minyak bumi

Minyak bumi (bahasa Inggris: petroleum, dari bahasa Latin petrus – karang dan oleum – minyak), dijuluki juga sebagai emas hitam, adalah cairan kental, coklat gelap, atau kehijauan yang mudah terbakar, yang berada di lapisan atas dari beberapa area di kerak Bumi. Minyak bumi terdiri dari campuran kompleks dari berbagai hidrokarbon, sebagian besar seri alkana, tetapi bervariasi dalam penampilan, komposisi, dan kemurniannya.

Komponen kimia dari minyak bumi dipisahkan oleh proses distilasi, yang kemudian, setelah diolah lagi, menjadi minyak tanah, bensin, lilin, aspal, dll.

Minyak bumi terdiri dari hidrokarbon, senyawaan hidrogen dan karbon. alam bidang kimia, hidrokarbon adalah sebuah senyawa yang terdiri dari unsur karbon (C) dan hidrogen (H). Seluruh hidrokarbon memiliki rantai karbon dan atom-atom hidrogen yang berikatan dengan rantai tersebut. Istilah tersebut digunakan juga sebagai pengertian dari hidrokarbon alifatik.

Sebagai contoh, metana (gas rawa) adalah hidrokarbon dengan satu atom karbon dan empat atom hidrogen: CH4. Etana adalah hidrokarbon (lebih terperinci, sebuah alkana) yang terdiri dari dua atom karbon bersatu dengan sebuah ikatan tunggal, masing-masing mengikat tiga atom karbon: C2H6. Propana memiliki tiga atom C (C3H8) dan seterusnya (CnH2·n+2).

SENYAWA HIDROKARBON senyawa ini merupakan senyawakarbon paling sederhana yang terdiri dari atom karbon(C)dan hidrogen(H).sampai saat ini terdapat lebih kurang 2 juta senyawa hidrokarbon.sifat senyawa-senyawa hidrokarbon ditentukan oleh struktur dan jenis ikatan koevalen antar atom karbon.oleh karena itu,untuk memudahkan mempelajari senyawa hidrokarbon yang begitu banyak,para ahli melakukan PERGOLONGAN HIDROKARBON BERDASARKAN STRUKTURNYA,danJENIS IKATAN KOEVALEN ANTAR ATOM KARBON.

* berdasarkan bentuk rantai karbon,hidrokarbon digolongkan menjadi tiga,yakni:

A.hidrokarbon alifatik
– alkana
– alkena
– alkuna
B.hidrokarbon alisiklik
C.hidrokarbon aroma

* berdasarkan jenis ikatan antar atom

A.hidrokarbon jenuh
B.hidrokarbon tak jenuh

Empat alkana teringan- CH4 (metana), C2H6 (etana), C3H8 (propana), dan C4H10 (butana) – semuanya adalah gas yang mendidih pada -161.6 °C, -88.6 °C, -42 °C, dan -0.5 °C, berturut-turut (-258.9°, -127.5°, -43.6°, dan +31.1° F).

Rantai dalam wilayah C5-7 semuanya ringan, dan mudah menguap, nafta jernih. Senyawaan tersebut digunakan sebagai pelarut, cairan pencuci kering (dry clean), dan produk cepat-kering lainnya. Rantai dari C6H14 sampai C12H26 dicampur bersama dan digunakan untuk bensin. Minyak tanah terbuat dari rantai di wilayah C10

Minyak pelumas dan gemuk setengah-padat (termasuk Vaseline®) berada di antara C16 sampai ke C20.

Rantai di atas C20 berwujud padat, dimulai dari “lilin, kemudian tar, dan bitumen aspal.

Titik pendidihan dalam tekanan atmosfer fraksi distilasi dalam derajat Celcius:

* minyak eter: 40 – 70 °C (digunakan sebagai pelarut)
* minyak ringan: 60 – 100 °C (bahan bakar mobil)
* minyak berat: 100 – 150 °C (bahan bakar mobil)
* minyak tanah ringan: 120 – 150 °C (pelarut dan bahan bakar untuk rumah tangga)
* kerosene: 150 – 250 °C (bahan bakar mesin jet)
* minyak gas: 250 – 350 °C (minyak diesel/pemanas)
* minyak pelumas: > 300 °C (minyak mesin)
* sisanya: tar, aspal, bahan bakar residu

Beberapa ilmuwan menyatakan bahwa minyak adalah zat abiotik, yang berarti zat ini tidak berasal dari fosil tetapi berasal dari zat anorganik yang dihasilkan secara alami dalam perut bumi. Namun, pandangan ini diragukan dalam lingkungan ilmiah.

(Diurutkan berdasar jumlah produksi tahun 2006) dan total produksi1nya dalam juta barrel per hari

1. Arab Saudi – 10,665
2. Rusia – 9,667
3. Amerika Serikat2 – 8,331
4. Iran – 4,148
5. Republik Rakyat Cina – 3,858
6. Meksiko – 3,707
7. Kanada – 3,288
8. Uni Emirat Arab – 3,0
9. Venezuela – 2,803
10. Norwegia – 2,786
11. Kuwait – 2,675
12. Nigeria – 2,443
13. Brasil – 2,166
14. Aljazair – 2,122
15. Irak – 2,008

(Diurutkan berdasar jumlah yang diekspor di 2006) dan total ekspor dalam juta barrel per hari

* Arab Saudi – 8,651
* Rusia – 6,565
* Norwegia – 2,524
* Iran – 2,519
* Uni Emirat Arab – 2,515
* Venezuela – 2,203
* Kuwait – 2,150
* Nigeria – 2,146
* Aljazair – 1,847
* Meksiko – 1,676
* Libya – 1,525
* Irak – 1,438
* Angola – 1,365
* Kazakhstan – 1,114
* Kanada – 1,071

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New Oil and Gas Exploration

Cara Membuat “Crop Circle”

Berita heboh munculnya Crop Circle di Berbah Sleman, Yogyakarta menjadi menarik ketika kita tidak tahu bagaimana membuatnya. Sehingga muncul spekulasi-spekulasi bahwa itu dibuat oleh Alien atau UFO.Bentuk dan macam ragam Crops memang secara geometri menarik sekali. Beberapa memiliki geometri Fraktal.Kalau Crop Circle itu mengherankan kamu karena cara pembuatannya, mestinya kita juga heran dengan pembuatan Candi Borobudur yang memiliki geometri segi-empat sempurna, kan ? Coba saja pikirkan apakah waktu pembuatan Borobudur itu sudah ada alat ukur Theodolite ? GPS belom ada, Sattelit belum juga ada namun geometri Borobudur benar-benar sempurna !.

Awali dengan rancangan (denah atau peta)

Setiap bangunan selalu dibuat dengan sebuah design rancangan. Rancangan ini dibuat dengan metode grafis dimana rancangan crops ini akan menjadi seperti peta. Mirip kalau membuat rancangan rumah. Semua dibuat dengan skala.

Berbagai design crops dijumpai didunia ini.

Setelah rancangan dibuat dalam kertas layaknya membuat rumah, maka barulah dibuat sesuai ukuran yang ada dalam kenyataan.

Bagaimana membuat lingkarannya ?

Tentunya kita harus mencari lokasi yang cukup luas supaya terlihat bagus. Juga daerah ini sedang ada tanaman yang cukup besar untuk dipatahkan. Bisa saja berupa sawah yang sedang menguning, maupun kebon tebu. Namun kalau kebon tebu perlu trantor membuatnya. Banyak cara dalam membuat lingkaran ini. Namun cara termudah tentunya dengan dua orang yang satu menjadi pusat lingkaran dan lainnya berjalan memutar.

membuat lingkaran

Setelah seluruh design diberi patok-patok, maka kita dapat merubuhkan tanaman padi dengan cara menekan menggunakan plat

Nah kalau memang geometri itu saja sudah mampu membuat terheran-heran dengan crops , mestinya orang lainpun akan lebih heran lagi melihat Borobudur beserta candi-candi di sana, kan ? Bayangkan ukuran Borobudur  dibawah ini.

Sumber : Dongen Geologi

 

Geothermal Energy

Geothermal energy (from the Greek roots geo, meaning earth, and thermos, meaning heat) is thermal energy stored in the Earth. Thermal energy is energy that determines the temperature of matter. Earth’s geothermal energy originates from the original formation of the planet, from radioactive decay of minerals, from volcanic activity, and from solar energy absorbed at the surface. The geothermal gradient, which is the difference in temperature between the core of the planet and its surface, drives a continuous conduction of thermal energy in the form of heat from the core to the surface.

From hot springs, geothermal energy has been used for bathing since Paleolithic times and for space heating since ancient Roman times, but it is now better known for electricity generation. Worldwide, about 10,715 megawatts (MW) of geothermal power is online in 24 countries. An additional 28 gigawatts of direct geothermal heating capacity is installed for district heating, space heating, spas, industrial processes, desalination and agricultural applications.

Geothermal power is cost effective, reliable, sustainable, and environmentally friendly,but has historically been limited to areas near tectonic plate boundaries. Recent technological advances have dramatically expanded the range and size of viable resources, especially for applications such as home heating, opening a potential for widespread exploitation. Geothermal wells release greenhouse gases trapped deep within the earth, but these emissions are much lower per energy unit than those of fossil fuels. As a result, geothermal power has the potential to help mitigate if widely deployed in place of fossil fuels.

The Earth’s geothermal resources are theoretically more than adequate to supply humanity’s energy needs, but only a very small fraction may be profitably exploited. Drilling and exploration for deep resources is very expensive. Forecasts for the future of geothermal power depend on assumptions about technology, energy prices, subsidies, and interest rates.

Electricity

The International Geothermal Association (IGA) has reported that 10,715 megawatts (MW) of geothermal power in 24 countries is online, which is expected to generate 67,246 GWh of electricity in 2010. This represents a 20% increase in online capacity since 2005. IGA projects growth to 18,500 MW by 2015, due to the projects presently under consideration, often in areas previously assumed to have little exploitable resource.

In 2010, the United States led the world in geothermal electricity production with 3,086 MW of installed capacity from 77 power plants.[4] The largest group of geothermal power plants in the world is located at The Geysers, a geothermal field in California.[5] The Philippines is the second highest producer, with 1,904 MW of capacity online. Geothermal power makes up approximately 18% of the country’s electricity generation.

Geothermal electric plants were traditionally built exclusively on the edges of tectonic plates where high temperature geothermal resources are available near the surface. The development of binary cycle power plants and improvements in drilling and extraction technology enable enhanced geothermal systems over a much greater geographical range.Demonstration projects are operational in Landau-Pfalz, Germany, and Soultz-sous-Forêts, France, while an earlier effort in Basel, Switzerland was shut down after it triggered earthquakes. Other demonstration projects are under construction in Australia, the United Kingdom, and the United States of America.

The thermal efficiency of geothermal electric plants is low, around 10-23%, because geothermal fluids do not reach the high temperatures of steam from boilers. The laws of thermodynamics limits the efficiency of heat engines in extracting useful energy. Exhaust heat is wasted, unless it can be used directly and locally, for example in greenhouses, timber mills, and district heating. System efficiency does not materially affect operational costs as it would for plants that use fuel, but it does affect return on the capital used to build the plant. In order to produce more energy than the pumps consume, electricity generation requires relatively hot fields and specialized heat cycles. Because geothermal power does not rely on variable sources of energy, unlike, for example, wind or solar, its capacity factor can be quite large – up to 96% has been demonstrated. The global average was 73% in 2005.

Direct Application

In the geothermal industry, low temperature means temperatures of 300 °F (149 °C) or less. Low-temperature geothermal resources are typically used in direct-use applications, such as district heating, greenhouses, fisheries, mineral recovery, and industrial process heating. However, some low-temperature resources can generate electricity using binary cycle electricity generating technology.

Approximately 70 countries made direct use of 270 petajoules (PJ) of geothermal heating in 2004. More than half went for space heating, and another third for heated pools. The remainder supported industrial and agricultural applications. Global installed capacity was 28 GW, but capacity factors tend to be low (30% on average) since heat is mostly needed in winter. The above figures are dominated by 88 PJ of space heating extracted by an estimated 1.3 million geothermal heat pumps with a total capacity of 15 GW. Heat pumps for home heating are the fastest-growing means of exploiting geothermal energy, with a global annual growth rate of 30% in energy production.

Direct heating is far more efficient than electricity generation and places less demanding temperature requirements on the heat resource. Heat may come from co-generation via a geothermal electrical plant or from smaller wells or heat exchangers buried in shallow ground. As a result, geothermal heating is economic at many more sites than geothermal electricity generation. Where natural hot springs are available, the heated water can be piped directly into radiators. If the ground is hot but dry, earth tubes or downhole heat exchangers can collect the heat. But even in areas where the ground is colder than room temperature, heat can still be extracted with a geothermal heat pump more cost-effectively and cleanly than by conventional furnaces. These devices draw on much shallower and colder resources than traditional geothermal techniques, and they frequently combine a variety of functions, including air conditioning, seasonal energy storage, solar energy collection, and electric heating. Geothermal heat pumps can be used for space heating essentially anywhere.

Geothermal heat supports many applications. District heating applications use networks of piped hot water to heat many buildings across entire communities. In Reykjavík, Iceland, spent water from the district heating system is piped below pavement and sidewalks to melt snow. Geothermal desalination has been demonstrated.

BY : Information and Publication AAPG

Recruitment INCO Tbk

PT Inco is one of the world’s premier producers of nickel. The Company is owned 58.73 percent by Vale Inco of Canada, one of the world’s leading nickel producers, and 20.09 percent by Sumitomo Metal Mining Co., Ltd. of Japan, a premier mining and smelting company. In addition, 20.14 percent of PT Inco’s shares are owned by public shareholders and the balance by four other Japanese companies.

Fully integrated nickel mining and processing, located in Sorowako, South Sulawesi. We’re proud to be benchmark for Efficiency, Real Growth, Sustainability and Reputation.

Engineering Staff ( Test : SURABAYA, JAKARTA, MAKASSAR, YOGYAKARTA, BANDUNG)
Position Requirements

* S1 graduate from leading Universities in Indonesia, or overseas graduate with GPA minimum 2.85 (out of 4.00)
* Maximum 28 years of age
* Major: Mining, Mechanical, Electrical, Instrument, Civil, and Metallurgy
* Highly involved in campus leadership and organizational activities
* Willing to be placed in Sorowako, South Sulawesi

CITY CAMPUS LOCATION DATE / TIME

1. Makassar
Universitas Hasanuddin
Gd. LP2 Fakultas MIPA, UNHAS November 30, 2010 09.00-11.30
2. Jakarta
Universitas Indonesia
R. 303 Gd. Engineering Center, Lt. 3, FT UI, Depok December 1, 2010 09.00-11.30
3. Bandung
Institut Teknologi Bandung
Ruang Presentasi ITB Career Center GKU Timur Lt. 2 December 9, 2010 09.00-11.30
4. Surabaya
Institut Teknologi Sepuluh Nopember (ITS)
R Seminar UPT Perpustakaan ITS December 14, 2010 09.00-11.30
5. Yogyakarta
Universitas Gadjah Mada
Ruang 1 Grha Karir ECC UGM December 20, 2010 09.00-11.30

Prepare CV, state your relevant qualifications, experiences, reference and a recent photograph. Please register online through:

BY : Informasi and Publication AAPG

Seismic Exploration

Seismic Exploration

Although this course will concentrate on the processing of reflection seismic data for hydrocarbon exploration, it’s probably worth reviewing the historical context and the other uses of seismic techniques.

The Chinese had a device as early as 100 AD. for detecting earth tremors – probably the first seismic receiver!  The first use of explosives to delineate structures under the earth was in the 1920’s and 30’s in the Southern US and South America.  The techniques used developed fairly slowly over the next twenty or so years until the advent of tape recording in the 1950’s, and digital computer processing in the 1960’s.  Since then the technology has increased exponentially, with the ups and downs of the world oil price controlling the overall research effort.

This course deals exclusively with seismic reflection data processing.  The recording of refracted seismic waves is used for shallow investigations and will be mentioned in passing (we can’t avoid recording refractions with the reflections).  Reflection techniques can also be used for very shallow site investigations (either for placing an oil rig, or for engineering work), or very deep penetration into the earth for examination of the limits of the earth’s crust.  Other geophysical techniques (gravity, magnetics etc.) will not be discussed.

Like most real-world activities, seismic exploration has not featured well in the movies.  The 1953 film “Thunder Bay” has James Stewart throwing sticks of dynamite from a boat in a Louisiana bayou, and the 1976 re-make of “King Kong” used the excuse of seismic exploration as a reason for visiting the appropriate island.  Neither of these is recommended viewing!  (I won’t mention the single shotgun blast at the beginning of “Jurrasic Park” producing a 3D image, though it would be interesting to develop such a technique!)

In simplistic terms, seismic exploration can be thought of as the sonic equivalent of radar.  An energy source produces sound waves that are directed into the ground.  These waves pass through the earth and are partially reflected at every boundary between rocks of different types.  The response to this reflection sequence is received by instruments on or near the surface, and recorded on magnetic tape for computer processing.  The process is repeated many times along a seismic “line” (generally a straight line on the surface), and the resultant processed data provides a structural picture of the sub-surface.  Sophisticated processing techniques can be used (usually in conjunction with calibration data recorded down a well) to turn the resultant seismic section into a direct indicator of rock types and (possibly) detect the presence of hydrocarbons (oil & gas) within the earth.

The data recorded from one “shot” (one detonation of an explosive or implosive energy source) at one receiver position is referred to as a seismic trace, and is recorded as a function of time (the time since the shot was fired).  As this time represents the time taken for the energy to travel into the earth, reflect, and then return to the surface, it is more correctly called “two-way time” and the vertical scale is generally measured in milliseconds (one thousandth of a second – 0.001 seconds).  During the processing sequence these traces are combined together in various ways, and modified by some fairly complex mathematical operations, but are always referred to as “traces”.  The display of many traces side-by-side in their correct spatial positions produces the final “seismic section” or “seismic profile” that provides the geologist with a structural picture of the sub-surface.

For reasons of efficiency and data redundancy, the results from each shot are actually recorded at many different receiver positions.  Receivers are placed at regular intervals around or to one side of the shot position typically extending over some 3 kilometres or more of the surface.  The resultant collection of traces from one shot is generally recorded together and referred to as a “Field Record”.  Each shot position is numbered, and the position of each shot (normally the “shotpoint”) is accurately mapped.  This “shotpoint map” shows the position of the seismic cross-section on the surface.  For conventional so-called two-dimensional (2D) seismic data (we’ll talk about 3D later…) this cross-section is assumed to lie directly below the surface “line”.

Since the early 1960’s seismic data has been recorded and processed digitally.  What we visualise as a seismic trace is actually nothing more than a string of numbers, where each number represents the amplitude (or height) of the seismic trace at a particular time.  Traces are typically recorded with a sample period (the time interval between numbers) of 1-2 milliseconds (0.001 – 0.002 seconds), and recorded to a total two-way time of (typically) 5 or 6 seconds.  Each trace thus consists of some 2,500 – 6,000 numbers recorded on tape.  As each of these numbers can take up to 4 bytes of computer storage, and as one field record can consist of (for example) 240 seismic traces recorded every 25 metres on the surface, the data storage problems are, even now, considerable.  Six seconds of data recorded at a 2 millisecond sample period, with one field record of 240 traces shot every 25 metres = 115,200,000 bytes per kilometre (recorded every 5-6 minutes offshore, or 1.3 gigabytes per hour!)

By : Mr. Erwin Rustam ( BGP ARABIA )

Pertamina Geothermal

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