User of laser technology for the treatment of asphaltene deposition in carbonate formations

Crude oils produced in many parts of the world contain asphaltenes. Asphaltenes plugging is a well-known cause of near-wellbore formation damage. The deposition phenomenon of asphaltene is mainly due to thermodynamic changes. Asphaltene deposition leads to production loss and requires expensive and in many times environmentally unfriendly corrective measures. This project proposes a novel technique for cleaning asphaltenes with laser energy. Laboratory laser diode modules were used to perform experiments. A two-inch column of bitumen/powdered limestone mixture was placed on top of a powdered limestone column in a flow cell, and the flow rates were measured before and after the laser treatment. The rate was correlated with permeability of this powdered limestone column in absence of bitumen. In a second series of experiments, actual consolidated limestone cores were subjected to flow of asphaltenic crude oil to simulate the damage process (i.e. permeability reduction). The damaged cores were subjected to laser treatments at various laser intensity and treatment time intervals. Experimental results indicated that asphaltene get disrupted after exposure to laser energy. However, the maximum amount of cleaning was noticed after an exposure of one hour and at higher laser intensity. The increased flow rate measured employing the powdered limestone column after treatment can be used in an oil field to disrupt, or desegregate asphaltene from the vicinity of oil production wells. However, the simultaneous pumping is required during the laser treatment to avoid the reprecipitation of the disrupted asphaltene. The laser cleaning technique appears to be disrupting the maltenes that form a continuous phase providing adhesive and ductile properties to the dispersed asphaltene. The proposed technique provides environmental friendly process and advanced technological breakthrough for treating asphaltene deposition in the petroleum industry.