The 18 chapters in the Petroleum Engineering Handbook (PEH) Volume I are as follows.
This post will review Chapter 9:
C1-3: Math
C4: Fluid Sampling
C5: Gas Properties
C6: Oil Correlations
C7: Thermo/Phase
C8: Phase Diagrams
C9: Asphaltene/Wax
C10: Produced Water
C11: Phase Behavior
C12: Emulsions
C13: Rock Properties
C14: Permeability
C15: Relative Permeability
C16: Economics
C17: International Law
C18: 21st Century Law
C9 Review:
PNA: Paraffinic, Naphthenic, Aromatic (includes resins & asphaltenes) fractions. (I-400)
SARA: Saturates, Aromatics, Resins, and Asphaltenes. SARA Analysis: weight fraction method.
Asphaltenes and Waxes (I-397-400)
Deposited solids: asphaltenes, waxes, or a mixture (with resins, crude oil, fines, scale, water)
Characteristics: Light C6 fraction (with N2, CO2, H2S), heavy end C6
Asphaltenes
Asphaltenes precipitation in reservoir: by decreasing pressure or mixing oil with injected solvent.
Asphaltenes precipitation near wellbore: by drilling, completion, acid, fracs, etc.
Heavier crudes have less asphaltenes-precipitation problems than lighter crudes.
Primary production has maximum asphaltenes around the saturation pressure.
Asphaltene precipitation/deposition envelope (APE) has dependence on both P & T.
APE: the region which asphaltenes precipitation occurs.
Waxes
Wax precipitation envelope vertical P/T curve; strong dependence on T but weak on pressure.
Wax crystals tend to fluid disperse (deposit on a surface more likely among fines, asphaltenes, clays).
Temperature drop is most common cause of wax deposition; oil/gas expansion (sandface, orifices).
Tuesday, March 27, 2018
Thursday, March 22, 2018
PEH Volume I Chapter 8: Phase Diagrams
Phase Diagrams:
Critical Temperature: max T two phases exist (higher T only vapor).
Critical Pressure: max P two phases exist (higher P only liquid).
Surfactant/Polymer Flood: oil/water soluble mix reduces interfacial tension oil/H2O interface.
Gas-Injection: miscible displacement eliminates oil/displacing phase interface capillary forces.
Phase Rule: component number determines max number of phases coexisting at fixed T, psi.
Phase Diagrams: Plait Point: where bi nodal curve liquid & vapor portions meet and compositions are identical..
Binary: Vapor/liquid; fixed T; pressure-composition (p-x-y) 2 components (I-373-375).
Ternary: 3 components; each component equilateral triangle. (I-376-381).
…composition expressed in volume, mass, or mole fraction; 100% on each corner.
…line parallel to a side is a constant fraction of the opposite corner component.
…perpendicular lines from any composition point to each side (LT) sums to any side.
…two phase regions fall on the triangle sides.
Quaternary: 4 components; tetrahedral diagram, faces are ternary phase diagrams.
Reservoir Fluid Systems: See Guidebook 13 RES 10
Much of this material is being added to the Guidebook; in the meantime, feel free to pencil it in.
Note that ternary diagrams are a rich target for questions; read section 8.5 carefully. Understand how the ternary diagram is used, and underline the key passages relating my notes above. Often, what makes sense physically isn't so clear when put into words, and vice-versa.
Be warned: I've observed each person will have their own weak areas on this subject; your needed focus may be different than mine or others. So skim all the material and underline key passages (in pencil: in a year the subject may seem bloody obvious so leave the option to erase half of it later to keep your focus on weak areas).
Critical Temperature: max T two phases exist (higher T only vapor).
Critical Pressure: max P two phases exist (higher P only liquid).
Surfactant/Polymer Flood: oil/water soluble mix reduces interfacial tension oil/H2O interface.
Gas-Injection: miscible displacement eliminates oil/displacing phase interface capillary forces.
Phase Rule: component number determines max number of phases coexisting at fixed T, psi.
Phase Diagrams: Plait Point: where bi nodal curve liquid & vapor portions meet and compositions are identical..
Binary: Vapor/liquid; fixed T; pressure-composition (p-x-y) 2 components (I-373-375).
Ternary: 3 components; each component equilateral triangle. (I-376-381).
…composition expressed in volume, mass, or mole fraction; 100% on each corner.
…line parallel to a side is a constant fraction of the opposite corner component.
…perpendicular lines from any composition point to each side (LT) sums to any side.
…two phase regions fall on the triangle sides.
Quaternary: 4 components; tetrahedral diagram, faces are ternary phase diagrams.
Reservoir Fluid Systems: See Guidebook 13 RES 10
Much of this material is being added to the Guidebook; in the meantime, feel free to pencil it in.
Note that ternary diagrams are a rich target for questions; read section 8.5 carefully. Understand how the ternary diagram is used, and underline the key passages relating my notes above. Often, what makes sense physically isn't so clear when put into words, and vice-versa.
Be warned: I've observed each person will have their own weak areas on this subject; your needed focus may be different than mine or others. So skim all the material and underline key passages (in pencil: in a year the subject may seem bloody obvious so leave the option to erase half of it later to keep your focus on weak areas).
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