Drilling at Ultra Deep Zones

Ali Alasosi

Copyright 2012, Colorado School of Mines

This paper was prepared for PEGN 361 Completion Engineering.

Abstract (Summary)

Ultra deep zone in the world are places with rich deposits of crude oil waiting for potential investors to drill. However, the high costs associated with drilling in these areas discourage potential investors from drilling. In addition to these high costs, there is high pressure and temperature in these ultra deep zones. Nowadays technology in drilling for this oil solves these issues for these companies and drilling is now easier for them. Problems arise after drilling when human beings conflict with the companies because of pollution from these companies. The issue of time and proper compensation for workers by these companies raises disagreements on many occasions. Ways to solve these problems are a priority for the stakeholders in this industry. Despite these disagreements, human beings have to tolerate, as they need the products of this industry.

Introduction

Drilling in the ultra deep places is a hard task for most engineers. In fact, it is amongst the biggest challenges in this industry. This is due to the many sites where this type of mining is available. This is in both the onshore and offshore areas. There are many challenges that the company that is drilling is likely to face in their operations. The operations face more challenges than if they were involved in the regular form of drilling. This means that it is more risky in the ultra deep drilling than it is when it is regular. However, the reward of the risk is in the benefits that the company is likely to accrue. The income that comes from these wells is exceptionally high and thus can compensate for all costs in the process (Luo 980). Therefore, it is imperative that a solution for the challenges is implemented. A technology can help in solving these problems. This technology is HTHP. Through this technology, engineers can come up with solutions for the problems. This is why companies are now looking for engineers who can work using this technology for maximum output.

Body of paper: Problems discussion

Problem resolution

Problem resolution support

A challenge that affects this work is the conditions involved. In deep drilling, the process is done up to extremely deep levels. In these regions, there are extreme conditions. There are high pressures that are in the wells, through the increase in depth. In some occurrences, these pressures are exceptionally high, and they exceed 30,000psi (Rempu 204). The temperatures are also proportional with the pressure. Therefore, there is an increase in temperature the more the well is deeper. Many problems entail because of these two challenges. The machinery that is used in the task is likely to depreciate at a remarkably fast rate. This is attributable to substances that have the ability to corrode the machinery and thus reduce its work rate. The stress that is accrued from the process also has a large impact on the machinery. This creates the necessity to replace the materials often. Consequently, this increases the costs that are involved in drilling. Persistence of such costs could lead to losses from the drilling process. Therefore, it is imperative that there are new methods that will reduce the risk available to these factors. Consequently, this will lead to the formulation of new strategies that will assist in better drilling.

Various strategies are easily adaptable to bring the necessary changes in this field. These mainly focus on the depreciation that machines have when it comes to withstanding the extreme conditions. The use of alloys could prove to be particularly beneficial in this instance. An alloy occurs when two materials combine to form one that has a better utility than both do. The alloy has a better chance of survival in the well than the machine that is currently in use. This saves on the costs that occur due to the constant replacement of the machinery. The fatigue behavior of the alloy is determined, and then modifications are done for any improvements (Rempu 205). The conditions that the machinery has to accommodate are dependent on the site. In the onshore wells, the equipment has to withstand the salient conditions. These include the chlorides and the air. Addition of hydrogen sulphide in this mixture provides a combination that has a large influence on the performance of the machinery. For this to occur, there needs to be study of the environments in the sites in of the wells. Through this, there is the determination of the appropriate products that are proper for the HPHT applications (Rempu 205).

The other aspect that poses a challenge to drilling is the geo hazards. This is mainly the case in the onshore wells. These geo hazards bring the probability of a few origins of problems. This includes the steep slopes. It is difficult for the drilling to occur in areas that have steep slopes. As a result, most of the areas have to be evened out for effectiveness of the process. This is because this complication leads to extra costs in the drilling process. In addition, such areas are not easily accessible. Another geo hazard is the irregularity of the topography. The site of the well may not be regular which leads to derailment in the process. The company undertaking the task has to go through extra costs, as they will have to make the area accessible. The problem with most of these areas that have the wells is that some of them are in extremely risky conditions. An example of this is the active faults. The area where the well has its location could have such physical constrains. This might lead to abandonment of the whole plan due to the high risk that is involved. This is due to the risk that the engineers carrying out the task may have. These natural hazards have more severity especially where there are gas hydrates (Van 37). These are acutely lethal, and the plan may have to be abandoned totally. Some of these require specific design of the equipment. The companies have to come up with equipment that has a design that is only specific to some wells. An example entails occurrences where the site could have rocks without normal consolidation. In addition, in an area with corrosive soils, there are high chances of destruction of the equipment. Therefore, it is imperative that the companies design appropriate equipment for specific drilling sites.

There are also situations that lead to the inability of drilling. This happens when the pressure margin is exceedingly narrow. This is a result of the low tolerance that if from the difference in the pressures. These are the pore and the fracture pressures. This difference in the pressures is probably the biggest challenge that affects the process of drilling. The fracture pressure difference decreases due to the overburden of the whole gradient.  There is a crucial observation that can be made from the deeper water case. This is the reduction in the fracture pressure gradient. The reason for this is the reduction in the overburden gradient. It is because of this that the operational window reduces. This window is a result of the two pressures.  The reduction of this window has drastic results. There is the inability to cover the total depth of the operation. This means that the drilling cannot give the best, as there are limitations in the production. Therefore, there is a need for new technology to help engineers detect the anomaly. An example of such a tool is the pressure while drilling (Van 39).

Drilling costs of oil is extremely high in comparison to drilling regular wells. Location of oil in the ground is deep in the earth’s layer and the efforts required to drill for it surpass those of the regular wells drilled every day. At these extreme depths, drillers encounter hard rocks that are extremely hard to drill (Kelessidis, 2009). The wells that are deeper than 15,000 feet 50 percentage of the expenses of drilling are in the final stages of drilling. Pipes needed in this case are of thicker quality and must be sharper than the starting pipes as the drilling gets deep so does the hardness of the rocks. Rate of penetration in such deep grounds is around two to three feet every hour. This is a slow rate compared to hundreds of feet drilled in normal wells per hour of drilling.

When workers are deep drilling for this oil, coming across salt domes overlaying tertiary sediments is an everyday common problem. These make the rock deposits below them rubberized. These rocks are extremely hard to drill into making a venture to get oil from underneath them an expensive undertaking. On drilling through these rocks, oil deposits have very high crude content. Recently in Brazil after drilling through for 21000 feet, miners get many barrels of oil deposits every day (Kelessidis, 2009). This being the goal of such an undertaking drilling through such hard obstacles is a key challenge but once successful it is worth the costs. At these deep ultra depth wells, temperatures and pressure are very high. This risks the life and durability of the pipes used. Pipes used are expensive, as miners have to use strong pipes to drill through the hard part of the earth’s crust. Even when the pipes are hard breakages still occur demanding for replacements which costs the investors drilling the wells extra money.

USA permits working on wells with 15000 and above feet but it is the companies that should invest in this undertaking that cower, as they fear losses from the investment. These companies are even at greater risk of blocking their paths with materials they introduce into the wells through breakages of these materials (Sircar, 2004). To set up the platform companies have to incur extra costs of unmanned submarines required for this exercise. In this exercise, there are great risks of loss even after the drilling starts. Most of the oil drilling platforms is in big water bodies. Many calamities occur in these deep waters. An example of these is the hurricanes that hit these oil wells once they occur. A good example is the Thunder horse platform after hurricane Dennis hit it. This made stakeholders call for deeper structures to hold these platforms to avoid reoccurrence of this.

The companies that drill oil faces criticism from labor unions as to the way they treat their workers. Some of these workers have to dive deep water to fix some of the problems that occur during drilling. They have poor equipments to dive into such depths and at times, they even end up dying due to the unfavorable conditions under which they work. At nights, temperatures in these water bodies are extremely low. Workers working in the night shifts, as the platforms need to be watched day and night experience health problems. This has been a big problem to these companies (Kelessidis, 2009). Most of their expenses they spend on paying these workers and buying them equipments. Many hours spent during the drilling period are also another added expense to the company. This is the period that the companies require much labor and they have to pay with the hope to recover the expenses with time to come. At times workers maybe inefficient and cost the company a great deal of loss. Solving the labor question to satisfaction is hard as it is hard to determine whom to blame. However, drilling companies need to ensure workers have good working conditions and better remuneration for their work. Companies need to fix overtime pay and pay workers according to any extra input a worker gives.

Conclusion: Recommendations

These companies will have to prepare adequately in preparation of a drilling process (Sircar, 2004). First, they need to determine how far deep into the ground they will drill. If they will do the ultra deep, mining companies need to get all the advanced equipments before they commence. This will increase speed in which the drilling will take place.

The second is get resources from different sources and pool them together to avoid running out of resources in the cause of drilling. Resources are the biggest challenge to drilling for many companies (Sircar, 2004). These companies run out of money to pay workers and sustain the drilling process.

These companies have to embrace technology. Scientists and geologists have come up with new methods to determine which part of the ground has rock deposits that are not very hard. This will make it easy for the drilling process to carry on without hindrances. Technology has also developed alloy pipes that are hard and can drill through these hard deposits of rocks. (Kelessidis, 2009). Machines, which are more efficient with an inbuilt monitoring system, are the best option for the industry. With enough investment into the technological word, experts can develop these machines and make drilling easier and eco friendly.

Drilling of oil is an important part of human beings daily life. Everyday human beings need petroleum products to carry out different activities (Kelessidis, 2009). It is thus important that they find better means to do this, as they will need to coexist and look for ways to reduce conflict. In response, these companies should draw well-documented payrolls for these laborers as a first step to resolving this conflict.

Bibliography

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Sircar, A., 2004. Hydrocarbon production from fracturedbasement formations, Current Science, 87(2), 147-151