Distribution and origin of underground water chemical fields in Songliao continental oil-bearing sedimentary basin

摘要

There are many factors affecting underground water chemistry of an oil-bearing sedi- mentary basin. The properties of underground water show variations in the vertical direction, giving rise to a vertical zonation with respect to underground water chemistry. Five zones could be divided downwards, including 1)the freshening zone due to meteoric water leaching(A); (2)the evaporation-concentration zone near the surface(B); 3)the freshening zone due to stra- tum compaction-released water(C_1)-infiltration-concentration zone during the mudstone com- paction and water releasing(C_2); 4)the freshening zone for clay mineral dehydration(D); and 5)the seepage-concentration zone (E).