Download presentation
1
Natural Gas Processing
2
If this guy can understand gas plant accounting, so can you…
3
Natural Gas Composition and Properties
4
Composition Well Stream Raw Gas Inert Gases Water Condensate
Contaminant Gases Hydrocarbons
5
Hydrocarbons H 1 C 6 Hydrogen 1.0079 Carbon
6
Hydrocarbons Hydrogen Carbon Chemical Bond
7
Hydrocarbons Methane
8
Hydrocarbons Methane Ethane
9
Hydrocarbons Methane Ethane
10
Hydrocarbons Methane Ethane Propane
11
Hydrocarbons Methane Ethane Propane Iso Butane
12
Hydrocarbons Methane Ethane Propane Iso Butane Normal Butane
13
Hydrocarbons Methane Ethane Propane Iso Butane Normal Butane
Iso Pentane Normal Pentane Neo Pentane
14
Hydrocarbons Residue Gas* Natural Gas Liquids (NGL) Methane Ethane
Propane Iso Butane Normal Butane Iso Pentane Normal Pentane Neo Pentane * Methane is the primary component. May contain some ethane, propane, etc. Hexanes Plus
15
Physical Properties Units of Measurement Volume (Gallons) Energy
(MMBtu) Volume (Mcf)
16
Physical Properties Conversions Convert between pressure bases
Uses ratios of pressures Convert between units of measurement Uses factors (Btu factor, Shrink factor, GPM)
17
Physical Properties Pressure Bases 14.65 psi 14.696 psi 14.73 psi
Atmospheric Pressure psi 14.73 psi psi
18
Physical Properties Conversion Factors Btu Factor:
Mcf x Btu Factor = MMBtu Gas Quantity Lost Due to Extraction of a Particular NGL Component Shrink Factor: Gallons x Mcf Shrink Factor = Shrink Mcf Gallons x MMBtu Shrink Factor = Shrink MMBtu GPM Factor: Mcf x GPM Factor = Component Gallons Theoretical Gallons of Particular NGL Component Contained in Gas
19
Physical Properties Converting volumes between pressure bases Volume
PB1 Volume PB2 PB1 x = PB2
20
Physical Properties Converting volumes between pressure bases Ex.
14.65 Psi x = Psi 14.73
21
Physical Properties Converting volumes between pressure bases Ex.
14.73 Psi x = Psi 14.65
22
Physical Properties Converting volumes to energy x Btu Factor @ P.B 1
= Volume (Mcf) Energy (MMBtu) @ P.B. 1
23
Physical Properties Summary of Conversions Between Pressure Bases
P.B. 1 P.B. 1 x = P.B. 2 P.B. 2 P.B. 2 Btu P.B. 1 x = Btu P.B. 2 P.B. 1 P.B. 1 Mcf Shrink P.B. 1 x = Mcf Shrink P.B. 2 P.B. 2 P.B. 2 P.B. 1 x = GPM P.B. 2 P.B. 1
24
Physical Properties Summary of Conversions Between Units of Measurement P.B. 1 x Btu P.B. 1 = MMBtu P.B. 1 x P.B. 1 = Gallons Gallons x Mcf Shrink P.B. 1 = P.B. 1 Gallons x MMBtu Shrink Factor = MMBtu
25
Physical Properties Tips for Conversions High Pressure to Low Pressure
=> Volume Increases Low Pressure to High Pressure => Volume Decreases
26
Physical Properties Tips for Conversions High Pressure to Low Pressure
=> Btu Factor, GPM, Mcf-Shrink Factor Decreases Low Pressure to High Pressure => Btu Factor, GPM, Mcf-Shrink Factor Increases
27
Field Operations From Well to Inlet
28
Metering Gas Meter P1, T1 P2, T2 Orifice Place
29
Separation Gas Oil Water Coalescing Plates Deflector Plate
30
Gathering Lines & Pigging
31
Gathering Lines & Pigging Physical Barrier between liquid and gas
Check pipe integrity and remove debris Provide known volume for meter calibration Coat inner pipe with corrosion inhibitors Remove condensed water any hydrocarbon liquids
32
Compression Due to the complexity of a compressor animation and the limitations of PowerPoint, I was unable to create a sufficient animation for compression.
33
Compression So here’s an animation of some baby chickens:
34
Compression Wait, here’s an animation from MAN Diesel and Turbo:
35
Compression Oil-free Rotary Screw Compressor Centrifugal Compressor
Pictures from Fundamentals of Natural Gas Processing 2nd ed., Kidnay 2006
36
Gas Processing From Inlet to Tailgate
37
Gas Flow Gas From Field Raw Helium Sales Gas Inlet Receiving Water &
Solids Nitrogen Rejection Helium Recovery Outlet Compression Inlet Compression Hydrocarbon Recovery Gas Treating Dehydration Natural Gasoline Liquids Processing NGLs Based on diagram from Fundamentals of Natural Gas Processing 2nd ed., Kidnay 2006
38
Components vary based on desired products
Hydrocarbon Recovery Components vary based on desired products
39
Hydrocarbon Recovery External Refrigeration Turboexpansion
Heat Exchangers Fractionators
40
Plant Configurations SWEET GAS Sales Gas EPBC CO2 High Pressure Gas
Propane Refrigeration Residue Compression Sales Gas Dehydration EPBC Hydrocarbon Recovery CO2 Amine Treating Heat Exchange High Pressure Gas Inlet Compression Compression PBC Deethanizer Low Pressure Gas Based on diagram from Fundamentals of Natural Gas Processing 2nd ed., Kidnay 2006
41
Accounting Gas Allocations and Other Principles
42
Allocations Principles Design Execution Validation
43
Principles Contractual
44
Reflects Operational Dynamics
Principles Reflects Operational Dynamics
45
Principles Equitable
46
Principles Start with most accurate method, simplify if no material effects and simplification is contractual
47
Designing Allocations
Step 1 – Identify Sources and Dispositions Step 2 – Determine Allocation Order Step 3 – Determine Allocation Pools Step 4 – Determine Allocation Basis
48
Designing Allocations
Step 1 – Identify Sources and Dispositions Compressor 1 Gas Plant
49
Designing Allocations
Step 1 – Identify Sources and Dispositions Compressor Fuel 1 NGLs Compressor 1 2 Gas Plant 3 Residue Gas Plant Fuel 4 5 6
50
Designing Allocations
Step 1 – Identify Sources and Dispositions Compressor Fuel 1 NGLs Compressor 1 2 Gas Plant 3 Residue Gas Plant Fuel 4 5 6
51
Designing Allocations
Step 1 – Identify Sources and Dispositions Compressor Fuel 1 NGLs Compressor 1 2 Gas Plant 3 Residue Gas Plant Fuel 4 5 6
52
Designing Allocations
Step 1 – Identify Sources and Dispositions Sources Dispositions Compressor Fuel 2 4 1 Residue Gas NGLs 5 3 6 Plant Fuel
53
Designing Allocations
Step 2 – Determine Allocation Order The further upstream a disposition, the sooner it is allocated The further downstream a disposition, the later it is allocated
54
Designing Allocations
Dispositions Designing Allocations Compressor Fuel Step 2 – Determine Allocation Order Residue Gas NGLs Plant Fuel
55
Designing Allocations
Dispositions Designing Allocations Step 2 – Determine Allocation Order Residue Gas NGLs Plant Fuel 1 Compressor Fuel
56
Designing Allocations
Dispositions Designing Allocations Step 2 – Determine Allocation Order Residue Gas Plant Fuel 1 Compressor Fuel 2 NGLs
57
Designing Allocations
Dispositions Designing Allocations Step 2 – Determine Allocation Order Residue Gas 1 Compressor Fuel 2 NGLs 3 Plant Fuel
58
Designing Allocations
Dispositions Designing Allocations Step 2 – Determine Allocation Order 1 Compressor Fuel 2 NGLs 3 Plant Fuel 4 Residue Gas
59
Designing Allocations
Compressor Fuel 1 Step 3 – Determine Allocation Pools 1 2 3 NGLs 2 4 5 6 1 2 3 Plant Fuel 3 4 5 6 1 2 3 Residue Gas 4 4 5 6 1 2 3
60
Designing Allocations
Step 4 – Determine Allocation Basis Is Gas Used? What determines usage? Is Gas Extracted, changes state (i.e. gas to liquid)? Unit of Measurement?
61
Executing Allocations
Starting with disposition 1 For each source in the allocation pool, compute theoretical volume: Source – Sum(Dispositions) = Theoretical Compute Total Theoretical For each source, computed allocated share: Source Theoretical X Disposition = Allocated Share Total Theoretical
62
Allocations Allocating NGLs is normally 2-step computation:
- Compute each source’s Mcf of inlet gas Apply Component GPM to Mcf => Theoretical Component Gallons
63
Allocations Least Accurate to Most Accurate NGL Allocation: Mcf MMBtu
Total GPM => Total Theoretical Gallons Component GPM => Theoretical Component Gallons
64
Verifying Allocations
Balance the System Balance each Well
65
Verifying Allocations
Balance the System Total Sources – Total Dispositions >>>> 0 (0%) Missing Disposition Bad (low) Disposition Measurement Significant, actual loss Bad (high) Source Measurement
66
Verifying Allocations
Balance the System Total Sources – Total Dispositions <<<< 0 (0%) Missing Source Bad (high) Disposition Measurement Bad (low) Source Measurement
67
Verifying Allocations
Balance Wells Apply Same Formula for System Balance on a well-by-well basis Cumulative, common differences among groups of wells can imply: Allocation did not reflect operational dynamics Wrong allocation basis chosen for one or more dispositions
68
This allocation process applies to all gas allocations, regardless processing
69
Documents Settlement Statements and Measurement Data
70
Heating Value (Btu/Scf
Gas Volume Statement March 2014 Meter No 212354 Name ExtraSpecial Well Pressure Base 14.73 Temperature Base 60 Day Differential (in. H2O) Pressure (psia) Temperature (F) Flow Time (hrs) Relative Density Plate (inches) Volume (Mcf) Heating Value (Btu/Scf Energy (MMBtu) 1 2.13 143.01 94.35 20.62 0.8155 0.3750 10.59 14.8 2 2.18 143.06 93.25 20.65 10.72 14.97 3 2.43 141.67 92.95 19.63 10.33 14.43 4 2.15 141.80 92.27 18.73 9.31 13.01 5 7.79 141.04 91.74 14.32 10.36 14.48 6 10.55 140.96 89.27 11.29 10.53 14.71 7 10.52 141.18 91.73 11.43 10.63 14.85 8 9.63 141.41 89.15 12.12 10.81 9 10.07 141.39 91.76 11.15 9.96 13.92 10 8.00 133.50 88.73 3.29 2.35 11 0.00 60.40 98.14 12 64.75 81.40 112.18 0.28 0.34 0.47 13 1.43 143.74 82.94 2.46 0.91 1.27 14 2.74 131.38 96.14 11.65 4.96 6.94 15 2.56 132.27 92.72 16.22 8.30 11.59 16 4.14 143.99 92.97 13.46 9.07 12.67 17 7.03 144.03 87.06 18.42 14.99 20.94 18 6.42 143.82 87.68 16.85 12.69 17.73 19 15.96 143.95 79.27 23.26 32.65 45.62 20 16.49 143.89 87.64 23.56 33.95 47.43 21 60.79 143.28 87.52 23.93 40.68 56.83 22 40.10 117.69 78.31 4.59 6.13 8.56 23 132.44 142.99 85.37 8.67 28.73 40.14 24 3.67 145.06 116.50 0.66 0.39 0.54 25 210.52 144.93 101.45 2.25 9.75 13.62 26 2.08 144.99 104.40 1.09 0.48 0.67 27 4.81 144.87 102.22 4.64 2.76 3.86 28 1.41 145.26 98.68 3.39 1.40 1.95 29 1.68 145.14 103.88 3.64 1.62 2.26 30 34.12 144.64 88.19 3.55 0.8155· 2.05 2.87 Total 34.64 141.96 88.80 325.79 307.42 429.51 Meter Statement Meter/Operator Information Measurement Conditions, Methods, Basis Daily Volume and Energy Data
71
Gas Analysis Statement
Meter/Operator Information General Sample Info Analysis Data
72
Plant Settlement Statement
Contract/Operator Information Gas Computations NGL Computations
73
Questions?
74
Thanks! The End!!!!!!
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.