Economics Assignment On Remaining Oil Saturation (ROS)

Question

Task: Identify nations remaining and residual reservoir oil saturation levels and also explain some essential oil and gas exploration tools.

Answer

Introduction
Oil reservoir levels explored in this economics assignment are noted to be falling due to consistent drilling that is occurring in the oil-rich nations. As the demand for oil and gas increases, so does the pressure on the reservoirs makes it important for the oil and gas producing nations to take action towards measuring and making future projections linked to the oil and gas reservoirs saturation levels (Shafiee & Topal 2009). Being prepared will help the companies and government better manage their oil reserves which can then be mined in a manner which offers the countries the most economic benefit. This is being experienced in nations like UAE where the government has turned its attention towards using its oil revenue towards development and tourism, thus offering the nation an alternative source of income once the nation’s oil and gas reserves run low. To better manage oil and gas reserves, the following aspects require to be taken in to close consideration as they would allow the oil drilling nations and companies better manage future development and growth.

Identifying a Nations Remaining and Residual Reservoir Oil Saturation Levels Oil and gas reservoirs are broken down into two forms of measurement whereby the different oil and gas wells saturation is measured in the amount of oil remaining in the wells. Since oil wells are made up of oil stored within the porous rock, it’s sometimes possible to find the oil and gas re-accumulated to stable levels when the wells are allowed to rest over long periods. This allows for the oil and gas to seep in from the further reaches of the well or reservoir thus replenishing the wells oil and gas deposits. This results in oil and gas wells remaining and residual oil reserves differing considerably and needing each of the terms to be carefully understood (Schmutz et al. 2010).

Remaining Oil Saturation (ROS)
Remaining Oil Saturation (ROS) refers to the amount of oil available within a well while the well is still producing oil or gas. This measurement allows for the drilling and oil exploration companies to estimate a wells life’s expectancy which allows them to make different calculation linked to the productivity and profitability of the well. This is important for the drilling companies as it allows them to know much regarding the wells productivity as well as the rate at which the wells produces oil thus allowing them to measure the exact speed and pace at which oil can be produced from the well. A well’s remaining oil level is not measured on the ground of the depth of the well alone but is better measured via the ratio of the remaining oil’s volume and the entire well’s volume (Akkurt et al. 2000).

Figure 1 - shared oil fields

An oil well maybe tapping into an oil reservoir from oil but would also mean the oil reservoirs can be tapped from other regions as well. In many oil-producing countries like Iraq and Kuwait, the oil wells are commonly shared thus prompting both nations to aggressively pump out the oil to increase their benefit from the well. This was one of the reasons mentioned in this economics assignment which linked to the political tensions experienced between Iraq, Iran and Kuwait as the three nations share several oil fields thus pushing the nations to vigorously tap them before other nations deplete the reservoirs.

Residual Oil Saturation Residual Oil Saturation involves the amount of oil which is left within a well, either intentionally or due to the oil and gas reserves being held within porous rocks and requiring some rest. Some oil and gas fields will act like large sponges which hold on to the oil and gas and release is gradually when left to rest. These oil and gas fields tend to last much longer. This is known as residual oil saturation and an important asset for all oil-producing nations since it allows the nations to plan for the future and also allows them to store their oil reserved for future use. This is being experienced and practised by several oil-producing nations such as the USA and India which simply identify and drill wells into their oil fields after which they are sealed and stored for future use (Iglauer et al. 2012).

Figure 2 - porous rocks

Another example of residual oil fields of wells illustrated in this economics assignment can be one which has the majority of oil and gas stored within the pores’ cavities inside the oil field. As mentioned earlier, certain oil fields will have to follow rock which releases oil and gas. Gradually as the deposits go further, this may require for wells to be sealed and left for a certain duration of time which would allow the oil or gas to re-seep into the empty cavities where it can be pumped out. On such wells, the oil or gas may be trapped in pores further away from the well thus requiring some time for the oil to drip and re-accumulate at the main well shaft for pumping. The time taken to re-accumulate will usually depend on the viscosity and thickness of the oil but with gas, the time is generally predictable as gases move faster through the pores.

Understanding the Differences between Micro and Macro-Porosity within the economics assignment in Oil and Gas Field
An oil and gas field’s soil or rock porosity plays a huge role in determining where the oil wells will be profitable or not. This results in the porosity of the oil field falling into two main categories which include Micro and Macro porosity fields (Rutqvist et al. 2002). The two terms may sound very similar but they are very different, with one being considered good while the other being observed as non-profitable to the oil drilling companies.

Micro Porosity Oil and Gas Fields
Microporosity involves the creation of porous rocks or soil with a pore diameter smaller than 2m resulting in the porous rock of soil not allowing liquid or gas to flow from one pore chamber to the next. Porosity is a major concern for oil exploration companies since these oil and gas fields may have lots of oil on them but due to the oil, and as being trapped within individual cells and not capable of flowing freely between the porous rocks of soil, the wells quickly run dry and are unable to be replenished by the neighbouring porous rocks or soil. This will result in such oil and gas fields being unprofitable for the oil and gas exploration companies but it is also important for the companies to consider developing new technology which would help increase micro porosity field productivity (Lipiec et al. 2006).

This has been done by developing technologies which are capable of drilling vertically to the oil and gas deposits, then turning horizontally across the field. This would help open up more surface area thus increasing the productivity of the fields but this technique would still limit the oil field productivity.

Microporosity discussed in this economics assignment in most situations result in oil fields being considered unviable and unprofitable to drill due to the oil or gas produced being limited to just where the oil drilling goes passed. Other areas of the porous soil and rock remain intact and do not release their oil or gas.

Macro Porosity Oil and Gas Fields
These are porous and solid rocks which are mostly interlinked and act like a sponge which would distribute liquid and gas across the entire porous region. This allows for the oil and gas companies to drill a single well which would continue extracting oil from the majority of the oil field due to the pores being interconnected. This can be observed in fig 3 provided in this economics assignment where the pores are interlinked allowing for liquids and gases to move from one pore the next and gradually drain to the lowest point(Holmes et al. 2012).

Figure 3 - Microporosity

Microporosity wells also vary in their porosity as the level of porosity will vary greatly with some wells allowing faster flow of the oil or gas from one pore to the next while others having a slower release rate.

Additional Oil and Gas Reservoir Forces
It’s also important for oil and gas drilling engineers to consider some additional aspects such as the crude oils viscosity, the oil fields and well’s capillary forces, and the gas field natural gas quality and concentration. All these aspects also require to be taken in to close consideration to determine the oil field productivity and the possibility of generating any profits from the oil fields.

Crude oil Viscosity
Crude oil viscosity is another major concern for oil exploration companies as well as the countries producing the oil. While thicker oils are considered to be more profitable due to their ability to produce more oil-based products, the extraction and transportation of heavy viscous crude oil is also considered to pose some serious problems for the oil companies. This is due to the capability of the oil of solidifying after it has been exposed from the well. While inside the well, the oil will usually remain as a liquid due to the thermal heating and lack of contact with air but when exposed to air the crude begins solidifying thus requiring extra energy in keeping the crude heated while being transported. This is not a problem in Saudi Arabia due to the intense desert heat but the problem tends to arise during the winter months where certain wells are shut down due to the viscose crude solidifying faster and causing further problems. Wells are usually classified according to the type and quality of oil viscosity they produce but the thickest crude qualities are always considered to be better due to their ability to produce a larger number of products (Hasan et al. 2010).

Oil Fields Capillary Forces
Capillary forces mentioned in this economics assignment involve the pressure exerted by the backpressure within the oil field resulting in the field pushing out the crude oil without the requirement for any pumps to be installed. The pressure each field exerts will depend on the number of wells suck into the reservoir and the amount of pressure placed on the oil deposit. Oil field having high capillary pressure result in reducing the energy required to pump or extract the oil from the well which flows out naturally under its pressure. The amount of time the oil continues flowing from the well will usually depend on many different factors but this neutral flow will usually contribute immensely onwards reducing the investment the oil exploration companies need to put into the oil exploration and extraction projects (Butt & Kappl 2009).

Gas and Oil Concentration and Quality
Quality of the oil and gas being produced on the field also requires to be closely monitored to ensure all the products are being sold for maximized profits and while demand lasts. Most oil-consuming companies and nations want only the highest quality crude and gas thus requiring the oil and gas producing nations to take some simple but effective steps linked to ensuring all their products are being sold. The oil and gas companies must consider ways of selling all oil and gas products for the highest price even if it requires considering techniques such as mixing them to deliver an average quality product. Only by offering an average quality product will the company be able to market their products to a much wider group of consumers and also ensure they sell all their oil and gas products (Stratiev et al. 2010).

Essential Oil and Gas Exploration Tools mentioned in this Economics assignment
Carbon/Oxygen Tool (Pulse Neutron Capturing, PNC)
Oil and gas fields and wells also tend to have a high level of nitrogen and oxygen which could result in serious catastrophes and require constant monitoring. This makes it important to put in place suitable Carbon/ Oxygen tools which constantly monitor the gas levels both inside and emitting from the well to prevent accidents from occurring. Both gases are highly flammable when found in high concentration in a certain area. Making use of the Pulse Neutron Capturing tool will help with monitoring and registering the different gases and their levels around the oil and gas field thus helping with their management. This is especially important on certain oil and gas wells such as those located out at sea on oil rigs where the occupants and people working on the rigs have no place to go in case of emergency. The tools thus help monitor the gases and allow for them to be burned so as reducing the risk they pose by keeping their pressures low.

Resistivity Logging Tools
These tools illustrated in this economics assignment play an essential part in oil and gas exploration as they allow for the oil and gas exploration companies to measure the density of the solid rocks on the oil field. This allows them to select the easier and softest areas to drill the oil wells as well as areas which offer the most porous and solid rocks which will ensure for easy seepage of the oil of gas through from other areas of the oil field. The tools are also very important towards identifying solid hard rock like granite which could hamper the good drilling efforts. It is also very important towards identifying underground water which is also an important requirement for any oil field to have and, oil, gas and water well drilling will usually all be near each other (Micheva & Smith 2007).

Production Logging Tool
Due to oil and gas being a pressure commodity, each well’s and field’s productivity must be closely monitored. To ensure the oil is produced from the oil wells is reaching the refineries and deports. This is due to there being many cases where oil pirates have tapped into the crude pipelines. It has become important for the companies to monitor all oil being produced by the wells making it very important for the companies and oil extraction companies to install and use state of the art equipment to monitor the production and ensure all the oil and gas reaches the intended destination. Production logging tools can be used to monitor oil and gas production via several techniques such as the use of barrel measurement as well as through monitoring pipe pressure to locate any fluctuation which could mean leaks or piracy.

Dielectric Tool (ADT)
This tool is used in the oil and gas exploration industry to measure the density of materials above and within the well. As mentioned earlier in this economics assignment, porous and solid stone play a huge role in the viability of the gas and oil fields. This makes it very important for the fields to be mapped before any wells can be sunk to ensure they are sunk in the most porous areas of the field. This would result in more productivity resulting in more profitability for the exploration companies (Virwani et al. 2007).

Conclusion
It is to be concluded in this economics assignment that for any oil and gas exploration company as well as sustainability authorities, it is important to put together strategic surveillance plans which help to map out each of the oil field’s regions. This information can then be used to help develop important approaches linked to mining the oil and gas as well as managing its usability in the future. It’s important that every aspect linked to oil and gas exploration are well planned and approaches linked to the countries reservoir management and sustainability are taken in to close consideration to ensure every drill delivers the maximum amount of oil and gas at the lowest cost. It’s important for every effort to be made towards increasing oil production as well as the lifespan of the well thus making it profitable for both parties as well as increases the amount of time the wells are mined (Babadagli 2007).

Reference List

Akkurt, R., Merkel, R.H. & Coates, G.R., 2000. Remaining Oil Saturation from NMR in a Mixed-Wet, Three-Phase Carbonate Reservoir. SPE 63216, pp. 1–12.

Babadagli, T., 2007. Development of mature oil fields - A review. Journal of Petroleum Science and Engineering, 57, pp.221–246.

Butt, H.J. & Kappl, M., 2009. Normal capillary forces. Advances in Colloid and Interface Science, 146, pp.48–60.

Hasan, S.W., Ghannam, M.T. & Esmail, N., 2010. Heavy crude oil viscosity reduction and rheology for pipeline transportation. Fuel, 89, pp. 1095–1100.

Holmes, M., Holmes, A. & Holmes, D., 2012. Economics assignment A Petrophysical Model for Shale Reservoirs to Distinguish Macro-Porosity, Micro-Porosity, and TOC *. In AAPG Annual Convention and Exhibition, Long Beach, California.

Iglauer, S. et al., 2012. Comparison of residual oil cluster size distribution, morphology and saturation in oil-wet and water-wet sandstone. Journal of Colloid and Interface Science, 375, pp. 187–192.

Lipiec, J. et al., 2006. Soil porosity and water infiltration as influenced by tillage methods. Soil and Tillage Research, 89, pp. 210–220.

Micheva, K.D. & Smith, S.J., 2007. Array Tomography: A New Tool for Imaging the Molecular Architecture and Ultrastructure of Neural Circuits. Neuron, 55, pp. 25–36.

Rutqvist, J. et al., 2002. A modelling approach for analysis of coupled multiphase fluid flow, heat transfer, and deformation in fractured porous rock. International Journal of Rock Mechanics and Mining Sciences, 39, pp. 429–442.

Schmutz, M. et al., 2010. Economics assignment Influence of oil saturation upon spectral induced polarization of oil-bearing sands. Geophysical Journal International, 183, pp. 211–224.

Shafiee, S. & Topal, E., 2009. When will fossil fuel reserves be diminished? Energy Policy, 37, pp. 181–189.

Strategies, D. et al., 2010. Evaluation of crude oil quality. Petroleum & Coal, 52, pp. 35–43.

Virwani, K.R., Malshe, A.P. & Rajurkar, K.P., 2007. Understanding dielectric breakdown and related tool wear characteristics in nanoscale Electro-Machining process. CIRP Annals - Manufacturing Technology, 56, pp.217–220.