Abstract: In this paper, the essential ideas and condition factors on economical value of onshore natural gas fields in China are analyzed preliminarily, and then the interrelated geological factors are discussed. Conclusions are deduced as follows. Firstly, the depth of reservoir and the sand parameters of natural gas fields have direct correlation with development investment. Secondly, geographical elements and corresponding material parameters of natural gas deposits exert greater effect on production cost. Thirdly, reservoir abundance, efficiency thickness, reservoir porosity, permeability, and types of onshore natural gas field have greater impact on gas production. On the basis of production per km-well per day, the economic production factor-weighed and computing formula of onshore natural gas fields in different capital, cost and price is approached, then the economic estimation criteria in different onshore natural gas fields are formulated, and some examples of typical onshore natural gas fields in China are analyzed, including the Sebei-1 gas field, the Changqing gas field, the Kela-2 gas field, the Hetianhe gas field, the Wubaiti gas field, the Wen-23 gas field and the Qianmiqiao gas field.

Key words: onshore China, natural gas field, geological factor, economic effect, weighed factor