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Steam injection
- 1. Heavy Oil Explotitation: SteamInjection Radhitya Perdhana
- 2. • Steam injectionadalah salah satu metode yang paling umum dilakukan untuk eksploitasi heavy crude oil. • Metode ini termasuk dalam metode thermal recovery yang tujuannya adalah untuk mengurangi viskositas minyak di dalam reservoir. • Dua metode utama steam injection adalah Cyclic Steam Stimulation dan Steam Flooding
- 3. • Keuntungan utamasteam injection adalah dapat diterapkan diterapkan di berbagai jenis reservoir. • Dua faktor pembatasnya adalah: kedalaman (kurang dari 5000ft) dan ketebalan reservoir (lebih dari 10ft) • Batas kedalaman berkaitan dengan tekanan kritis steam (+3202 psi) dan ketebalan berkaitan dengan heat loss kearah base dan cap-rock
- 5. Steam Generating • Steamadalah istilah teknis untuk uap air. • Ketika air dipanaskan pada tekanan konstan, ia akan mencapai suhu maksimum yang disebut saturation temperature • Jika terus dipanaskan dan tekanannya dijaga konstan, maka suhu tidak akan berubah hingga air berubah fase semuanya menjadi uap. • Kalor yang dibutuhkan untuk mengubah air menjadi uap disebut enthalpy of vaporization
- 6. Kualitas steam (fraksi airyang akan diubah menjadi uap) dapat dikontrol dengan mengatur entalpinya.
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- 8. Steam Injection Method: CyclicSteam Stimulation • The most widely used steam injection methods for heavy oil • Dikenal juga dengan nama “Huff and Puff”. • Terdiri dari 3 tahapan: injection, soaking, and production.
- 9. Cyclic Steam Stimulation: TheMechanism • Steam is injected into a well at a high rate and high pressure for short time (10 days to one month). • Following the well may be shut in for a few days “soaking period” for heat distribution. After that, the well is allowed to flow for about 6-12 months. • When production rate decrease to the minimum economic rate, the whole cycle is repeated. • In some operations in California, more than 20 cycles have been conducted. • The ultimate oil recovery by cyclic steaming could be in excess of 20% as reported by ESSO or could be much lower.
- 12. Steam Injection Method: SteamFlooding • “Steam flooding”, “steam drive”, or “steam displacement” is an important heavy oil recovery method. • It has been shown to be effective in low viscosity oil formation. • The main effects present in steam flooding are the oil viscosity reduction and its thermal expansion.
- 13. Steam Flooding: The Mechanism •Consider a five-spot pattern, consisting of a centre steam injector and four corner producer • As steam is injected into the centre well, an expanding “steam zone” is formed. • The hot condensate leaving the steam zone creates a hot waterflood effect ahead of the steam zone. • Finally, as the condensate cools down to the formation temperature, it gives rise to a cold waterflood. • The steam drive process consists of a steam zone, a hot waterflood zone and a cold waterflood in the remaining pattern volume.