Controlling Effects of Overall Basin Uplift on Tight Sand Gas Resources - Case Study of Xujiahe Formation in the Sichuan Basin and Upper Paleozoic in the Ordos Basin.pdf

SPE 168721 / URTeC 1577339

Controlling Effects of Overall Basin Uplift on Tight Sand Gas Resources —
Case Study of Xujiahe Formation in the Sichuan Basin and Upper
Paleozoic in the Ordos Basin
Congsheng Bian1*,Wenzhi Zhao 2 ,Hongjun Wang1,Zhaohui Xu1
Institute of Petroleum Exploration & Development, Petrochina; 2.
Petrochina Exploration & pany, Petrochina

Summary
Tight sand gas, as a kind of important unconventional gas resources, distributes extensively in different
petroliferous basins in China. In 2010 the annual tight sand gas yield in China went beyond 23 billion cubic
meters, nearly one quarter of which came from tight sandstone of the Triassic System in the Sichuan Basin and
the Carboniferous and Permian System in the Ordos Basin. Tight sandstone and coal measures have formed gas-
bearing assemblage in large scale in these two basins, which is a prerequisite to tight sand gas generation and
accumulation. Similar to most shale gas basins in North America, the Sichuan Basin and Ordos Basin all
experienced overall uplift in the Mesozoic and Cenozoic Era and a certain extent stratigraphic erosion after deep
burial process, which promoted the formation of tight sand gas resources.
According to adsorption principles and simulation experiments, pressure drop and desorption may occur in coal
measures during formation uplift; a gre