Papers

Turbine meters have been used for the custody transfer of refined petroleum products and light crude oils for over
40 years. When correctly applied, they offer high accuracy and long service life over a wide range of products and operating conditions. Traditionally turbine metes were used for the measurement of low viscosity liquids and PD meters for higher viscosities. However, new developments in turbine meter technology are pushing these application limits while increasing reliability and accuracy. This paper will examine the fundamental principles of turbine meter measurement as well as new developments including: smart preamps for real-time diagnostics, helical flow turbine meters for higher viscosity applications, higher performance flow conditioners to increase accuracy, and viscosity compensation to extend the application limits.

The purpose of this paper is to discuss in depth the systems we use as a standard to sample natural gas liquids, or
NGL’s. Before we discuss the systems and methods used to sample these products, we must first clearly define what NGL’s
are. NGL’s can be a combination of any fluid in liquid form that is taken from the pipeline under pressure. Typically, “NGL” refers mainly to ethane, propane, butanes, and natural “gasolines” (pentanes) & condensates. Because of the broad range of products that can be claimed as NGL’s, there are many different approaches to the methods by which we sample them. The common thread among all NGL’s is that these products; in order to be maintained and properly sampled, require the use of specific sampling techniques unique to light liquid and NGL sampling.

This paper provides a fundamental overview of an NGL meter station design reviewing the nuances of configuring similar
components in different ways. There are multiple considerations that influence the meter station design and all must be taken into account. Major considerations are: what product or products will be measured, what meter technology to utilize, and the process design limitations.
The first thing that must be taken into account is whether the product is a purity product or a mixed compositional product. Most purity products are measured and accounted for by volume, while a mixed compositional product is measured and accounted for by mass. This influences the meter skid design, since mass product skids must be set-up to allow for the stream’s mass and stream’s composition to be measured properly.
The second consideration that influences the skid design is the meter technology chosen. The skid components required can change depending on the meter technology selected. There are numerous meter technologies available on the market, but the three major meter technologies commonly used for NGL custody measurement are Turbine meters, Coriolis meters, and Positive Displacement (PD) meters. Other minor considerations will be discussed at the appropriate times throughout the paper.

The measurement of natural gas liquids (NGL) is similar in many respects to that of other hydrocarbon liquids but is
markedly different in other aspects. The main difference in NGL measurement is the need to properly address the effects of solution mixing. Measuring NGL by mass measurement techniques will properly address solution mixing effects because the mass measurement process is not sensitive to the effect that pressure, temperature and solution mixing have on the fluid measured.
Another difference is the effect of higher vapor pressures on the measurement of natural gas liquids. In static measurement methods, the liquid equivalent of the vapor space must be determined. In dynamic measurement methods, the equilibrium vapor pressure, or that pressure at which a liquid and its vapor phase is in equilibrium at a given operating temperature, must be deducted from the operating pressure when determining the compressibility effects on measured volumes. This paper will describe the basic concepts used to measure and report the quantities of NGL streams.

This paper will verify the history, requirements and operation of all Provers accepted for liquid pipeline meter uncertainty verification in the Liquid Oil/Gas Industry. It will continue with an explanation and the industries wide acceptance of the Uni-directional Captive Displacement Prover (UDCDP). This document will supply the reader with information regarding meter types and the flow volumes that can be used with the UDCDP and will look at the opportunities for the use of a UDCDP as a mass prover. It will also provide the information for field verification of provers known as a water draw.

The first flow meter utilizing the Coriolis force to measure mass flow was patented in 1978. Today, hundreds of
thousands of Coriolis meters are in service in the hydrocarbon industry to measure mass, volume, and density of a wide variety of fluids. The American Petroleum Institute published Chapter 5.6 entitled “Measurement of Liquid Hydrocarbons by Coriolis Meters” in October 2002 and reaffirmed the standard in 2013. The standard describes methods to achieve custody transfer levels of accuracy when a Coriolis meter is used to measure liquid hydrocarbons.

This paper will discuss the use of pycnometers for densitometer provings. The primary objective will be to provide guidance in the operation and maintenance of a densitometer and pycnometer (pyc), as well as common issues found during normal operation.

With the proliferation of horizontal drilling allowing access to tight oil formations, liquid production in the U.S. has significantly increased over recent years. Consequently, there is renewed interest in accurate measurements for both custody transfer and allocation purposes. Advances in measurement automation have yielded operators’ savings in the millions of dollars annually. Over the last several years, the increase of shale play drilling has created a problem within the industry. Most of the shale plays have been developed in primarily natural gas production areas, where a lack of liquids measurement knowledge may exist.
While there certainly are knowledgeable people in these areas, measurement personnel can be spread thin due to the many
active drill sites. Both allocation measurement and custody transfer measurement occur in these areas, so measurement
personnel must be well versed on both. Typical questions that come up are: What is the right technology to use in each of the areas of measurement? Should I use turbine meters, Coriolis meters, or maybe just orifice meters? What data do I need to get back to my host system? Should I just count barrels or do I want to get some real insight into the process?

The word “Auditing” is often used to imply that activities related to a review of general business practices, and procedures for an asset or business unit, are under way.
The objective of those activities is to assure compliance with corporate policies and procedures, industry and government standards, and sound management principles. Additional objectives may include review of accounting and financial transactions for accuracy, completeness and timeliness. The Institute of Internal Auditing defines the process as:
“Internal auditing is an independent, objective assurance and consulting activity designed to add value and improve an
organization’s operations. It helps an organization accomplish its objectives by bringing a systematic, disciplined approach to evaluate and improve the effectiveness of risk management, control, and governance processes.”