HPHT Well Completion
Drilling high pressure high temperature wells are dangerous and need to be done after careful planning and preparation. These wells put out temperatures on excess of 300°F (146°C) and have a pressure in excess of 0.08 psi per foot. This means that these well require not only expert skill and knowledge, but also specialised equipment.
Once a well has been drilled, the content is analysed and it is then decided whether the project will continue, or the well must be plugged and abandoned. This decision is not an easy one as drilling a high pressure high temperature well is extremely expensive. However, working a dry well is also not an economical alternative.
When the well is found to be viable, the proper equipment is brought in and the following steps are followed:
- Casing
The casing consists of a steel pipe forming a hollow tube and is used to prevent the well’s hole from closing in on itself. The pipe is fed into the hole and will start varying in diameter as the various stages of the hole are reached. There are 2 types of casing that can be used. The first one is solid casing which consists of 1 piece of solid steel. This type of casing is used in solid formations. When there is loose sand and other agents that can block the pipe, the casing is also equipped with a sieve. - Cementing
Cementing the well means literally pumping cement into the spaces between the pipe and the side of the hole to firm it up and prevent it from collapsing. When the cement is pumped in, it displaces the drilling fluids and makes the well firmer. - Perforation
The casing of the well is run into the reservoir. To enable production, the casing walls are the perforated so that the hydrocarbons can enter the pipe and taken into the well. - Gravel packing
In some wells there is a chance that sand will enter the well. Although a casing with a filter lining is inserted, gravel is pumped into the well, fitting between the lining and the sides of the wellbore.
Completing the well is just as dangerous as drilling it as there is always the risk of a blow-out. There are also a variety of factors that play a role in the successful completion of the well. If each step is not carefully executed, the drilling crew’s lives will be in grave danger. So much depends on the planning and preparation of the project, as well as the continued teamwork of the drilling crew. Without these components, the well cannot be successfully completed and many lives could be lost.
Why Do Gas and Oil Rigs Need to be Decommissioned?
There are gas and oil rigs in place all over the world where we are drilling for these fuels. There is a huge demand for both of these fuels and that is why there are so many of these rigs and other structures in place all over the globe. Oil and gas drilling takes place both inshore as well as offshore. Offshore drilling has seen these companies being able to yield very large amounts of gas and oil but these structures cannot last forever and there will come a time when decommissioning has to take place.
There are two main reasons why decommissioning of oil and gas rigs will occur. The first reason is because the structure which has been put in place for the drilling of these fuels may be at the stage where decay has taken place over time. A lot of oil and gas rigs have been sitting around for years and obviously they will start to become prone to wear and tear. When this happens, it may be necessary to consider decommissioning because it may get to the stage where it is unsafe for those working on the rig.
Another reason why decommissioning of oil and gas rigs takes place is because it may get to the stage where it is no longer feasible to drill for these fuels in that location. If there is a huge decrease in the amount of oil or gas that can be produced from a specific rig then there will be no point in continuing to try and drill there. It will therefore be necessary to decommission the rig.
With many oil and gas rigs situated quite a distance from shore these days, it can be a difficult job to carry out the decommissioning. The company will have to arrange for the equipment required for the decommissioning of these rigs to be taken from shore out to the location of the rig. It is a long drawn out procedure to remove oil and gas rigs that have been in place for decades. It also requires the skills of various industry experts so can be quite costly.
Apart from the fact that decommissioning an oil or gas rig can be tricky and expensive, it can also be a risky job for those involved. It is dangerous and there are certain health risks involved too. This type of work can be very hazardous so it needs to be done over time and health and safety is paramount. Companies involved in decommissioning not only need to protect their workers but they also need to ensure that marine life is not affected by the job.
HPHT condition in the past and today!
Higher pressure and higher temperature targets were very few in the past than it is today. Reservoirs with very high temperature and pressure are turning to be the main development sites today unlike in the past.
High temperature and pressure are highly challenging and they affect the functionality, durability, efficiency, physical power of equipments and tools used in HPTP conditions. It had always been challenging then and now. Though the HPHT solutions were used even in the early days, it was not as much as efficient as it is today. This is a very big barrier that many industries have to face today in order to develop and integrate these reservoirs which are to be used as the exploration and development sites.
There had been a high demand in the market for conventional well in the past. And today when compared to the HPHT wells there is a high question in the market for the conventional wells. This is because most companies are very much reluctant to invest in a new technology based project and they fear the high cost of basic investment into the project. The market for the HPHT wells will definitely go up very high if the companies could realize the high yield from the HPHT wells than the yield from the conventional wells. The reluctance of these companies to invest in the HPHT reservoirs is a big down fall for the development and exploration of the HPHT reservoirs.
Today many HPHT solution companies are working very efficiently to serve their clients with the best technology to be used in the explorations and developments in the HPHT reservoirs. They offer strategies for faster and safer production to suit the client beyond his needs. The high engineering technologies and the risk reduction techniques of these service providers can be highly effective to invest into HPHT reservoirs.
Hot Tapping Basic Application
Pressure tapping or hot tapping is a process of linking the connection to the present piping or vessel without interruption of emptying that section of the pipe or a vessel. This simply means that the pipe or the tank can continue to operate while maintenance or modification is being done on it. This is a very useful way to drain pressurized casing fluid.
Hot tapping is done in such a way that a hole saw is used to make an opening in the pipe so that a plugging head that can be inserted in the line to be stopped. Work can be done on that section of pipe without shutting down other sections. However, there are certain situations where wielding cannot be done on equipment which contains certain substances. Few of them are listed below:
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Hot tapping is not possible where there are mixtures of gases or vapours which tend to get inflamed as a result of wielding operation.
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There could be substances which might react or decompose leading to increase in pressure, explosion or attack on the metal leading to some accident. There can be instances where certain combinations of concentration, temperature and pressure, acetylene, ethylene and other unsaturated hydrocarbons initiated by the wielding hot spot result in explosion.
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Hot tapping is not advised in oxygen enriched atmosphere, which can lead to explosion in presence of hydrocarbons in the environment or deposited inside the pipe.
And based from above, the welding equipment or the pipe that contains hazardous substance or condition as listed even in smaller quantities, may not be performed unless the positive evidence has been acquired that welding or the hot tapping can be done safely.
Applications
A normal application may include the use of fitting designed to have system pressure, valves, used in control of the new branch connections, clamp, weld and drilling machine to create the hot tap. Drilling machines normally consists of the mechanically driven into telescoping bar that advances a cutting tools.
Necessary element in the most hot tap connection is a full ported valve that can become a controlled valve for a new connection and then enables the drilling machines to be removed after cutting operation. Gate valve and the other full ported valve with flange and screwed connection, normally includes 150 pounds through 900 pounds ANSI rating.
The PHL purchase machinery from the leading international supplier of the hot tapping equipment and resulted in the access of the latest development in this fast acting engineering process. PHL is on the other hand be able to place wider range of solution together, testing the boundary, while maintaining a good practice and adhering stringent safety code.
Line Stopping
Line stopping is the process that allows positive temporary isolation to the system that contains wide range of some substances as well as pipeline materials. When used in the conjunction with a by-pass that flow the system that can remain online, as a result of preventing costly downtime while the repair, modification and the relocation can take place.
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