EQUALIZED METHOD: A NEW METHOD TO OPTIMIZE GAS LIFT SPACING DESIGN BACHELOR THESIS Axel Perwira Indro 12215053 Submitted as partial fulfillment of the requirements for the degree of BACHELOR OF ENGINEERING in Petroleum Engineering study program PETROLEUM ENGINEERING STUDY PROGRAM FACULTY OF MINING AND PETROLEUM ENGINEERING INSTITUT TEKNOLOGI BANDUNG 2019 EQUALIZED METHOD: A NEW METHOD TO OPTIMIZE GAS LIFT SPACING DESIGN BACHELOR THESIS AXEL PERWIRA INDRO 12215053 Submitted as partial fulfillment of the requirements for the degree of BACHELOR OF ENGINEERING in Petroleum Engineering study program Approved by: Thesis Adviser, ………………………… (Prof. Dr. Ir. Sudjati Rachmat, DEA) NIP: 195509021980031005 Field Thesis Adviser, ………………………… (Farasdaq Muchibbus Sajjad, S.T., M.Sc.) 1 EQUALIZED METHOD: A NEW METHOD TO OPTIMIZE GAS LIFT SPACING DES IGN A. P. Indro*, S. Rachmat**, F.M. Sajjad*** Copyright 2019, Institut Teknologi Bandung Abstract In gas lift valve spacing design, there is a common misconception where killing fluid is represented as static no matter the state of the well’s depletion. Killing fluid level, however, changes over time due to fluid infiltration into the reservoir. An innovative method is proposed to optimize gas lift design by considering fluid infiltration movement into the reservoir. The new method is highly effective in depleted reservoirs, where spaces to accommodate the killing fluid entrance are abundant. This paper presents the equalized method as a solution to optimize gas lift valve spacing design. The authors derived an equation based on Darcy’s law and hydrostatic equation to modify the starting depth, at which the equalized condition is reached. The equalized condition is reached when killing fluid movement has reached its final static depth, after a period of time. A case study of Well X, which targets a depleted reservoir, is included to serve as verification to the model. A gas lift system is necessary to maintain oil production in Well X. Using a fixed compressor pressure, conventional gas lift valve spacing design requires a total of eight unloader valves. In contrast, by implementing the equalized method, the number of unloader valves required can be reduced significantly to a total of four valves. The reduction of valves results in higher gas lift operating pressure, higher gas injection passage, and ultimately higher oil production rate obtained compared to conventional design method. This paper presents an optimized gas lift spacing design using the equalized method. The equalized method alters spacing design starting depth using reservoir parameters, well data, and other supporting data. For further application, equalized method can be applied in most gas lift system cases, for a better economic profit. Keywords: Gas Lift, Killing Fluid, Optimization, Equalized Method Sari Dalam desain spacing katup gas lift, terdapat kesalahpahaman umum dimana killing fluid direpresentasikan statis tanpa menimbang keadaan deplesi sumur. Ketinggian killing fluid sebenarnya berubah seiring waktu dikarenakan infiltrasi fluida ke reservoir. Sebuah metode inovatif diajukan untuk mengoptimasi desain gas lift dengan mempertimbangkan pergerakan infiltrasi fluida. Metode ini sangat efektif di reservoir yang depleted, dimana terdapat banyak rongga untuk mengakomodasi masuknya killing fluid. Paper ini menyajikan metode ekualisasi sebagai solusi untuk mengoptimasi desain spacing katup gas lift. Penulis menurunkan sebuah persamaan baru berdasarkan hukum Darcy dan persamaan hidrostatis untuk mengganti kedalaman awal dimana kondisi terekualisasi telah tercapai. Kondisi ekualisasi tercapai ketika pergerakan killing fluid telah mencapai kedalaman statis terakhirnya setelah periode waktu tertentu. Sebuah studi kasus dari Sumur X, yang menargetkan reservoir depleted, dilakukan untuk menjadi verifikasi dari model. Sebuah system gas lift diperlukan untuk menjaga produksi minyak di Sumur X. Menggunakan tekanan kompresor yang telah ditentukan, desain spacing gas lift konvensional membutuhkan delapan katup unloader. Sebaliknya, dengan menerapkan metode ekualisasi, jumlah katup yang dibutuhkan dapat dikurangi secara signifikan hingga menjadi empat katup. Pengurangan jumlah katup menyebabkan tekanan operasi gas lift yang lebih tinggi, kapasitas gas injeksi yang lebih tinggi, dan akhirnya tingkat produksi minyak yang lebih tinggi diperoleh dibandingkan dengan metode desain konvensional. Metode ini menyajikan desain spacing katup gas lift yang dioptimasi menggunakan metode ekualisasi. Metode ekualisasi mengubah kedalaman awal dari desain spacing dengan menggunakan parameter-parameter reservoir data sumur, dan data pendukung lain. Untuk implementasi lebih lanjut, metode ekualisasi dapat di aplikasikan di hampir semua kasus sumur gas lift, untuk keuntungan ekonomi yang lebih baik. Kata kunci: Gas Lift, Killing Fluid, Optimasi, Metode Ekualisasi. *) Student of Petroleum Engineering Study Program, Institut Teknologi Bandung, 2015 batch **) Thesis Adviser in Petroleum Engineering Study Program, Institut Teknologi Bandung ***) Field Thesis Adviser in PHE ONWJ, Pertamina Hulu Energi Offshore North West Java.