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Natural Gas Processing

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Presentation on theme: "Natural Gas Processing"— Presentation transcript:

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!!!!!!


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