Dr.Eng. Suryantini Geothermal Enginering FTTM ITB Geology Engineering FITB - ITB

Dr.Eng. Suryantini Geothermal Enginering FTTM – ITB Geology Engineering FITB - ITB Outline 1. Distribution of Geothermal System in the World 2. The ...
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Dr.Eng. Suryantini Geothermal Enginering FTTM – ITB Geology Engineering FITB - ITB

Outline 1. Distribution of Geothermal System in the World 2. The heat transfer from the earth 3. Volcanism and geothermal manifestation

Dr.Eng. Suryantini Geothermal Enginering FTTM – ITB Geology Engineering FITB - ITB

1. Distribution of Geothermal System in the World in association with seismicity zone

Dr.Eng. Suryantini Geothermal Enginering FTTM – ITB Geology Engineering FITB - ITB

1. Distribution of Geothermal System in the World in association with volcanoes distribution

Dr.Eng. Suryantini Geothermal Enginering FTTM – ITB Geology Engineering FITB - ITB

1. Distribution of Geothermal System in the World in association with plate boundary

Dr.Eng. Suryantini Geothermal Enginering FTTM – ITB Geology Engineering FITB - ITB

1. Distribution of Geothermal System in the World in association with heat flow QW/m2 = k W/ W/m m°K dT dT//dZ °K /m+ T0 °K

At Oceanic Plate

At Continental Plate

The younger the plate, the higher the heat flow, and at Continental Plate, show the processes such as plutonism, plutonism, volcanism, uplift, subsidence, folding, etc., all of which have variable surface thermal effects even for the same age. Thus high heat flow may be locallized at young Dr.Eng. Suryantini orogenic zones and regions where cooling magma bodies occur at shallow depths. Hence Geothermal Enginering FTTMthe – ITB Geology Engineering FITB - ITB volcanic belt has high heat flow.

1.

Distribution of Geothermal System in the World; A conclusion

Geothermal System (fields) are located in association with plate boundaries, earthquakes (or seismicity zone), volcanoes, and regions of high heat flow

Dr.Eng. Suryantini Geothermal Enginering FTTM – ITB Geology Engineering FITB - ITB

2. Heat Transfer from the Earth Litosfer < 200 km: Kerak (Crust) dan bagian atas dari mantel: Padat/rigid Astenosfer 200-300 km, mantel bawah : lebih plastis

http://geothermal.marin.org/GEOpresentation/sld003.htm

The structure of the earth

Dr.Eng. Suryantini Geothermal Enginering FTTM – ITB Geology Engineering FITB - ITB

2. Heat Transfer from the Earth

http://geothermal.marin.org/GEOpresentation/sld013.htm

Thermal structure of the earth

Dr.Eng. Suryantini Geothermal Enginering FTTM – ITB Geology Engineering FITB - ITB

Earth Heat Transfer heat sink is the earth surface

http://www.geothermal-energy.org/geo/

Dr.Eng. Suryantini Geothermal Enginering FTTM – ITB Geology Engineering FITB - ITB

Heat transfer from mantle to earth crust are happened and the manifestation of this process can be seen This surface manifestasion are used to predict the occurrence of subsurface geothermal system arround the manietation. manietation.

Dr.Eng. Suryantini Geothermal Enginering FTTM – ITB Geology Engineering FITB - ITB

3. Volcanism and geothermal manifestation

Dr.Eng. Suryantini Geothermal Enginering FTTM – ITB Geology Engineering FITB - ITB

Surface manifestation Hockstein & Browne, 2000, Encyclopedia of Volcanoes

(1) features at ground surface where fluids discharge, mainly as single-phase fluids (e.g., hot springs, hot lakes and pools, fumaroles); (2) features resulting from fluid/rock interactions and hydrothermal mineral deposition, also at ground surface. The term, in its widest sense, refers to both active and inactive thermal features. Volcanism atau kegunungapian, juga merupakan manifestasi permukaan yang dapat menjadi indikasi adanya anomali termal dibawah permukaan. Sistem panas bumi yang Dr.Eng. Suryantini bersosiasi dengan gunung api dan produk letusannya akan memiliki karakteristik tertentu. Geothermal Enginering FTTM – ITB Geology Engineering FITB - ITB

Geothermal system and its surface manifestasion • Surface manifestasion is the product of thermal fluid (liquid / vapour) with the host rock (surrounding rock) • The non-convective geothermal system show no surface manifestasion • Thus the intensity and type of surface manifestation is controlled by – Hidrology, – Chemistry of fluid and surrounding rock – Temperature (Heat source condition)

Dr.Eng. Suryantini Geothermal Enginering FTTM – ITB Geology Engineering FITB - ITB

Processes that produce various type of surface manifestation • Conductive heat transfer from rock and soil • Convective heat transfer from water, vapour/steam, and gas • Boiling (phase change from water to steam) • Mixing or Dilution (Mixing / dilution of various thermal fluid with meteoric water/ground water) • Condensation (the cooling reaction of steam and gas by ground water) • Water-rock interaction (reaction between thermal fluid with surrounding rock)

Dr.Eng. Suryantini Geothermal Enginering FTTM – ITB Geology Engineering FITB - ITB

Types of geothermal fluid

Before we learn about various type of geothermal surface manifestation, we will discuss the principal type of thermal fluid

Dr.Eng. Suryantini Geothermal Enginering FTTM – ITB Geology Engineering FITB - ITB

Chloride Water (Cl Cl)) •

Indicates reservoir fluid



SiO2 rich and often with silica sinter precipitate arround the springs



Nutral pH but can be slightly acid depend on the CO2



Cl

SO4

HCO3-

The water is vary clear, bluish or greenish Dr.Eng. Suryantini Geothermal Enginering FTTM – ITB Geology Engineering FITB - ITB

Sulfate Water (SO4) •

Form at the shallowest part of the system



Due to steam condensate into near surface water (steam heated water)



High SO4 due to oxidasition of H2S



Acid due to low pH



Shown by the appearance of mud pool and dissolution of the surrounding rock , occasionally shown by collapse ground

Cl

SO4

HCO3-

Dr.Eng. Suryantini Geothermal Enginering FTTM – ITB Geology Engineering FITB - ITB

Air Bikarbonat (HCO3) •

Terbentuk sebagai akibat adsorbsi gas CO2 dan kondensasi uap air ke dalam air tanah (steam heated water)



Berada di daerah tepi sistem dan dangkal



Anion utama HCO3 dan kation utama adalah Na

Cl

SO4



Cl rendah dengan SO4 bervariasi



Apabila dibawah permukaan terdapat batugamping maka dapat terbentuk endapan sinter travertin (CaCO3) di permukaan

HCO3-

Dr.Eng. Suryantini Geothermal Enginering FTTM – ITB Geology Engineering FITB - ITB

The other water type is the result of mixing between these primary waters type, therefore it shows the intermediate chemical composition and characteristic

Dr.Eng. Suryantini Geothermal Enginering FTTM – ITB Geology Engineering FITB - ITB

Dr.Eng. Suryantini General Conceptual Model shows distribution of various manifestationGeothermal on highEnginering temperature FTTM – ITB Geology Engineering FITB - ITB flat or low terrain system. Nicholson, 1993

General Conceptual Model shows distribution of various manifestation on high temperature high terrain system.

Nicholson, 1993

Dr.Eng. Suryantini Geothermal Enginering FTTM – ITB Geology Engineering FITB - ITB

Berbagai Macam Manifestasi Permukaan • Acid Crater Lake (Danau Kawah Asam) • Fumarols (Fumarol) • Solfatar (Solfatara) • Steaming Ground (Tanah beruap) • Warm Ground (Tanah hangat) • Boiling Springs (T>90 C), Hot Springs (T 60-90 C), Warm Springs (T 30-60 C), Cool Springs (T < 30 C atau T udara) • Neutral Hot Springs (Mata air panas pH netral ~ 7) • Acid Hot Springs (Mata air panas pH asam < 4) yang bersosiasi dengan (mudpools/ mudpots, ground collapse) • Hot Pool ; calm, boiling, or ebulliant • Geyser • Hydrothermal Eruption • Batuan terubah (Altered Rock)

Dr.Eng. Suryantini Geothermal Enginering FTTM – ITB Geology Engineering FITB - ITB

Acid Crater Lake (Danau Kawah Asam) • It is in the crater of a volcano • Indicates the manifestation of volcanic hydrothermal system • High temperature than ambient temperture • Low ph • The water in this lake is the product from meteoric water that mixing with the condensate water from condensation of steam and magmatic gas from the volcano. • Example: Kawah Ijen East Java Dr.Eng. Suryantini Geothermal Enginering FTTM – ITB Geology Engineering FITB - ITB

Acid Crater Lake (Danau Kawah Asam) • Kawah Ijen • The biggest acid crater lake in the world • Green color • Temperature 36 °C • pH = 0,5 • DHL = 29.000 umhos/cm. • Water level at 2160 masl • Steam above the water level is about 20 m from water surface. Irritated on the eyes Dr.Eng. Suryantini Geothermal Enginering FTTM – ITB Geology Engineering FITB - ITB

Acid Crater Lake (Danau Kawah Asam)

Kawah Ijen Fumarol

Dr.Eng. Suryantini Geothermal Enginering FTTM – ITB Geology Engineering FITB - ITB

Analisis Kimia air danau Kawah Ijen ppm

http://www.vsi.esdm.go.id/gunungapiIndonesia/ijen/umum.html

Perubahan komposisi disebabkan oleh aktivitas vulkanik dan pengenceran dari air Dr.Eng. Suryantini Geothermal Enginering FTTM – ITB permukaan

Geology Engineering FITB - ITB

Fumarol • Fumarol is vapor (uap panas) which sometimes mix with gases. Appear through the rock crack. • Originally this terminology is to describe the manifestation that emit volcanic gas. • Fumarol which associate with volkanic-hidrotermal system can emit steam with velocity >150 m/s. • The steam generally contain reactive magmatic gases such as HF, HCl dan SO2 and sublimes S. • If the SO2 content is dominant, the temperature can reach >130°C. • May contain boric acid (the term for soffioni) • The humidity or wetness and temperature : wet fumaroles has temperature < 100oC which is formed in water dominated system, dry fumaroles with temperature 110 -150oC is formed in vapor dominated system. Dr.Eng. Suryantini Geothermal Enginering FTTM – ITB Geology Engineering FITB - ITB

Fumarol Kawah Domas, Tangkuban Perahu (Suryantini 2011, KK Geologi Terapan ITB)

Dr.Eng. Suryantini Geothermal Enginering FTTM – ITB Geology Engineering FITB - ITB

Fumarol Kawah Domas, Tangkuban Perahu (Suryantini 2011, KK Geologi Terapan ITB)

Dr.Eng. Suryantini Geothermal Enginering FTTM – ITB Geology Engineering FITB - ITB

Solfatara • The name is from the active volkanic-hydrothermal system in Italia; Phlegrean Fieds. • Solfatar is the crack in the rock that emit steam that mix CO2 and H2S (and sometimes with SO2) • Surrounding the vent (crack) may be found significant sulfur deposit. • This sulfur deposit can be mined , example at Kawah Ijen, East Java. Dr.Eng. Suryantini Geothermal Enginering FTTM – ITB Geology Engineering FITB - ITB

Solfatar and sulfur mine at Kawah Ijen

Dr.Eng. Suryantini Geothermal Enginering FTTM – ITB Geology Engineering FITB - ITB

9-12 ton/hari sulfur ini ditambang dengan sistem konvensional

Dr.Eng. Suryantini Geothermal Enginering FTTM – ITB Geology Engineering FITB - ITB

Steam Vent, Soffioni, Moffete dan Kaipohan • Steam vents is a general term to describe the rock crack that emit steam or gas or mix of both • Steam vents that emit gas with high concentration of boric acid is called Soffioni • Steam vent that emit CO2 and low temperature is called Moffete • Steam vent that emit mixing of CO2 dan H2S with cool temperature is called Kaipohan (Philippines word)

Dr.Eng. Suryantini Geothermal Enginering FTTM – ITB Geology Engineering FITB - ITB

Tanah beruap (Steaming Ground) • When the steam appear with small number and low velocity through the pore inside the soil or rock it will appear as steaming ground, not fumarol. • Steaming ground shows warm white smog, quite because the pressure is small • The vegetation in this area shows stress anomaly vegetation • May be detected by infra-red

Dr.Eng. Suryantini Geothermal Enginering FTTM – ITB Geology Engineering FITB - ITB

Steaming Ground, Kawah Domas, Tangkuban Perahu (suryantini 2011, KK Geologi Terapan ITB)

Dr.Eng. Suryantini Geothermal Enginering FTTM – ITB Geology Engineering FITB - ITB

Tanah Hangat (Warm Ground ) • Steam and gases that ascending to the surface will increased the temperature around this area by conduction, resulting temperature higher than surrounding area. • The temperature can reach 30-40 ºC. • Often direct indication is unobservable • The stressed vegetation may be found • Stressed vegetation: the leaf is yellow, red, brown Dr.Eng. Suryantini Geothermal Enginering FTTM – ITB Geology Engineering FITB - ITB

Mata air panas netral (Neutral Hot Springs) • ph 6-7 • It is associated with ’direct discharge’ of reservoir fluid to the surface • Chloride ion is high • Usually has temperature >75 °C even near boiling such as 98 °C • White smog over the manifestation due to high temperature • silica sinter and sulfide mineral such as galena, pyrite etc can be occur.

Dr.Eng. Suryantini Geothermal Enginering FTTM – ITB Geology Engineering FITB - ITB

Kolam panas pH netral (neutral hot pools)

• It is formed by high volume of neutral hot springs discharge that concentrated in a discharge area

• The pools are divided into: calm (t < 100oC), boiling, dan ebullient pools (flashing of steam atau gas) Dr.Eng. Suryantini Geothermal Enginering FTTM – ITB Geology Engineering FITB - ITB

NEUTRAL-CHLORIDE POOLS

http://geothermal.marin.org/GEOpresentation/sld011.htm

Neutral Chloride Hot springs / pool, is neutral ph, clear, bluish, nearly boiling temperature, Dr.Eng. Suryantini show whitish steam at the surface of the pool, silica sinter are deposited surrounding the Geothermal Enginering FTTM – ITB Geology Engineering FITB - ITB edge.

Dr.Eng. Suryantini Geothermal Enginering FTTM – ITB Geology Engineering FITB - ITB

Yellowstone National Park, USA

Dr.Eng. Suryantini Geothermal Enginering FTTM – ITB Geology Engineering FITB - ITB

Kolam air panas asam (Hot Acid Pool) • pH