Accumulation and Diffusion Gas Rate Characteristics for the Formation of  Large and Medium Gas Fields with Different Reserves Abundance in China

Key words: 
• reserves abundance /
• large and medium gas fields /
• gas diffusion rate /
• gas accumulation rate

Abstract: By the calculation of gas diffusion amount of 41 large and medium gas fields in china and statistics of their geological reserves, gasbearing area and formation period, gas diffusion rate, gas accumulation rate and the ratio of gas accumulation and diffusion rate were studied. It was considered that gas diffusion rate of 41 large and medium gas fields in China 0.2×106  m3/km2Ma to 49.5×106  m3/km2Ma, average 7.2×106  m3/km2Ma. Gas accumulation rate is 2.1×106  m3/km2Ma to 528.1×106  m3/km2Ma, average 79.4×106 m3/km2Ma. The ratio of gas accumulation and diffusion rate is 1.5 to 94.2, average 14.5. By the study of the relation between reserves abundance and ratio of gas accumulation and diffusion rate of 41 large and medium gas fields in China, it was considered that they have proportional relation. The greater the ratio of gas accumulation and diffusion rate is, the greater the reserves abundance of large and medium gas fields is, conversely the lower. The ratio of gas accumulation and diffusion rate for the formation of large and medium gas fields with high reserves abundance should be at least greater than 4.1. The ratio of gas accumulation and diffusion rate for the formation of large and medium gas fields with medium reserves abundance should be at least between 4.1 and 2.3. The ratio of gas accumulation and diffusion rate for the formation of large and medium gas fields with low reserves abundance should be at least lower than 2.3.