Concepts and Mechanisms of Enhanced Oil recovery (EOR) Processes

Concepts and Mechanisms of Enhanced Oil recovery (EOR) Processes ABSTRACK Suatu reservoir minyak akan menurun kemampuannya dalam berproduksi akibat terbatasnya tekanan alamiah reservoir dan kehilangan tekanan selama proses produksi berlangsung. Pada saat produksi berlangsung, tekanan reservoir akan terus menurun sehingga laju produksi yang dihasilkan pada proses produksi tahap pertama (primary recovery) akan semakin kecil dan cenderung menjadi tidak menguntungkan lagi.  Proses perolehan minyak tahap pertama merupakan proses perolehan dengan menggunakan tenaga pendorong alami, seperti tenaga pendorong gas terlarut (solution gas drive), tenaga pendorong air (water drive), dan tenaga pendorong tudung gas (gas cap drive). Mengingat masih cukup besarnya minyak yang tersisa setelah produksi tahap pertama, maka untuk mengatasi hal tersebut diupayakan suatu usaha untuk meningkatkan perolehan minyak. Metode peningkatan perolehan minyak tahap lanjut ini dikenal dengan metode peningkatan perolehan tahap kedua (secondary recovery) dan metode peningkatan perolehan tahap ketiga (tertiary recovery). Teknik perolehan minyak tahap kedua dan tahap ketiga biasa dikenal dengan teknik peningkatan perolehan minyak (enhanced oil recovery – EOR). Secara umum EOR didefinisikan sebagai teknik peningkatan perolehan minyak dengan melakukan injeksi material, yang secara normal material tersebut tidak berada di reservoir. OUTLINE 1. Introduction       • Units and conversion factors       • Oil recovery phases and definition of oil recovery factors      • Overview of EOR processes 2. EOR Mechanisms and Screening Guidelines      • Displacement efficiency in immiscible floods      • Displacement efficiency in miscible floods      • Areal sweep efficiency      • Vertical sweep efficiency      • Fluid trapping in reservoir rocks      • Parameters that affect oil recovery      • EOR screening and evaluation guidelines 3. Phase Behavior of Hydrocarbons     • Pressure-temperature diagrams     • Ternary equilibrium diagrams     • First contact miscibility     • Condensing and vaporizing gas drive miscibility     • Phase behavior experiments

    • Selecting pseudo components

4. Miscible Floods

    • Comparison of solvents

    • Designing a miscible flood

    • Miscible slug processes

    • Water-alternating gas (WAG) processes

    • Estimating oil recovery factors

5. Chemical Floods

     • Polymer characteristics

     • Comparison of polymers

     • Viscosity of polymer solutions

     • Inaccessible pore volume

     • Permeability reduction and  visco-elastic effects

     • Polymer degradation and retention in reservoir rocks

     • Type and required amount of polymer

     • Surfactant characteristics and phase behavior of surfactant-oil-water       systems

     • Optimal salinity and capillary de-saturation curves

     • Surfactant retention in reservoir rocks

     • Thin film spreading agents

     • Type and required amount of surfactant

     • Alkaline characteristics

     • Effect of chemicals on fractional flow

     • Estimating oil recovery factor for chemical floods

6. Steam Injection Processes

     • Thermodynamic properties of steam

     • Surface heat loss

     • Wellbore heat loss

     • Vertical heat loss in reservoirs

     • Thermal properties of reservoir rocks

     • Steam generation and co-generation of steam and electricity

     • Mechanisms of cyclic steam stimulation

PARTICIPANT This is a general course on enhanced oil recovery methods designed for petroleum industry professional staff. Participants include production engineers, drilling engineers, facilities engineers, geologists, supervisors, managers, etc. who are associated with the evaluations and screening of oil

reservoirs for potential applications of enhanced oil recovery methods.