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SPE PCP Conference, Houston, TX, April 28-29, 2008 1© C-FER 2008

PCP System Failure Tracking and Benchmarking Analysis

for Run-Life Improvement

Paul SkoczylasFrancisco Alhanati

Cam Matthews

C-FER Technologies

2SPE PCP Conference, Houston, TX, April 28-29, 2008

Introduction

Failure tracking and failure data analysis is key to determine where the best opportunities are for Run-Life improvementThis presentation reviews important aspects of such initiatives necessary to increase their chance of success


Overview

Data Collection & QualificationInformation to TrackTerminology/Consistency

Individual Failure AnalysisReason for PullFailure MechanismFailure Cause

Improving Performance Through Data Analysis

Key Performance IndicatorsBenchmarkingIndustry Cooperation/Interaction


Data Collection and Qualification


Data Set Requirements

What information should we be able to retrieve from a PCP Failure Tracking System?

When was the PCP System started and when did it fail? ➨ System Run-Life StatisticsHow it failed? ➨ Main Failure MechanismsWhy it failed? ➨ Main Failure CausesWhat was the condition of all system components? ➨ Components Service Life Stats Overall operating conditions and equipment characteristics


Parameters Every Record Should Contain

Field/Well/Fluid/Reservoir dataRun time information

Install, Start, Stop, Pull dates, etc.Production and Operating Information

Producing rates, Speed, Torque/Current, GOR, Sand/water cut, API gravity, Wellhead Pressure and Temperature, etc.

Equipment dataPump model, rated capacity (displ. & press. rating), materials, etc.Manufacturer “Catalogue” information

e.g. Elastomer characteristicsEquipment conditions when installed and after pulling

Failure informationDid a failure occur?Reason for workover (whether or not a failure occurred)Item(s) Failed, Component Conditions, Descriptor(s), Failure Cause, and associated comments


Data Qualification

Confidence in any analysis will always be strongly dependent on perception of the quality of the data collectedGoal of data qualification process is to yield “quality data”; as per the ISO* :

Complete – in relation to the specification of the information each record should contain Compatible and Consistent – with a standard set of definitions and formats, with other information pertaining to the record, with the principles of PCP technologyAccurate – truly representative of the PCP installation that it describes

*ISO 14224: Petroleum and Natural Gas Industries –Collection and Exchange of Reliability and Maintenance Data for Equipment


Terminology

Conducting proper analyses is very difficult if a consistent terminology is not used

Definition of FailureA PCP System has “failed” if any of its components is no longer able to perform its required function

Failure Mechanism Descriptors“Torn” vs. “Missing Rubber” vs. “Chunked”“Hardened” vs. “Burnt” vs. “Overheated”

Equipment Characteristics How can we compare “similar” elastomers from different manufacturers without knowing key properties?


Individual Failure Analysis


Importance of Individual Failure Analysis

“How” and “Why” Failure Mechanism and Failure CauseThe only way to improve run-life is to address the main Failure CausesIt usually involves changes in practices:

System Design System InstallationSystem Operation Manufacturing QA/QC

Specific field conditions or company approach will dictate which operating strategy or mitigation strategy is optimal

Usually based on economics


PCP System Failures and Diagnosis

To do a proper job one must look at: Main symptoms that indicated the need for a system pull

High/Low Torque, Low Pump Efficiency, etc. “Reasons for Pull”Not clear at this point what the Failure Cause is!

Observations during pull and equipment inspectionComponent condition, and evidence of the physical and chemical processes through which they may have failed Plugged pump, broken rotor, missing rubber, etc.“Failure Mechanisms”Still may not be clear what the Failure Cause is!

Other pertinent informationproduction data, monitoring data, equipment specification and history of use, etc.Gather this data immediately after the failure (so that it is not lost)


Reason for Pull Example: Low Pump Efficiency

Used pump installed in a different well, pulled after 55 days; stator discarded due to low volumetric efficiency (stator “worn”, rotor “scored”)

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1/18/1999 1/28/1999 2/7/1999 2/17/1999 2/27/1999 3/9/1999Date

Speed(RPM)

VolumetricEfficiency

(%)

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Pump SpeedVol EffOil RateTotal Liquid RateProduction Period

Drop in performance after only 14 days


Failure Mechanisms

Tubing Wear Rotor Wear

Elastomer OverheatedRod Fatigue

Photo Courtesy of Kudu



Identifying the Failure Cause (or root cause of the failure) usually requires a comprehensive investigation …

Inspection at the shop only one step in the process

Frequency, nature and detail of investigation may vary depending on situation and previous experience with PCPs in the well/field



Circumstances that may have led to the failure, that is, possible Failure Causes, include:

Improper system design or equipment selectionImproper handling or installationImproper operation Manufacturing problems, QA/QC issuesNormal wear and tear… (run life must have met or exceeded expectations)

Assign a Failure Cause that indicates what you can do better next time …

Don’t confuse Failure Cause with Failure MechanismIt is seldom an issue with the quality of the equipmentDon’t blame the reservoir or the produced fluids… (unless conditions vary significantly from expectations)


Failure Terminology – Example

Example:Symptom, Reason for Pull:

Low torque, no flow to surfaceFailure Mechanism

Rod pin threads strippedSeveral possible scenarios

Possible Failure CausesImproper make-upManufacturing

True cause(s) can only be discovered by carefully sorting through the evidence available


Failure Analysis – Example

To find out the root cause, one should keep asking “why” …

Why did the rods part? Because a connection was not properly made up (e.g. failure due to excessive make-up downhole; unthreaded during backspin event)

Why was it not properly made up? Because the necessary amount of torque was not applied

Why was the necessary amount of torque not applied?Because the rig crew did not have the proper tools or knowledge

You now have a mitigation action you can take: Provide the proper tools and training to the rig crews


Improving Performance

Through Data Analysis


Types of Failures to Focus On

Chronic – failures that occur often high frequency, or high failure rate (number of failures per time in operation)

Short Runs e.g. less than 90 days RuntimeMay be sporadic …

One needs not only a tracking system but also proper reliability analysis tools to determine which mitigation actions could have the highest impact on economics in the future or to measure success of past actions taken


Run-Life and Service-Life

Run-Life usually refers to the whole PCP SystemFrom the time it was installed until the time it failed

One usually does not know the exact average Run-Life in one operation

Many systems are still running or have been pulled for other reasonsOne can only estimate average Run-Life, based on the known Runtime of several systems, and the number of failures observed over a period of time

Service-Life usually refers to one specific component

From the time it was first installed until it was deemed unsuitable for use and it was discarded Equal to the sum of all component Runtimes in the same well or in different wells


Run-Life and Service-Life

Run-Life of the PCP System directly affects:Workover frequency and costs Deferred Production

Service-Life of the specific components directly affects:

Equipment capital costsRelative importance of these cost factors depends on the application/locationManufacturing QA/QC and System Design Effectiveness affect both Run-Life and Service-Life


Key Performance Indicators

MTTF & Failure RateFailure Rate is number of failures divided by total exposure (including systems still running and those which were pulled without failing)

No. Failures per Well per YearMTTF is reciprocal of Failure Rate

Average Time in Operation per Failure Failure rates of all individual components in a system sum to the failure rate of the system

Equipment Service LifeHow long does an individual component last in use from the factory to the scrap heap?

Need to know the full life of each part, whether or not a failure occurred in each installation


Key Performance Indicators

Average Runtime of Pulled SystemsA measure of workover frequency and therefore reliability of the whole production system, including other completion componentsTotal exposure of systems which have been pulled (whether or not they failed) divided by the number of systems pulled

Reliability FunctionsSurvival Function, S(t), describes % of systems that survive until a given time in operation


Data Set: Population

All systems must be included in Data SetNot just Failed systemsSystems which are Still on Production or Pulled Without Failing contribute valuable information to many analyses

These are required to calculate:Service Life of equipmentMTTF and Failure RateWorkover frequencyetc.


Example of a Successful Failure Tracking and Operations Improvement Program

Doria, Vahnovan, & Marques: Manantinales Behr Field Case HistoryRepsol-YPF2006 SPE PCP ATW


Benchmarking: What Does it Involve?(1)

Benchmarking usually encompasses:Regularly comparing aspects of performance(functions or processes) with best practitioners;Identifying gaps in performance;Seeking fresh approaches to bring about improvements in performance;Following through with implementing improvements; andFollowing up by monitoring progress and reviewing the benefits.

1. Public Sector Benchmarking Service (PSBS), http://www.benchmarking.gov.uk/about_bench/whatisit.asp


Benchmarking: On What Basis?

Scope for Benchmarking may vary between:

Wells Fields Divisions / Op Units Companies

Performance Comparisons can also vary:Pump VendorsPump ModelsElastomer CharacteristicsWell Conditions…

Companies

Divisions

Fields

Wells Pump Vendors

Models Elastomers


Benchmarking Analysis: Notes

It is unrealistic to expect that all PCP applications can reach the same MTTF

Sandy heavy oil (CHOPS) wells may have MTTF under a year and be doing well, while lighter oil, high water cut wells with no sand may typically last several yearsApplications with H2S, high CO2, high temperatures, or high aromatic content will also have lower run times, in general


Benchmarking Analysis: Notes

Caution is required in interpreting resultsAn analysis shows that Company A’s pumps last much longer than Company B’s. However, majority of Company B’s pumps are installed a much harsher application than Company A’s

As much as possible make comparisons based on similar applications

Most frequent failed item not necessarily an indication of a manufacturing (QA/QC) problem with that component

Frequent “pump failures” not necessarily an indication of poor pump qualityMust look at associated Failure Causes


Final Thoughts


How well are we doing as an industry?

Run-Lives (MTTF) as high as ten years in some applications

Run-Lives (MTTF) as low as three months in some others…

Certain Failures still occur very often: Worn Stators and Rotors, Swollen Elastomers, Stuck Pumps, Burned Elastomers, Broken Rods, Leaking Tubing Strings Why? Not economic to fix the situation?

Are best practices being effectively transferred across the industry?


How can we best learn from each other?

Sharing Information and Best Practices is key for the industry to improve Run-Life Performance of PCP Systems For best knowledge transfer:

We need to start using a common terminologyDefinition of FailureDescriptors for Observations During Operation, Pull and Pump Inspection

We need to start tracking the same parametersWe need to start using the same measures of performance


Vendor-Operator Interaction

Operator and Vendors Share ResponsibilitiesKey questions to be agreed upon:

Who should take ownership of the tracking system?Who should provide which data?Who should enforce certain standards? Who should do the analysis?

To what level of detail? How often?

In what format should results be transferred to different staff in different parts of their organizations and across the industry?


How Do We Get There?

ImproveEquipment Reliability

Feedback to Vendors

VendorR&D

JIPR&D

Identify Areas for Development

Analysis(Parametric,

Benchmarking,Drill-Down)

High-QualityData

LiteratureReview

DefineMetrics

UnderstandKey Factors

This refers to changesin equipment design ormanufacture.

Extend Range of Application

May include lab testsor field tests

FundamentalStudies

TRAINING


Where do I find the time?

“If you haven’t got time to stop these failures from recurring, how are you going to find the

time to keep fixing them?”

Alexander (Sandy) Dunn, “Getting Root Cause Analysis to Work for You”© Assetivity Pty Ltd and ICOMS® 2004


Acknowledgements

PCP Run-Life Improvement JIP Participants:ChevronConocoPhillipsExxonMobilHuskyNexenPetrobrasRepsol-YPF Shell

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