The applicability of casings and liners composite patch repair in Iranian gas and oil wells

The applicability of casings and liners composite patch repair in Iranian gas and oil wells

The applicability of casing and liner patch repair in Iranian gas and oil wells has been one of the main concerns of the National Iranian Drilling Company’s engineers (authors). This is due to the facts that casings and liners can experience several stresses due to different loads in Iranian oilfield formations. In this work, the field application of a new rigless technique to repair a casing and liner leak is described. This unique repair method utilizes a non-metallic, composite sleeve composed of elastomers and thermo-setting resins reinforced with fibers [1]. A description of the technology is presented, along with characteristics of the patch. Compared to the cost of a rig workover, the setting of the patches will result in a saving of approximately 50 percent [1]. If this type of repair be applicable in Iranian formations, it will be economically superior to a rig workover which is performed in Iran. But field tests of this technology will be very costly. Meanwhile, Computational methods may be used such as the work done by the authors to investigate patch repaired burried pipes [2]. This research investigates maximum stress produced in patch repaired defected casings and liners. The analysis will be performed through a comprehensive finite element process. The maximum local stresses in pipes and patches will be determined and compared to their critical values for a patch repaired at various depths and formations