Design for the Environment/Oil Sands Extraction Technique

Consider that Suncor Energy requires the extraction of bitumen from its new project site, Millennium site commons:Image:Millennium_site.PNG. Out of the several possible extraction techniques, the four alternatives considered are Surface Mining, SAGD (Steam Assisted Gravity Drainage), THAI (Toe to Heel Air Injection) and VAPEX (Vapour Extraction process).Suncor also requires that this bitumen is converted to an equal volume of synthetic crude oil.

The purpose of this project is to investigate into functional, environmental, economic and societal feasibility of these alternatives if implemented. The study was done such that the common goal to be achieved by each of the alternatives is to extract 250000bpd of crude bitumen from the Millennium mine site and convert it to an equal volume of synthetic crude oil. Surface Mining is extensively followed by Suncor Energy on its existing mine sites . Hence this is chosen to be the baseline technique. The rest of the techniques are relatively novel ideas.

Project Information

Name of project Section 2 - Group B20

• Leo Joseph (Leojohnjoseph)

• Qasim Khan (qasim.qasim)

• Baber Ali (knight87)

• Usman Ahmed (usmanahmed)

• Bilal Yaseen (bilalx)

Background

Catering to the rising world oil demand has developed the need for finding new oil reserves. Hubbert's theory , named after American geophysicist M. King Hubbert, predicts that upon discovering new reserves, production increases exponentially till peak production is reached. Peak production is then followed by an approximated exponential decline. Hubbert's model did correctly predict US peak production period and as he predicted, the US has been experiencing production decline since 1970 . The International Energy Agency, upon probing into production information from around the world, predicts the peak of world reserves to be reached between 2013 and 2037 .

The discovery of Canadian Oil Sands reserves [1] has shifted this peak by 50 years. This signifies the importance of Canadian Oil Sands reserves in meeting world oil demand. However, exploitation of these reserves comes with the cost of detrimental environmental effects at a local and global scale. Oil Sands reserves contain crude bitumen. This bitumen has to be extracted and needs to undergo a series of processes to obtain synthetic crude oil. Suncor Energy is the world’s second largest producer of oil sands crude . This company was chosen to be the group’s client since they would be interested in the findings of this study.

Highlights and Recommendations

Certain decision parameters were chosen. These parameters prove to be significant in determining which alternative is most suitable for the desired objective. A scoring scheme was used to determine how each alternative weighed with respect to the decision parameter under consideration. The decision parameters are as follows:

Economic Profitability

The costs that would be incurred by Suncor Energy if it were to undertake the project using each of the alternatives are discussed in the details of cost analysis section. The analysis reveals that VAPEX is the most profitable with a profit of 90.1$ per barrel of synthetic crude oil produced. This is because energy inputs during the primary operation stage of VAPEX are the least.

Economic Input-Output Life Cycle Analysis (EIOLCA)

To draw a conclusion on which alternative is the least destructive to the environment, certain gauging parameters were considered.

GWP

GWP which directly relates to the release of Green House Gases (GHG) is taken seriously. This is because the project has to comply with government GHG emissions. Implementation of the Surface Mining alternative would result in the emission of largest quantity of GHGs (120 million MT CO2). This quantity accounts for emissions produced during all the five life stages and over a period of 30 years. The primary process operation over this 30 years accounted for most of the emissions. With similar considerations, THAI if implemented emits least quantity of GHGs.

Energy usage

Energy usage is a factor that is critical to the decision making process. The enegry used during the operation lifestage of each of the alternatives are primarily reliant on the natural gas reserves of the region (Western Canada Sedimentary Basin (WCSB)[2]). Assembly of plant equipment are usually done locally and so depend on these reserves. This dependency has not bee appropriate acconted for in the EIOLCA model. Higher energy use would result in the faster depletion of these resources and also add to the overall GWP. THAI stands out as that alternative which is the most energy demanding, 8.42 million TJ (over what 30 years of operation). VAPEX consumes the least amount of energy. This gives one more reason to implement VAPEX.

Land usage and land releases

Setting up of facilities essential to each of the techniques requires a large amount of land. To meet this demand for land, deforestation of the site becomes inevitable. The Boreal forest becomes victim to this deforestation and this tampers with the natural ecosystem of the region (hyperlink this to the jpeg of the map). Surface mining requires the highest land use. Land remediation activities that occur in par with surface mining operations ensure that land releases are removed and the soil becomes reusable. However, the displaced wildlife are able to return to these lands only after several years which again indirectly affects the ecosystem. To deal with this issue Group B20 strongly recommends that National parks in the nearby areas be interconnected. As for the in-situ techniques, lesser land is required. THAI and VAPEX require the injection of solvents which overtime are absorbed by the soil and could potentially contaminate it.

Water usage and Water releases

The project site is situated in the midst of two river banks, the Athabsaca River and its tributary, Steepback River commons:Image:River_site.PNG. Positive height gradient of the location is responsible for the flow of contaminants downstream. Surface Mining in particular use tailing ponds which release harmful chemicals like Naptha (reference qasim) into the Athabasca river body. Depletion of water in the Athabasca river and its tributary has been an issue of excruciating importance. Dwindling water levels is primarily due to Oil Sands operations . This adversely affects the availability of water for drinking and sanitation. The Athabasca River aquatic ecosystem is highly dependent on water level and flow rate . Depletion of water quantity could lead to destruction of habitats of different species. Therefore, water usage poses to be of grave importance. During the Extraction phase of Surface Mining, water from the river would be used extensively (close to 1.9 million cubic metre of water per year) to separate the oil sands into 3 layers that has bitumen in it (reference from qasim). VAPEX requires no water at all for involved operations. Here too VAPEX outweighs the rest of the alternatives.

Streamlined Life Cycle Analysis (SLCA)

The SLCA revealed neck to neck scores for all the alternatives. This analysis proved to be insufficient in reaching a conclusion. This is because this is a very subjective analysis technique. Scores of 0 and 4 are given to fixed parameters as given by the scoring guidelines. But, scores of 1, 2, and 3 are based on personal judgement. This accumulation of inaccuracies detrimentally affects the potential of the SLCA in helping to a judgement on which alternative is the best. However, the group tried hard in making sure that similar assumptions were made and scoring was done fairly and uniformly. This way VAPEX had the highest score.

Extra Parameters

Time efficiency

If an alternative takes relatively less time to produce 250000 barrels (not per day) of synthetic crude oil, then, it has the potential to focus on increased production during the time saved over the rest of the day. This would proportionally increase negative environmental impact. However, economic profitability due to increased production outweighs costs associated with the environmental impacts. Surface Mining took 1.56 seconds/crusher to produce one barrel of synthetic crude oil. This method is the fastest. This explains why Surface Minig is more extensively (quicker returns).

Land use efficiency

The significance of this parameter can be explained using the following example. An alternative that uses 30% of the available land on the project site can utilize the rest of the site for increased production. In this respect, THAI outweighs the rest of the alternatives. It needs 800 hectares of land to produce 250000 bpd while Surface Mining requires 150 this area.

Associated Risk

The chances of on-site explosions increase if pressure and temperature conditions to be maintained for the operations are high. A highly inaccurate approximation revealed that SAGD maintains the most dangerous of conditions because of the high pressure of steam and solvents rushed into the resevoir.

To compare the alternatives using these parameters, a scoring scheme was used wherein the highest score of 3 is given to that alternative which performed the best with respect to the parameter considered. These scores can be seen in table E1 commons:Image:Scoring_for_conclusions_1.PNG.

Description of Alternatives

Surface Mining

Please refer to Fig A1 for the details of the steps involved in producing synthetic crude oil from Surface Mining.

1) In the mining phase, the oil sands (overburden and bitumen) are mined approximately 75 m deep using shovels. This is then transported to sizing plant using heavy dump trucks. The overburden is restored back to the mined site during the reclamation process .
2) At the sizing plant, the ore is crushed and is delivered to the extraction plant.
3) The ore enters rotary breakers where it is crushed further, mixed with hot water to form slurry. The ore is then mixed in large tumblers to separate the ore into three layers: bitumen, midlings, sand. The midlings are further processed in a secondary separation to get more bitumen froth. The sand clay mixture is sent to tailing ponds where it accumulates.
4) The diluted bitumen is sent to the upgrading plant where bitumen goes through a coking and distillation process that lowers the weight of the bitumen and removes harmful contents like Sulphur.

The end product is synthetic crude oil that is acceptable by oil refineries.

SAGD

Steam Assisted Gravity Drainage (SAGD) is an in-situ oil sands recovery technique which involving the use of steam to heat and then extract bitumen out of reservoirs too deep for surface mining to be economically viable. Initiation of the process involves the digging of a well pair with each of the wells being 75 to 150 metres deep and upto a 1000 metres long horizontally (wells dug form an L-shape). The two wells' horizontal parts are vertically aligned with the upper of the two being 5 metres above the lower one and the vertical components approximately 20 metres apart. The lower of the wells is called the production well due to the fact that the bitumen is pumped out of this well for production, while the upper one is named the injection well referring to the fact that this well is responsible for the injection of the steam which heats and mixes with the bitumen allowing it to flow. The oil and the condensed steam are pumped out via the production well and then separated allowing the transportation of the oil by a pipeline to an upgrading plant where it is upgraded to synthesized crude oil. The de-oiled water from the seperation process is recycled by treating it and then feeding it back into the system via the steam generators.

THAI

The process involves injection of air under pressure into vertical injector wells up to a depth of 300m. This Air burns the bitumen in the reservoir hence creating a combustion front. Heat generated from the process increases the fluidity of the bitumen allowing for an easy flow along the production wells where it is collected by gathering lines and transported to upgrading plants where final conversion to synthesized crude oil takes place. For a more detailed summary refer to chart C1 commons:Image:Flowchart.PNG].

VAPEX

The VAPEX process is an in-situ method where the bitumen is recovered from the reservoir by injecting a hydrocarbon solvent into it by oil wells. The solvent dissolves the bitumen in place reducing the viscosity of the bitumen. This allows the btiumen to flow into the wells allowing it to be pumped to the surface where the bitumen is separated from the solvent and transported to an Upgrading plant where it is upgraded to produce synthesized crude oil. recycled by feeding it back into the system. The solvent extracted from the mixture is recycled by feeding it back into the cycle through the injector pumps.

Details for Cost Analysis

Introduction

The cost analysis was done over a study period of 30 years. A lifetime of 30 years was chosen because this time span roughly accounts for the operational lifespan of the equipment and infrastructure in use. This choice does not affect the study since a linear scaling is used to account for cost variations over time. To proceed with the cost analysis, complexities in involving certain cost drivers had to be dealt with by making some simplifying assumptions.

To do the analysis, direct and indirect costs over the 30 years are considered. Expenses involved in the process implementation, operation and disposal/remediation stages are part of the direct costs category. The only indirect cost considered is that of the GWP of each of the alternatives. Royalties worth $18.81 billion [E.6] (in 2007 dollars, for each of the alternative) are paid to the government over 30 years. It is assumed that all alternatives operate within government regulations and hence, no fines are incurred. Costs per unit of service, i.e. production of 1 barrel of synthetic crude oil, are found for each alternative. Upgrading costs are the same for all.

Surface Mining

The capital costs are high due to upgrading plant and surface mining equipment costs. However, the capital costs are minor (10 billion $2008) in comparison to the operational costs that are incurred over a period of 30 years (90 billion $2008) as shown in Fig A2.

The highest operational costs arise during the upgrading process because upgrading bitumen to synthetic crude oil involves energy intensive processes like distillation and hydrotreating. This brings forward the need for large quantities of natural gas and coal that adds to operational cost. The comparison of operating costs is shown in Fig A3.

Overall, the profit generated per barrel of synthetic crude oil from surface mining technique is $63.3 ($2008).

It is worth mentioning that there are indirect costs as well as disposal costs. However, these are minor costs and account for less than 10%.

SAGD

An SAGD setup of a 250000bpd capacity has capital costs of approximately $7.61 billion with the upgrading plant followed by the power generator and the steam generators being the most expensive. Operating costs were calculated to be $48.9 billion for producing 2.74 billion barrels over a period of 30 years. Total project costs with operating, capital and disposal costs came to $72.3 billion this leads to a per barrel cost of $26.39, converting these costs to 2007 and calculating profit at a per barrel price of $107 leads to a profit of $74.72 per barrel.

THAI

The entire cost of the project was converted to $2007 .Final profit calculated in terms of profit/barrel was $87.5. Capital cost calculated for the project was approximately $6.93bn. Power plant and upgrading facility proved to be the largest contributors. Operating cost accounted for approximately 70% of the overall cost at approximately $27.35bn. Besides these major costs, royalties and external cost of GWP emissions was also determined which also had a signifant impact on the overall cost. It was noticed that the major operational cost was incurred during the upgrading operaton, followed by cost of power input for air compression and injection into the wells as well as to pumps and motors associated with the motion of oil along the wells. Disposal cost were althouh large, but as compared to the overall cost of the entire project, proved to have no major influence in driving the cost.

VAPEX

The cost per barrel for the VAPEX process at a production rate of 250000bpd is $16.9, which results in a profit of $90.1 for every barrel produced. The Operating costs are claculated to be $2.628 million per day, which are high due to the energy consumption of solvent separation process. The Capital costs are $4821 million in which well drilling and power plant construction are the most expensive. The Disposal costs are $253 million of which recycling is $221 million. Indirect costs are $796 million which are accounted by GWP emissions. A sensitivity analysis shows that increasing the operating costs by 25% increases the cost per barrel by only $4.8.

Assumptions made to perform cost analysis

Over 30 years it is assumed that the operation costs and production rate of 250000bpd remain static. The latter assumption avoids the need to consider purchase of more inventories in future. Current oil prices are assumed to be 107$/barrel [D.8]As the world energy demand increases over this interval, static supply gives birth to higher oil prices. However, it is assumed that, to cater to this rise in demand, additional supply is met by other oil reserves. (explain hubberts theory in the summary section) This assumption ensures that oil price over the 30 year study period remains constant.

Details for EIOLCA

Introduction

The EIOLCA model (available at www.eiolca.net) developed by Carnegie Mellon University, accounts for the entire supply chain requirement to achieve the goal of each life stage of the process. The model uses a linear scale simplification. To achieve the common goal of obtaining 250000bpd of synthetic crude oil from an equal volume of bitumen, each of the processes were broken down into four life-stages, namely; process implementation, primary, complementary process operation and decommissioning cum reclamation of the project site. A Hybrid EIOLCA is done because sectors that correspond to the different life-stages of the individual processes were not readily available in the software. Therefore costs of inputs to the different life-stages were determined prior to using the software to investigate into their individual environmental impacts. Certain simplifying assumptions were made. Owing to the expanse and complexity of the project, determining costs of all equipment, involved in the resource implementation stage, were impractical. Only those equipments that individually accounted for more than 10% of the overall costs were accounted for in the EIOLCA. This could generate misleading environmental impact results; i.e. a machine that accounts for only 1% of the overall costs could potentially cause 80% of the overall environmental damages. However, it should be noted that, equipment involved in the resource implementation and operation stage (for all alternatives) can be broadly classified into four categories:

• mechanical drives that convert electric or fossil fuel energy into rotary, linear motion or a combination of both (for examples; rotary breakers, conveyer belts, shovels, centrifuges )
• Heat exchangers (for examples; boilers , air coolers)
• Pressure drives (for examples; pumps, pipelines, solvent injectors)
• Equipment required for infrastructure setup and oil wells (if required)

The environmental effects for the manufacture of these equipments are a direct function of size and number of equipment used. Environmental impact of the operation of these equipments is directly related to the energy intensiveness of the activity. This justifies the assumption that, there is only the need to account for those pieces of equipment that account for more than 10% of the overall project cost because only these equipments are responsible for significant environmental damage. Costs for some equipment were deduced from manufacturer’s price quotes. Wholesale prices were used instead of retail prices since these are closer approximations to manufacturing costs. Detailed EIOLCAs for the alternatives are documented below:

Surface Mining

The surface mining operations has the highest GWP contribution over a course of 30 years (116 million MTCO2E); hence, it has the largest environmental impact as shown in Fig A4 in comparison to the process implementation and disposal stage.

The Oil and Gas and petroleum refining sector contributes maximum to the GWP contribution and accounts for 92% of GWP (results in CO2 emissions) and almost 100% of the total energy needed for surface mining operations. Most energy is obtained from fossil fuels that are needed for the mobile equipment for surface mining and for other equipment during extraction and upgrading process that result GHG. Table A1 below shows the energy consumption and GWP from top sectors:

Upgrading plant, during operation, has the highest energy and GWP contributions mainly because huge amounts of natural gas are used to carry out the distillation and hydro treating processes and the fossil fuels required during the process are extracted from energy intensive processes. Table A2 gives the GWP and energy consumption during the life stage of the surface mining operation.

SAGD

The EIOLCA provided us with a variety of data, with some of it conforming to expectations while some of it not being exactly as expected. Much of the data that was not meeting expectations was due to the fact that the sectors in the EIOLCA method are an aggregate of many different sectors rather than just the required sector. The total GWP for the process over a thirty year period came out to be 90.3 million metric tons with 95% of this value coming from the operational phase. Major contributors to the operational GWP were the water treatment and reservoir stimulation. The high energy requirements for the reservoir stimulation and the air releases for the water treatment phase seem to be responsible for the GWP values. For the operational energy consumption, reservoir stimulation and transportation are the top two sectors confirming expectations. The process implementation phase (capital costs) had power generator plant and water treatment plant construction as the major GWP contributors. The power generator’s construction is within expectations but the water treatment plant’s construction is too high due to the fact that the sector also has urban water treatment as a component (a major GWP contributor). As for the energy consumption in the initial setup, power generator, well pair/pad setup as well as the steam generator required the bulk of the energy use, a representation meeting expectations.

THAI

The figure on the right is an indicator of the environmental impacts for the complete life cycle of this alternative. For simplicity environmental impact was measured primarily in terms of GWP emissions and energy consumption. Total amount of GWP emissions was calculated to be 58.9bn Mt/CO2E and Energy input of 8.49mn TJ. Quantitative environmental impacts of the primary process phase out numbered the impacts of all the remaining stages with a total of 55.9bn Mt/CO2E and an energy consumption of 8.42mn TJ. Disposal phase accounted for approximately 382040 Mt/Co2E and an energy consumption of 3402.8 TJ. Hence the influence of environmental impact disposal phase was negligible as compared to the overall environmental impact

VAPEX

The EIOLCA analysis was carried out for 250000 bpd operation which required 1000 well pairs to achieve capacity. The total GWP emissions for the whole project over 30 years are 61,297,419 MTCO2E and the total energy usage is 559,279 TJ. The Process Implementation phase had 2,476,429 GWP MTCO2E emissions and used 31,457 TJ of energy. The main reason is due to the high power and material processing needed for well drilling and power plant construction. The Process Operation phase had 58,505,850 GWP and 5,191,395 TJ of energy consumption. Most of the energy usage is consumed by the boilers and compressors which can be seen by that 86% of the GWP emissions for this phase are from the “Power and Generation Sector”. The Disposal phase has 315,140 GWP MTCO2E and 8683.8 TJ of energy usage. Recycling accounts for 202,000GWP and 8,325TJ of that. This is due to the high amount of steel used in all the equipment and its resulting environmental impact by refining.

Details for SLCA

Introduction

Performing a Streamlined LCA of each of the alternatives gives a rough indication of how these alternatives affect the environment. This analysis is largely qualitative since it depends on personal judgements unlike the EIOLCA technique. Appendix B of the book ‘Streamlined Life Cycle Assessment by T. Graedel’ was used to assign scores to the SLCA matrix elements. Higher the numerical value of the summated total of the scores, the less detrimental is the alternative’s effect on the environment. The streamlined LCA for each of the alternatives are detailed below:

Surface Mining

The streamlined life cycle assessment for surface mining technique showed the following results:

From table A3 it is observed that the primary process and resource provisioning has the lowest scores (5 and 7 respectively). This is due to two reasons. First, high amounts of fossil fuels are needed for the upgrading and extraction process and these processes also release toxics in the form of tailing ponds. Second, CO2 emissions result due to the high amounts of natural gas needed during the mining (dump trucks), upgrading phases, and natural gas and coal extraction (main energy source).

The results from SLCA matched very well with the EIOLCA analysis for surface mining technique. The primary process operation has the highest GWP and energy consumption and, therefore, a low score in SLCA agrees well with EIOLCA results.

SAGD

Resource Provisioning (11/20): Major resources provisioned are water needed to create steam and natural gas to fulfill energy requirements. Extraction of said resources result in various levels of residues and mediocre energy usage.
Process Implementation (5/20): Due to the massive scale of the equipment used, such as power generator, upgrading plant etc. energy used for the manufacture and transportation of equipment will be immense.
Primary Process (9/20): The primary process of extracting bitumen using steam requires massive amount of energy which is obtained by burning natural gas this results in sizable amounts of greenhouse gas emissions. Other than the massive amount of water being used to produce the steam required the primary process life stage has no additional environmental impacts.
Complementary Process (11/20): Maintenance and cleaning operations are performed during this phase. It is a low energy consuming process since such operations are performed on an infrequent basis.
Refurbishment, disposal (7/20): It is a high energy consuming process mainly due to the equipment recycling. The primary material used, however is steel that can be recycled using electric arc furnace using relatively low energy. Power plant upgrade is a part of the plant decommissioning which is also a high energy consuming process.

THAI

A qualitative analysis of the environmental impacts was performed from which it was predicted that the primary process phase had the largest negative environmental impacts followed by the process implementation. Upgrading to crude oil and pumping operations within the wells were predicted to be the largest contributors to environmental impacts due to large amount of conventional pollutant, toxic waste and non-point air emissions associated with it. Process implementation phase was also predicted to have significant impacts associated particularly due to greenhouse gas and conventional pollutant emissions from power plant and upgrading facility installation. Complementary process involved cleaning of wells which is however, occasional in such an operation although the material usage phase involved use of CFCs. Disposal phase was also thoroughly researched and involved plugging of thewells, site abandonment and reclamation and thus resulted in high production of solid andgas residue. However, considering that process life cycle is 30 years, the overall environmental impact during the primary process phase was expected to overshadow all other stages

VAPEX

The SLCA analysis reveals that energy usage and gaseous residues score poorly in comparison to materials choice, liquid residues and solid residues. Energy and Gaseous residues have low scores due to the high energy usage at each process stage and hazardous gaseous emissions like VOC’s, NO,CO2,CO, toluene etc. Also resource provisioning (8/20), process implementation(6/20) and primary process(9/20) have low scores as compared to Complimentary Process(12/20) and Disposal(13/20).This is due to the heavy energy usage in manufacturing and operation of the heavy equipment and their resulting hazardous emissions. The Disposal phase scores well due to recyclability of steel. Complimentary process has low energy usage and non hazardous emissions.