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MRF Magnetic Resonance Fluid Characterization Method

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Improve reserve estimates with advanced NMR fluid characterization

The patented MRF magnetic resonance fluid characterization method lets you directly identify and analyze hydrocarbons. MRF characterization reliably extracts the oil and water signals from nuclear magnetic resonance (NMR) data by integrating downhole data acquisition and wellsite inversion with a multifluid response model to determine

  • fluid saturations
  • fluid volumes
  • oil viscosities.

The MRF method directly detects hydrocarbons in

  • fresh, unknown, or varying formation water resistivities—where Archie resistivity analysis is difficult
  • low-resistivity, low-contrast pay and thin beds.

The MRF method also remedies incorrect permeability calculations caused by hydrocarbon effects.

Resistivity and lithology independent

From NMR measurements obtained with MR Scanner expert magnetic resonance service or any of the CMR combinable magnetic resonance tools, analysis by the MRF method extracts lithology-independent formation porosity and separate T2 distributions for brine and oil. Hydrocarbon-corrected bound-water volume and permeability are computed from the T2 distributions. This is a vital real-time analysis for completion decisions.

Constituent viscosity model

The engine of the MRF method is the constituent viscosity model (CVM), which is based on fundamental physics and has been empirically validated for both live and dead crude oils. The CVM properly accounts for the broad diffusivity and T2 spectra of bulk crude oils. Individual T2 distributions are separated out to compute water, gas, and oil volumes, along with oil viscosity and hydrocarbon-corrected bound-fluid volume.

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Wellsite NMR Fluid Volumes, Saturations, and Viscosities

Figure 1. Example of real-time MRF analysis performed at the wellsite. The direct, user-friendly analysis provides a comprehensive formation evaluation of the near-wellbore region and includes quality control indicators.Figure 2. Small or light-end member molecules move quickly; heavier long-chain molecules move more slowly. Hydrocarbon molecule relaxation rates and diffusion coefficients are related to the molecule size. With their wide range of molecular sizes, crude oils have a broad distribution of nuclear magnetic resonance (NMR) relaxation times and molecular diffusion coefficients. The Constituent Viscosity Model (CVM) relates molecular diffusivity and T2 relaxation of the individual components to bulk viscosity.
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