Influences Of Salt Rocks To Produce Hydrocarbon, North Central Of Ordos Basin

It is reported that about more than 40% oil-natural gas fields are relative with the salt rocks in the world. Some of the slat rocks are important reservoirs or migrations, and some of them are the mostly source rocks. It is explicit to show the intrinsic relationship between the salt rocks and the oil-natural gas.There are lots of energy resources in Ordos Basin such as uranium, natural gas, oil and coal, and it is called"Cornucopia"of west. The research area is located in Mizhi area , and there are several layers good salt rocks sediments on top of Ordovician.To study the relationship between the salt rocks and formation of the hydrocarbon, the samples are taken from the profile of salt rocks area in the north and middle part of Ordos Basin and the comparison samples are from the north. Based on the experiments of GC (gas chromatogram), MS (mass spectrum) and trace element, the author discusses the organic characteristic, biomarker and mineralization model. To study the influence of the salt rocks on the forepart hydrocarbon generation by organic, the simulative experiment is carried in laboratory. The formation mechanism of low maturity oil and immaturity oil and the influence of the salt on them are discussed. Further, some evidences on the effect of the trace element and some parameter are also given in this paper. Some conclusions are made such as:Based on the analysis about the GC of ARO (aromatic hydrocarbon), it can find that the contents of some long chain ALK (saturated hydrocarbon) decrease from Triassic and Permian to Carboniferous. The long chain ALK disappears in some samples of carboniferous, but there are still the long chain AIK in the samples of Ordovician. It shows that the high salty condition has the effect of choice on life. Furthermore, the odd carbon takes extremely little advantages in some high-carbon-samples of Ordovician because of some bacterium in the salt rocks.The GC of ARO shows that the contents of Na-PAH increase towards the bottom section of the profile. It accords with the maturation. But some differences appear in the samples of the Ordovician, it may because high salinity may have the effect of anti-catalysis on the hydrocarbons pyrogenation.Some biomarkers likeβ-carotane and MTTC appear in MS. Most of the Pr/Ph >1, it indicates that the high salinity and the strong deoxidize setting exists in some stratum. It indicates that the salt rocks have the effect of catalysis on the hydrocarbon generation by low plants in the simulative experiment.In the aspects of trace elements, the ratio between uranium and thorium of is obviously below 4.2 in Ordovician and Carboniferous, and that of Permian and Triassic is mostly above it. The author concludes that Ordovician and Carboniferous is the strong deoxidize with dissipation of uranium; the mutation of Permian and Triassic indicates that the oxygenation liquid ever flowed through the study area.