Session: 11-03-02 Well Control and Managed Pressure Drilling-2

Paper Number: 81450

81450 - Mitigation of Barite Sagging for Proper Well Control: Lab Investigation and Field Application 

For high-density fluids, achieving the right fluid formula with the right fluid rheology is difficult since excessive heat, dehydration, and solid loading can deteriorate mud properties. Addition of weighting materials such as barite or hematite is needed to achieve the desired density to overbalance the well and avoid any possible flow from the formation. However, maintaining high volume of solid content for barite particles (or any other material) in suspension might be challenging, especially for extended period. The separation of weighting material particles (usually barite) from the mud can lead to undesirable density fluctuation as drilling fluid is being circulated throughout the hole.  This phenomenon (often referred as barite sag) may lead to potential well control incidents and stuck pipes.

The objective of this study is to relate the importance of proper designs of drilling fluids and relate to potential well control incident. Different high solid content water based drilling fluids designs were evaluated for optimum results and minimum barite sagging.

The experimental work in this paper involved rheological properties, thermal stability, HT/HP filtration, and static sagging (vertical and deviated). This paper also describes field cases of wells with potential barite sagging for potential kick indicators in relation to the drilling fluids’ properties

To mitigate well control incidents, several factors must be considered when designing the drilling fluid. The equivalent circulating density (ECD) value has to be minimized by minimizing PV value especially with high-density fluids that require high solid loadings. The gel strength values have to be within acceptable range. If the gel strength value is too low, particles will not be suspended and sag will occur. One the other hand, high gel strength value will increase torque and drag and may lead to stuck pipe which can develop to potential well control incident. 

The paper will highlight field cases of proper maintainace program on fluid properties to mitigate any potential well control incidents and will recommend ideal fluids formulation properties when using high solid content water based fluids.  

Presenting Author: Vikrant Wagle Saudi ARAMCO

Authors:

Abdullah Al-Yami Saudi ARAMCO
Vikrant Wagle Saudi ARAMCO