Pernah anda tahu bagaimana minyak digali dari bawah tanah?

First of all, ingin saya membetulkan fahaman sekalian alam. Tiada istilah GALI MINYAK dalam kamus industri minyak dan gas ni. Mengapa sedemikian, saya harap anda akan menemui jawapannya sebaik anda habis membaca entry saya kali ini. Selamat membacaaaa!

Dulu masa saya mula2 masuk undergrad, otak saya zero pasal ilmu2 minyak ni. Dan saya sendiri tak tau ape yang perlu saya tahu. Semuanya mengharap suapan lecturer. Apa yang disuap itu juga yang ditelan. Diberinya bulat, ditelan juga bulat2. Tapi sekarang saya sedar, kalau nak belajar lebih, kita tak boleh telan bulat2. Kalau disuap bulat, telan petak2. Kalau disuap petak2, telan heksagon2. Kalau disuap cheese cake, baru lah kita boleh telan bulat2. Haaa camtu lah resipi untuk melebihkan ilmu.

OK. Macam mana kita dapat minyak dari bawah tanah? Jawapannya simple.

Cuba bayangkan anda diberi setin minuman berkarbonat. Nah.

Kita bagi nama air ni Koka Koala atau KK for short. Apa akan jadi kalau kita kasi goncang sama itu tin dan pastu bukak penutup tu?

Mestilah meletup kan?

So that's how basically oil is produced from the underground. The concept is simple, but the execution is not as easy as that.

Dalam oil production, we first do surveys to confirm that we do have oil reservoir beneath. Lepas 100% confirm, we install platform at the location and start drilling.

Ngenggg ngenggg ngenggg ngennnnngggggggggggggg (bunyi mesin drilling)
Pics taken from http://www.wellideas.com.sg/well_design.php

Ade banyak isu yang perlu diambil kira waktu drilling. We can't simply drill a hole and expect nothing would happen and assume everything is naturally secured. No, we can't. Though we're drilling, we have to secure the drilled hole to be as if there was no hole drilled at all ie, we have to maintain the hole pressure to be equal with the surrounding formation. Faham tak? This is actually safety issue. Lagipun, kalo tak maintain pressure within the hole, the wall of the annulus will collapse and tadaaaa tersekat la drilling tools kite nanti. So that's basically it.


Imagine that you're drilling a wall. The habuk will come out from the hole kan? So the same thing we're expecting while drilling the earth. We don't want the habuk (ie tanah) to be dumped in the hole. Kite mesti keluarkan sisa tanah tu. Tapi, kalau dalam sangat, mestilah payah tanah2 tu nak keluar kan? So here come the magic fluid yang dipanggil DRILLING FLUID. This fluid will exit from the bit nozzle at a very high velocity and then sweeps the debris up to surface menggunakan kuasa jettttt! (The two arrows show you the flow direction of the cuttings - kalau aku panggil habuk gerudi tu habuk, in drilling operation we name the habuk as cuttings)

Ok. Actually, I didn't plan to tell you on how we drill the well. This will just complicate me. Haha. Bukan tak ikhlas nak menaip, tapi nanti my entry will always end as DRAFT. Kire bertuah la korang kalau dapat bace entry ni. That means, entry ni terselamat dari CERITA YANG TIADA KESUDAHAN. Haha. mari sambung cerita. Eh. Tadi cerita pasal buat lubang. Banyak lagi yang dicerita ni. Ok. Tabah Fad, tabah! Teruskan menulis!

Then, bile dah buat lubang, we secure the well mechanically by installing a CASING.

Ok. Yang kelabu tu, kite panggil casing. Alah, rupe die sebijik macam simen yang kite tengok dalam telaga air. Sebijik lah tu. Tapi yelah, bile da drill tu, die takdelah drill perfectly ikut size casing yang kite nak letak. Adelah tolerance sikit. So bile kite install casing, mebi ade lubang sikit kat keliling casing tu. So that's why we need to do the following:

Pump cement. Ok, dalam gambar atas ni, yang kale kelabu cair kat keliling casing to is what we call CEMENT and it is pumped through the casing anulus. Kire function cement ni lebih kurang macam gam la. Nak buat casing tu kasi lekat sama tanah tu. Faham? Ok proceed.

Kau ingat kite dah boleh produce minyak sekarang? Haihh belum lagiiiik. Ni baru sikit!

Yang aku cite tadi tu, baru Part 1 out of 10 parts in drilling a well. Sebabnye, to build a well, we do it stage by stage. Yelah, cube kau bayangkan. We might aim to drill a 10,000ft well. Takkan lah kau nak drill sampai 10,000ft then baru install casing semua? No, no, nooo. Tak boleh camtu. Tak selamat! Because, the hole might collapse dan ini akan melibatkan kerugian kepada kita!

Inilah kejadian yang perlu kita elakkan!

So that is why, to drill a well, we do it stage by stage. Katakan nak buat 10,000ft punya well. So we build the first interval. Lepas install casing and pump cement for the first interval, we start to drill the second interval. Lepas drill second interval, we put casing, then pump cement. And finally, this is how our well will look like:

Fad, pehal kau lukis casing tu tak balance? Apsal atas besar bawah kecik?

Haaa ni lah aku nak cite ni. It is actually ikut fikir logik je. Bayangkan, lepas ko set casing for the first interval, then how do set the casing for the second interval with the same size? Impossible kan? So that is why, oil well selalunya macam ni rupe die. The casing size gets smaller and smaller when it goes deeper.

Fuuuh. Baru pasal well. Meh aku pakai shortcut untuk habiskan entry ni.

Then bila ko nak produce minyak tu, kau masukkan straw dalam well tu (kejadah straw Fad?). Ala, assume kite gune analogi tin KK tu laa. Ok. This so-called straw, kami panggil TUBING. We then run the tubing into the well.

Sroooottt (bunyi masukkan tubing into the well)

Tadaaa. The black line is the tubing in the well. Tubing inilah laluan minyak kite nanti. That's why I call it straw. Cause it's the one that makes the oil flow. Hihi

Tapi, how do we make the oil from the formation to flow? We run in PERFORATION GUN! Dalam industri oil & gas ni, pembuat perforation gun yang terkenal adelah Schlumberger. Berteknologi tinggi, dan hebat. This perforation gun acts like a gun. It can shoot you dead, mann!


Ok. You can assume that the blue dot in the picture is the bullet from the gun. The gun is driven down using WIRELINE (green line in the picture in circles). When the gun fires, the bullets will perforate both of tubing and casing and penetrate into the formation. Dan tadaaaa! Tubing dan casing kita sudah berlubang! :D

Kemudian, kita keluarkan wireline kita tu, dan kita boleh let the oil flow dengar memegang prinsip bahawa the will be a flow whenever the formation pressure is higher than that of the tubing pressure. Kalau guna analogi tin air KK kita, camnilah :

Macam inilah basically oil kita flow dari bawah tanahhhhh! Cuma beza gambar kiri ngan gamba kanan, aku letak straw kat gamba kanan to demonstrate the oil well :D

Cuuplah tu. Aku nak pengsan dah. Kau ingat senang ke aku nka lukis2 ni? Haha

P/S : Ketahuilah anda bahawa sesungguhnya kalau mengikut hukum alam, tekanan bawah tanah itu tidak akan selamanya mampu untuk membolehkan minyak mengalir masuk tubing. Ada satu masa, pergerakan minyak akan berhenti kerana penurunan tekanan dalam reservoir tersebut. Mengikut peratusan, minyak biasanya direcovered 30%-40% dari jumlah total kalau kita bergantung kepada tekanan reservoir kita. Ini memang hukum alam. Yalah, macam kau minum air dalam cawan guna straw. Pernah kau dapat sedut titisan last tu? Renung2kan lah..

P/S dua kali : Kalau aku rajin aku citelah ape yang kitorang buat bile oil production da capai tahap seperti yang dinyatakan di ataasss okekkk

Next entry : Entry pergi offshore barang kali?

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Tunguuuuuu ;)