0 - 2000m fluid profiles and sources in Chinese Continental Scientific Drilling Project
中国大陆科学钻探主孔0～2000米流体剖面及流体地球化学研究

The fluid samples from the Chinese Continental Scientific Drilling ( CCSD) project were analyzed in the on-site laboratory. Mud from the hole was degassed and determined by an on-line procedure. The experiments were conducted on identification of the fluids from the drilling hole studied. The profiles of gases in CCSD were provided and the origins of them discussed. The on-site geochemical measurements indicate there is no significant correlation between CH4 concentration and H2 concentration, so is the correlation between CO2 and O2. There are positive and negative correlations between CO2 and CH4. In some cases, no such correlation can be found. One of the interesting cases is the presence of positive correlation between He concentration and the elevated concentrations of CO2 and CH4. The concentration of N2 is negatively correlated with the concentration of O2, which is similar to the correlation in KTB, but the positive correlation. As the high concentrations of N2, O2, Ar in the air conceal possible change of them from the hole, the gas components are difficult to be used as the criterion of identification of the deep fluids. The rather high concentration of CO2 and the low concentrations of CO, CH4 , C2H6 , C3HS, C4H10 , He and N2 have been found in the hole from 300 to 2000 meters. Some of them have been identified to be from the deep earth, which are primarily CH4, CO2 and He. Where the fluids are identified from the deep earth, crannies, crystal holes, fracture or fault faces can always be visible in the corresponding rock cores. The crannies, crystal holes, fracture or fault faces may be the paths of transference and the spaces of reservation of fluids under the earth and be considered as a necessary condition for keeping and finding fluids.