Abstract
High inclination and horizontal 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. Adequate displacement during the cementing operation is important to ensure annular barrier integrity and zonal isolation of wells. Since all wells must be permanently plugged before abandonment, annular barriers should be made 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, both for cementing and other fluid displacement operations such as casing cleaning
Results from laboratory experiments in a 10 meters long test section using water-based model fluids at horizontal and highly deviated angles are presented. The wellbore and casing are represented by 6.5" ID and 5" OD transparent pipes, respectively.
Water and viscosified water, respectively, were displaced by a potassium formate brine (1.3 – 1.4 sg) at low and high flow rates, without and with string rotation and with concentric and partially eccentric inner pipe (casing). The displacement was monitored using conductivity probes and video camera recordings. The results show that the density difference between the displaced and displacing fluid totally dominates the displacement process. Thus, neither inclination, string rotation, eccentricity or wellbore inclination were found to have significant impact on the displacement process.
Results from laboratory experiments in a 10 meters long test section using water-based model fluids at horizontal and highly deviated angles are presented. The wellbore and casing are represented by 6.5" ID and 5" OD transparent pipes, respectively.
Water and viscosified water, respectively, were displaced by a potassium formate brine (1.3 – 1.4 sg) at low and high flow rates, without and with string rotation and with concentric and partially eccentric inner pipe (casing). The displacement was monitored using conductivity probes and video camera recordings. The results show that the density difference between the displaced and displacing fluid totally dominates the displacement process. Thus, neither inclination, string rotation, eccentricity or wellbore inclination were found to have significant impact on the displacement process.