Improving operation of wells equipped with electrical submersible centrifugal pumps with unstable production rates in the samotlor field conditions

Date
2012
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Abstract
The purpose of this research is to develop recommendations for operating wells with unstable production rates. The geological section of Samotlor field is represented by a thick (up to 3,000 m) series of sedimentary rocks located on the eroded surface of folded foundation. As of January 1, 2010, there were 1,576 wells of which 65% are equipped with ESPs and 24% are equipped with sucker rod pumps. The wells equipped with ESPs ensure 74% of production. An analysis of the existing methods for selecting ESPs was carried out in accordance with the established objectives. The analysis demonstrated that pump is selected on the basis of several assumptions without taking into consideration possible changes in well operation which may occur with time. Thus one can assume that when the well parameters change in the process of operation, the selection of equipment may no longer be appropriate. An analysis of technological modes of operation of oil wells demonstrated that there are groups of wells that are characterized by technologically stable and unstable modes as well as the groups with an unvaried decrease of production rates and successful and unsuccessful optimization. This analysis was based on the data from 900 wells. The analysis of pump modes of operation indicated that pumps are often operated in non-optimal mode outside of their working ranges, main types and sizes. Thus, despite numerous existing methods and software for selecting submersible equipment for wells, it is not always possible to optimize the well operation which results in a fairly large number of wells with unstable production rates. The unstable production rates during well operation lead to reduction of ESP's efficiency and an increase of their vibration. It also adversely affects the formation by drawdown pressure drops. There are various control methods and technkaJ devices that aJlow ensuring various modes of operation of hydraulic systems. As a result of performed analysis the most effective devices for stabilization of well operation are identified: automatic transmission and indirect bypass valve. To reduce the adverse impact on ESP and formation it 1s recommended to use the thyristor turbulent flow wave frequency converter. ESP benchmark tests were carried out in the Central Production Maintenance Base in Langepas to study the vibration level in various modes. The tests demonstrated that the vibration level exceeds allowable level by approximately 25% with pump operating at the limits of its working ranges. Such vibration may be reduced by thyristror wave frequency converter. A bench test in the field and in the laboratory of the chair of Machinery and Equipment for Oil and Gas Industry demonstrated high effectiveness of this device.
Description
Bibliography: p. 116-117
A few pages are in colour.
Keywords
Citation
Lysyanyy, A. (2012). Improving operation of wells equipped with electrical submersible centrifugal pumps with unstable production rates in the samotlor field conditions (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/5044
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