The
big success in marine shale gas exploration and production
made China the third country worldwide to commercialize shale gas
development. However, the Upper Ordovician Wufeng Formation and the
Lower Silurian Longmaxi Formation in and around the Sichuan Basin
are currently the only targets that have realized shale gas industrial
development. Great challenges are emerging since tremendous shale
gas resources of marine facies, continental facies, and transitional
facies that are trapped in new areas and multiple other formations
are yet to be successfully developed. Thus, we find it a great necessity
to provide suggestions on shale gas exploration and development in
China, which hopefully can be helpful for global shale gas exploitation.
To meet this goal, this work provides a critical review on the history
and current status of China’s shale gas exploration and development
and summarizes key practical experiences. In the light of characteristic
analysis of typical industrial gas fields and wells, research status,
problems and challenges, along with suggestions on pivotal scientific
issues are addressed including the development of organic-rich shales,
reservoir types and characteristics, shale gas content, and the main
controlling factors on shale gas enrichment. Further, future directions
of shale gas exploration and development are nailed down, incorporating
three levels: areas to improve development technology, areas to seek
exploration breakthrough, and areas to conduct preliminary studies.
The normal-pressure and deep shale gas retained in the Wufeng and
Longmaxi Formations in and around the Sichuan Basin are the first
level, which are the most realistic resources that can be commercially
developed. For the normal-pressure shale gas, detailed research on
the sweet spot selection, drilling–encounter ratio enhancement,
and cost minimization by advanced technologies are most imperative;
for the deep shale gas, state-of-the-art technology to maximize the
stimulated reservoir volume of lateral wells is the key. Gas resources
in other shale formations in the Sichuan Basin and its periphery such
as the Cambrian marine shales, Permian transitional shales, and Jurassic
continental shales are the second level, which have the greatest prospective
to claim exploration breakthroughs, while shale gas resources in other
basins or regions still demand grand scientific and technological
tasks for exploration and development preparation. All in all, as
a country with diverse shale gas types and such intricate geological
and surface conditions, the summary of China’s shale gas exploration
and development practices is of vital significance that will not only
shed light on China’s shale gas development directions but
also provide references for the shale gas industry in other countries
and regions.
