Coiled tubing, also known as flexible tubing, is made of low carbon alloy steel tubing with good flexibility to meet the requirements of plastic deformation and toughness required by downhole operations. Commonly used coiled tubing specifications are: Phi 1/2 three-quarters of 3/8 25.4mm, φ31.75mm, φ38.1mm, φ44.45mm, φ50.8mm, φ60.325mm, φ66.675mm, φ73.025mm, φ82.55mm, φ88.9mm, etc., yield strength 55000Psi~120000Psi. Coiled tubing, which is wound on a roller and can be several thousand meters in length, can replace conventional threaded tubing for continuous downhole operations with pressure. Coiled tubing has been widely used in drilling, logging, completion, workover operations, and more and more in oil and gas exploration and development.
Although our country long ago began using coiled tubing technology in underground work, but because of the influence of various factors result in coiled tubing technology didn't get a wide range of popular development in our country, the theory and technology level compared with the developed countries there is still a certain gap, resulting in the actual use in the process of coiled tubing to fully exert the use of the advantage. In addition, most of the underground work in our country exists in the use of coiled tubing technology blindly, no detailed construction plan before use, such as the use of equipment and technology methods and using range, lead to the coiled tubing technology is applied to the underground work lower adaptability, frequent technology in equipment use don't form a complete set of problems, the reality of the equipment The international use condition causes certain bad influence.
Relative aging of coiled tubing equipment
At present, most of the domestic applicable coiled tubing equipment is imported equipment, equipment is relatively backward, some even reached the scrap deadline. Injection head, blowout preventer, hydraulic system and control system wearing parts are difficult to replace and maintain. Suitable tubing diameter range is small, some special downhole operations do not meet the requirements of construction.
Application of coiled tubing technology
Application of gas lift oil recovery
Gas lift oil recovery technology is to inject gas into the well and use the expansion of gas to reduce the density of the mixed liquid in the well, so that the oil in the well can flow out more easily. The application of coiled tubing technology has greatly improved the amount of crude oil recovery and the level of oil recovery technology. In many fields, ammonia gas is injected to the bottom of the hole through coiled tubing (CT) technology to enhance oil and gas recovery.
New ct vertical Wells were drilled
New coiled tubing Wells are drilled using a composite rig with a top drive that is drilled in a conventional manner at the start of drilling. When the drill reaches a certain depth, it switches to coiled tubing drilling, after which it can either run casing or complete the well open-hole. Undirected drilling accounts for the majority of new ct Wells.
The advantages of ct drilling new Wells are safety, fast drilling (no collar), easy transportation, small footprint, high automation and labor-saving. At present, the speed of coiled tubing drilling abroad is very fast. For a CBM well of 700m to 1000m, it only takes 4 days from the layout of drilling equipment to the removal of all drilling equipment after construction. Canada is currently the world's most active region for coiled tubing drilling.
Downhole operations in oil fields are risky, and the use of coiled tubing technology requires expertise and strict equipment operation requirements. Through various advanced equipment to carry out downhole operations can effectively improve the efficiency of the operation, for the safety of the construction personnel to provide a basis for the guarantee. However, in order to minimize the construction time, reduce costs and improve profits, most of China's petroleum enterprises continue to innovate related construction technology and process, but at the same time, there are still some problems in equipment manufacturing, so that in the process of underground operation, there is a relatively severe equipment shortage. To promote the wide popularity of coiled tubing technology, first you need a comprehensive system of equipment as a support, for our country to strengthen the production of related equipment, increase capital investment, to make proper equipment and facilities to meet the requirement of development in our country, improve the quality of performance and use of equipment, thus providing basis for the implementation of the coiled tubing technology guarantee.
Development prospect of coiled tubing
To combine the shortcomings of coiled tubing operations, in the late stage of oilfield development, take the ascension of the best technology, to improve the application effect of coiled tubing, increases the chances of the coiled tubing operation, play a coiled tubing operation ability, guarantee the successful implement of underground work, help to make it better for oilfield production.
The development prospect of coiled tubing in the later period is analyzed to improve the automation degree of surface control equipment of coiled tubing, constantly optimize the technical measures of coiled tubing operation, improve the speed of underground operation and construction, shorten the period of operation and construction, and ensure the smooth completion of underground operation and construction. Research downhole tools, make it cooperate with coiled tubing technology measures, improve the operation and construction level of horizontal Wells in the later stage of oilfield development, take the best potential exploration and stimulation technology measures, improve the reservoir output, meet the production requirements of oilfield development.
Continuous improvement of coiled tubing materials, the application of new materials and new technology to coiled tubing operation technology, change the diameter or change the taper of coiled tubing application, to solve the difficult problems of special well downhole operation. Convenient downhole operation and construction in deep Wells, reduce wear on coiled tubing and extend the service life of coiled tubing.
Post time: May-23-2022