Distribution and Controlling Factors of Tight Oil in Deep Continental Fault Lacustrine Basin in East China- A Case Study on Nanpu Depression in Bohaiwan Basin
Jiang, Hua; Hu, Suyun; Wang, Zecheng; Wang, Ruiju; Wang, Tongshan; Zheng, Hongju
Unconventional tight oil reservoirs, as a new kind of potential resources in deep continental fault lacustrine basin, have given a very attractive show in East China. However, it is a difficult problem how to evaluate tight oil resource of the lacustrine basin, because they were great different with many founded unconventional tight oil reservoirs in marine basin. Take Nanpu depression of Bohaiwan basin as a case, we researched distribution and controlling factors of tight oil in deep continental fault lacustrine basin in East China.
There are three advantages for tight oil resources
in deep continental fault lacustrine basin: firstly,There are many sets of
high-quality source rocks, such as Es1,Es34,in which abundance of organic matter
are high, furthermore, in oil-producing stage. And It was best source rock in
which TOC>1.0 and 0.8<Ro<1.25;secondly,There are favorable depositional facies
for tight oil in deep basin. Deep lake facies are main facies, there are made of
thick mudstone, delta front sand bodies and gravity flow deposited sand bodies,
thin or knoll-like sands are interstratificated with mud and near resource rock.
There are also three features for tight oil resources in deep continental fault lacustrine basin: firstly,distribution of tight oil in fault basin is limit and areas are also relatively small, for basins are divided into many sub basins by faults in lateral direction.secondly,Depth of tight oil reservoirs are larger than 4000m, shallow reservoirs are usually conventional reservoirs, so it is a question how to exploit them.thirdly,Vertical distribution of tight oil reservoirs are controlled by two overpressure belts, which are respectively Ed2-Es1(pressure coefficient in-between 1.2 and 1.4) and Es2- Es3(pressure coefficient in-between 1.3 and 1.7).
AAPG Search and Discovery Article #90163©2013AAPG 2013 Annual Convention and Exhibition, Pittsburgh, Pennsylvania, May 19-22, 2013