Recommendations to Collect Good Informationpage 1

Recommendations to Collect Good InformationPage 1

Status

• Document written and edited
• Chair: Cleon Dunham,
• Team: Not applicable
• Comments: Not applicable

A.7 Annex 7 – Recommendations to Collect Good Information

The recommended practice to collect good information of operation, surveillance, and optimization of gas wells is to use a state-of-the-art production automation system and have this system operated by trained personnel who are dedicated to its use on a continuous basis.

This topic is fully covered in Chapter 15 of “Gas Well Deliquifcation, Second Edition,” by James F. Lea, Henry V. Nickens, and Mike R. Wells. Chapter 15 on Production Automation is by Cleon Dunham and Greg Stephenson. There is no need to repeat the information from that document here. The following table summarizes the key recommendations in that chapter.

• Instrumentation is at the heart of any automation system.
• It must support accurate measurements, control, and optimization.

• Instrumentation

• This is not the place to save money.
• Buy reliable, accurate instrumentation.

• Electronic flow measurement

• Use electronic flow measurement for all cases where gas flow measurement must be accurate; for example for any custody transfer application.

• Controls

• Control equipment must be reliable.

• RTU’s and PLC’s

• Acquire RTU’s and PLC’s that are specifically designed for each application, type of artificial lift system, etc.
• Do not try to use one general RTU or PLC for all applications.
• Consider variable speed drives when needed to effectively control pumping systems.

• Host systems

• Use one “host” system that can communicate with and support all different forms of RTU’s, PLC’s, and applications.
• This is the place to standardize on one system.

• Communications

• Insist on reliable communications that can transmit information at the needed speed.
• Where possible use wireless communication to reduce installation and maintenance costs.

• Data base

• Most real-time databases (on the production automation system) have relatively limited storage.
• Consider supplementing this with a data historian (see below).

• Other

• Where pertinent, considerintegration of the automation system with other systems for well analysis, artificial lift system design and optimization, etc.

• General applications are part of most generic automation systems.
• They are essential but not sufficient to meet the needs for a production automation system.

• User interface

• The user interface should be the same as or very similar to the window interface from Microsoft, since more people are familiar with it and find it easy to use.

• Scanning

• The scanning system collects information from the wells, artificial lift systems, and facilities.
• It must collect the amount of information required, atthe desired frequency.

• Alarming

• Automation systems are designed to produce alarms.
• However, many systems produce so many alarms that people can’t make effective use of them.
• The alarm system must be flexible so it can produce “important” alarms without generating so many as to create “noise.”

• Reporting

• The Operator must be able to design reports to meet his/her needs.
• Reports should support internal calculations, averaging, summaries, sorting, etc.

• Trending and plotting

• Trend plots of variables vs. time must permit plotting of one or more measured or calculated variables on a plot, for any desired duration.
• Graphs must also provide x vs. y plots.

• Displays

• The display processor must support static displays, generic displays (e.g. a display for a type of well that can be used for any well of that type), and dynamic displays where the user can enter data, commands, etc.

• Data historian

• Most automation systems have relatively limited data storage capabilities.
• A data historian can store vast amounts of data, over a long period of time, and permit rapid access to the information.

• For a production automation system for gas well operations, the system must provide unique services for each type of artificial lift system, in addition to the general applications listed above.

• Plunger lift

• There are several ways to monitor and control plunger lift wells.
• The automation system should support all of the proven methods so the Operator can choose the one best suited to his/her wells.

• Sucker rod pumping

• Modern sucker rod pumping systems use rod pump controllers (PRC’s) to monitor and control the pumping units.
• The automation system must support the functions of the several different types of RPC’s, correct information from them, and support the functions of sucker rod monitoring, control, problem diagnosis and analysis, design, and optimization.

• PCP pumping

• Unique automation applications have been developed for progressing cavity pumping.
• The system must support each of these so the Operator can choose the best approach for his/her wells; rod driven pumps, or pumps driven by downhole electric submersible pump motors.

• ESP pumping

• ESP’s are operated with Fixed Speed Drives or Variable Speed Drives.
• Each ESP Company typically provides the ESP controller that is installed at the surface.
• The automation system must support both types of drives and each type of controller.

• Hydraulic pumping

• Hydraulic pumping is little used for gas well Deliquifcation.
• Chapter 15 discusses the automation information needed for surveillance and control of these units.

• Chemical injection

• Chapter 15 discusses the automation information needed for surveillance and control of chemical injection systems.

• Gas-lift

• Gas-lift of gas wells is primarily focused on adding enough gas to keep the gas flow rate above critical at all times.
• The system must determine the amount of gas needed for critical flow and then control the injection rate to meet this need.

• Wellhead compression

• Chapter 15 discusses the automation information needed for surveillance and control of wellhead compression systems.

• Heaters

• Chapter 15 discusses the automation information needed for surveillance and control of heater systems.

• Cycling

• Chapter 15 discusses the automation information needed for surveillance and control of cycling systems.

• Production allocation

• Chapter 15 discusses the automation information needed for accurate allocation of gas production which is measured at a production station and allocate it back to individual wells.

• Other unique applications

• Other applications can include control of gas well production to meet specific needs to increase or decrease gas production rates to meet delivery demands.

• There are several “soft” issues that must be addressed for successful automation systems.

• Typical benefits

• It is necessary to identify the anticipated tangible benefits that can be measured in economic terms.
• It is equally important to identify intangible benefits (e.g. safety, environmental protection, system security, personnel issues) that are as or more important.

• Potential problem areas

• There are potential problem areas or “pitfalls’ that must be avoided through careful design of the system.
• Chapter 15 enumerates a number of these.

• Justification

• The system must be well justified to obtain the buy-in and support of management and all other “stake holders.

• CAPEX

• Capital expenditures will be required up front on a project, and over time as equipment must be added, exchanged, upgraded, etc.

• OPEX

• Operating costs will persist throughout the life of the project.

• Design

• The system design must consider: (1) the people needed to design, install, operate, and optimize the system, (2) the corporate project management processes that must be followed, and (3) the technology to be used – not too much and not too little.

• Installation

• Installation of the system, including thorough upfront testing, is essential.

• Security

• Security of both the physical equipment in the field and the data/information produced by the system must be addressed.

• Staffing

• At least three teams of people are needed: (1) Steering Committee, (2) Automation Team, and (3) Surveillance Team.

• Training

• Each team must be properly staffed and the people on the teams must be well trained.
• This is essential over time as team members change.

• Commercial vs. in-house

• Few companies build in-house automation systems.
• The challenge is to find the best commercial system and work with the Supplier to meet the needs of the Operating Company.

• We can learn from the successes and failures of the past.

• Success stories

• Most success stories followed the recommendations in Chapter 15, and continued to follow them over time.

• Failures

• Most failures occurred when companies failed to follow the recommendations.
• Many of the failures occurred not because of inadequate automation hardware or software, but failure to take care of the “soft” issues.

• Systems that haven’t reached their potential

• Some systems have yet to reach their potential.
• This is most often caused by failure to follow the project plan to fully implement the systems, or again, a failure to address all of the “soft” issues.

• The value of gas is high; the costs of staff and services are high; the negative impact of liquid loading is high.
• So, the case for production automation is compelling.

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