石油地質(zhì)學(xué)英文課件Chapter1

1、China University of Geosciences,China University of Geosciences, Wuhan Petroleum Geology Chapter 1 Crude Oil, Natural Gas, Oilfield Water1. Crude oils 2. Natural gases 3. Oil-field watersChina University of Geosciences,China University of Geosciences, Wuhan Petroleum Geology 1 Crude oils1.1 Definiti

2、on1.2 Chemical properties1.3 Distillation1.4 Classification1.5 The differences between marine and terrigenous oils1.6 Physical propertiesChina University of Geosciences,China University of Geosciences, Wuhan Petroleum Geology 1.1 Definition Crude oil is defined as a mixture of hydrocarbons and non-h

3、ydrocarbons that exists predominantly as liquid, with varying amounts of dissolved gases and/or semisolid hydrocarbons in natural underground reservoirs. China University of Geosciences,China University of Geosciences, Wuhan Petroleum Geology 1.1 Definition The word petroleum originates from the Lat

4、in words petra(“rock and stone”) and oleum(“oil”), just like its Chinese word, 石油石油 means “石石” and “油油”. Petroleum is a kind of mineral resources that occurs in the earth as gas, liquid, semi-solids or in more then one of these states. Liquid petroleum is called crude oil that consists chiefly of th

5、e liquid hydrocarbons, with varying amounts of dissolved gases, bitumens, and impurities, which can be produced from underground reservoir rocks through a drill pipe.China University of Geosciences,China University of Geosciences, Wuhan Petroleum Geology General Features Chemically any liquid petrol

6、eum is an extremely complex mixture of hydrocarbon compounds, with varying amounts of non-hydrocarbon compounds of nitrogen, sulfur, oxygen and also vanadium(V) and nickel(Ni) as impurities. The proportions of the hydrocarbon constituents and the contaminants are different in various petroleum accum

7、ulations or oil fields. The physical properties of petroleum are different in various accumulations/fields. China University of Geosciences,China University of Geosciences, Wuhan Petroleum Geology 1.2 Chemical properties(1) Elemental composition lThe main elements are Carbon and Hydrogen;lThe minor

8、elements are Sulfur,Nitrogen and Oxygen (normally less than 3%);lTrace elements are heavy metals,such as V and Ni. China University of Geosciences,China University of Geosciences, Wuhan Petroleum Geology Natural GasCrude OilAsphaltCoalKerogenCarbon7684.5 (83-87) 848379Hydrogen2413 (11-14)1056Sulfur0

9、1.5 (1%)315Nitrogen00.5 (0.2)112Oxygen00.5 (0.1-4.5)2108total100100100100100The table below shows the elemental contents in natural gas, crude oil, asphalt, coal and kerogenChina University of Geosciences,China University of Geosciences, Wuhan Petroleum Geology (2) Alkane series ParaffinslThe genera

10、l formula is CnH2n+2.lC1-4 are gases. methane/CH4, ethane/C2H6，propane/ C3H8, butane/C4H10lC5-20 are liquids.lC20+ are usually waxy solids.lIn CnH2n+2 in crude oil, usually n80.lAlkane series can be divided into 2 types: a. the normal alkanes: n-alkanes b. the isomeric arkanes: i-alkanesChina Univer

11、sity of Geosciences,China University of Geosciences, Wuhan Petroleum Geology MethaneEthanePropaneButanePentaneHexaneHeptaneChina University of Geosciences,China University of Geosciences, Wuhan Petroleum Geology (3) Naphthene or Cycloparaffingeneral formular: CnH2n n5The Cycloparaffins that are form

12、ed by joining the carbons in ring are the most common molecular structures in crude oils.The most common naphthenes in crude oil are methylcyclopentane and methylcyclohexane.The average content of naphthenes is about 50% in crude oils, with the quantities increasing in the heavier fractions and decr

13、easing in the lighter fractions.China University of Geosciences,China University of Geosciences, Wuhan Petroleum Geology NaphthenesChina University of Geosciences,China University of Geosciences, Wuhan Petroleum Geology (4) Aromatic HydrocarbonslWith general formular CnH2n-6;lThe term aromatic hydro

14、carbon originated from pleasant-smelling compounds in crude oils. However most HCs have very little odor in pure state.lAll aromatic HCs contain at least one benzene ring.lThey are unsaturated cycloHC series with double bonds between carbon atoms, likes benzene and its homologous:BenzeneNaphthaleneP

15、aranaphthaleneChina University of Geosciences,China University of Geosciences, Wuhan Petroleum Geology (5) Nitrgen, sulfur, oxygen compounds (Asphaltics)They are complex structural arrangements made of naphtheno-aromatic nuclei with chains and heteroatoms (O,N,S).Sulfur compounds：an average content

16、of sulfur in crude oils is 0.65% by weight.Low or high sulfur crude oil: S1.0%b) Nitrogen compounds：Nitrogen content is usually much lower than sulfur content in crude oils. The average nitrogen content is 0.094% by wt, in most crude oils nitrogen content is less than 0.2%. The most important nitrog

17、en compound is porphyrin: Nickel(Ni) and Vanadium(V) porphyrin.c) Oxygen compounds: as saturated fatty acids: phenols China University of Geosciences,China University of Geosciences, Wuhan Petroleum Geology About porphyrin Porphyrins are characterized by a tetrapyrrolic nucleus(4 pyrrole rings), pro

18、bably inherited from chlorophyll or hemin. So nickel porphyrin and vanadium porphyrin are biological markers indicating crude oils derived from organic matters. Chlorophyll, the green photosynthetic pigment of plants. Hemin, the red pigment of animal blood. There are other metals, like iron(Fe), zin

19、c(Zn), copper(Cu), lead(Pb), arsenic(As), molybdenum(Mo), cobalt(Co), magnesium(Mg), chromium(Cr) etc in crude oils, but only a very little amount.China University of Geosciences,China University of Geosciences, Wuhan Petroleum Geology 1.3 Distillation and uses Distillation is the principal method f

20、or separating crude oils into useful products. The common distillate fractions are:Gasoline (C5-C10) Kerosine (C11-C13)Diesel oil (C14-C18)Heavy gas oil (C19-C25) Lubricating oil (C26-C40) Residuum (C40) China University of Geosciences,China University of Geosciences, Wuhan Petroleum Geology A disti

21、llation tower A refinery tower is equivalent to a series of individual distillation flasks, in which the distillate fractions from the first flask is condensed in the second flask, and then redistilled to produce a distillate for the third flask.China University of Geosciences,China University of Ge

22、osciences, Wuhan Petroleum Geology AromaticsNaphthenoaromaticsNitrogen,sulfur, and oxygen compoundsThe light gasoline fraction of oil is dominated by the normal,iso-, and cycroparaffins. From Gasoline into the heavier fractions,There is a marked increases in the Aromatics + naphthenoaromatics. China

23、 University of Geosciences,China University of Geosciences, Wuhan Petroleum Geology AromaticsNaphthenoaromaticsNitrogen,sulfur, and oxygen compoundsAfter diesel, NSO compounds content increases markedly, the residuum is dominated by NSO compounds.China University of Geosciences,China University of G

24、eosciences, Wuhan Petroleum Geology 1.4 Classification Some classifications have been proposed by geochemists and oil refiners. A classification of petroleum has been proposed by Tissot and Welte (1978) based primarily on the contents of the various structural types of hydrocarbons: P =Paraffin N=Na

25、phthenes AA=Aromatics and Asphaltenes+resins S= Saturated hydrocarbonChina University of Geosciences,China University of Geosciences, Wuhan Petroleum Geology 1) S50%, AA40%,PN: Paraffinic oils2) S50%, AA40%,NP: Naphthenic oils 3) S50%, AA10%: Aromatic intermediate oils5) S50%, AA50%, P10%,N25%: Arom

26、atic naphthenic oils 6) S50%, AA50%, P10%,N25%: Aromatic Asphaltic oils China University of Geosciences,China University of Geosciences, Wuhan Petroleum Geology ParaffinicParaffinicNaphthenicNaphthenicParaffinicParaffinic naphthenicnaphthenicAromatic Aromatic intermediateintermediateAromatic Aromati

27、c naphthenicnaphthenicAromatic Aromatic AsphalticAsphalticP =ParaffinP =ParaffinN=NaphthenesN=NaphthenesAA=Aromatics and Asphaltenes+resinsAA=Aromatics and Asphaltenes+resins25254040505050504040606050506060909010107575China University of Geosciences,China University of Geosciences, Wuhan Petroleum G

28、eology lOn oil typeslOn wax contentslOn sulfur contentslOn trace elemental contents, as V,Ni, V/NilOn stable isotopes of carbon 1.5 The difference between marine and terrigenous crude oilsChina University of Geosciences,China University of Geosciences, Wuhan Petroleum Geology 1.6 Physical properties

29、1) Density and Specific Gravity2) Viscosity Smell3) Fluorescence4) Color5) Smell6) Calorific ValuesChina University of Geosciences,China University of Geosciences, Wuhan Petroleum Geology 1) Density and Specific gravity Oil density is usually less than 1000kg/m3, oil is lighter than water. But some

30、crude oils, dense oils, can heavier than water, their density can larger than 1000kg/ m3 . To produce dense oil is very difficult.China University of Geosciences,China University of Geosciences, Wuhan Petroleum Geology Viscosity is an inverse measure of the ability of a substance(fluid) to flow. The

31、 greater viscosity of a fluid, the more difficult it flows. Oil viscosity is generally dependent chiefly on the amount of gas dissolved in it and on the temperature. 2) ViscosityChina University of Geosciences,China University of Geosciences, Wuhan Petroleum Geology 3) Fluorescence All oils exhibit

32、more or less fluorescence, the aromatic oils are the most fluorescent. Fluorescent color of crude oils can be yellow, green, or blue. Fluorescence must be observed under ultraviolet radiation. Fluorescence is used in well logging to locate oil showing in cores, cuttings, and drilling muds.China Univ

33、ersity of Geosciences,China University of Geosciences, Wuhan Petroleum Geology 4) Color5) Smell6) Calorific ValueChina University of Geosciences,China University of Geosciences, Wuhan Petroleum Geology 2 Natural Gases 2.1 Concepts2.2 Chemical compositions2.3 Physical properties2.4 About gas hydrateC

34、hina University of Geosciences,China University of Geosciences, Wuhan Petroleum Geology 2.1 Concepts Petroleum gas, commonly called natural gas or hydrocarbon gas, consists of the lighter paraffin hydrocarbons, of which the most abundant is methane gas (CH4). In the oil industry, natural gas is defi

35、ned as a mixture of hydrocarbons and varying quantities of non-hydrocarbcons that exists either in the gaseous phase or in solution with crude oil in underground reservoirs. China University of Geosciences,China University of Geosciences, Wuhan Petroleum Geology 2.1 Concepts Associated gas: the gas

36、occurs with oil. Non-associated gas: the gas occurs alone. Aggregated gas: The gas in gas reservoir, Condensed gas. The gas in oil and gas reservoir. Decentralized gas: The gas dissolved in oil, the gas dissolved in oil-field waters, the liquefied gas, the coal bed gas, and the methane hydrate.China

37、 University of Geosciences,China University of Geosciences, Wuhan Petroleum Geology 2.2 Chemical compositions1. Hydrocarbon gas:Methane/CH4, main composition of gas Ethane/C2H6, Propane/C3H8, takes various amounts in gasButane/C4H102. Non-hydrocarbon gas: N2, CO2, H2S, H2, CO, SO2, Hg, etc. China Un

38、iversity of Geosciences,China University of Geosciences, Wuhan Petroleum Geology Sour Gas(%)Frequency(%)Hydrogen Gas(%)Hydrocarbon Gas(%)China University of Geosciences,China University of Geosciences, Wuhan Petroleum Geology 2.3 Physical properties 1 Density and specific gravity of natural gas Dens

39、ity means the weight of a given volume, such as kilograms per cubic meter. The density of a natural gas depends on its pressure (p), temperature (t), apparent molecular weight (m) and compressibility factor (z). Dg= 0.1196571pmg/(zt)China University of Geosciences,China University of Geosciences, Wu

40、han Petroleum Geology The density of nature gas under the reservoir condition is larger than that of standard gas, usually 150 250kg/m3. The specific gravity of natural gas means the ratio of natural gas density to that of air (28.97). Also the ratio of molecular weight of natural gas to that of air

41、: rg=mg/28.97 China University of Geosciences,China University of Geosciences, Wuhan Petroleum Geology 2 The solubilitya. in water Henly formula: Q=C*P Q:solubility, C:solution coefficient, P: pressure. b. in crude oil the solubility depends on the pressure, temperature, composition of gas, the cont

42、ent of light HC in crude oils.China University of Geosciences,China University of Geosciences, Wuhan Petroleum Geology 2.4 About the gas hydrate (Just for reference) Gas hydrates are crystalline compounds in which the ice structure of water is distorted to form cages that contain the gas molecules.

43、The hydrates are solids resembling wet snow in appearance, and they form both above and below 0under specific pressure - temperature conditions. The water molecules form two kinds of unit cell structures. China University of Geosciences,China University of Geosciences, Wuhan Petroleum Geology The sm

44、aller unit structure contains 46 water molecules, which can hold up to 8 methane molecules. Gases such as CH4, C2H6, H2S, and CO2 can fit into this structure. The larger unit cell contains 136 molecules of water. Gases such as propane and iso-butane can fit into it. These are the only gaseous hydroc

45、arbons that form hydrates. The pentanes and n-butane molecules are too large. A methane hydrate in which all the ice stages are completely filled with methane contains about 172 m3 CH4 of hydrate at STP. In nature the more typical ratio is 40 m3 CH4/m3 of hydrate. Natural hydrate units generally hav

46、e six or seven H2O molecules per CH4 molecule.China University of Geosciences,China University of Geosciences, Wuhan Petroleum Geology The pressure-temperature diagram for methane and a 0.6 gravity gas (C1+C2+C3) is shown in Figure 7-8. Hydrates are formed by increasing pressures and are decomposed

47、by increasing temperatures. Since the pressure required to form gas hydrates increases logarithmically as the temperatures increase linearly, it is apparent that the hydrates in most sedimentary basins decompose in the temperature ranging 70 to 80 (21 to 27), because the pressures are inadequate to

48、preserve them. Hydrate usually occurs in permafrost territory, polar region, and deep sea bottom sediments. It is estimated that there is very rich amount of hydrate around the world. But, now it is difficult to exploit hydrate in technical.China University of Geosciences,China University of Geoscie

49、nces, Wuhan Petroleum Geology China University of Geosciences,China University of Geosciences, Wuhan Petroleum Geology 3 Oil-field Waters3.1 Concepts3.2 Source of oil-field waters 3.3 Chemical compositions and degree of mineralization3.4 Classification China University of Geosciences,China Universit

50、y of Geosciences, Wuhan Petroleum Geology 3.1 ConceptsOil-field waters in general are termed brines. The water found in petroleum reservoir rocks is usually referred to as interstitial water, but it is improbable that the water which now exists in the pores of a reservoir rock is the same water whic

51、h was in the same group of pores at the time when the sediments were first laid down.The expressions bottom water meaning water underlying the oil and edge water“ means water lying down dip and therefore laterally with respect to the oil zone. Clearly, both terms are concerned with the same body of

52、water in a given reservoir rock.Also, top water, intermediary waters.China University of Geosciences,China University of Geosciences, Wuhan Petroleum Geology Bottom waterEdgewaterUnpermeable covering strataChina University of Geosciences,China University of Geosciences, Wuhan Petroleum Geology Upper

53、 waterInterbedded waterBottom waterEdge waterUnderlayer waterChina University of Geosciences,China University of Geosciences, Wuhan Petroleum Geology Intermediary waterphreatic waterwater barrierChina University of Geosciences,China University of Geosciences, Wuhan Petroleum Geology 3.2 Source of oi

54、l-field waters Sedimentation water: the water in which sediments were deposited. Infiltration water: the water that has fallen as rain water and has filled up the porous and permeable rocks. Transform water: the water transformed from clay minerals or organic matters. Plutonic water: the water forme

55、d by magmatism or metamorphism.China University of Geosciences,China University of Geosciences, Wuhan Petroleum Geology 3.3 Chemical composition and degree of mineralization sodium(Na+)+potassium(k+), calcium(ca2+), magnessium(mg2+) chlorides(Cl-), sulfates(SO42-), bicarbonates(HCO3-)+carbonates(CO3

56、2-), and other trace elements.3 positive ions3 negative ionsChina University of Geosciences,China University of Geosciences, Wuhan Petroleum Geology 2 Organic: HC, Phenols, salt of organic acid Indeed, it has been proposed that a lateral increase in the benzene content of the brine in a given stratum may point towards an oil accumulation in that stratum.3 the gas dissolved