Reliability Improvement in Beam Pumps by Use of a Unique Methodology

Abstract

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 171372, “Reliability Improvement in Beam Pumps by Use of a Unique Methodology Combining Real-Time Automation and Failure Analysis,” by Blair Gardner, SPE, Santos, prepared for the 2014 SPE Artificial Lift Conference and Exhibition—North America, Houston, 6–8 October. The paper has not been peer reviewed. This paper focuses on analysis of beam-pump-failure root causes and trends and how the operator has used these data combined with automated equipment to reduce failure frequency and operating cost. The paper also presents data and findings to support the benefits of a beam-pump-automation and -control program. Introduction The operating company has operated a fleet of beam pumps in the Cooper basin in central Australia since 1985. The basin extends over 30 000 km2 in a remote, harsh, arid desert. Ambient air temperature can range from 0°C to greater than 50°C, and there is potential for flood events in the wet season. The remote location and variety of weather conditions present numerous operational challenges and technical constraints. Historically, the beam pumps have run in a traditional manual mode whereby production operators measure, record, and analyze operating parameters and monitor surface-equipment condition. The operator implemented an automation program in 2006 to help improve run life; increase production; and decrease environmental, health, and safety risk. Artificial-Lift Selection The operator installs and operates many mainstream artificial-lift systems (ALSs) including electric submersible pumps (ESPs), progressing-cavity pumps (PCPs), jet pumps, and beam pumps. Artificial lift is installed on every oil well, with selection criteria being based on the expected fluid rate in conjunction with any surface- facility constraints. The operator installed its first beam pump in 1985; these have been the dominant ALS for yielding fluid rates from 20 to 1,000 BFPD, a range into which most oil wells fall. In 2005, a decision was made to switch to PCPs as the preferred ALS for new wells; this decision was reversed back to beam pumps in 2008 following poor PCP reliability. Past Operating Strategy Failure Diagnosis and Analysis. In the past, following discovery of a suspected downhole failure, the operator would run a standard suite of diagnostics, which included collecting a manual dynacard and running a pump-up pressure test, before placing the well “on tap” (or tagging bottom) in an attempt at reinstating production. If this was unsuccessful, the well was transferred to the production engineer to justify and scope a downhole-repair workover. No formal record of diagnosis or activities attempted to reinstate pumping action was preserved. Once a pump repair was executed, the rig reports were filed in the field-office well file. Consequently, information regarding the root cause of failure was often inconsistent in reporting standard, and it was not recorded and collated systematically in any central repository to enable future analysis. Cooper Basin and the Digital Oil Field—Beam-Pump Automation and Telemetry Implementation. In 2006, none of the operator’s Cooper basin beam-pump fleet had any form of automation or telemetry. One of the outcomes of the unsuccessful PCP program was a better understanding of the benefit that control and telemetry have on artificial-lift performance and reliability. When the switch was made back to beam pumps as the preferred ALS, it was evident that some level of automation would be required. The operator retrofitted two platforms of control to its beam-pump fleet. The selection criteria were based predominantly on individual-well economics, rather than a generic approach. Variable-Speed Drive (VSD) (Advanced). A VSD is used to automatically adjust an electric motor and, consequently, pump speed to match well inflow; target pump fill is used as a feedback loop to the VSD control algorithm. Benefits include maximized production by self-optimization, advanced condition monitoring, and equipment protection. This is the preferred system for all new beam-pump installations. Pumpoff Control (POC) (Basic). A rod-pump controller (RPC) was retrofitted to existing engine-driven beam pumps that could not justify the cost of VSD installation. The system has no ability to self-optimize; however, the RPC shuts the pump down if a severely pumped-off condition is reached or if rod-load limits are exceeded. Benefits include basic condition monitoring and equipment protection.