System and method for permanent storage of carbon dioxide in shale reservoirs

Abstract

The present disclosure provides a system, method and apparatus for the removal of natural gas / methane from in situ loci within shale reservoirs to (i) provide fully de-carbonized surplus electricity, and (ii) power re-injection of the resulting carbon formed (CO2) upon combustion in an electric generator along with large volumes of atmospheric CO2, such as for large scale removal of CO2 from the Earth's surface / atmosphere.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is a continuation in part and claims priority to the U.S. Non-Provisional patent application Ser. No. 15 / 186,162, docket no. PROS012USOTR, filed Jun. 7, 2016, and is hereby incorporated by reference in it's entirety.FIELD OF THE INVENTION[0002]The present disclosure relates generally to systems and methods for storing carbon dioxide, and more specifically, to systems and methods for permanently storing carbon dioxide in shale reservoirs.BACKGROUND OF THE INVENTION[0003]Carbon sequestration can be divided into two categories: the enhancement of the natural sinking rates of CO2 and direct discharge of human generated CO2.[0004]The sequestration options in the first category include terrestrial sequestration by vegetation, ocean sequestration by fertilization, and an enhancement of the rock weathering process. In the direct discharge options, the CO2 produced from large point sources, such as thermal power stations, would be...

AI Technical Summary

Benefits of technology

[0014]Subject matter of this disclosure provides a method for sequestration in deep underground formations of large amounts of CO2, with improved risk of leakage such as, for example, long-term leakage.

[0015]In an embodiment, a sequestration method may include storing CO2 in an underground formation by introducing the CO2 into a well formed in the formation by hydraulic fracturing, and closing the hydraulic fractures to seal the well with the CO2 stored in the formation and prevent escape of the stored CO2 through the well fractures. In an embodiment, such a sequestration method may include introducing the CO2 into a well formed by hydraulic fracturing for the production of shale gas from a reservoir of the underground formation. In an embodiment, a method for large-scale sequestration of CO2 may include introducing the CO2 into a plurality of wells formed by hydraulic fracturing associated with production of shale gas from reservoirs of at least one underground formation, such as a regional formation, wherein the well includes sealed hydraulic fractures preventing escape of stored CO2 from the formation through the hydraulic fractures.

[0023]Concerning de-carbonization, the result of this process via this invention is the permanent, in terms of geologic time, storage of CO2 that is not dependent upon wellbore sealing or the long term integrity thereof. Concerning fully de-carbonized power generation, this system fully supports the continued and economic use of intermittent supplies of electricity such as wave, wind and solar generators.

Problems solved by technology

The sequestration options are less beneficial in terms of cost per unit CO2 reduction compared to other options.

It has been stated that biological sequestration is a natural approach; however, despite this advantage it is now known that there are significant disadvantages.

Although the oceans represent possibly the largest potential CO2 sink, ocean sequestration involves problems including poorly understood physical and chemical processes, efficiency, cost, technical feasibility, and possibly the most worrying, long-term environmental impact.

In addition, ocean circulation poses legal, political and international limitations to this technology.

Carbon dioxide forms carbonic acid when dissolved in water, so ocean acidification is a significant consequence of elevated carbon dioxide levels, and limits the rate at which it can be absorbed into the ocean.

However, the total volume of material required to make an impact on global CO2 emissions would be cost prohibitive (Huijens, et al., 2005).

While hydrostatic pressure acts to keep CO2 in a liquid state, this does not ensure that leakage cannot occur.

In fact, this is one of the biggest problems with the technology.

However, questions of CO2 leaks from the project have been raised.

While in a typical well, the CO2 would be sealed by capping the well with cement, degradation of the cement may prevent such wells from being a long-term solution.

Carbonation rates were relatively low, but most detrimental were the cracking of specimens as a result of massive CaCO3 formation which comes along with expansion (Lesti et al., 2013).

Although some of the reactions with cement can be beneficial, a loss of compressive strength of the cement is observed (Condor and Asghan, 2009).

In summary, current CO2 geologic sequestration technology suffers various problems and inadequacies.

Failure of the geologic formation or reservoir to contain the CO2 due to cement failure may result in catastrophic release of vast quantities of CO2 at some undetermined point in the future.

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