1 / 17

CHAPTER 2- Physical and Chemical Properties of Hydrocarbons

CHAPTER 2- Physical and Chemical Properties of Hydrocarbons. Gas Dry Gas Methane Wet Gas Ethane, Butane… Condensate *gaseous in subsurface liquid at surface Liquid H/C- oil, crude oil, crude Plastic H/C- asphalt & related… Solid H/C- Coal and Kerogen

elaine
Télécharger la présentation

CHAPTER 2- Physical and Chemical Properties of Hydrocarbons

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. CHAPTER 2- Physical and Chemical Properties of Hydrocarbons • Gas • Dry Gas • Methane • Wet Gas • Ethane, Butane… • Condensate • *gaseous in subsurface • liquid at surface • Liquid H/C- oil, crude oil, crude • Plastic H/C- asphalt & related… • Solid H/C- Coal and Kerogen • Gas Hydrates- ice crystals containing H/C • Natural Gas- mixture of H/C and non H/C in gaseous phase • or in solution with crude oil

  2. Gases Dissolved- in solution with other liquids in reservoir Associated- gas cap gas- in gas phase above liquid Non associated- little or no crude in reservoir Organic vs inorganic Wet vs Dry Gas- dry <0.1 g/mcf Sweet vs Sour- H2S in sour gas

  3. H/C gases- major constituent - H/C paraffin series CH4 most common, C2, C3, … Ethane, butane (the inferior gas), propane all common All others uncommon

  4. Methane- swamp gas, fire damp- Coal mine shale gas- drillers term Genesis- *mantle *biogenic gas *thermogenic gas 20% of natural gas produced is Biogenic (methane only)

  5. Inert Gases He, Ar, Ra He- 5 ppm in atmosphere up to 8% in reservoirs He-rich deposits derived from U, Th, Ra- i.e. granites and shales- basement rock Natural production rate from parent low, expulsion and transport rate high Panhandle Hugoton Field, gas processing plant since 1929, contains 1.86% He

  6. Nitrogen *inorganic- volcanic in origin *organic- degradaton of ammonia and nitrates shallow diagenesis Fig. 2.2 97% N 2% He 1% CO2 Atmospheric N also Trapped in connate gas

  7. Hydrogen H- rare – highly reactive and mobile 1.36 TCF found in Mississippian Age sediments in Kansas 40% H, 60% N, CO2, Ar, CH4- thermogenically mature, never escaped CO2- Biogenic and Volcanic major constituent of volcanic gas 3CH4 + 6O2 = 3CO2 + 6H2O CaCO3 + H2 = Ca+ + H2O + CO2- Acids flowing through limestones

  8. H2S Free gas and highly soluble Major concern when drilling- kills people on rigs in the USA several times a year Highly corrosive to steel- sour gas and oil Low H2S- bad, drives production costs up- have to scrub out High H2S- good, produce S Volcanic and biogenic origin CaSO4 + 2CH2O = CaCO3 + H2O + CO2 + H2S 2CH2O = organic matter Also associated with carbonates and Pb-Zn deposits and deep basin brines Anydrite  calcite- exothermic- hot enough to mobilize Pb-Zn sulfide brines

  9. Crude Oil Mixture of H/C in a liquid phase which remains a liquid at the surface Yellow, green, brown, black Wide variety of viscosities Most lighter than water Vary in Specific Gravity Chemistry- C, H, V, Ni,… no two oils the same. Ponca Crude, 234 compounds

  10. Hydrocarbons- cont. Paraffins- alkanes- straight chain carbon with branching n < 5 gas at surface 5 < n 1< 5 liquid at surface n> 15 grade into solid wax for given molecular wt. Straight chain higher boiling point than isomers Isomers-branching

  11. Naphthenes Cyclo alkanes- single bond All liquids at surface Aromatics Benzene ring structure Liquid at surface Occurrence: Toluene>xylene>benzene

  12. Hetero compounds Organic compounds containing O, N, S & metals, acids, esters, Ketones, phenols, alcohols In younger oils- fatty acids, isoprenoids, naphthenic and carboxylic acids Sulfur also common, both as H2S and other phases Nearly any ions found in sedimentary minerals can be found in crude Va & N occur as organometallics generally in porphyrin- derived from chlorophyll and hemoglobin Metals most often associated with resins Sulfur and asphaltene fraction most common in shallow, younger, degraded crude.

  13. Classification of Crude Oil Many classification schemes *engineering based- refineries Physical properties: viscosity boiling pt refractive index molecular wt density

  14. Classification of Crude Oil *geochemical based- maturation, genesis, and history and other geoparameters of occurrence. Molecular structure: key to source and geological history

  15. Classification of Crude Oil Paraffins, Naphthenic and intermediates based on distillation factors time and temperature Tissot and Welte (1978) used ratio between para & naph & aromatics Oils vary not only w/ age, but w/ variatin in source and degree of Degradation- degradatin causes wide variations , esp. w/shallow oils

  16. Gas Hydrates

More Related