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Electronic Liquid Measurement - API Chapter 21.2Terrell Ledbetter
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FOREWORD Prior to going into the specifics on "Real Time Electronic Flow Measurement" it is important to understand why you should develop an integration plan that has established goals and system configurations defined. As you will see later the definition of "Real Time" in itself might mean something different to various companies or even departments within the same company. The "Integration Plan" is where most companies will go wrong, the matrix of a Flow Measurement System is much broader than we all first think. The term "Real Time EFM Flow Measurement" like many others involving new technologies it has an ominous sound to it, at times this is true. Most "systems" can act like the house of mirrors; after unlocking the first door to success, what do you find?... about a thousand more doors with all kinds of variables, problems, and situations. The only way you can effectively handle those variables is to have a logical, well organized plan. The process of creating a plan forces you to take a realistic, objective, unemotional, more or less detached look at the measurement system. Most companies establish plans department by department; operations vs administrative, this style of compartmentalized development will not work in the area of electronic measurement and control system integration. Writing down the specifics related to your EFM integration plan provides you with the opportunity to evaluate the system in its entirety and see how many departments are involved within the project matrix. This goes a long way toward establishing what interaction is needed between dissimilar departments that become joined by a "Real Time EFM System". This integration plan does several things for you:
During this process your company can establish its immediate goals in relation to the final objective. It is imperative that a company do as much research and investigation as it feels comfortable with, but keep in mind many great plans lose focus if the timetable for implementation is set too far into the future. A key to success is to let everyone know what your final company objective is as early as possible, this keeps all the departments within the matrix working toward a single conclusion and greatly lessens the chance of one area running off on a tangent and slowing down the integration process while an odd piece of the puzzle is fit in. Just developing a EFM system integration plan is an indispensable management tool to introduce discipline and a logical thought process into multiple departments on a project team. Plans like this covering such a complex problem will let a company know where it is going, how to get there, and what the system will look like once completed. REAL TIME ELECTRONIC FLOW MEASUREMENT By Mr. Charles Derr "Real Time" seems self explanatory, however, it has different meanings to different operating scenarios. DEFINITION: Equivalence in time or speed between the output of an electronic computer and a particular physical process which depends on the data or solutions for its continuation or completion. This definition explains a computer which, when operating, sends information to control something. In the definition above "Real Time" is the time period between the computers output and the usage of that output. In the current world of measurement with "Real Time" electronic flow computers......... the term is equally as elusive as it is given no exact clock time value. Truly; REAL TIME is any time frame wherein we get data or results which occur often enough to satisfy the data users requirements. To many people, Real Time means virtually instant. In measurement it has evolved to mean "IN TIME..." Even though the common denominator exists for many groups who use the same form of electronic flow meters (EFMs), time has different weights of consequences to different operational conditions. A production field operator may need to approximate for management, (within 5-10%) daily the total volume that the field can deliver to a gas plant within the next 48 hours following that daily report. This may be that operator's REAL TIME DATA requirement. An interstate carrier pipeline may need supply data and need to give delivery data on a time frame where two day old data would be useless. They may need hourly or on a basis of only minutes between reporting updates. Real Time usually means AS FAST AS I NEED IT. Real Time systems as those have the hardware, software and telemetry to get the user the data when needed. WHO NEEDS REAL TIME MEASUREMENT?WHAT CAN IT DO FOR US.? FIELD OPERATION GROUPS........ have a few questions to answer each day PRODUCTION:
GATHERING:
GAS PROCESSING
PIPELINE:
REAL TIME ELECTRONIC METERING GIVES YOU THE EDGE ON BEING ABLE TO ANSWER THESE QUESTIONS READILY AND TIMELY. IT BENEFITS OTHER GROUPS ALSOMEASUREMENT: Every component of every primary element and every transmitter is a small multiplier to the bottom line of a energy company. MEASUREMENT ERROR = FINANCIAL ERROR We all get upset if our employer makes an under payment on our paychecks. Energy companies must also be profitable and the only way to plan their operations and get equitably paid for their products delivered is to Accurately measure them. Real Time EFMs enable a company to:
INFORMATION SYSTEMS GROUPS: Telemetry links between EFM / RTUs and SCADA systems maximize the investment of the field measurement hardware. Automatic timed retrieval of rates and volumes is the real return on the investment on EFMs. Exception reporting on exceeding alarm levels and automatic dial- out notification avoid major losses, penalties, safety hazards and maximize key field people's time by having them where needed quickly after problems first arise. Information groups acquire data, route it for auditing and input the data into the central billing system computers as well as archive the data for future operational, commercial, and legal reasons. Real Time systems are now direct feeding sophisticated data auditing, presentation, archiving and billing systems which have multiple interface drivers to make final presentations appear the same regardless of which EFM / RTU they were acquired from. Real Time EFM / RTUs on telemetry assist the huge tasks of measurement, control, product accounting, maintenance, field personnel dispatching, product sales and marketing. REAL TIME ELECTRONIC MEASUREMENT SYSTEMSWHAT IS NEEDED TO IMPLEMENT ONE ? HARDWARE
SOFTWARE:
Many vendors of EFMs and RTUs have sources which integrate these programs to ensure compatibility. Its a big job and an emerging specialty, but the paybacks are tremendous once implemented.
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