Element Balance Method and Application of Appraising Biogenic GasLow Maturity Gas in Tuha Basin

Key words: 
• biogenic gas /
• low maturity gas /
• gasgenerated quantity /
• element balance method

Abstract: The proved reserves of nonhigh temperatureoriginated natural gas (biogenic gaslow maturity gas)in Tuha basin is already near 100×109 m3, but we didn’t sees the reported about appraises to the effective method of generation quantity and resource quantum yet, this has affected the decisionmaking to its exploration potential and the favorable target. In view of this problem, considering regardless the generation mechanism of biogenic gas and low maturity gas, they were an organic element balance process; this article explored and established element balance method to appraise the gasgenerated amount of biogenic gas and low maturity gas.We use massive actual analysis data of Tuha basin to demarcate and apply this assessment method. The result indicated that biogenic gaslow maturity gas generation rate of ⅡOM is higher than III OM in Tuha basin, the two accumulate separately may reach 134.40ml/g and 83.99ml/g, total generation quantity of biogenic gaslow maturity gas in Tuha basin approximately 1436.28×1012m3; The resource quantum is possibly situated between 7.09×1011m3~24.42×1011m3 it indicated that nonhigh temperature originated natural gas in the Tuha basin has big exploration potential. J2x and J1 and the nearby position in Taibei hollow are the favorable exploration target.