API RP 87-2007 pdf download
API RP 87-2007 pdf download.Recommended Practice for Field Analysis of Crude Oil Samples Containing from Two to Fifty Percent Water by Volume.
1 Scope The purpose of this document is to provide the user with recommended ‘field’ methods of sampling, sample handling and analysis for high water content streams up to 50 % water on a volumetric basis. In particular, this RP was developed giving consideration to offshore installations (both floating and fixed platforms). These installations are generally subject to motion and vibrations, have minimal laboratory equipment, and perform S&W analysis with multi- skilled operations personnel as opposed to laboratory chemists. The techniques described, however, are also applicable to onshore locations. This document provides design and operating guidelines for sampling, sample handling and sample analysis of high water content streams, up to 50 % water by volume. As a guide, this RP targets a relative accuracy of 5 % of reading up to a maximum of 50 % water content as a qualifier for the various methods described herein. For example, the corresponding absolute accuracy for a 1 0 % water content stream is ± 0.5 % and for 20 % water content is ± 1.0 %. This recommended practice may involve hazardous materials, operations, and equipment. This RP does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this RP to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. The laboratory testing contained within this RP (see Annex A) is based on a single laboratory—single operator set of results. As with other API standards for field S&W determination methods, no precision and bias calculation was performed and therefore, no inter-laboratory or round robin style testing was performed. The results of the testing of the various methods are primarily intended to provide a general comparison between different methods to facilitate operational choices. 2 References 2.1 Normative API MPMS Chapter 8.2 (ASTM D 4177), “Automatic Sampling of Petroleum and Petroleum Products”
3 Terms and Definitions The majority of terms used in this RP are defined within API MPMS Chapter 20.1 or other related chapters and are therefore not defined here. Following are the terms that are specific to this RP: 3.1 aliquot A small portion of a larger sample which is analyzed in a laboratory and assumed to represent to whole sample. 3.2 bubble point (in non-stabilized hydrocarbon liquids) The lowest pressure at which the liquid remains fully in the liquid state (see also gas break-out). 3.3 gas break-out (in non-stabilized hydrocarbon liquids) The act of dissolved gas coming out of liquid solution and residing as free gas within the predominately liquid flow (see also bubble point). 3.4 jet mixer A system of pump(s) and nozzle(s) where a small portion of a stream is extracted and pumped and then re-injected through a nozzle back into the stream in order to provide turbulence within the stream and mix free water and oil such that a representative sample may be extracted at a point downstream. 3.5 lab mixing system A system similar to an automatic sampler circulating mixing system but located in a laboratory where it is used to re- mix a large sample for aliquot delivery. 3.6 slip stream (in single phase liquid flows) A stream or bypass line of approximately the same velocity as the main stream utilized for extracting representative proportional-to-flow samples (sometimes referred to as fast loop). 3.7 static mixer A series of internal obstructions designed to use the flowing velocity force of the stream to mix and evenly distribute water throughout the pipe cross-section. 4 Symbols and Abbreviated Terms
