Abstract
Electrical Submersible Pumps (ESPs) are widely used as a form of artificial lift. ESPs need to be installed in a straight section of the well to avoid contact and friction between the stationary and rotating parts. In this paper, 4 case studies demonstrate how high density data together with a tortuosity processing algorithm and visualization software reduced failures and workover frequency or lead to alternative forms of artificial lift because of the high tortuosity of the well, all having a significant financial benefit for the operator.
The algorithm uses high density data and computes the wellbore tortuosity, the maximum diameter of a cylindrical device of a given length and the bending of a device placed in a particular section of the well with given length and diameter. The results can be presented as 3D representations of the wellbore.
The first case study focused on a highly tortuous well and the fact that the tortuosity analysis was able to find a 120 ft straight section of well to land the ESP and the pump is still running. A second case study showed that the currently used dogleg severity (DLS) and the tortuosity analysis differ in their conclusion; a pump placed using the tortuosity analysis ran without problems until it was replaced by a beam pump because of production volume. In the third case study, an ESP was placed using DLS information alone and suffered from a broken shaft after less than two weeks. The tortuosity analysis revealed that the wellbore was highly tortuous at the original depth. The pump was placed at a different depth and ran for almost a year until it was replaced by a beam pump due to reduction in production volume. Finally, a forth case study demonstrated the additional benefit of the tortuosity analysis in relation to the speed of descent of the pump and on pump placement.
The use of high density data together with the processing algorithm can effectively be used to determine the best lift type and the best location for the device. In addition, it shows the degree of bending of the device during its descent in the well, which can also help to prevent problems, and has resulted in changes in drilling practices with the focus on wellbore quality.
