Introduction and background
There have been problems that have been encountered with the drilling of deepwater and ultra-deep water. These issues have caused the problems to be seen in the oil drilling process. The challenges that are seen while drilling ultra-deep water depths have led to redesign the drilling programs for search of oil. In the past, the drilling used to start with the top soils which were easily to excavate. This is no longer the problem as there are machines and tools that are used to take away this soft top soil. The issue that is being met with this drilling is the challenges that are met when undertaking ultra-drilling. The challenges that are experienced have been seen to affect the depth that the drilling process will undertake. This paper will assess three papers that try to address the various aspects of drilling ultra-drilling procedures. Wells which are drilled in depths which are more than 1500 meters are classified as ultra-deep wells. The drilling process that is undertaken for such drilling experience is referred to as ultra-deep water drilling process. On the other hand, the deepwater wells are referred to the water wells which range from between 300 meters to 1500 meters.
There are various challenges that have been met while undertaking ultra-deepwater drilling. The deepwater drilling that is undertaken with dynamic positioned rigs has been in existence in Brazil for a long time. This has been seen to have started from the year 1984 when ultradeep water drilling seemed to be of great interest to many.
Technical review of the articles
Accroding to Rocha and Roque (2003), there have been these challenges and these issues from a long time. The deesired hole shoul dbe attained for a drilling experience to be regarded to be successful. The argument of Rocha and Roque (2003) is based on the experience of one company which has been concerned with drilling of ultra-deep water drilling. This is an imprtant aspect that has been dwelt with in the paper. The company is that of Petrobras. The authors describe the situatiosn that are met for a drillimng xpereince to be regarded as successful. The research work shows with the experience that have been met by experienced ultra-deep water drilling company. The authors also brong about the issue of shallowness and failures of the drilling equipment that are regarded to be the source of challenges that have been found and experienced in this aspect. In the introductiuon section of Shaughnessy, Daugherty, Graff, and Durkee (2007), the authors give the bemefits that have been seen in ultra-deep waterdrilling expeience. The authord choose to focus on the success thast have been experienced in ultra-deep waterdrilling mechanisms. The article Mishra (2006) shows us the various computattions that the drillers will have to consider and take in order to have successful ultra-deep water drilling processes. All the three articles focus on the problems with ultra-waterdrilling experiences.
Challenges of ultra-deep waterdrilling
The three articles show that there are challenges that are being experienced in the process of drilling ultra-deep water drilling boreholes. Rocha and Roque (2003) and Mishra (2006) argue that there are challenges that are met in their drilling. One issue that comes out in these two articvles is the roles of the top soil in the drilling process. Shaughnessy, Daugherty, Graff, and Durkee (2007) argue that there are envieonmenta challenges that are common with ultra-deep water drillimg. The environment forms a significant role that they play in the drilling process. Both articles have shown that the environment plays an imprtant role in tehsuccess of the drilling process. Shaughnessy, Daugherty, Graff, and Durkee (2007) argue that the eddy currents which have been experinced in Mexico have been a major hindrance in ultra-deep water drilling process. This is an important factor that affects drilling to the ultradeep.
There is another issue that Rocha and Roque (2003) bring about as a challenge. This is the issue of lower overburden stress that come as a result of long water burden. This is also an environmnetal issue although Rocha and Roque (2003) categorises this as a geohazard factor. The authors also bring other geohazrads which include steep slopes, and topography which is not regular and does not follow the required line. The eventual effect that eth geohazard will cause to the environment will depend on the activities that are taking place in the area that the drilling is taking place.
Well design
This is a design element that affects the success of the drilling process. This is adversely mentioned in the Rocha and Roque (2003) article where the authors describves the evolution in which the design of the borehole has taken in the drilling proces of Petrobras. There are dimensions whiuch are required in order for the deep water drilling to be considered to be successful. The pipes and their dimensions are supoosed to be described in the entire process. This is an important aspect that should be described and understoood. Shaughnessy, Daugherty, Graff, and Durkee (2007) do not bring about the issue of the design of the well but rather bring about the important aspect of the design of the equipment. According to the authors, the design and the effectiveness of the equipment affect the success of the drilling prpocess. There is also another issue that the authors bring up in the drilling and the design of the borehole, the formation factor. This is something that can be related to the design issues that has been mentioned before. The authors argue that there is an important factor that should be considered in eth formation of the well. The issue that the authors mention are the margins between the mud weight that is required and the fracture gradient. Mishra (2006) describes the design requiremetns almost the entire article. This shows that the author values the design issues of the borehole and believes that the success of the drilling process will depend on the design of the borehole. There are factors that the author bring about like the control of the liquid flow, the control of the transition time and the shrinkage level and degree. All these shoild be controlled in order to attain the right drilling pace and success. There are also operational requirements that are required in the drilling process.
Theoretical results
Validation
The design of the borehole drilling procedures that have been stated in the previous section have been applied by Petrobras which is a drilling company. This is in the case of Shaughnessy, Daugherty, Graff, and Durkee (2007) artile. These results are seen to be woring out. The article gives the developments that took place to the state where the design measurements were obtained. This, theerfore, validates the design that has been proposed.
Conclusion
The three articles have shown the various considerations that should ne put in mind in handling challenges that come with ultradeep water drilling. The three articles have almost the same aspects and factors that should be considered while handling the design of the drillling boreholes. The rigs and their design have also been widely dealth with by the authors of the three articles. This is an imprtant aspect that is being considered when handling the drilling process of ultra-deep water drilling tasks.
References
Mishra, P. (2006). Ultradeepwater cementing: Challenges and solutions. SPE/IADC Indian Drilling Technology Conference and Exhibition (pp. 1-10). Mumbai, India: Cengage Learning.
Rocha, L. A., & Roque, J. (2003). Overcoming deep and ultra deepwater drilling challenges. Offshore Technology Conference (pp. 1-12). Texas: OTC.
Shaughnessy, J., Daugherty, W., Graff, R., & Durkee, T. (2007). More ultradeepwater drilling problems. SPEMADC Drilling Conference (pp. 1-12). Amsterdam: Cengage Learning.
