Introduction to Geological Sequestration - Introduction to Carbon Capture and Sequestration - page 373

In Salah
The In Salah Gas Project (see Figure 8.4.2 ) is located in the central
Saharan region of Algeria. The natural gas in surrounding gas fi elds
contains up to 10% CO 2 , which is removed through absorption with
amines, the technology discussed in Chapter 5. This is required for
natural gas to meet commercial specifi cations. The unique aspect of
this project is that the CO 2 was re-injected into long horizontal wells at
a depth of 1,800 m, and annually up to 1.2 Mt CO 2 was stored. Carbon
dioxide injection started in April 2004. An abundance of caution and
lack of CCS incentive led to the cessation of CO 2 injection for the pro-
ject in 2011.
Natural gas reservoirs may contain as much as 60-70% CO 2 .
Extracting methane from these fi elds without re-injecting the CO 2 would
make these fi elds signifi cant greenhouse gas emitters. As we have seen
for carbon capture, the equipment for these gas separations can be very
large. This poses few problems for gas fi elds in the Sahara, but is very
diffi cult to implement for off-shore production. Therefore, fi nding tech-
nologies that can do the separation using far less space presents a very
interesting research topic.
Figure 8.4.2 In Salah storage project
Figure from IPCC [8.7], reproduced with permission.