Environmental Engineering Reference
In-Depth Information
policy encourages private investment in the construction of new gas
pipelines and infrastructure. Government also issued the mandatory
requirement of ''non-discriminatory infrastructure access'' to pipe-
lines. CNPC said it had started building the country's first shale gas
pipeline at Changning in the Sichuan Basin and the pipeline in China
will be extended to 150 000 km by 2020 (four times longer than its
current length). This will help the delivery of shale gas in the future.
(5) To ensure environmental protection.
At the current time, an environmental assessment must be done
when a shale gas well is planned and the drilling, hydraulic fracturing,
waste disposal and emissions must meet environmental requirements.
During hydraulic fracturing, the cementing process is monitored to
ensure the integrity of the wellbore and prevent formation fluids from
contaminating the shallow aquifer zone. After the treatment job, the
drilling mud and fracturing fluids are required to be recycled.
7 Challenges for Shale Gas Development in China
China is looking forward to replicate the shale gas boom in the US and the
outlook for the development and extraction of shale gas in China seems
favorable. However, China still faces many formidable challenges related to
geology, ground conditions, policies, technology, finance, water supply, in-
frastructure, etc. Generally speaking, there exist at least the following five
major challenging categories:
7.1 Complex Geology
So far, both academia and industry lack fundamental understanding about
China's shale geology, stress field (i.e. a region in a body for which the stress
is defined at every point), and the technology suitable for Chinese shale
fracturing and production.
The complex geologic and tectonic setting and different geomechanical
regime in China's basins challenges many international companies with
successful US shale experience attempting to fracture shales in China. Despite
the rich reserves, the Chinese marine gas shale is either buried deeper than
3000 metres (over 5000 metres in West Sichuan Basin and the Tarim Basin) or
faulted and folded or outcropped. The lacustrine shale is clay-rich and has
rapid property change spatially. Historically, little shale geology data has been
available and there has been little exploration activity. So basic geological
elements are not yet well understood and it is dicult to locate the best plays.
US shale-gas producing basins have relatively simpler geological and tectonic
settings than those in China. The Chinese shales have more complex geologic
settings than US shales in terms of depositional and tectonic settings and
geological history. The promising marine shale in China is similar to the
brittle Barnett shale in the US with regard to its mineralogy and gas content;
the complex tectonic setting, much more complex diagenetic history and
