Improving the Viscoelastic Properties of Cement for Oil and Gas Well Cementing Operations.

摘要

The importance of cement integrity in the downhole well cannot be over looked. Cement designed for a particular well may not work for another well. As a result, there is a need to design well cement based on appropriate well conditions in order to achieve good integrity during the life time of the well. This research focused on micro-annulus and crack problems associated with downhole well cements. Waste tires have contributed to environmental problems.;Waste tires can be crushed into small particles and used for construction purposes. This is seen as a promising avenue to get rid of the waste tires. This research focused on the possibility of adding tire rubber particles to well cement to reduce the effect of micro-annuli and cracks in well cement. Tire rubber particles of 4 different sizes were used in this research, which was then divided into two parts. The first part dealt with rheology and compressive strength of concretes. These parameters were used to select cement designs with optimum value for subsequent tests. The other part included permeability and creep tests. Permeability measured the amount of water the concrete materials could yield while the creep test measured strain developed when concrete specimen was subjected to a constant stress for 30 minutes and the amount of strain recovered when the concrete specimen was unloaded for another 30 minutes. Creep compliance was done to measure the rate at which strain was developing, which is a function of time under constant stress.;Concrete containing the largest rubber particle size had good amount of strain recovery after unloading while concrete samples containing the smallest rubber particle size had the lowest amount of strain recovery.