Production Operation in Each Stages : Session 3 Production Operation in Each Stages : Primary Secondary EO Recovery

PRIMARY RECOVERY

SECONDARY RECOVERY

Secondary Recovery Secondary recovery didefinisikan sebagai operasi dimana suatu reservoir yang telah depleted atau hampir depleted diperbaharui kembali. Reservoir telah terproduksi Ketidaktahuan atau sesuatu yang tidak dapat dihindarkan adanya kehilangan energi karena kebocoran Investor tidak ingin lagi menanam modal lebih banyak Besarnya biaya penelitian untuk mendapatkan recovery maksimum Kegagalan operator untuk mengetahui keuntungan-keuntungan yang didapat dari perencanaan dan pengontrolan operasi reservoir yang dini.

Pressure Maintenance Jika tenaga pendorong air lemah atau tenaga pendorong gas terlarut dari reservoir yang berpermeabilitasnya rendah maka operator dapat melakukan pressure maintenace sampai ke suatu tingkat tertentu dengan cara pengurangan produksi atau dengan penambahan energi dari luar untuk mendapatkan recovery dan keuntungan yang lebih baik.

Untuk memaksa gas atau air melalui reservoir minyak dan secara fisik memaksa minyak keluar dari pori-pori dan masuk ke lubang sumur. Dapat membantu energi yang ada dan mengganti energi dari tenaga gas terlarut. Untuk menjaga gas tetap berada dalam larutan minyak menjadikan viskositas minyak tetap rendah sehingga mudah bergerak, sehingga minyak lebih mudah mengalir ke arah lubang sumur produksi.

Pola Suntikan - line Drive 5-spot 7-spot 9-spot - Yang tidak beraturan - Penyuntikan dari pinggir (periphery) lapangan

Pola Suntikan Line Drive 5-Spot 7-Spot 9-Spot

ANALYZING FUNDAMENTALS OF WATERFLOODING IN POROUS MEDIA THE DISPLACEMENT PROCESS Piston Like Displacement Water Oil Figure 1. Fluid displacement in piston like manner

Figure 2. Fluid displacement in a leaky piston like manner Leaky Piston Like Displacement Water Oil W O Figure 2. Fluid displacement in a leaky piston like manner

Figure 3. Schematic of linear displacement below bubble point pressure Linear Displacement Process Water Oil SATURATION Injected Water Bank Initial Oil Saturation Connate Water DISTANCE Figure 3. Schematic of linear displacement below bubble point pressure

Figure 4. Saturation distribution during waterflood Water Bank Oil Bank UNAFFECTED RESERVOIR SATURATION Water Oil Trapped Gas Connate Water Initial Free Gas Distance Figure 4. Saturation distribution during waterflood when trapped gas is re dissolved

EOR

Enhanced Oil Recovery (EOR) EOR sebagai setiap proses yang digunakan untuk meningkatkan ultimate recovery dari suatu reservoir kecuali hanya injeksi air atau gas saja.

Steam atau hotwater flooding In situ Combustion Miscible displacement Immiscible Displacement Thermal Recovery Chemical Recovery Microbial EOR Vibro Seismic

Enhanced Oil Recovery is a means of producing oil with the introduction of external fluids,substances and energy into the oil reservoir Fluids, substances: water, steam, chemical, microbes Energy : mechanic, thermal or combination of the two

ENHANCED OIL RECOVERY Immiscible Displacement Immiscible displacement: injection of fluid that is immiscible with oil Water, Gas (Hydrocarbon, CO2, Nitrogen, Air)

ENHANCED OIL RECOVERY Miscible Displacement Injection of fluid which is miscible with oil Displacement fluids: hydrocarbon solvent, CO2, Flue Gas, N2

ENHANCED OIL RECOVERY Chemical mixture of polymer, alcohol, sulfonate Surfactant: mixture of polymer, alcohol, sulfonate reduce interfacial tension reduce capillary pressure increase microscopic displacement efficiency

ENHANCED OIL RECOVERY Chemical Polymer: Improving water-oil mobility ratio (↓) Increasing Sweep Efficiency (ES) - Macroscopic Often used in combination with surfactant Most widely used polymer in EOR: Polyacyrlamide:artificial, flexible Polysaccharide:fermentation, rigid, effective for reservoir with high viscosity oil

ENHANCED OIL RECOVERY Chemical Alkaline: Increase pH until 11 – 12 Could reduce interfacial tension to 0.01 dyne/cm NaOH in water: 0.05 – 0.2% (500 – 2000 ppm)

ENHANCED OIL RECOVERY Thermal Thermal recovery is a process to improve oil recovery by introducing heat to the oil reservoir so the oil viscosity will be reduced or oil phase changes into vapor phase Thermal recovery: Hot – water flood Steam processes In situ combustion

ENHANCED OIL RECOVERY Thermal Steam processes: In Situ Combustion: Cyclic Steam Stimulation (Huff ’n’ Puff) Steam Drive (Steam Flood) In Situ Combustion: Injecting air and burn some oil Reducing oil viscosity, changing oil into vapor phase, and displacing with combination of steam, hot water and gas

ENHANCED OIL RECOVERY Thermal Steam processes: In Situ Combustion: Cyclic Steam Stimulation (Huff ’n’ Puff) Steam Drive (Steam Flood) In Situ Combustion: Injecting air and burn some oil Reducing oil viscosity, changing oil into vapor phase, and displacing with combination of steam, hot water and gas

ENHANCED OIL RECOVERY Microbial EOR MEOR is a process to improve oil recovery by using microbes Microbe characteristics: Able to live in high pressure and high temperature Anaerobe Able to live in low pH and high salinity Able to live in less nutrition environment Able to use Hydrocarbon as nutrition source

ENHANCED OIL RECOVERY Microbial EOR MEOR mechanism: Producing acid dissolve rock matrix so that will increase porosity and permeability Producing gas (basically similar with CO2 flood) Producing solvent (ethanol, butanol, acetone, isopropanol) miscible with oil, and reducing oil viscosity and giving better mobility ratio.

ENHANCED OIL RECOVERY Microbial EOR MEOR mechanism: Producing surfactant basically similar with surfactant flood Selective plugging Producing polymer reducing water mobility and able to control water mobility by increasing water viscosity

ENHANCED OIL RECOVERY Factors Affecting EOR Wettability Petrophysical properties Rock type Oil type P & T of the reservoir Reservoir driving mechanism Formation water salinity Heterogenity Present Oil Saturation Remaining Oil Reserves Reservoir Dip Economics

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