The influence of drilling variables on barite sag
- and others
Barite sag is a significant variation in mud density caused by the settlement of barite or other weight material in high-angle wells. The wide fluctuations in mud weight can lead to severe operational problems, including well-control, induced wellbore instability, downhole mud losses, and stuck pipe. A laboratory flow loop has been used to evaluate the influence of key drilling parameters on barite sag. Results show that the highest sag occurs at angles in the region 60-75{degrees}, particularly at low annular velocities. Drillpipe rotation is shown to be particularly beneficial in minimizing barite settlement. Rotation also assists in re-distributing barite deposits formed on the low side of the hole. Data from the tests clearly demonstrate the interdependence of drillpipe eccentricity, rotation, and mud flow rate. Results from the study have been combined with field observations to develop guidelines to minimize barite sag and manage the associated risks. The conclusions of the study are that barite sag can be minimized by attention to detail at the planning and execution stages of drilling a well. In particular, recommendations in four key areas are addressed: well planning, mud properties and testing, operational practices, and wellsite monitoring procedures.
- OSTI ID:
- 457353
- Report Number(s):
- CONF-961003-; TRN: 96:006576-0075
- Resource Relation:
- Conference: 71. annual technical conference and exhibition of the Society of Petroleum Engineers, Denver, CO (United States), 6-9 Oct 1996; Other Information: PBD: 1996; Related Information: Is Part Of 1996 SPE annual technical conference and exhibition: Drilling and completion; PB: 944 p.
- Country of Publication:
- United States
- Language:
- English
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