After the discovery of Brazilian pre-salt reservoirs, the partnership between PETROBRAS and the university gained a new scale, making possible the rising of new research areas. Besides the economic benefits of this discovery, the pre-salt also brought the challenge of exploring and producing in deeper waters, at 5,000 m below the sea level: under a water layer of over 2,000 m and trapped by huge layers of salt rocks of around 2,000 m thickness.
Drilling in Salt Rocks
When drilled, these rocks tend to close the well due to the creep phenomenon faster than in other materials in nature. Because of this, in the operational phase, these rocks produce problems related to well stability and coating integrity.
Computational Simulation of Wells
PETROBRAS has a long term tradition of using computational simulation in the study and design of wells drilling in salt layers. These simulations, aside from being complex, involve the study and definition of many parameters that describe the drilling scenario. Data processing and the interpretation of the results are also computational demanding. The numerical simulation of the behavior of wells crossing large salt layers has been made by PETROBRAS using the simulator ANVEC (Costa, 1984), widely used by CENPES in several Geomechanics studies since 1984. The well modeling and the visualization of results are performed using the program Sigma2d, developed by Tecgraf/PUC-Rio, also a member of Rede Galileu. In order to speed up this process, LCCV has developed a supporting system which employs data supplied by PETROBRAS (obtained from several years of studies and research), computational modeling, laboratory tests and successful pre-salt well projects.