Session: 11-05-02 Well Cementing Theory & Practice-2

Paper Number: 79937

79937 - Experimental Investigation of Flow Velocity Dispersion in Annuli 

Deviated well sections are common in modern well construction. In mature areas like the North Sea region, practically all producers or injector wells will have highly deviated sections. These wells must be completed in an optimal manner including annular barrier integrity. This is important for zonal isolation through all stages of the well's life cycle. Since all wells must be permanently plugged before abandonment it is important to ensure that annular barriers are designed with a long term perspective and not only to minimize construction time and cost. Controlled laboratory environments with various fluid compositions and flow parameters are important to develop, validate and improve models and practices. Laboratory testing may often require significant simplifications to fit available resources, premises etc. and will not always be optimally designed to match relevant practical operations. Cement displacement is the objective for many such studies, while due to selection of fluids, in reality casing cleaning operations are investigated.

This paper presents results from laboratory studies with geometries that permits comparison with field operations. Fundamental flow properties are investigated so that effect of critical parameters in laboratory conditions are identified. Water with and without viscosifiers are used to displace similar fluids from the annular section. The effects of inner string rotation are included. It is shown how this give fundamental data providing a relevant background for understanding cement displacement. Still, the results are even more relevant for casing cleaning operations where the results can be more directly applied.

The experiments have been performed in a flow loop that consists of a 10 meters long test section with 5" OD transparent pipe inside a 6,5" transparent pipe. The inner pipe can rotate and eccentricity/stand-off can be adjusted. Experiments were performed at different test section inclinations. The applied flow loop dimensions are designed so that the results should be relevant for highly inclined sections in field operation.

Presenting Author: Bjørnar Lund SINTEF

Authors:

Jan David Ytrehus SINTEF Petroleum
Bjørnar Lund SINTEF
Ali Taghipour SINTEF
Arild Saasen University of Stavanger