Casing and cementing with potential gas influx

Tóm tắt

It is well known that wells should be reinforced by running the casing and cementing the annulus to create a competent cement sheath that helps to prevent the caving of the bore-hole. Other than supporting the casing, cementing the annulus also provides zonal isolation. The presence and migration of gas into the well annulus have been known as a problem in hydrocarbon exploration when complete isolation has not been achieved. This report presents the general concept of gas migration in the well annulus and introduces some practical examples from experience of running casing and cementing in production and exploration wells in abnormally high pressure formations with substantial risks of gas migration in Vietsovpetro’s fields.