RIASSUNTO
ABSTRACT
This paper introduces a BHA with integrated casing cutting and fishing tools applied in offshore operations of well abandonment. This kind of tool systems successfully applied in an offshore project of permanent abandoned wells. The advantage of the system is the combination of both cutting and fishing operations, and thereby the completion of the both operations implemented in one string tripping. The benefit through the application of this novel combination could be of reducing numbers of make-up of BHAs and tripping. Therefore, the operation process is simplified, and the operation efficiency and reliability are significantly improved.
INTRODUCTION
More and more high levels for further development of offshore exploration technology, it is necessary for the company to promote the efficiency of abandonment of offshore wells. All the exploration wells obtained the required reservoir data, production wells completed, the production life of offshore oil and gas fields must be permanently abandoned. It is to eliminate their potential threats on the environment. Dong and Wang (Dong and Wang, 2011) raised similar proposal that a critical process utilized in well abandonment is the cutting and recycling of casing pipes.
It is particularly important to apply appropriate cutting and fishing tools through controlling reasonable cutting parameters, to ensure the casing pipes cut and recycled quickly and efficiently because of the high cost of offshore operations. Traditional method of casing pipe cutting and recycling requires that the cutting is performed under the state of drill string compression, and that the tripping out is implemented after cutting. Finally, the fishing spear drilling tools run down for casing pipe fishing in the wells. Although the tools and technical performances are stable using the traditional method, it takes a long time. In addition, misjudgment and repeated operations could take place from time to time and therefore, it would be difficult to get the costs to strictly control within the specified budget.