Method for judging natural gas genesis

The invention discloses a method for judging natural gas genesis, and belongs to the field of oil-gas exploration. The method comprises the steps of: acquiring a crude oil sample, and obtaining carbonisotope data of the hydrocarbon composition before C H in the crude oil sample; acquiring a natural gas sample, and obtaining the carbon isotope data of the hydrocarbon composition after C H in the natural gas sample; comparing the carbon isotope data corresponding to the natural gas sample with the carbon isotope data corresponding to the crude oil sample; and, if the difference value of the carbon isotope data corresponding to the natural gas sample and the carbon isotope data corresponding to the crude oil sample is less than or equal to five parts per thousand, determining that the natural gas sample and the crude oil sample have the genetic relationship. According to the method in the invention, due to comparison of carbon isotope data in crude oil and natural gas, the genetic relationship between the crude