Abstract
The precipitation or block of asphalts, asphaltene and other or-ganics in the porous media near the wellbole will reduce per-meability due to change in temperature, pressure and compo-sitions of reservoir oil. Injection of organic aromatic solvents and soaking is one feasible method to remove the precipitates. The objects of this paper are to confect economical and efficient solvents and optimize injected rate, volume and soak time of solvent. To obtain the objects, core flooding experiments by solvents are conducted to select optimum solvents and a simulator to remove the formation damages caused by organic deposition by soaking of aromatic solvents is developed. The influences of different injected rates, volume and soak time of solvent are simulated to improve the permeability of the damaged region. And the permeability is also predicted after soak. A project to remove organic formation damage near the wellbole by injection aromatic solvents started Nov, 1998 at an offshore oil field in China. And the production of the first well increased from 90t/d to 270t/d after injection solvent U-01 selected by core flooding experiments. The simulated results coincide well with the data from the oilfield.
