Research on the Definition of Economic Limits for the Development of Unconventional Natural Gas under New Situations

Table 1

PPIs of oil and natural gas exploitation industries in supply markets of three unconventional natural gases in recent 10 years (last year = 100) (The oil and natural gas producer price indexes (O&GPPI) come from Chongqing Statistical Yearbook, Sichuan Statistical Yearbook, Shanxi Statistical Yearbook, and China Statistical Yearbook in recent 10 years; the PPI of China in 2018 only includes data of the first 9 months. The PPI data by province is not available, so it is calculated according to the national PPI changes by proportion).

Category	Market	2009	2010	2011	2012	2013	2014	2015	2016	2017	2018	Mean
CBM	Shanxi	100.7	100.3	106.5	100.3	100.9	103.8	99.4	90.7	110.3	98.5	101.14
Shale gas	Sichuan and Chongqing	99.96	104.94	104.63	100.08	101.41	100.89	94.77	89.53	100.19	98.6	99.5
Tight gas	China	66	137.8	124.5	99.6	96.5	96.6	62.7	83.6	129	98.2	99.45