EOS Higher Oil School 2017/5/26

Transcription

1 EOS Higher Oil School 2017/5/26

2 Introduction What is EOS? Equation of State Also known as Cubic EOS because of equation of 3 rd degree Instrumental to calculate PVT Relationship between Pressure, Volume and Temperature In process engineering problems and especially in petroleum equilibrium calculations Successful PVT model based on a fitting EOS can be helpful to determine the state of the flow regime, the parameters for handling the reservoir fluids and dynamics, piping and sizing Copyright 2017 INPEX CORPORATION. All rights reserved. 1

3 Introduction Reservoir fluid sampling Representative sample acquisition Laboratory fluid analysis Accurate measurement Fluid characterization Reliable EOS (Equation of State) modelling Calsep, Inc. Copyright 2017 INPEX CORPORATION. All rights reserved. 2

4 Agenda Reservoir Fluid Sampling Reservoir Fluid Analysis Reservoir Fluid Characterization Fluid composition Heavy end component Splitting and lumping EOS modelling EOS selection Regression Volume shift EOR screening Swelling test MMP Slim tube test Copyright 2017 INPEX CORPORATION. All rights reserved. 3

5 Reservoir Fluid Sampling Reservoir Fluid is essential information in E&P industry Good quality sample is required for the optimum petroleum field development Exploration and geochemistry Biomarker, isotope etc. Composition Hydrocarbon (C1, C2, C3 ) Others (CO2, H2S, Hg etc.) PVT, volumetric behavior, rheology Reserves, dynamic behavior, EOR Flow Assurance Hydrate, emulsion, foaming Wax, Asphaltene etc. Basis of Design for Wells & Facilities HSEMS Marketing Crude Oil Assay etc. Copyright 2017 INPEX CORPORATION. All rights reserved. 4

6 Reservoir Fluid Sampling Downhole sampling Wireline / slick line sample Sampling While Drilling Sample carrier with test string Surface sampling Wellhead sample Isokinetic sample etc. Separator sample Oil and Gas recombined sample Wellhead sampling Separator sampling Separator Sample carrier WFT Downhole sampling Copyright 2017 INPEX CORPORATION. All rights reserved. 5

7 Bottom Hole Pressure Reservoir Fluid Sampling Well Conditioning for fluid sampling To maintain the single phase flow in the bottom-hole Keep above saturation pressure To avoid gas liberation or condensate drop-out Without water coning / gas cusping Clean-up before sampling Remove contamination by drilling or completion fluid Wellbore Static Reservoir Pressure Drawdown with well conditioning Bubble Point Pressure Flowing Reservoir Pressure with well conditioning Flowing Reservoir Pressure without well conditioning Drawdown without well conditioning Drawdown is pressure difference between static reservoir pressure and flowing bottom-hole pressure Copyright 2017 INPEX CORPORATION. All rights reserved. 6

8 Reservoir Fluid Sampling Phase envelope Drawdown during sampling should be above saturation pressure Only oil single-phase Static Reservoir condition Only gas single-phase Bubble Point Curve Oil and Gas mol% equal Dew Point Curve Separator condition Copyright 2017 INPEX CORPORATION. All rights reserved. 7

9 Reservoir Fluid Sampling Phase envelope Drawdown during sampling should be above saturation pressure Small drawdown Static Reservoir condition Bubble Point Curve Oil and Gas mol% equal Dew Point Curve Separator condition Copyright 2017 INPEX CORPORATION. All rights reserved. 8

10 Reservoir Fluid Sampling Phase envelope Drawdown during sampling should be above saturation pressure Small drawdown Static Reservoir condition Dissolved gas liberated from oil under bubble point 2phase flow by large drawdown Separator condition Copyright 2017 INPEX CORPORATION. All rights reserved. 9

11 Bottom Hole Pressure Reservoir Fluid Sampling Well Conditioning for fluid sampling To maintain the single phase flow in the bottom-hole Keep above saturation pressure To avoid gas liberation or condensate drop-out Without water coning / gas cusping Clean-up before sampling Remove contamination by drilling or completion fluid Wellbore Static Reservoir Pressure Drawdown with well conditioning Bubble Point Pressure Flowing Reservoir Pressure with well conditioning Flowing Reservoir Pressure without well conditioning Drawdown without well conditioning Drawdown is pressure difference between static reservoir pressure and flowing bottom-hole pressure Copyright 2017 INPEX CORPORATION. All rights reserved. 10

12 Reservoir Fluid Sampling Recovering Sample Bottles Transporting Sample Bottles Hand-over to Laboratory Copyright 2017 INPEX CORPORATION. All rights reserved. 11

13 Reservoir Fluid Analysis Routine analysis Compositional analysis Gas chromatography etc. Constant Composition Expansion Differential Liberation Test Separator test Viscosity Others (CVD, saturation point etc.) EOR analysis Swelling test MMP Slim tube Others (Multiple contact etc.) Others Crude oil assay, flow assurance etc. Copyright 2017 INPEX CORPORATION. All rights reserved. 12

14 Reservoir Fluid Analysis Constant Composition Expansion Differential Liberation Test Copyright 2017 INPEX CORPORATION. All rights reserved. 13

15 Reservoir Fluid Analysis Above bubble point Under bubble point Solution Gas Free Gas + Solution Gas Stock Tank Oil Stock Tank Oil Oil Gas Oil Liberated free gas is more movable than oil More easy to produce gas DLT is more realistic underground behavior Copyright 2017 INPEX CORPORATION. All rights reserved. 14

16 Reservoir Fluid Analysis Constant Composition Expansion - Example Differential Liberation Test - Example Copyright 2017 INPEX CORPORATION. All rights reserved. 15

17 Reservoir Fluid Analysis QC Check detail of report and equipment spec. Check consistency of fluid sample Composition, GOR/CGR, saturation pressure etc. Check sampling condition, process, mud contamination etc. Check mass balance and equilibrium state for recombined sample Check accuracy without regression Saturation point STO density etc. Pressure, bara Phase envelopes separator compositions Separator Condition Temperature, C Separator Gas Separator Liquid Separator T,P Separator Oil Separator Gas Copyright 2017 INPEX CORPORATION. All rights reserved. 16

18 Reservoir Fluid Characterization Input fluid analysis result Laboratory fluid analysis Accurate measurement Fluid characterization Reliable modelling Select representative sample Tuning EOS Export to other software Reservoir simulator (e.g. Eclipse, Nexus) Pipe flow simulator (e.g. Olga, Prosper) Process simulator (e.g. Hysys) EOS simulator EOS export for various simulators Dynamics model Schlumberger, Ltd. Petroleum Experts, Ltd. CMG Calsep, Inc. Copyright 2017 INPEX CORPORATION. All rights reserved. 17

19 Fluid composition Fluid composition shall be input first into the EOS modelling software Example of composition input Calsep, Inc. Copyright 2017 INPEX CORPORATION. All rights reserved. 18

20 Fluid composition Heavy end component Compositional analysis shows the various heavy end component Typical heavy end component C7+ C12+ C20+ C36+ Copyright 2017 INPEX CORPORATION. All rights reserved. 19

21 Fluid composition Recombination is required for separator sample Mixing oil sample and gas sample with measured gas-oil ratio Oil & Gas flowing into Separator Gas sample acquired Gas Flow Rate measured Oil sample acquired Oil Flow Rate measured Mixed with measured gas-oil ratio Recombined Sample to represent reservoir fluid Copyright 2017 INPEX CORPORATION. All rights reserved. 20

22 Mole % Fluid composition Wireline sample often affected by drilling fluid Drilling fluid invaded into near wellbore formation Drilling fluid shall be sampled, and its composition analyzed Oil Based Mud is dominated by heavy component, C14-C18 Decontamination is required before EOS modelling Affected by Oil Based Mud Contaminated Sample Fluid Composition True Clean Reservoir Fluid Composition Molecular weight /95/wll-logging jpg?cb= Copyright 2017 INPEX CORPORATION. All rights reserved. 21

23 Fluid composition PVT simulation to check consistency with measured data Bubble point STO density Others Select good initial guess for EOS selection & heavy end component Measured data Copyright 2017 INPEX CORPORATION. All rights reserved. 22

24 Fluid composition Fluid Composition Splitting heavy end component Lumping component group Grouping by similar K-factor etc. Into grouped pseudo component Too many component for compositional simulation!! Split heavy component Lumped similar component Composition from Lab. analysis Copyright 2017 INPEX CORPORATION. All rights reserved. 23

25 Equation of State Ideal law P RT V Copyright 2017 INPEX CORPORATION. All rights reserved. 24

26 Equation of State Ideal law Actual law Van der Waals P RT V P RT V b a V 2 Copyright 2017 INPEX CORPORATION. All rights reserved. 25

27 Equation of State Ideal law Actual law Van der Waals Molecular size P RT V P RT V b a V 2 Molecular size Copyright 2017 INPEX CORPORATION. All rights reserved. 26

28 Equation of State Ideal law Actual law Van der Waals Molecular size Intermolecular force P RT V P RT V b Intermolecular force a V 2 Molecular size Copyright 2017 INPEX CORPORATION. All rights reserved. 27

29 Equation of State Ideal law Actual law Van der Waals Molecular size Intermolecular force Various EoS developed Redrich Kwong (RK) Soave Redrich Kwong (SRK) Zudkevitch Joffe (ZJ) Peng Robinson (PR76 / PR78) P RT V P RT V b Molecular size Intermolecular force a V 2 SRK P RT V b a V(V b) PR P RT V b V a V b bv b Copyright 2017 INPEX CORPORATION. All rights reserved. 28

30 Equation of State How to determine a & b Law of Corresponding States a & b of each component determined by Tc, Pc and ω Tc: Critical temperature of each component Pc: Critical pressure of each component ω: Acentric factor of each component a Ω a ( RT P c c ) 2 1 m 1 T T c 2 b Ω b RT P c c SRK P RT V b a V(V b) PR P RT V b V a V b bv b m ω 0.176ω Ω a Ω b 2 m ω 0.276ω Ω a Ω b 2 Copyright 2017 INPEX CORPORATION. All rights reserved. 29

31 Regression Tuning of uncertainty parameters is required to realize the experimental data Regression applied to minimize the object function Object function indicates the degree of error against experimental data Object Function No. of data i1 Calci Exp Expi i user specified weight 2 Measured data EOS model before regression EOS model after regression Regression Regression Regression Oil Volume vs. Pressure Dissolved Gas vs. Pressure Density vs. Pressure Copyright 2017 INPEX CORPORATION. All rights reserved. 30

32 Regression Tuning of uncertainty parameters is required to realize the experimental data Regression applied to minimize the object function Object function indicates degree of error against experimental data Typical tuning parameter Mw: Molecular weight of heavy end component (plus fraction) Tc: Critical temperature of each component Pc: Critical pressure of each component ω: Acentric factor of each component Binery Interaction Parameter/Coefficient of each component combination Volume shift of each component Copyright 2017 INPEX CORPORATION. All rights reserved. 31

33 Regression - Example 1 st Regression: Objective Function = Mw: ±20%, Pc: ± 20%, Tc: ± 20%, ω: ± 20% Measured data EOS model before regression EOS model after regression DLT: Oil Volume vs. Press. DLT: Dissolved Gas vs. Press. CCE: Oil Volume vs. Press. DLT: Oil density vs. Press. DLT: Gas gravity vs. Press. CCE: Y-factor vs. Press. Copyright 2017 INPEX CORPORATION. All rights reserved. 32

34 Equation of State How to determine a & b Law of Corresponding States a & b of each component determined by Tc, Pc and ω Tc: Critical temperature of each component Pc: Critical pressure of each component ω: Acentric factor, acentricity / non-sphericity of a molecule Mixing Rule a & b of multi-component system is determined by a & b of each component and Binary Interaction Coefficient θ: Binary Interaction Coefficient Mixing Rule b a xi x j 1i, i i i a i j j i j x b a Copyright 2017 INPEX CORPORATION. All rights reserved. 33

35 Regression - Example 2 nd Regression: Objective Function = Tc: ±20%, Pc: ±20%, ω: ±20%, BIP: C1-C3 Density improved, compressibility & Y-factor slightly improved EOS model EOS model Measured data before regression after regression DLT: Oil Volume vs. Press. DLT: Dissolved Gas vs. Press. CCE: Oil Volume vs. Press. DLT: Oil density vs. Press. DLT: Gas gravity vs. Press. CCE: Y-factor vs. Press. Copyright 2017 INPEX CORPORATION. All rights reserved. 34

36 Equation of State Ideal gas law Actual gas law SRK Van der Waals Intermolecular foce Molecular size Various EoS developed Redrich Kwong (RK) Soave Redrich Kwong (SRK) Peng Robinson (PR)» Volume shift applied possibly RT a(t) P V b V(V b) Volume shift PR P P RT V P RT V b Molecular size RT V b V a V 2 at V b bv b Volume shift Intermolecular force P RT V b (V a(t) c)(v b 2c) P RT V b at V cv 2c b b cv b Copyright 2017 INPEX CORPORATION. All rights reserved. 35

37 Regression - Example 3 rd Regression: Objective Function = Volume-shift adjusted, Density and Oil FVF improved Measured data EOS model before regression EOS model after regression DLT: Oil Volume vs. Press. DLT: Dissolved Gas vs. Press. CCE: Oil Volume vs. Press. DLT: Oil density vs. Press. DLT: Gas gravity vs. Press. CCE: Y-factor vs. Press. Copyright 2017 INPEX CORPORATION. All rights reserved. 36

38 Regression - Example Check characterized property Pc: Monotonically decrease Tc: Monotonically increase Others: ω, Vc etc. Avoid physically unrealistic modelling CO2 N2 Copyright 2017 INPEX CORPORATION. All rights reserved. 37

39 Regression - Example Check overall regression result and phase envelope Copyright 2017 INPEX CORPORATION. All rights reserved. 38

40 Regression Summary Regression performed to simulate reliable fluid behavior EOS modelling is the critical process to plan field development Hand-over to Subsurface, Wells, Facilities department EOS model Dynamics model Copyright 2017 INPEX CORPORATION. All rights reserved. 39

41 EOR Fluid modelling is also important for EOR potential evaluation Viscosity reduction is the key factor for Thermal EOR Especially, heavy oil has extra high viscosity Miscibility is the key factor for Gas Injection Efficiency of oil displacement Temperature increase Swelling Test Copyright 2017 INPEX CORPORATION. All rights reserved. 40

42 EOR What is Miscibility? Miscible when mixed together in all proportions and all mixtures remain single phase e.g. gasoline and kerosene Miscibility is important for Gas Injection EOR Foaming a homogeneous solution Miscible Gas Injection EOR Interfacial tension between oil and displacing fluid approaching to zero Two types First-contact miscible process» Miscible condition achieved soon after contacting Multiple-contact miscible process» Miscible condition achieved gradually by contacting some times Gas Injection Single Phase (miscible) No interfacial tension Copyright 2017 INPEX CORPORATION. All rights reserved. 41

43 EOR Slim Tube Test Gas injected into the slim tube which is saturated by reservoir oil Recovery factor is measured MMP(Minimum Miscible Pressure) determined by RF vs. Pressure plot Numerically calculated by PVT simulation software Gas Injection Production Calsep, Inc. Saturated with Reservoir Oil Copyright 2017 INPEX CORPORATION. All rights reserved. 42

44 EOR Slim Tube Test Example CO2 injected by 120% pore volume 2,000cells and 4,000 time steps Oil phase Gas phase Profile at 3,300psia Injected by 6% Pore Volume Quick gas move Early gas breakthrough Injected by 60% Pore Volume Un-swept Oil Copyright 2017 INPEX CORPORATION. All rights reserved. 43

45 EOR Slim Tube Test Example CO2 injected by 120% pore volume 2,000cells and 4,000 time steps Oil phase Gas phase Profile at 5,000psia Injected by 6% Pore Volume Flood front moving slowly Approaching to miscible condition Injected by 60% Pore Volume Piston like displacement Miscible Condition Copyright 2017 INPEX CORPORATION. All rights reserved. 44

46 EOR Slim Tube Test Example CO2 injected by 120% pore volume 2,000cells and 4,000 time steps MMP indicated around 4,500psia Gravity override and un-swept oil (Pressure < MMP) Same density and viscosity of oil & gas at flood front (Pressure > MMP) If reservoir pressure is above MMP, CO2 injection is good candidate for possible EOR method Copyright 2017 INPEX CORPORATION. All rights reserved. 45

47 Summary Make your best effort for the appropriate fluid evaluation One of the most essential and important factor in any technical study and petroleum field development planning in Oil and Gas industry Thank you for your attention!!! Copyright 2017 INPEX CORPORATION. All rights reserved. 46