Review on the inorganic geochemical methods of paleo-fluid study

The study of paleo-fluid activity related to hydrocarbon accumulation helps us profoundly understand the oil and gas accumulation process. It has important significance on evaluating reservoir quality and analyzing paleo-fluid activity at different stages in oil and gas accumulation process for economic objectives. At present, petroleum geologists at home and abroad mainly apply inorganic geochemical methods (isotope geochemistry, element geochemistry and fluid inclusion analysis) to analyze paleo-fluid activity characteristics and its influences on hydrocarbon accumulation. On the basis of analyzing the previous research achievements, this paper summarizes the latest research progresses of inorganic geochemical methods. And these following conclusions are found: isotope geochemistry method is suitable for analyzing the paleo-fluid source and causes of formation; element geochemical method is beneficial to trace the migration of hydrocarbon fluid; fluid inclusion analysis technique combined with petrography is helpful to analyze migration time, stages, phase, pathway and accumulation regularity of oil and gas, which can also indicate the favorable direction of migration and accumulation. Using inorganic geochemical methods to analyze paleo-fluid activity should not be limited to a single method. Comprehensive utilization of a variety of inorganic geochemistry methods will be more beneficial to the comprehensive analysis of paleo-fluid activity.