The contamination characteristics of oil polluted soils were analyzed by investigating and sampling in different oilfields of China

and its relationship with the physicochemical properties was investigated in detail in this research. Oil contents and component analysis indicated that the soils in oilfields of China were polluted by petroleum universally

with the highest oil content reaching 23%

which was 500—1000 times as much as the background value of oil in unpolluted samples. The light components

including alkanes and aromatic compounds accounted for more than 50% of the total hydrocarbon

and were readily degraded by bacteria and improved the degrading microbe activities than the heavy oil components. The water contents of soils in oilfields decreased to below 5% mostly when oil contents were higher than 8%

which indicated that the water contents were restricted by crude oil in contaminated soils in different oilfields. The organic matter contents of soils were in positive correlation with oil contents

there fore the organic matter contents increased to above 10% when oil contents were higher than 7%. The major soil texture of the investigated oilfields was fine doras and sandy clay (65% of the total soil samples)

which could provide suitable soil condition for the bioremediation of oil contaminated soils in oilfields of China.