Carbon Capture and Storage (CCS) in the light of Oil Industry

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“__It is a process in which waste CO2 is being captured at large point sources and then transported to the site where it will be sequestered in geologic formation__”

Purpose of CCS

1. The atmosphere will be protected from release of CO2 and Global Warming will be reduced

2. It can be used in EOR processes to increase oil recovery

Stages involved in CCS

It is a three step process:

1. Capturing: First CO2 is captured at the fossil fuel and industrial power plants

2. Transport: CO2 is transported via pipelines to the storage site

3. Sequestering:Then it is injected into declining oil fields to increase oil  recovery or it is stored in geologic formation

In above statement it is mentioned that gas is injected into the declining oil fields, now question arises that:

Why abandoned oil fields are candidates of Carbon Storage?

Answer to this question has several explanations:

1. Oil and gas that originally accumulated in traps did not escape for many millions of years, demonstrating their reliability and safety

2. Geological structure and physical properties of most oil and gas fields have been extensively studied and characterized

3. Computer models have been developed in the oil and gas industry to predict the movement, displacement behavior and trapping of HC

4. Some of the infrastructure and wells already in place may be used for handling CO2 storage operations

5. Depleted fields will not be adversely affected by CO2 and if hydrocarbon fields are still in production, a CO2 storage scheme can be optimized to enhance oil or gas production

It’s Application in Enhanced Oil Recovery

EOR through CO2 flooding offers potential economic gain from incremental oil production.

Driving Mechanism

Percentage Recovery References

Conventional Primary Production

05-40% of OGIP

Holt et al., 1995

Secondary Recovery

10-20% of OGIP

Bondor, 1992

CO2 used for Enhanced Oil Recovery 07-23% of OGIP

Martin & Taber, 1992; Moritis, 2003

How does it work?

Continuous CO2 injection or alternate water and CO2 gas injection are two of the CO2 Injection Schemes in which oil is displaced by gas injection. These mechanisms vary from immiscible displacement at low pressure to miscible displacement at higher pressure applications. In these processes 50 to 67% of CO2 returns to the surface with produced oil, and is usually separated and re-injected into the reservoir to minimize operating costs.

The remainder is trapped in the oil reservoir by means of irreducible saturation and dissolution in reservoir oil that it is not produced and in pore space that is not connected to the flow path for the producing wells.

Advantages of CCS
  • CCS is attractive because the geology of HC reservoirs is generally known
  • Storage costs will be offset by the sale of additional oil recovery
  • It is a key tool in tackling climate change, providing energy security, creating jobs and economic prosperity
  • CCS could reduce global CO2 emissions by 19%, and that fighting climate change could cost 70% more without CCS
  • CCS could play an important role in order to reduce Green House Gas Emission
Disadvantages
  • Disadvantages of old oil fields are their geographic distribution and their limited capacity
  • Subsequent burning of the additional oil recovered will offset much or all of the reduction in CO2 emissions
  • Presence of impurities in the CO2 gas stream affects the processes of capture, transport and injection mainly due to corrosion and fouling
  • Leakage of stored CO2 is a major concern with CCS
  • CCS technology leaves behind dangerous waste material that has to be stored, just like nuclear power stations
  • The technology is expected to use between 10 and 40 percent of the energy produced by a power station
  • The use of CCS can reduce CO2 emissions from the stacks of coal power plants by 85–90%, but it has no effect on CO2 emissions due to the mining and transport of coal
Conclusion

There is an urgent need to tackle climate change and we need “all the tools in the box” to do so; we cannot tackle climate change effectively without CCS. And if this technology is being used in EOR processes, we can not only recover additional Oil but also can prevent our environment from further demolition.

 

About author

Mehwish Khanam

I am Final Year Student of Petroleum & Gas Engineering at University of Engineering & Technology Lahore and Ambassador of YoungPetro in Pakistan.

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