addressing uncertainty in oil and natural gas industry greenhouse

Table of Contents
SECTION
Page
FOREWORD
vi
DOCUMENT AT A GLANCE
viii
1.0 INTRODUCTION 1-1
1.1 Importance of Accurate and Reliable GHG Accounting 1-1
1.2 Overview of Uncertainty Terminology 1-2
1.3 Types of Errors 1-3
1.4 Determination of Uncertainty Intervals 1-3
2.0 SOURCES OF UNCERTAINTY 2-1
2.1 Overview of Emissions Inventory Uncertainty 2-1
2.2 Emissions Inventory Uncertainty in the O&G Industry 2-3
2.3 Sources of Measurement Uncertainty 2-5
2.4 Emission Estimation Approaches 2-7
2.5 Inventory Steps and Data Aggregation 2-9
3.0 OVERVIEW OF MEASUREMENT PRACTICES 3-1
3.1 Flow Measurement Practices
3.1.1 Measurements by Orifice Meters
3.1.2 Measurement of Flow to Flares
3.1.3 Example: “Custody Transfer” Measurements
3.2 Uncertainties of Flow Measurements for GHG Inventories 3-9
3.3 Uncertainties of Sampling and Analysis for GHG Estimation
3.3.1 Gaseous Samples Collection and Handling
3.3.2 Quantifying Sampling Precision
3.4 Carbon Content Measurement Practices
3.4.1 Laboratory Based Measurements
3.4.2 On-line Measurements
3-3
3-3
3-5
3-7
3-13
3-13
3-15
3-15
3-16
3-18
3.5 Heat Content Determination 3-19
3.5.1 Direct Measurements
3.5.2 Computational Methods
3.6 Laboratory Management System 3-22
4.0 STATISTICAL CONCEPTS AND CALULATION METHODS 4-1
4.1 Measurement Uncertainty
4.1.1 Precision and Bias
4.1.2 Confidence Intervals
4.2 Overview of Uncertainty Propagation
4.2.1 Propagation Equations
4.2.2 Correlation Coefficient
3-19
3-21
4-1
4-1
4-3
4-4
4-6
4-7
Pilot Version, September 2009
ii