How To Distinguish The Thread Of Oil Pipeline?

Oil pipe thread, which is the most common tools, is a part that difficult to distinguish. Thread is very important to the tool division or supervisor. If a tool division is unaware pipeline thread, it is difficult to work from preparation to direct operations. Here we recognize some common tubing joint on the market, each of them has their own advantages and each have their own usefulness.

Common tubing thread

Tubing thread is commonly divided into EU, NU and NewVam. The EU and NU, which is a triangular joint type, is difficult to distinguish from the joint appearance. But from the whole string can be easily distinguished that EU means external upset and NU means no external upset. New Vam is actually a buttress thread connections and it is not external upset, so it is very easy to distinguish.

EU(External upset)

EU is a kind of external upset oil pipe joint,  there are three biano logos related to EU. EUE (External Upset End) represents outside the thick end, EUB (External Upset Pin) denotes an outer thickened pin thread, EUB (External Upset Box) indicates external upset box thread. In addition to the use of pin and box represent the male thread and female thread, the other said male thread: 1 external thread 2 male 3 male thread; female thread:1. female buckle 2 internal thread 3 box 4 box thread.

NU(Non-upset)

NU is a kind of non-upset oil pipe joint, in addition to no external upset, NU is usually 10 threads per inch and EU is 8 threads per inch. NUE represents a non thickening end or end thickening

New VAM

This thread is substantially rectangular-shaped cross section, equal pitch intervals, little taper and no external upset. The VAM with excellent performance, high connecting strength and good sealing effectcan meet requirements of different service conditions. This thread is widely used in all kinds of special thread and it belongs to the high quality special thread. VAM follow the thread specification of API, thus inherits the advantages of high bonding strength. It improved Screw seal form in order to overcome the poor sealing performance.

Common drill connection

REG(Regular Style Connection)

This type of drill pipe joint thread was used to connect the inner upset drill pipe so that drill pipe diameter is smaller than the inner diameter of the thickened and the inner diameter of the thickened is smaller than the diameter of the inner tube diameter. The main purpose of API design regular style connection is applied to the bit connection. Since the drill bit is located in the end of drill string, the stress concentration phenomenon of thread is not relevant, so API retained their all specifications.

IF(Internal-flush style connection)

This type of tool joint thread connects EUE or inside and outside thickened drill pipe, forming the inner diameter of the drill pipe joints, tube inner diameter and thick pipe inner diameter is equal to the inner diameter or approximate size. All specifications are used thread V-0.065 flat top and bottom triangular tooth type, which width is 0.065 inches (1.651mm). Because of this type easily lead to stress concentration, API has gradually replaced it.

FH(Full-hole style connection)

This type of joint screw connects inside and outside thickened drill pipe, forming the inner diameter of the drill pipe joint is equal to thickened end diameter and they are smaller than the inner diameter of the pipe. Although the thread specification is not much, but it has three models named V-0.065、V-0.05 and V-0.040 so that it has been widely used in kelly, drill pipe, drill collars and drill.

API thread specification

API Round Thread

There are short round thread casing and the long round thread casing points. There are some advantages about round thread casing as follows:

• Improve the abrasion caused by resistance when the thread tightening
• Tighten the screw, the tooth tip provides a reasonable space for foreign particles and dirt
• The circular arc tooth is not sensitive to local scratch or dent damage

Round thread due to its easy processing, good sealing performance and low price, is widely used in casing connection. In addition, it’s simple in site maintenance and use. In the test of different specifications of the round thread casing, use appropriate specifications of the thread gauge to test, when necessary carries on corresponding processing to the data

Buttress Thread

In oil field tubing, buttress thread is a pipe thread form designed to provide a tight hydraulic seal. The thread form is similar to that of Acme thread the force is transmitted almost parallel to the axis and thread is about the same strength as standard v threads.

The advantages of buttress thread:

• Buttress thread can withstand large tensile or compressive load, especially having sufficient tensile strength.
• The design of the thread parameters are optimized to ensure that at least there is a tight fit around the thread, there is no gap, so that the sealing capacity of the terminal is greatly improved.

Some Issues About OCTG Market And Price

The analysis shows that the key factors affecting the oil pipe market include the global oil distribution, the global demand for oil pipe, and the growth trend of crude oil prices. High volatility is not only a recent feature of the global stock market, but also the best term for the international oil price. The fluctuation of oil price has a significant impact on the oil pipe market. So analysis of the oil pipeline market is very important to the rational allocation of resources and adjust the sales strategy.

Current situation analysis about oil distribution

Oil is not evenly distributed around the world. More than half of the world's proven oil reserves are located in the Middle East, that is, the Middle East contains more oil than the rest of the world combined. Followed by Canada, Russia, the United States, these regions contain less than 15% of the world's proven reserves of oil. But the production of oil is not proportional to the reserves. For example, the Middle East contains more than 50% of the world's proven oil reserves, but only 30% of the world's oil production (although the figure is still higher than elsewhere). In contrast, the United States, which claims less than 2% of the world's oil reserves, produced 10% of the world's oil.
Clearly the Middle East has the most urgent desire in the oil drilling industry. Oil casing is necessary equipment for oil drilling, therefore Asia-Pacific is the largest market and China held the maximum share in demand of OCTG products, which has suffered half of API's share of the Asia Pacific Oil Pipeline. America Market is the most influential market. There are large offshore drilling activities in Golden Triangle, Mexico Bay, West Africa. As a result, the demand for high quality oil pipe grades will increase in the above areas. In addition, Russia, another key oil and gas producing nation, will see oil and gas pipe demand rise at a strong pace.

Which country or regions need OCTG?

Global demand for oil pipelines is expected to increase by more than five percent per year to close to 55 million metric tons by 2017. The demand for different countries and regions are not the same, the demand for oil pipeline will be especially strong in the area of development and the construction of energy infrastructure will increase the demand for the line pipe.

China, which dominates oil and gas pipe demand in Asia, will experience solid growth as it continues to construct energy infrastructure, particularly in the gas segment. Demand in Africa will grow because of the development of offshore wells off the west coast. In addition, the Middle East will have strong gains resulting from sustained growth for large producers, such as Saudi Arabia. With a strongly expanding offshore sector, including considerable activity in pre-salt zones and increased onshore activity, demand in Brazil will increase as well. In North America,Oil and gas pipe demand will benefit from the development of shale plays,Line pipe demand in the region will benefit from the additional infrastructure built to transport oil and natural gas from the well site.

What is the price of the oil pipe?

In recent years,world oil demand growth slowed, but oil supply continues to grow, the market supply and demand facing relaxed, international oil prices are still low levels. At the same time, the international oil price of the roller coaster situation will have a great impact on the oil drilling industry.

Oil price trends

By 2016, economic recovery in the developed economies have improved somewhat, But remain weak oil demand. Emerging economies are slowing down, boosting oil demand underpowered. World oil demand is expected in 2016 to 95.5 million barrels / day, an increase over the previous year by 1.1 million barrels / day, lower than the 2015 growth rate. Non OECD (Organization for Economic Co-operation and Development) countries are still the main source of demand growth, an increase of 1 million barrels per day over the previous year.

From the country, the oil demand growth will come from China, India and the United States. 2016, non OPEC oil production will be reduced by 500 thousand barrels per day over the previous year, to 57 million 700 thousand barrels / day. OPEC oil production continues to grow. Oil revenues is OPEC's core interests, under the threat of unconventional oil resources, alternative energy, new energy and renewable energy，to defend the market share and ensure the position of OPEC oil in the global energy supply system will be the core of its long-term strategy. Therefore, the possibility of reaching a reduction agreement in 2016 is still small, but with the deepening of the degree of financial pain in OPEC countries, there is not rule out the possibility of its decision to cut the appropriate. Overall, oil inventories still further accumulation on a global scale in 2016, thereby limiting the rise in oil prices.

Price trend for OCTG

In the state of global oil prices depressed, what is the price of the oil pipeline? Asian and African oil pipe markets, the price of oil pipe slightly rise, but compared with previous years, the demand is not as good as before. Traders' demand is slack, and money is a key factor in the purchase of oil casing. And the increase in railway costs, steel mills may continue to raise prices, the issue of steel prices has become one of the issues of concern. Compared to Asian and African markets, America's casing price remains stable. In recent years, American countries have been on the development of shale oil production and offshore drilling, so the demand will continue to increase. Experts estimate that this year's oil casing market will continue in the weak state and prices will rise slightly, but overall remained stable.

What's The Difference Between ERW Pipes And Seamless Pipes?

What is ERW pipe and seamless pipe

ERW pipe, shorted for electronic resistance welded pipe, is manufactured by cold forming the steel coil into a round cylindrical pipe. Current passes between the two edges of the steel to heat the steel to a point at which the edges are able to connect together to form a bond using the actual welding process. ERW is normally used to transport liquid, such as petrol and gas, playing a significant role in the world line pipe transporting area.

Seamless steel pipe, or SMLS, refers to a hollow steel pipe having no seam around. Due to its unique feature of strength and anti-bending, seamless pipe is widely used in construction, oil refining and chemical industries.

According to the definition of ERW pipes and seamless pipes above, it’s obvious that there are some differences between them.

Comparison of tube billet quality

Tube billet, a key raw material in manufacturing process, is a solid round bar of steel used to produce many pipe products. Compared with seamless pipes, the chemical structure of the tube billet of ERW pipe has more advantages. The processing method such as desulfurization, dephosphorization and degassing makes the purity of ERW pipe billet much higher. The adding-in of specific chemical elements improves the toughness and the strength of the tube billet.

Besides, the ERW pipe tube billet is made of hot-rolled steel strip with cold rolling process while the seamless pipe tube billet is produced in hot rolling condition. The situation where seamless pipe tube billet is produced has some negative effects on the grain size, thus resulting in a less satisfying performance.

Comparison of manufacturing process

Seamless pipe is formed when steel in the billet is heated and then either pushed or pulled over a mandrel with a piercing point located in the center of the billet. This produces a hollow tube or “shell”. The tube is then further processed until it becomes the desired size and wall thickness. The whole manufacturing process doesn’t involve any welding part, so there is no welding line in seamless pipes. ERW pipe is cold formed a strip steel into a round pipe section, the edges of which are heated by high frequency welder. Then the welding is inspected electronically and cooled down by air and water.

Comparison of structure

The biggest visible difference between ERW pipes and seamless pipes in structure is that ERW pipe has a welding seam which is produced by the welding process while seamless pipe doesn’t. The less recognizable the welding line is, the better ERW pipe will be. Nowadays, with the advancement of the technology, two ways are coming into use to eliminate the welding line, the geometric seamless and physical seamless. Geometric seamlessly is to remove the burr inside and outside of the ERW pipes. Physical seamlessly refers to the difference between the microstructure and the parent metal on the inside of welding line resulted in decrease of the welding area and mechanical properties.

In contrast to the ERW pipes, seamless pipes, without the seam or the welding line, is able to maintain a uniform shape and great strength under high pressure, temperature or heavy loads.

Advantages of ERW pipe and seamless pipe

Seamless pipe owns three unique advantages, namely high pressure endurance, great strength and uniformity of structure.

Seamless pipe is most favored by its high pressure endurance. Normally, the weakest part of pipes is the welding line, but seamless pipe doesn’t have a seam, so the entire circumference of the pipe can evenly withstand high pressure. Besides, owing to the lack of the welding line, seamless pipe is able to support its own weight as well the heavy loaded weight, and maintain its original structure. There advantages bring seamless pipe a number of commercial applications, not only in oil field, but also in ship building, offshore rigs, pressure vessel and so on.

As for ERW pipe, one of the biggest benefits is that only the tube billet ends are heated during the manufacturing process, therefore the rest of the whole ERW pipe remains clean and only the welding part needs to be cleaned. This reduces the post-welding cleaning work, largely increasing the working efficiency and saving cost. Besides, owing to the almost clean and smooth surface, ERW pipes are easy to be applies with coating method.

Generally speaking, though having much difference in making process and structure, ERW pipes and seamless pipes in Anson Company are both widely applied in oil and gas transporting field. Both pipes complied with API specification are acceptable for most applications. To fully enjoy the benefits of the two pipes, customers shall choose the more suitable pipe based on their own actual needs.

How Does The Hollow Sucker Rod System Work?

What is hollow sucker rod?

Hollow sucker rod is a special oil pumping rod designed specially for high freezing point, high viscosity and high wax oil extraction. It is combined with threaded joints, sealing and rod body. The rod body is made of seamless steel pipe, and the screw thread joint is connected with the rod body through friction welding and heat treatment. Because the hollow sucker rod is designed on the surface of the bearing, the joint is more reliable. Design of a hollow structure can be injected into the hot oil or steam, it can also be used for the operation of heating cable. The hollow sucker rod reduces the viscosity of oil and wax deposition, and improves the efficiency of the pump. There is a plastic cap protects the thread of the hollow sucker rod and the plastic cap can also be painted with color. The hollow sucker rod also saves space of the metal pallet packaging, which is convenient for transportation.

Application of hollow sucker rod

• The hollow sucker rod is used for the exploitation of heavy oil, high freezing point and waxy crude oil.
• Hollow sucker rod can be used for sand flushing. It is a kind of ideal small and independent oil reservoir exploitation.
• The hollow sucker rod can be used as heat carrier oil extraction. The injection of chemicals and heat carrier, including hot oil, hot water and steam.
• The hollow sucker rod can be used in an electric heating device, which only runs on the center hole of the hollow sucker rod.
• Screw pump drive rod is a kind of specially designed hollow sucker rod, which can be used to drive the screw pump, because the hollow sucker rod has high rigidity and large torsional performance.

Except with common sucker rod transmission power, hollow sucker rod can also reduce the viscosity of crude oil, anti-corrosion insulation, control of the paraffin wax, to improve the physical properties of the shaft, so as to improve the pump efficiency; The anti torque ability of the hollow sucker rod is better than that of the traditional sucker rod, which can be used to drive the downhole screw pump, and the hollow sucker rod shaft is very convenient to be installed on the controller.

Hollow sucker rod electric heating device

In view of the problems in the crude oil extraction process, such as: crude oil is difficult to lift, the sucker rod load overweight, downward difficult, pumping oil airborne load increased and so on, hollow sucker rod electric heating device was successfully developed.

Working principle

The device is to make the cable which through the hollow rod to the bottom of the well shorted connected to the sucker rod. The circuit is composed of a cable and a hollow rod. When the cable and the hollow rod simultaneously pass through the positive and negative alternating current, the hollow rod is integrally heated due to the skin effect of the current. The heat energy produced by electric heating is used to heat the crude oil in the oil pipe, so as to improve the fluidity of the crude oil. Effective solution to a variety of technical problems is to achieve the purpose of increasing production and efficiency of oil wells.

Characteristics of skin effect

When there is an alternating current or electromagnetic field in the conductor, the current in the conductor will be concentrated on the surface of the conductor. The resistance of the wire increases and the loss power is increased, which is called the skin effect.

Product features

As the temperature of crude oil in the wellbore is increased, the viscosity of crude oil drops significantly, the oil well lifting resistance is obviously reduced, and the pump efficiency can be increased by more than 20%. At the same time, due to the acceleration of the oil well, the production of oil well is generally improved. The production efficiency of oil well is increased, and the production cycle is prolonged. The installation and management of the device is convenient, and the comprehensive economic benefit is very significant.

Conclusion

Hollow sucker rod also has some problems:
In order to ensure that there is sufficient contact area, the hollow sucker rod will use too many joints, resulting in the improvement of the cost. In the threaded connection, due to the stress concentration and the generation of the prestressing force, the root of the external screw thread is easy to break. Due to the friction motion of the vibration, the neutral point and the wall surface, the trip performance of the joint of the hollow sucker rod is poor.The sealing performance of the joint of the hollow sucker rod is poor. It is difficult to ensure the strength safety of the joints due to the limitation of the geometrical size.

To sum up, the selection of sucker rod is very learned. According to the actual situation and needs to choose the appropriate sucker rod to better finish the work.