Effect of mud properties in subsalt drilling

Nikhil G Barshettiwar, MIT Pune

Large oil and gas reservoirs are associated with salt structures. In Gulf of Mexico USA, Brazil and

West Africa also known as golden triangle, vast exploration has taken place since past 20 years

in this field. Today subsalt contributes more than 28 % of oil and gas production for Brazil.

Drilling in subsalt reservoirs has complete set of new challenges in front of E&P industry.

Industry needs multidisciplinary approach to resolve this hurdle.

This paper discusses about the effect of mud properties in subsalt drilling. Best suitable mud

needs to designed in order to overcome the set of hole problems. The most known fact about

subsalt is wellbore closure. Since salt sheets inside the earth acts like viscoplastic fluid, it tries to

encroach in wellbore and eventually closure of hole. In order to combat with wellbore closure,

one needs to maintain mud properties which include suitable mud weight, temperature and its

chemical composition. All the aspects related to mud design and effect of its properties

mentioned in this paper.