Research On The Expansion Technology Of The Rotary Expandable System

As the development of each oil field is in medium or later term, the number of the casing damaged well is becoming more and more. And the damaged casing directly effects normal production of oil-water well in oil fields, even leads to stop production and scrap of oil-water well. As the time of oil development goes, the casing repair is becoming an important question in the process of oil development. The expandable casing repair technology is better than any other repair technologies of all various repair technologies. The more and more oil fields use this kind of technology after expandable casing repair technology developing. But when using this kind of technology, the staffs find out that the ground equipment need to offer more expandable strength and expandable casing may larger shrinkage in the process of expansion work. According to aboved questions, Weatherford company improves the structure of the expandable tool and uses the rotary expandable tool to work for overcoming aboved disadvantages. However, the concept of the rotary expandable technology is proposed in recent years, and most oil fields are still in the testing stage. So this topic importantly studies on expansion mechanism about rotary expandable system in order to use this kind of technology in ample oil fields.This topic researches on expansion technology, which includes two contents of the rotary expandable tool and expandable casing, about rotary expandable system. For the rotary expandable tool, firstly, the paper derives theoretical formula about expandable force by using the elastic-plastic deformation theory which offers the way of caculating expandable force. Based on this, the article determines and designs the structure of the rotary expandable tool. Secondly, the paper analyzes that the facts (casing angle, friction coefficient, the length sizing, angular velocity) change with expandable parameters (expandable force, fluid pressure, the maximum residual stress, axial shrinkage, amount of wall thinning) of the rotary expandable system, and obtains the corresponding variation. The aboved analysis not only offers the foundation to design the rotary expandable tool but also proves that formula which is derived is correct. Finally, this topic analyzes that expandable effects about the rotary expandable tool under the three common rotating expandable process of oil fields, and obtains the expandable process that is fit for the rotary expandable tool. So oil fields greatly increase the efficiency of wokover and ensure the safety of staffs. In addition, the article studies that initial geometric imperfections of expandable casing impact on expadable effects based on expandable casing of the rotary expandable system. After analysis, the change law on expandable casing of initial geometric imperfections is mastered. It is very important to design the expandable casing and improve the theoretical research of the rotary expandable system.