【国外标准】 Standard Test Method for Determination of Light Hydrocarbons and Cut Point Intervals in Live Crude Oils and Condensates by Gas Chromatography

5.1 This test method determines methane (nC1) to hexane (nC6), cut point carbon fraction intervals to nC24 and recovery (nC24+) of live crude oils and condensates without depressurizing, thereby avoiding the loss of highly volatile components and maintaining sample integrity. This test method provides a highly resolved light end profile which can aid in determining and improving appropriate safety measures and product custody transport procedures. Decisions in regards to marketing, scheduling, and processing of crude oils may rely on light end compositional results.5.2 Equation of state calculations can be applied to variables provided by this method to allow for additional sample characterization.1.1 This test method covers the determination of light hydrocarbons and cut point intervals by gas chromatography in live crude oils and condensates with VPCR4 (see Note 1) up to 500 kPa at 37.8 °C.NOTE 1: As described in Test Method D6377.1.2 Methane (C1) to hexane (nC6) and benzene are speciated and quantitated. Samples containing mass fractions of up to 0.5 % methane, 2.0 % ethane, 10 % propane, or 15 % isobutane may be analyzed. A mass fraction with a lower limit of 0.001 % exists for these compounds.1.3 This test method may be used for the determination of cut point carbon fraction intervals (see 3.2.1) of live crude oils and condensates from initial boiling point (IBP) to 391 °C (nC24). The nC24 plus fraction is reported.1.4 Dead oils or condensates sampled in accordance with 12.1 may also be analyzed.1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.5.1 Exception—Where there is no direct SI equivalent such as tubing size.1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.