Troubles, Problems and Improvements of ESP

Abstract

Abstract Since 1975 Abu Dhabi Oil Co., Ltd (ADOC) has been applying artificial lift with ESPs in one of its offshore fields and has aquired experience in the installation and use of more than 300 ESPs, 45 of which are currently in operation. This paper will highlight the problems that have occurred with these ESPs, together with the technical improvements and countermeasures that have been put in place in order to achieve a longer ESP run-life. The failure of the ESP cables delivered in 2003 caused the ESPs to cease production, after a short period of time, due to cable damage in 2004. Following inspection, we concluded that the problems were related to the quality control of the cables. In order to avoid further cable problems, we reviewed the quality control system, including cable handling during transportation. Furthermore, we investigated the potential for technical improvement of the ESP cable, in order to extend the ESP run-life. As a result, the lead thickness was increased and the pothead coating material was changed. Since improving the quality control system of the cable, no further problems have been observed to date. The build up of asphaltene and CaCO3 scale is another problem which we face with regard to ESP wells. Once scale is deposited at the down hole, it is difficult to remove and, as a result, oil production will decrease. To avoid asphaltene deposit, Xylene is injected into the annulus periodically. To avoid CaCO3 scale deposition, the brine pH is controlled during stimulation and, if necessary, a scale inhibitor is squeezed after stimulation.