Practicle Aspects of Well Unloading and Operation 0 comments
The guidelines in this section are adapted primarily from API RP 11 V5 (1999), Recommended Practice for Operations, Maintenance and Troubleshooting of Gas Lift Installations.
Initial Unloading
The first step in bringing a well on production after gas lift valves have been installed is to unload the fluids from the wellbore and obtain a stabilized production rate. Normally, a well placed on continuous gas lift is unloaded continuously, and a well placed on intermittent gas lift is unloaded intermittently. Primary considerations in unloading include avoiding excessive pressures that could damage the valves, and using clean, filtered workover fluids to avoid plugging or abrasion of the valves.
Prior to unloading, a two-pen pressure recorder should be installed at the surface to monitor both the gas injection pressure and the production (tubing) pressure. These pressures should be measured as close to the wellhead as practical. In any case, the gas injection pressure should be measured downstream of the injection choke, and the production pressure should be measured upstream of any flowline choke that is present. The wellhead pressure should be bled down to the pressure of the downstream separator, and the flowline choke, if present, should be either fully open or removed.
Continuous Gas Lift Wells
With continuous gas lift, the unloading process begins when gas is injected slowly into the annulus, probably through a choke located at the surface. Pressure is incrementally raised by approximately 50 psi every eight to ten minutes until it reaches about 400 psi, and 100 psi every eight to ten minutes thereafter. The kill fluid is displaced through the standing valve, up the tubing and to the surface into a disposal tank, until gas starts coming around the first valve or oil appears in the produced fluid. A steady stream of fluid will be then unloaded. If these fluids are directed into a separator, it is important to keep the backpressure on the well as low as possible. As gas is continuously injected into the annulus, a gradual increase in casing pressure will be required to keep fluids flowing from the tubing string.
Valve 1, the uppermost valve, is the first valve to be uncovered; gas first enters the tubing string at this point. This is noted at the surface by an immediate increase in the velocity of the fluid stream coming out of the tubing. A mixture of gas and liquid is soon produced at the surface, and the casing pressure levels off at the surface operating pressure of Valve 1. As gas continues to enter the annulus, the liquid column in the annulus is lowered until Valve 2 is uncovered. As soon as this valve is uncovered, gas flows through it and enters the tubing. Casing pressure then drops to the surface operating pressure of this valve. At about the same time, pressure in the annulus opposite Valve 1 should have been reduced to a level low enough to cause that valve to close.
Unloading continues from valve to valve until the deepest operating valve is uncovered. At this point, the bottomhole pressure has been reduced to a level that allows the formation fluid to move into the tubing, and the volume of gas injected through the operating valve is sufficient to lift the production under design conditions.
Intermittent Gas Lift Wells
With intermittent gas lift, fluid is unloaded at the surface in the form of piston-like slugs. The unloading process is the same as that for continuous flow until the uppermost valve (Valve 1) is uncovered. At that point, the well is placed on intermittent control for unloading. This is accomplished with a choke or a time-cycle controller at the surface so that the well is alternately produced and shut-in. During this period, the fluid in the annular space will continue to be U-tubed into the tubing and will be produced as slugs. A good cycle for unloading is obtained with 2 to 4 minutes of gas injection every 20 to 30 minutes. This allows ample time for stabilization to take place between slugs.
When the well is unloaded down to the operating valve, the choke size or cycle time should be adjusted to suit the well’s production characteristics. Thus the unloading operation may start with a high number of cycles per day and then, in response to the well’s production behavior, the number of cycles will be adjusted downward as fewer cycles will be needed to maintain optimum production rates. If the fluid production rate begins to fall off, then the number of daily cycles is too low for optimal production. With this information, it is possible to make further refinements to the process by reducing the duration of gas injection during each cycle. The objective is to maximize production and minimize the gas volume required. A very useful monitoring procedure involves simultaneously recording the shapes of the tubing and casing pressures curves. Adjustments are made on the basis of the shapes of these two curves.
System Adjustments
Once a well is unloaded, the next step is to optimize its production rate and gas usage. This will require some adjustment of its operating parameters. For detailed procedures, refer to API RP 11V5 (1999).
In a continuous gas lift installation, adjustments are generally made using an adjustable choke to control the rate of gas injection (a positive choke could also be used, but this would require interrupting gas injection to change the choke size). To prevent freezing, the gas system may be equipped with a dehydrator, gas heater or heat exchanger, or methanol may be injected upstream of the choke. To adjust the gas injection rate, the choke is initially set at a diameter that is larger than required for the design rate. The diameter is reduced incrementally until the production rate begins to drop, and then readjusted to establish the optimal production rate.
Similar types of adjustments are made for intermittent gas lift installations that employ time cycle control: the controller is initially set for a duration that will exceed the design gas injection requirements, and then the number of cycles per day is reduced until the well can no longer produce at its desired rate. The controller is then reset in steps until the optimal production and gas injection rates are established. For intermittent wells operating on choke control, the choke is initially sized for the design production rate, and then adjusted in the same type of trial-and-error manner.
Gas Lift System Monitoring
Successful gas lift performance depends largely on the efforts of field personnel. A gas lift installation requires close supervision during the unloading process, and when injection gas is adjusted and regulated.
A common practice is to analyze the system only when a problem arises. A better approach is to analyze each well while it is operating satisfactorily to determine if the installation has been properly designed. This provides a baseline measure of performance for reference in the event of trouble, and helps to indicate needed design changes. It is important to analyze this baseline information before planning well servicing or workover operations—otherwise, the operator will not know what changes are needed.
Diagnostic tools for monitoring and troubleshooting gas lift wells include:
Two-pen pressure recorder charts and calibrated pressure gauges installed at the well
Acoustical and production logging surveys
Fluid level determinations using wireline
API RP 11V5 (1999) describes these tools and their applications in detail.
Remote Monitoring
Gas lift wells are a common area of application for remote monitoring and control techniques. These systems can measure the performance of a single well or an entire field using sensors and data transmitting devices that alert field personnel to changes in well performance. By comparing performance parameters over time, the operator can analyze well stability, allocate lift gas injection, and optimize the operation of the entire field. This capability leads to improved efficiency, better field operations management, and increased profitability.
A significant feature of monitoring systems is their ability to remotely control gas injection and change well settings using two-way control devices. Continuous monitoring and comparison of parameters such as injection pressure, wellhead pressure, and flow rate lets the operator identify potential problems and take preventive and corrective action from a central location. In many cases, the operator is notified automatically when sensors detect significant changes to key parameters.
Primary components of remote monitoring systems include:
Downhole Pressure & Temperature Sensors
Sensor Data Process System
Well Controller
Remote Terminal Unit (RTU)
The downhole pressure and temperature sensors communicate via a system controller to adjust gas injection through the sensor data process system. This allows the operator to control the well or the field based on changing surface or downhole conditions.
A remote terminal unit (RTU) can transmit data continuously or store well performance data for later transmission and analysis. The RTU is a two-way system, thus allowing the operator to communicate back to the well.
The monitoring and communication equipment is powered by solar cells, which are backed up by a battery system to ensure a constant power supply.
Through monitoring of gas lift injection and production systems, field efficiency can be improved and future gas lift valve design, valve placement and unloading programs can be designed on the basis of actual field operating experience.
Source : www.reggieoilservices.com
Halul Island 0 comments
The island is home to 11 large crude oil storage tanks, with a total capacity of 5 million barrels, crude oil pumping facilities, power generation and water desalination plants. Oil is blended and exported from Halul to customers’ oil tankers moored offshore. In 2003, 108 commercial tankers were loaded at Halul.
Halul Island expansion plans include the Phase II upgrade of the harbor to accommodate larger vessels, a new control room building a new marine building and the upgrade of power and water utilities.
The island is provided with suitable housing accommodation and all related domestic facilities including restaurants, a clubhouse, and recreational areas to play sports such as volleyball, basketball, football and tennis. Between 750 and 900 personnel, including contractors are present on the island on a daily basis.
Safety is a priority at Halul. As the operator of Halul terminal, QP has given it considerable attention and a safety procedure is provided and strictly followed. The safety requirements set out in the checklist are based on the safety practices widely accepted by the oil tanker industry and recommendations by ISGOTT. All fire fighting and lifesaving appliances are properly placed and maintained in a state of readiness for immediate use.
In order to enhance greenery and landscaping, a variety of flowering plants, trees and shrubs are being planted around the island. A project has been initiated for a sewage and waste water treatment plant and this gray water will be utilized to enhance the greenery on Halul’s undeveloped areas.
The island (about 1.5 sq. km) is home for 11 giant crude oil storage tanks, pumping stations, power generation, water desalination plants and a heliport in addition to staff accommodation, sports and recreational facilities.
Halul Island accommodates about 800 personnel including contractors on a daily basis.
Source : www.qp.com.qa
i-Handbook 0 comments
Interactive, field-specific computations
i-Handbook, an electronic version of the Field Data Handbook, displays data that helps compute results fast. This eliminates the time-consuming and error-prone practice of first assimilating data and obtaining results using a separate calculator.
The i-Handbook was designed with three objectives
- retain the book format of the Field Data Handbook
- present data without additional training
- focus on the needs of a varied audience, from on-site personnel to design and planning engineers in offices.
An interactive wellbore diagram lets you build a graphical view of the wellbore with drag-and-drop data from the tubular tables. You can define various flow paths in the well. The volumes of defined sections are calculated automatically and displayed on the diagram.
Quick and accurate
Tubing and casing data tables can be expanded so you can see additional physical properties. You can send data entered in any calculator or a particular wellbore to your team. Correct information is exchanged fast.
Design help saves time
A thorough understanding of the treatment and the effects of recommended wellbore actions is communicated through visual, sometimes animated, schematics. You can prepare diagrams illustrating the various combinations of pipe strings. This lets you create realistic, multiple design options in one session.
More data
New information is included in sections on pipe, tubing, casing, tanks, volume, fracturing, cement, and acid/oil/brines.
Minimum system requirements:
- PC Windows®
- 200-MHz Pentium® processor-based computer
- Microsoft® Windows 2000 or Windows XP
- 128 MB of RAM
- 10-MB free disk space
- i-Handbook is not compatible with Microsoft® Windows 95, 98 or NT®
Lebaran 2007 1 comments
Corps dharma wanita Halulindo
Pak Novi kok nggak makan nih...
E-book : 168 jam dalam sandera 0 comments
Suara Budianto mengagetkanku. Tangannya menghentakkan tas yang kupakai sebagai bantal. Budi mengulangi teriaknya, “Bangun Meut! Bangun!”
Entah apa gerangan yang sedang terjadi. Otakku belum bekerja seratus persen, namun bisa kucerna nada kepanikan dalam lengkingan suara Budi. Setahuku, Budi adalah tipe lelaki Jawa yang halus tutur katanya. Tak pernah ia meninggikan suara kepadaku seperti ini.
Belum sempat aku bertanya, Budi kembali berteriak, “Paspor Meut! Passpor…!” Paspor? Kenapa ada yang meminta paspor, padahal rasanya aku sudah lama tertidur sejak melintas perbatasan. Tapi tanganku refleks merogoh tas mencari paspor.
“Cepat Meut! Cepat!” Lagi-lagi Budi berteriak, kali ini lebih keras. Mungkin karena panik, tanganku sulit sekali menemukan paspor. Kuaduk-aduk isi tas. Mataku yang belum awas benar mencoba melihat sekeliling.
Rupanya kami berada di sebuah pom bensin. Posisi mobil yang kutumpangi seperti tengah mengisi bensin. Mataku menangkap sosok tiga lelaki mengepung mobil kami. Wajah mereka tertutup kain sorban yang biasa disebut kafiyeh. Hanya mata mereka yang terbuka. Aku yakin mereka warga Irak.
Budi duduk di jok depan, badannya membalik ke arahku karena tak sabar menungguku mencari paspor tanpa hasil. Di sebelah Budi, kursi tampak kosong. Kemana Ibrahim? Perhatianku beralih ke suara orang menghardik dalam bahasa Arab. Matanya memelototiku.
“Paspor!!” Hanya itu yang bisa kupahami dari rentetan bahasa Arab yang meluncur dari mulutnya.
Aku semakin bingung, tapi pasti ada yang tidak beres. Bukan hanya satu, tiga lelaki itu kini memaksaku dengan tatapan menusuk dan tidak sabar. Kutemukan pasporku, seorang dari mereka langsung menyambarnya. Pada saat bersamaan Ibrahim berlari entah dari mana. Rautnya panik.
“Sahafi! Sahafi! Muslim! Andonesi!” Setengah berteriak Ibrahim menjelaskan pada tiga lelaki itu bahwa kami wartawan muslim dari Indonesia. Ketiga lelaki itu tak mempedulikan berondongan penjelasan Ibrahim. Malah mereka menimpali dengan rentetan pernyataan yang lebih sengit. Itu membuat Ibrahim semakin pucat. Pasti posisinya tak berdaya.
Pintu mobil dibuka, tubuh Ibrahim yang tinggi besar didorong paksa ke arahku. Lalu seorang lelaki memaksa masuk dari samping Ibrahim, dan melompat ke kursi paling belakang. Tangannya menenteng senjata laras panjang jenis AK. Ia mengarahkan moncong senjatanya padaku sambil berteriak dalam bahasa Arab. Sepertinya ia mengatakan, “Jangan berontak, jangan bergerak!”
Di kursi depan, lelaki lain masuk dari pintu kanan, memepet tubuh Budi. Seorang lagi masuk dari pintu depan kiri, duduk di belakang kemudi. Ia membalik ke arah Ibrahim dan merebut kunci dari tangannya. Kasar dan beringas. Tubuh Budipun didorong ke kursi tengah sehingga posisinya terjepit tubuhku dan Ibrahim. Mesin dihidupkan, mobilpun dilarikan sangat kencang. Sekelebat aku melihat beberapa orang di pom bensin hanya melongo tanpa mampu menolong.
Mobil terus melaju kencang, membuat barang-barang bawaan kami, termasuk perangkat liputan, terguncang. Semuanya terjadi begitu cepat. Aku berharap ini hanya bagian dari mimpi tidurku. Kakiku serasa melayang, tubuhku tak lagi menempel di kursi. Mimpikah? Bukan! Walau perasaanku sulit menerima, tapi otakku yang sudah terjaga terus menerus meyakinkan, “Ini kenyataan, Meut, bukan mimpi!” Akhirnya aku pasrah. “Inilah akhir hidupmu.”
Inikah perjalanan menuju kematian? Dunia pun gelap.
Penasaran? Silakan baca sendiri e-booknya… Klik download button di atas. Jangan lupa siapin kacang goreng dan kopinya….
Lebih jauh tentang penulis...
Maen Banshee yuk... 0 comments
Bagi yang sudah lama tinggal di Qatar, apalagi rumahnya di Wakrah tentunya tidak asing lagi dengan Sea Line Beach. Apalagi kalo bukan tempat rekreasi pantai, yang menjadi andalan warga Ummsaid...
Nah kali ini, saya mau mengajak rekan-rekan menuju ke sana... Tapi bukan untuk nyemplung ke laut, tapi mencoba menaklukan desert meski hanya kecil-kecilan menggunakan banshee ...
Ifthar Bersama 2007 0 comments
Pak Camat sedang ngasih instruksi....
Pak Risna takut gak kebagian...
Tim dapur kita
Sudah nggak sabar menunggu bedug
Alhamdulillah... sampai juga buka puasanyaSelamat buat Koh Ruslan.... 0 comments
Akhirnya.... bakal berkurang juga nih jumlah bujangan di Pulau Halul, setelah sekian lama Koh Ruslan Lukman berstatus bujangan akhirnya beliau akan mengakhiri lajangnya pada 17 Januari 2009 nanti. Berikut undangan tepatnya e-invite yang beliau kirim ke warga Halulindo :
Dear friends.
Please consider this email as an official invitation to our wedding celebration on Saturday 17 January 2009. Our Holy Matrimony will attend at GII Hok Im Tomg Church, Veteran RI Building 12th floor, The Plaza Semangi South Jakarta at 11am and Wedding reception at Ancol Cordova Tower Pasir Putih Raya Block E/5 8th floor Ancol Timur North Jakarta, Indonesia at 7pm. Any inquiries please click http://www.ewedding.com/sites/bekoar.
Our happiness will be more complete with your presence and blessing.
Love
Antonius Ruslan Lukman & Gan Mei Cen
Selamat ya Koh... Kami warga Halulindo hanya bisa berdo'a semoga Koh Ruslan ame ce' Mei bisa langgeng jadi oma dan opa...
Kumpulan E-book Halulindo
Silakan klik pada link sesuai kategori berikut :
- E-book Umum : Berisi beberapa e-book tentang novel, memoar, biography atau yang bersifat umum lainnya.
- E-book Handbook : Berisi beberapa e-book tentang handbook dari berbagai disiplin ilmu.
- E-book Islami : Berisi beberapa e-book tentang agama Islam.
Kumpulan Artikel Halulindo
Silakan klik pada link sesuai kategori berikut :
- Article - Oil Knowledge : Berisi beberapa artikel tentang pengetahuan perminyakan dari berbagai disiplin ilmu.
- Article - Management : Berisi beberapa artikel tentang pengetahuan management.
- Article - Umum : Berisi beberapa artikel yang bersifat umum.
Download 0 comments
Berikut beberapa file yang bisa anda unduh :
- E-Book Islami :
- Ringkasan Do'a Haji dan Umroh
- Hisnul Muslim (Kumpulan do'a sesuai Al-Qur'an dan Assunnah)
- 100 Pesan Nabi Untuk Wanita Solihah
- E-Book Umum :
- 168 jam Dalam Sandera by Meutya Hafid (File exe berupa digi-book, jika ada peringatan maleware terutama di Vista, abaikan saja. Aman kok...).
- Novel Laskar Pelangi by Andrea Hirata (pdf file 761 kb)
- Kumpulan Cerpen Islami by dunia kata (pdf file 298 kb)
- Kick Andy : Kumpulan Cerpen Inspiratif
- Barack Husein Obama : Candidat Presiden Amerika yang punya Muslim Connection.
- Menerjang Harapan dari Jakarta Menuju Gedung Putih
- Software :
- Schlumberger i-handbook (Penjelasannya lihat di sini)
- Text-book :
- Terjemahan Basic Chemistry by Y. Takeuchi (Penjelasan lihat di sini)
- Terjemahan Kimia Organik by Taro Saito
- Terjemahan Kimia Kuantum by Koichi Ohno
- Pedoman tata nama kimia
- Tips Melamar kerja dari A. Fatih Syuhud
- Tips umum menulis surat lamaran.
- Menulis surat lamaran di email.
- Tips umum membuat resume.
- Aspek-aspek yang ditonjolkan dalam resume.
- Hati-hati menuliskan hal berikut dalam resume.
- Persiapan menghadapi wawancara.
- Cara berpakaian yang baik dalam wawancara.
- Bersikap percaya diri.
- Pengaruh kontak mata dan suara dalam wawancara.
- Persiapan Psikotes.
- Sopankah menanyakan hasil wawancara?
- File Arsip di Milis Halulindo (File berekstensi word)
