are used to identify productive intervals, oil-water contacts, residual oil zones (ROZ), and to aid in the evaluation of the viability of enhanced recovery projects.

Fluid Saturation Analysis

Pore Fluid Saturation data is determined by Dean Stark Toluene extraction. Followed by further extraction with additional solvents to remove any residual hydrocarbon and salts. It is vital that all water, salts, and hydrocarbons be removed from the samples in order to prevent suppression of the porosity and permeability measurements.


  • Characterize the reservoir

  • Improves accuracy of log derived fluid saturation data

  • Identify different zones within cored intervals

  • Helps identify ROZ

  • Helps identify water contacts

  • Improves fluid saturation adjustments when using a mud tracer to identify drilling fluid invasion

Full Diameter Dean Stark

Weatherford Laboratories' technicians monitor the Dean Stark apparatus during all phases of the extraction process to ensure that the data is properly recorded, whether full diameter or plug. Data derived from the Dean Stark extraction is utilized in fluid saturation calculations. Oil density and water salinity values are provided by the client and used to adjust the saturations to the actual reservoir fluid properties. With the use of a mud tracer, the fluids can be further adjusted for drilling fluid invasion. These adjustments allow for a more accurate representation of the fluid saturations present in the reservoir.

As one of the most critical measurements made on your core, Dean Stark fluid saturations play an essential role in evaluating the reservoir and identifying completion zones.