Method for Automated, Real-Time Drilling Fluid Rheological Parameter Determination Using Downhole Sensor Data

Physical Sciences : Petroleum

Available for non-exclusive licensing


  • Eric van Oort , Petroleum and Geosystems Engineering
  • Ali Karimi Vajargah , PGE
  • Besmir Hoxha , PGE

Background/unmet need

One of the most critical metrics affecting safety and performance of any drilling operation is the rheological properties of the drilling fluid. Density (mud weight) and viscosity of the drilling mud are continuously monitored for compliance with design specifications determined by the expected down hole conditions.

Currently, the rheology determination is carried out with simplistic equipment at
standard temperature and pressure at the surface. These measurements, therefore, do not properly reflect the actual well conditions experienced by the fluid within the wellbore and conditions thousands of feet below the surface. Additionally, due to the long run lengths of most well bores, circulation of the fluid to the surface for sampling means measurements are not performed in real time and are conducted depending on the availability of the mud engineer.

Inaccurate measurement of the rheological properties can lead to costly lost circulation events and potentially catastrophic kicks resulting in blow out.

Invention Description

Researchers at The University of Texas at Austin have developed a novel method to determine important mud rheological parameters using data obtained from downhole drillstring sensors (pressure and temperature). In this method the well itself is used as the equivalent of a pipe viscometer, with pressure measurements conducted along its length using sensors placed at strategic positions in the drill string. The rheology determination is performed at actual downhole pressure and temperature in real time.


  • Real-time measurements of drilling fluid rheological properties under downhole conditions
  • Improved hydraulic planning to maintain the optimal mud weight window and eliminate non-productive time
  • Precise prediction of the annular pressure profile in Managed Pressure Drilling (MPD)
  • Precise prediction of Equivalent Circulating Density (ECD), particularly in deep offshore wells with narrow mud windows


  • The present invention eliminates the need for surface equipment entirely and therefore the need for the associated human interaction.
  • The present invention lends itself inherently to automation, and specifically to automation through algorithm manipulation of sensor data.

Market potential/applications

Operating companies in oil and gas.
Oil and gas service companies (e.g., National Oilwell, Varco, Baker Hughes)

Development Stage

Proof of concept

IP Status

  • 2 foreign patents application filed
  • 1 U.S. patent application filed
  • 1 U.S. patent issued: 9,909,413