Are you interested in cooking and trying new recipes? Then working with cement can be also an interesting subject for you. Working with cement and preparing a good cement slurry is like cooking food, but not for the family, this is going to be eaten by the drilled well under ground. This is the oil well’s dish for building a robust barrier for the life of the well.
Well cementing and the problems
In the oil and gas industry, after a hole is drilled to a pre-set depth, a large steel pipe, so-called casing, will be placed into the hole followed with the process of placing cement slurry in the space between the casing and the surrounding rock. The cement slurry will harden providing a strong, tight barrier to keep away the fluids in the surrounding rocks from entering the well and migrating to the other zones. Under induced loads in the well, this cementitious barrier might lose its properties due to cracks formed within its structure and debonding from the rock or casing. This will result in production capacity reduction, costly repair operations, environmental problems and in worst-case loss of the well. Therefore, this weakened barrier needs to be healed through repair operations. Sometimes this process might be too difficult or so expensive that the operators decide to plug and abandon the well. In order to prevent extra cost of repairing, or in the worst case well abandonment, modified recipes are needed to make a cement feed for the whole life of the well in the first step.
New materials/technologies could be a promising solution
Different additives can be used in cement slurry to adjust its properties according to the well’s condition. These additives play the role of spices and flavors to create desired properties, ‘taste’, for the cement slurry. There have been numerous advances in materials industry such as nanomaterials, polymeric materials and smart materials/techniques. These advancements can be applied in cement industry to solve problems encountered in oil and gas well cementing. However, in the case of nanomaterials, their high-cost might make the oil and gas companies reluctant in applying them in well construction. Therefore, mass production of nanomaterials at lower cost is crucial for growth of their application in well cementing. Development of new optimal production methods could be the solution for cost reduction, which facilitate the application of nanomaterials in well construction.
Application of nanomaterials in oil well cement systems can be a promising technique in providing an engineered cement sheath for the whole life of the well. Developments in designing smart systems can be the future direction for a life-lasting cement sheath with capability of self-repairing and self-sensing.