Economic+and+Environmental+Impacts

= Economic Impact of THAI: =

Conventional in-situ recovery techniques use large volumes of water. For instance, SAGD requires about 7 bbl of water for every barrel of bitumen produced. Moreover, principal and operating costs associated with water management can sometimes account for half the project cost. Process such as steam flooding and SAGD burn significant quantities of gas to produce the steam required to carry out the process increasing the environmental footprint due to the release of greenhouse gases (primarily CO2). Statistically, 1000 cu.ft is needed to produce 1 bbl of bitumen and 1 bbl of water is required for every barrel of oil recovered.

Since the THAI process employs combustion of the part of the fluid mixture within the reservoir itself there are less external start up and maintenance cost associated with the process. Limited water needs to be used, consequently minimal costs associated with water management needs to be dealt with. Moreover, the cost associated with sustaining and regulating a low steam to oil ratio associated with traditional ISR is internalized with the THAI process.


 * Energy Performance Review:**

The economic analysis of THAI presented here will be based on an energy returned on energy invested (EROEI) approach. EROEI is defined as the ratio of the amount of usuable energy acquired from a particular energy resource to the amount of energy expended to obtain that resource (http://en.wikipedia.org/wiki/Energy_returned_on_energy_invested) Ideally a large EROEI number would imply a self-sustaining resource with significant scope for commercialization.

The pilot project in May River (phase 1) has provided Petrobank with significant data in aiding economic analysis. Petrobank cites the efficiency of the central processing facilities and well sites to 90.6%. This implies that for every 10 units of energy taken from the reservoir 1 unit is used up in the process. The following figures outlines the energy performance review from Petrobank’s Whitesand’s project: Image courtesy of http://www.theoildrum.com/node/6183

Note that the figure shows the net energy export and input without the opportunity cost and resulting profit retrieved from the value added products.

As it is evident in the picture, the THAI process has immediate potential to cater the demanding electric grid through the cogenerative capacity of the post-combusion phase in producing electricity. Another usuable byproduct of the THAI process is the produced gas which not only serves as fuel gas for the central processing facilities and wellsites but could also be used in other cogeneration applications.

The THAI process currently has an EROEI number of 6 to 56 depending on the input of energy allocated for the naptha diluent. Conventional in-situ recovery processes (ISR) have an EROEI number under 6. The following diagram shows the energy cost breakdown with the associated EROI calculation. Image courtesy http://www.theoildrum.com/node/6183

The THAI-CAPRI process alone tremendously reduces the processing cost required to operate these central processing facilities. Depending on the specific type of heavy oil, the CAPRI process can be optimized to improve the grade of the oil produce downhole offsetting all surface upgrading cost. Engineering, construction, operation and maintenance of an equivalent surface upgrader facility employing a fixed bed reactor would cost anywhere from 100 – 300 million dollars wheras the CAPRI upgrading process produces the same result by operating downhole at a marginal cost.[0]
 * Environmental Impacts of THAI: **

The oil sand projects are one the largest industrial projects that are known to be destructive in nature. Mining in the oilsands is estimated to release at least three times more CO2 as regular oil production [2]. Oil sands have the potential to become the single largest industrial contributor to the climate change in North America. Moreover, oil sands in general have adverse effects on the environment. Some of the areas that are already impacted are as follows [3]:


 * Impacts on the air quality
 * land use
 * water resources
 * climate change
 * public health issues
 * deformation of aquatic life
 * social issues, housing crises to the vast expansion of temporary foreign workers

Bitumen from the oil sands is extracted from the reservoir in many different ways. Open-pit mining technique as one of the oldest, have been utilized to recover the bitumen from the surface but about 90% of the available bitumen in the world are too far deep in the ground, therefore requiring the need for in-situ mining[3]. Toe to Heel Air Injection (THAI) is one of the new and experimental methods of this kind. What is the most favorable about THAI is that it is found to be environmentally promising. Other in-situ methods use substantial amount of energy into steam generation, consequently leading to the emission of greenhouse gases. According to the Petro-bank website, the company who have taken a lead into establishing this new method, THAI methodology is a superior method in helping to reduce the environmental impacts in the following ways ,

· Negligible use of water as compared to the methods such as SAGD, [4] · Producing less greenhouse gas and toxic gas emissions [4] · Leaving a small foot print on the land, leading to an easier reclamation of the land afterwards [4] · Able to upgrade the oil down-hole, so the oil produced will need less refinement on the surface. This way less greenhouse gases will be emitted since the need for the refineries is reduced [5].

As mentioned earlier, one of the significant advantages of THAI is that it uses less amount of water to generate steam. This advantage is significant in reducing the greenhouse gases as well as the water usage. This is due to the fact that steam is only needed to be injected prior to the combustion process to heat up the ground for a short period of time[7]. Therefore, the amount of natural gas burned to heat the steam is much less than other in-situ techniques such as SAGD which uses steam continuously. According to the Petrobank, THAI is one of the only in-situ method that has the potential to cut the emission of greenhouse gas emissions by 50% [3].

It is also worth mentioning that while some water is lost during the heating process, most of it is recycledable.

THAI on the other hand is able to upgrade the oil. When the combustion reaction occurs under the surface, the heat generated causes a portion of the asphaltine content of the oil to remain as coke[6]. This coke is used as a fuel for continuous combustion. As a result, THAI is able to fuel itself, making it less needed for further energy usage.


 * Life Cycle Assessment: **

LCA is a “cradle-to-grave” or “well-to-Wheel (WTW)” approach for the assessment of industrial systems. LCA is helpful in evaluating the stages of a product’s life from the point that one operation lead to the other [8]. Overall, a LCA can help to give an estimation of the cumulative environmental impacts of a product in a bigger picture or the amount of greenhouse gases produced by a particular product.

Studying the life cycle of emerging bitumen in-situ extraction technologies is important because it can contribute to the improvement of their design. Figure below represent one of the methods of Life Cycle Assessment (LCA) of bitumen extraction from the oil sands. The system includes two stages of bitumen extraction and upgrading process. The use of it can allow one to calculate the greenhouse gas (GHG) intensity per barrel of Synthetic Crude Oil (SCO) produced. This lets us calculate how much an in-situ recovery method can contribute to the amount of greenhouse gases generated.

Since THAI is a fairly new method, the exact data are unavailable but the methodology is similar.

Image courtesy of http://archivos.labcontrol.cl/wcce8/offline/techsched/manuscripts/f7et68.pdf

As seen from the figure, the system chosen only evaluates the potential benefits of the recovery method up to the production of Synthetic Crude Oil (SCO). This is because that after the SCO production, the environmental impacts will be similar to the other technologies of its kind.

** Application of Green Chemistry Principles: **

By applying the green chemistry principles to the THAI process, we can determine if this new technology can contribute into moving the oil sand industry towards a greener future. The relevant principle from the top 12 principles of green chemistry are chosen and summarized in the table below. It is also described that how these principles apply to the to the THAI method.

· THAI is able to recover up to 80% or more of the initial oil in place. This makes THAI more energy effiecient as compare to the other in-situ techniques[5]. || Click here for next page: Case Studies
 * Table 1.0: Showcasing the core principles of green chemistry associated with THAI: **
 * ** Green Chemistry Principle ** || ** Application and Relevance to THAI ** ||
 * ** Prevention ** || · THAI can help to reduce heavy metals in the produced oil such as V and Ni [5]. ||
 * ** Safer Solvents and **
 * Auxiliaries ** || · THAI only uses steam to heat up the ground as a start to the process, and the amount of the water used is mostly recyclable [7]. ||
 * ** Design for Energy **
 * Efficiency ** || · THAI as compared to SAGD uses less steam; therefore the need for natural gas to prepare the steam is reduced [7].
 * ** Catalysis ** || · CAPRI is the catalytic extension of the THAI process. Lab tests have shown that it can upgrade the oil further under the ground by using a CoMo hydro-treating catalyst [5]. ||
 * ** Pollution Prevention ** || · Since the amount of the steam needed is significantly reduced, THAI is able to reduce the greenhouse gas emissions by up to 50%[3]. ||


 * References:**

[0] Shah A, Wood J, Fishwick R, Greaves M, Rigby S. In-Situ Up-Grading of Heavy Oil/ Natural Bitumen: CAPRI Process Optimization. Department of Chemical Engineering; University of Birmingham. IOR, Department of Chemical Engineering, University of Bath [Online] 2007,11, 383-393 http://archivos.labcontrol.cl/wcce8/offline/techsched/manuscripts%5Cqrc251.pdf (acc. Sep 28, 2011).

[1] EROEI, Wikipedia - The Online Encyclopedia. Retrieved from the URL: http://en.wikipedia.org/wiki/Energy_returned_on_energy_invested (Accessed on 9th Nov, 2011)

[2] Oil Sands Truth.Retrieved from, http://oilsandstruth.org/ (accessed Nov 10, 2011)

[3] Wikipedia- The online Encyclopedia. Retrieved from http://en.wikipedia.org/wiki/Oil_sands#Environmental_issues (Accessed Nov 10,2011)

[4] Extracting Heavy Oil: Using Toe to Heel Air Injection (THAI). Retrieved from [] (Accessed on Nov 11, 2011)

[5] Greaves, M.; Xia, T. X. Upgrading of Athabasca Tar Sand Using Toe to Heel Air Injection. Society of Petroleum Engineers. 2000, pp1-38.

[6] The Canadian Association of Petroleum Producers: A Revoloution in Heavy Oil Recovery. Retrieved from http://www.capp.ca/energySupply/innovationStories/Water/Pages/undergroundCombustion.aspx#0cARi111gAUK (Accessed on Nov 10, 2011)

[7] Wikipedia- The online Encyclopedia. Retrieved from http://en.wikipedia.org/wiki/Petrobank_Energy_and_Resources_Ltd (Accessed on Nov 11, 2011)

[8] Kofoworola, O. and McKellar, J.M. A Life Cycle Investigation of Emerging Oil Sands Technologies [online]. http://archivos.labcontrol.cl/wcce8/offline/techsched/manuscripts/f7et68.pdf (Accessed Nov 10, 2011)