?Coil tubing and coil tubing tools have changed the face of the oil industry. They were first used at the time of Second World War and have been improvised with time to resemble the coil tubing used in today's time. It is basically a metal piping and its diameter can range from 1 inch to 3.25 inches in diameter. These days it is made up of continuously milled steel and coiled sections which though lead to low flexibility but the coil tubing is nevertheless very useful. It is used for two major purposes: for maintenance purposes inside the oil and gas wells and to revive the killed wells. Basically coil tubing has come to be one of the most important tools used in oil drilling operations. other important tools include valves, wireline equipments, couplings, union, swivel joints etc. Almost all the companies that produce tools and equipments related to the oil industry produce coil tubing and some of them also provide the option of getting customized coil tubing made. The oil industry in capital intensive and quality control is everything. The manufacturers have to pay special attention towards the Quality of their products if they have to survive for long term markets. The companies engaged in oil drilling tasks have to be very careful while procuring tools and equipments. They can in no circumstances compromise upon the quality of the peripherals used as it may lead to dire circumstances and heavy losses. The coil tubing is used for a lot of purposes including the major two as stated above. The coil tubing tools work in such mechanisms as circulations, pumping, drilling, logging and perforating. For each of these tasks such custom changes are made to the coil tubing tools. In other words there is as such no generic coil tubing that can perform each of these functions with precision. But a lot of companies have taken up Research and development activities towards that end as well and soon there would be more innovative coil tubing and wireline equipments and other tools. In wells that are said to have been killed due to presence of a hydrostatic head which obstructs the flow of formation fluids out of the well. Coil tubing can be used to solve this problem by encouraging circulation of the fluids out of the hole with the help of Nitrogen gas. This practise is also used to restore depleted wells. It can be used for pumping the fluids to a specific location inside the well in order to carry out some other task in the vacated area. Pumping has also become easier than what it was before the introduction of innovated coil tubing tools. On papers a coil tubing can be unwound and inserted into bore well of considerable diameter at the rate of 30 metre every minute. Practically due to a lot of other factors and sometimes due to the narrowness of the diameter of the bore well, the tube is unwound and inserted at the rate of 20 metre per second. Snehil Shrivastva is the author of this article on Coil Tubing Tools . Find more information about Unions here.