Dongting Basin

covering an area of 1.5×10

4

km

2

is a Meso-Cenozoic fault-depressedbasin developed on the basement of the Proterozoic.It subsided several times and received 100～334 m thick Quaternary sediments under the influence of neotectonic movement. Biogasshowing could be seen very often. The accumulation of the biogas is primarily controlled bygas source and reservoir conditions. The organic-rich dark sediments are good source beds;sand beds and gravel beds are major places for biogas accumulation

the clay and sand claybeds of the upper part of the Proterozoic are fine regional cap beds.It is suggested thatXiaojiawan-Yazigang and Sanxianhu-Chapanzhou regions are favourable for Quaternary biogas exploration of the basin.