Petroleum geoscience (cơ sở kỹ THUẬT dầu KHÍ SLIDE TIẾNG ANH)

Vietnam National University - Ho Chi Minh City University of Technology Course Introduction to Petroleum Engineering Presenter: Trần Nguyễn Thiện Tâm Falcuty: Geology & Petroleum Engineering Department: Drilling - Production Email: trantam2512@hcmut.edu.vn 3/29/21 Introduction to Petroleum Engineering Chapter Petroleum Geoscience 3/29/21 Introduction to Petroleum Engineering Contents  Generation of hydrocarbon  Petroleum system  Requirements for petroleum accumulation 3/29/21 Introduction to Petroleum Engineering Learning outcomes Explain the generation of hydrocarbon List the kerogen components Differentiate the kerogen types and related hydrocarbon Apply the Van Krevelen diagram to define the kerogen types Define the characteristic parameter of oil window Analyse the role of components and processes of petroleum system Summarise the requirements for petroleum accumulation 3/29/21 Introduction to Petroleum Engineering Generation of hydrocarbon 3/29/21 Introduction to Petroleum Engineering Diagenesis of Organic Matter There are three important stages in the burial and evolution of organic matter into hydrocarbons:  Diagenesis;  Catagenesis;  Metagenesis 3/29/21 Introduction to Petroleum Engineering Diagenesis Diagenesis of organic matter begins as soon as sediment is buried However, the point at which diagenesis ends is subject to how the term is used Some geologists use the term in a restricted sense to include only processes that occur as sediment consolidates into sedimentary rock 3/29/21 Introduction to Petroleum Engineering Diagenesis Freshly deposited muds are unconsolidated and may contain more than 80% water in their pores These muds compact very quickly Most of the porosity is lost in the first 500 meters of burial After that, compaction to form mudstones or shales continues much more slowly 3/29/21 Introduction to Petroleum Engineering Kerogen Components Under the microscope, kerogen appears as disseminated organic fragments Some of this material is structured It is recognizable as plant tissue fragments, spores, algae, and other pieces with a definite biological organization These plant-derived structured fragments can be grouped into distinct biological units called macerals Macerals in kerogen are equivalent to minerals in rocks Three major maceral groups are important: vitrinite, exinite and inertinite 3/29/21 Introduction to Petroleum Engineering Kerogen Components Vitrinite is the dominant maceral type in many kerogens and is the major component of coal It is derived almost entirely from woody tissue of the higher land plants Because it is derived from lignin and is difficult to break down, vitrinite can appear in almost any depositional environment, marine or nonmarine, and is generally the most abundant type of structured particle 3/29/21 Introduction to Petroleum Engineering 10 Trap 3/29/21 Introduction to Petroleum Engineering 115 Seal Seal is impermeable rock that forms barrier on top of the reservoir rock of an oil and/or gas reservoir 3/29/21 Introduction to Petroleum Engineering 116 Seal Seal is impermeable rock that forms barrier on top of the reservoir rock of an oil and/or gas reservoir 3/29/21 Introduction to Petroleum Engineering 117 Seal Traps must be sealed by impermeable barriers in order to stop the continued upward migration of petroleum 3/29/21 Introduction to Petroleum Engineering 118 Seal Shale is the dominant caprock of worldwide reserves and is overwhelmingly the seal in basins rich in terrigenous sediments, where sandstones are the dominant reservoir rock 3/29/21 Introduction to Petroleum Engineering 119 Seal Evaporites, however, are the most efficient caprock They are particularly common in carbonate-rich basins, and they often form seals for carbonate reservoirs Furthermore, evaporites commonly develop in restricted basin settings, where accumulations of organic-rich source rocks are also favored Dense carbonates are the third most abundant caprock lithology and seal about 2% of the world's reserves 3/29/21 Introduction to Petroleum Engineering 120 General properties Permeability in seal are mostly < 10-4 darcies Seal are important and commonly overlooked component in the evaluation of a potential hydrocarbon accumulation Effective seals for hydrocarbon accumulation are typically thickness, laterally continuous, ductile rocks with high capillarity entry pressure 3/29/21 Introduction to Petroleum Engineering 121 Micro properties of seal Capillary pressure, Pc Pc = 2γcosθ/R γ: Hydrocarbon –water interfacial tension; θ: Wettability; R: Radius largest pore throats Hydrocarbon pressure, P P = (ρw - ρhc)×gh ρw: density of the water; ρhc: density of the HC; g: the acceleration of gravity; h: the height of HC column A seal is broken when P > Pc 3/29/21 Introduction to Petroleum Engineering 122 Macro characteristic of seal     Lithology Ductility Thickness Stability 3/29/21 Introduction to Petroleum Engineering 123 Lithology Almost effective seals are evaporite, fine grained classtics, and organic-rich rocks These lithologies are seen as seals because: • Have high entry pressure • Are laterally continuous • Maintain stability of lithology over large areas • Are relative ductile • Are a significant portion of the fill of sedimentary basins 3/29/21 Introduction to Petroleum Engineering 124 Ductility Ductility is a rock property to deform and flow without visible fracturing that varies with pressure and temperature (burial depth) as well as with lithology Ductile lithologies tend to flow plastically under deformation, whereas brittle lithologies develop fractures The evaporite rock group make good ductile seal under overburden of several thousand feet, but can quite brittle at shallow depths 3/29/21 Introduction to Petroleum Engineering 125 Ductility Seal lithologies arranged by ductility • Salt • Anhydrite • Kerogen – rich shales • Clay shales • Silty shales • Carbonate mudstones • Cherts (most ductile lithologies at top of column) 3/29/21 Introduction to Petroleum Engineering 126 Thickness A few inches of ordinary clay shale are theoretically adequate to trap very large column heights of hydrocarbons (particle size of 10-4mm ⇒ have 600 psi ≅ 915m of hydrocarbon column) Unfortunately, there is a low probability that a zone only a few inches thick could be continuous, unbroken, unbreached, and maintain stable lithoic character over a sizable accumulation 3/29/21 Introduction to Petroleum Engineering 127 Stability  Stability in lithology  Stability in thickness 3/29/21 Introduction to Petroleum Engineering 128 Chapter The End 3/29/21 Introduction to Petroleum Engineering 129 ...Chapter Petroleum Geoscience 3/29/21 Introduction to Petroleum Engineering Contents  Generation of hydrocarbon  Petroleum system  Requirements for petroleum accumulation 3/29/21 Introduction to Petroleum. .. which a complete petroleum system has some likelihood of existing 3/29/21 Introduction to Petroleum Engineering 39 Petroleum System 3/29/21 Introduction to Petroleum Engineering 40 Petroleum System... processes of petroleum system Summarise the requirements for petroleum accumulation 3/29/21 Introduction to Petroleum Engineering Generation of hydrocarbon 3/29/21 Introduction to Petroleum Engineering