API Publ 2566-2004 pdf free download

API Publ 2566-2004 pdf free download.State of the Art Multiphase Flow Metering.
where a small amount of liquid is present. On the other hand, elements of the multiphase metering technology have been modified to develop wet gas metering systems. Sections 12-15 discuss types of wet gas, measurement techniques used in wet gas metering, and the performance of wet gas metering systems. Performance assessment and verification of multiphase and wet gas meters are complicated by the lack of commonly accepted protocol and standards. Current approaches used by operators and industry projects to address these issues are discussed in Section 17. Guidelines to be used for installations, qualification testing, and field testing of multiphase and wet gas metering systems are discussed in Sections 18-21. The users of multiphase and wet gas meters face three major technical challenges in addition to justifying the cost and risk of the deploying new technology. These challenges are: • Selecting and qualifying multiphase meters for different applications. • Assessing the performance of the multiphase meters after installation. • Getting approval to use multiphase meters from appropriate regulatory bodies. There is currently no single document that users of multiphase metering systems can consult to address the above issues. Users have relied on vendor information for procurement of multiphase metering systems in a majority of the current installations. There is concurrence within the industry that a “Standard” or “Recommended Practice” (RP) be created to establish a common language to describe the performance of these systems. There is also a need to develop a commonly accepted protocol and procedures to evaluate the performance of multiphase metering systems. Should API decide to pursue the development of a “Standard” or a “Recommended Practice” on multiphase flow meters, the information in this report, as well as a number of currently available specifications listed in Section 22, should provide helpful direction and technical resource for the development of the new document.
8- CLASSIFICATION OF MULTIPHASE METERS Multiphase measurements systems used in production operations utilize a diverse range of equipment from full three-phase conventional separators to in- line multiphase meters that consist of a spool piece with no separation. From the perspective of users, these systems have one common purpose – i.e. to provide accurate flow rates for oil, water and gas. In each system, however, the processes schematically shown in Figure 7 must occur. The processes shown in Figure 7 consist of some type of fluid conditioning, mixture density determination, mixture rate determination, mixture composition determination, and application of a flow model. These functions can be supplied by an instrument or by an assumption in a model (III-4). The volumetric fraction and component velocity measurement techniques described in sections 8 and 9 are commonly used in these systems. Several references, listed in Appendix 2, have attempted to categorize the multiphase metering systems (II-4, II-11, II-18, II-24, III-4, XII-3). Terms such as on-line and off-line have been used to describe various systems. There is considerable confusion and even an argument that the term multiphase meter should only be applied to systems that can make multiphase measurements without the separation process. The following classification of the multiphase metering systems is proposed as a way to develop a commonly accepted language for multiphase metering. It is proposed that we use the following definitions to designate three types of multiphase metering systems.
8.1- T YPE I M ULTIPHASE M EASUREMENT S YSTEM These systems are conventional separators where by definition the gas is saturated at separator conditions and there is no free gas in the liquid. The separated streams are measured and recombined to form the original stream. This category includes 3-phase and 2-phase units both measuring oil, gas and water. These systems may employ some of the continuous oil/water monitoring devices (II-13, XII-5) that were discussed in section 7. 8.2- T YPE II M ULTIPHASE M EASUREMENT S YSTEMS In these systems the main flow stream is divided into “gas rich” and “liquid rich” streams. Each stream is subjected to multiphase measurements then recombined to form the original stream. 8.3- T YPE III M ULTIPHASE M EASUREMENT S YSTEMS All three phases go through a single conduit and are measured at the same time. This category includes all the so-called inline meters. These meters may use flow conditioning – i.e. use of elbow, mixers, etc (II-9).