STUDI PENINGKATAN PEROLEHAN MINYAK DI ZONA A LAPANGAN X DENGAN METODE INJEKSI AIR
TESIS
Karya tulis sebagai salah satu syarat untuk memperoleh gelar Magister dari Institut Teknologi Bandung
Oleh :
RADEN DANIELI SAPYUDIN NIM : 222 05 007 Program Studi Teknik Perminyakan
INSTITUT TEKNOLOGI BANDUNG 2007
ABSTRAK
STUDI PENINGKATAN PEROLEHAN MINYAK DI ZONA A LAPANGAN X DENGAN METODE INJEKSI AIR
Raden Danieli Sapyudin NIM: 222 05 007
Reservoir Zona A Lapangan X merupakan reservoir batu pasir yang termasuk dari bagian Cekungan Sumatra Utara. Zona A dipilih sebagai objek studi simulasi reservoir karena minyak yang tersisa setelah pengurasan primer masih cukup banyak. Tingkat pengurasan primer yang telah dicapai hingga saat ini adalah 25% dengan OOIP sebesar 19.30 MMSTB. Kondisi ini dijadikan dasar pemikiran perlunya dilakukan upaya pengurasan minyak yang tersisa dengan metode lebih lanjut dalam hal ini injeksi air. Model geologi, inisialisasi, dan history matching sudah dilakukan oleh peneliti terdahulu. Pada penelitian ini dilakukan screening properti fluida reservoir apakah memenuhi kriteria injeksi air atau tidak dan prediksi dengan berbagai skenario pengembangan. Dari berbagai skenario pengembangan yang dilakukan pada penelitian ini didapatkan bahwa secara teknis skenario XI, Injeksi peripheral IV disertai workover sumur-sumur potensial dan infill drilling III, merupakan skenario yang paling optimal dengan produksi minyak kumulatif 6.236 MMSTB dan faktor perolehan 32.31 %
Kata kunci : simulasi reservoir, injeksi air
ABSTRACT
STUDY OF ENHANCED OIL RECOVERY IN ZONE A FIELD X WITH WATER INJECTION
Raden Danieli Sapyudin NIM: 222 05 007
Reservoir Zone A Field X is a sandstone reservoir which inclusion from part of Sumatra Utara Basin. Zone A is selected as reservoir simulation study object by oil remaining after primary recovery still be quite a lot. Recovery factor of primary production which has been reached till in this time is 25% with OOIP of 19.30 MMSTB. This condition became the main idea of enhanced recovery method, in this case water injection, to recover the remaining oil. Geological model, initialization, and history matching have been done by former researcher. The research is done by property screening of reservoir fluid whether it has criteria for water injection or not and prediction with various scenarios. From various development scenarios that were done in this research was obtained that technically the Scenario XI, Injection peripheral IV accompanied by workover potential wells and infill drilling III, was the optimal scenario with the production of cumulative oil of 6.236 MMSTB and recovery factor of 32,31 %
Keywords : reservoir simulation, water injection
DAFTAR ISI
Halaman ABSTRAKSI ................................................................................................................... i ABSTRACT................................................................................................................... iv KATA PENGANTAR .................................................................................................. vii DAFTAR ISI .................................................................................................................. ix DAFTAR TABEL .......................................................................................................... xi DAFTAR GAMBAR ................................................................................................... xiii BAB I
PENDAHULUAN............................................................................................ 1
1.1 Latar Belakang Masalah ...................................................................................... 2 1.2 Tujuan Penelitian ................................................................................................ 3 1.3 Batasan Masalah ................................................................................................. 3 1.4 Metode Penelitian ............................................................................................... 3 1.6 Sistematika Penulisan ......................................................................................... 4 BAB II
TINJAUAN LAPANGAN.............................................................................. 5
2.1 Geologi Regional ................................................................................................ 5 2.1.1 Kerangka Tektonik .................................................................................... 6 2.1.2 Stratigrafi Regional .................................................................................. 10 2.2.3 Sistem Petroleum ..................................................................................... 12 2.1.3.1 Potensial Reservoir ..................................................................... 12 2.1.3.2 Perangkap Hidrokarbon ............................................................... 12 2.1.3.3 Batuan Induk dan Migrasi Hidrokarbon ..................................... 13 2.2 Stratigrafi Daerah Studi .................................................................................... 14 2.2.1 Interpretasi Data Sumur ....................................................................................... 14
2.2.1 Identifikasi Tipe Lapisan Reservoir..................................................................... 14 2.2.1.1 Tipe Reservoir Z-850 ............................................................................... 14
BAB III
TINJAUAN PUSTAKA ............................................................................. 16
3.1 Teknik Menigkatkan Perolehan Hidrokarbon ................................................... 16 3.2 Injeksi Air ......................................................................................................... 18 3.3 Faktor Penentu Keberhasilan Metode Peningkatan Perolehan Minyak ............ 18 3.3.1 Heterogenitas Reservoir........................................................................... 18 3.3.2 Kemiringan Reservoir .............................................................................. 19 3.3.3 Sifat-sifat Petrofisik ................................................................................ 19 3.3.4 Mekanisme Pendorong............................................................................. 20 3.3.5 Saturasi Minyak Sisa ............................................................................... 21 3.3.6 Viskositas Minyak .................................................................................. 21 3.3.7 Fluida Tak Tercampur ............................................................................. 21 3.3.8 Tegangan Antar Muka ............................................................................ 22 3.3.9 Sifat Kebasahan ...................................................................................... 23 3.3.10 Rasio Mobilitas ..................................................................................... 24 3.3.11 Tekanan Kapiler..................................................................................... 25 3.4 Simulasi Reservoir ............................................................................................. 25 3.4.1 Peramalan Produksi ................................................................................ 25 3.2.2 Efisiensi Perolehan .................................................................................. 26 3.4.3 Pola Geometri Injeksi ............................................................................. 26
BAB IV
METODOLOGI PENELITIAN ................................................................. 27
4.1 Metodologi Penelitian ........................................................................................ 27 4.1.1 Tinjauan Model Geologi .......................................................................... 27 4.1.2 Penyeleksian Propreti Fluida .............................................................................. 29 4.1.3 Peramalan Produksi ............................................................................................ 29
BAB V
SIMULASI RESERVOIR ............................................................................ 30
5.1 Model Simulasi .................................................................................................... 30 5.2 Data PVT .............................................................................................................. 35 5.3 Permeabilitas Relatif ............................................................................................. 35 5.4 Hasil History Matching...................................................................................... 37 5.5 Peramalan Produksi ........................................................................................... 42 5.5.1 Skenario I ................................................................................................. 42 5.5.2 Skenario II................................................................................................ 46 5.5.3 Skenario III ............................................................................................. 51 5.5.4 Skenario IV ............................................................................................. 56 5.5.5 Skenario V ............................................................................................... 60 5.5.6 Skenario VI ............................................................................................ 65 5.5.7 Skenario VII............................................................................................ 69 5.5.8 Skenario VIII ......................................................................................... 74 5.5.9 Skenario IX ............................................................................................ 79 5.5.10 Skenario X ........................................................................................... 83 5.5.11 Skenario XI .......................................................................................... 88 5.4 Analisis dan Pembahasan Hasil Peramalan ...................................................... 92
BAB VI
KESIMPULAN DAN SARAN ................................................................... 99
6.1 Kesimpulan ............................................................................................................. 99 6.2 Saran ..................................................................................................................... 100 DAFTAR PUSTAKA .................................................................................................. 100 DAFTAR SINGKATAN DAN SIMBOL ................................................................... 101 LAMPIRAN
DAFTAR GAMBAR
Halaman Gambar II.1
Lokasi Lapangan X, Tenggara Pangkalan Brandan ............................... 6
Gambar II.2
Elemen Tektonik Cekungan Sumatera Utara dan Lokasi Lapangan X .. 7
Gambar II.3
Pola Struktur Cekungan Sumatra Utara .................................................. 7
Gambar II.4
Stratigrafi Lapangan X ........................................................................... 8
Gambar III.1 Efek Kemiringan Reservoir Terhadap Proses Pendesakan .................. 19 Gambar III.2
Ilustrasi Minimum Miscible Pressure, MMP ........................................ 21
Gambar III.3 Ilustrasi Tegangan Antarmuka, TAM .................................................. 22 Gambar III.4
Sudut Kontak Sebagai Representasi Sifat Kebasahan Batuan ............. 23
Gambar III.5
Fenomena Viscous Fingering Pada Proses Pendesakan ....................... 24
Gambar III.6 Pola Geometri Sumur Injeksi – Produksi ............................................. 27 Gambar IV.1
Alur Metodologi Penelitian .................................................................. 28
Gambar V.1
Penampang Grid Top 2D Reservoir Zona A lapangan X .................... 32
Gambar V.2
Penampang grid top 3D Reservoir Zona A Lapangan X Arah Utara.... 32
Gambar V.3
Penampang Grid Top 3D Reservoir Zona A Lapangan X Arah Barat . 33
Gambar V.4
Penampang Grid Top 3D Reservoir Zona A Lapangan X Arah Selatan33
Gambar V.5
Penampang Grid Top 3D Reservoir Zona A Lapangan X Arah Timur 34
Gambar V.6
Distribusi Porositas Reservoir Zona A Lapangan X ............................. 34
Gambar V.7
Distribusi Permeabilitas Reservoir Zona A Lapangan X ...................... 35
Gambar V.8
Distribusi NTG Reservoir Zona A Lapangan X................................... 35
Gambar V.9
Kurva Rs dan BoTerhadap Tekanan...................................................... 36
Gambar V.11 Kurva Kro-Krw Terhadap Sw................................................................ 37 Gambar V.12 Kurva Krg-Krog Terhadap Tekanan .................................................... 37
Gambar V.13 History Matching Laju Alir Minyak Reservoir Zona A Lapangan X .. 38 Gambar V.14 History Matching Laju Alir Air Reservoir Zona A Lapangan X .......... 39 Gambar V.15 History Matching Laju Alir Gas Reservoir Zona A Lapangan X ......... 39 Gambar V.16 History Matching Water Cut Reservoir Zona A Lapangan X............... 40 Gambar V.17 History Matching Tekanan Reservoir Zona A Lapangan X ................. 40 Gambar V.18 Oil Recovery Factor Reservoir Zona A Lapangan X............................ 41 Gambar V.19 Distribusi Saturasi Minyak, So Awal dan Akhir History Macthing...... 41 Gambar V.20 Distribusi Saturasi Air, Sw Pada Awal dan Akhir History Matching .... 42 Gambar V.21 Distribusi Tekanan Pada Awal dan Akhir History Macthing ............... 42 Gambar V.22 Posisi Sumur Produksi Pada Skenario I ................................................ 44 Gambar V.23 Plot Produksi Kumulatif, Laju Alir Minyak Vs. Waktu, Skenario I...... 45 Gambar V.24 Plot Kumulatif Air, Laju Alir Air Terhadap Waktu, Skenario I ........... 45 Gambar V.25 Plot Kumulatif Gas, Laju Alir Gas terhadap Waktu, Skenario I........... 45 Gambar V.26 Plot Water Cut Terhadap Waktu, Skenario I ........................................ 46 Gambar V.27 Oil Recovery Factor, Skenario I ........................................................... 46 Gambar V.28 Posisi Sumur Produksi yang di Workover pada Skenario II ................ 47 Gambar V.29 Produksi Kumulatif, Laju Alir Minyak Terhadap Waktu, Skenario II . 48 Gambar V.30 Plot Kumulatif Air, Laju Alir Air Terhadap Waktu, Skenario II ......... 48 Gambar V.31 Plot Kumulatif Gas, Laju Alir Gas terhadap Waktu, Skenario II ......... 49 Gambar V.32 Plot Water Cut Terhadap Waktu, Skenario II ....................................... 49 Gambar V.33 Plot Tekanan Reservoir, Skenario II ..................................................... 50 Gambar V.34 Oil Recovery Factor Reservoir, Skenario II.......................................... 50 Gambar V.35 Distribusi So Pada Awal dan Akhir Simulasi Skenario II..................... 51 Gambar V.36 Posisi Sumur Produksi dan Sumur Workover pada Skenario III .......... 52 Gambar V.37 Produksi Kumulatif, Laju Alir Minyak Vs. Waktu, Skenario III ......... 53
Gambar V.38 Produksi Kumulatif, Laju Alir Air Terhadap Waktu, Skenario III ...... 53 Gambar V.39 Plot Kumulatif Gas, Laju Alir Gas terhadap Waktu, Skenario III ....... 54 Gambar V.40 Plot Water Cut Terhadap Waktu, Skenario III ..................................... 54 Gambar V.41 Plot Tekanan Reservoir, Skenario III ................................................... 51 Gambar V.42 Oil Recovery Factor Reservoir, Skenario III ....................................... 56 Gambar V.43 Distribusi So Pada Awal dan Akhir Simulasi Skenario III ................... 56 Gambar V.44 Posisi Sumur Produksi, Workover, dan Injeksi Pada Skenario IV........ 57 Gambar V.45 Produksi Kumulatif, Laju Alir Minyak Vs. Waktu, Skenario IV ........ 58 Gambar V.46 Produksi Kumulatif, Laju Alir Air Terhadap Waktu, Skenario IV....... 58 Gambar V.47 Plot Kumulatif Gas, Laju Alir Gas terhadap Waktu, Skenario IV........ 59 Gambar V.48 Plot Water Cut Terhadap Waktu, Skenario IV ..................................... 59 Gambar V.49 Plot Tekanan Reservoir, Skenario IV ................................................... 60 Gambar V.50 Oil Recovery Factor Reservoir, Skenario IV ....................................... 60 Gambar V.51 Distribusi So Pada Awal dan Akhir Simulasi Skenario IV ................... 61 Gambar V.52 Posisi Sumur Produksi, Workover, dan Injeksi Pada Skenario V ......... 62 Gambar V.53 Produksi Kumulatif, Laju Alir Minyak Vs. Waktu, Skenario V .......... 62 Gambar V.54 Produksi Kumulatif, Laju Alir Air Terhadap Waktu, Skenario V ........ 63 Gambar V.55 Plot Kumulatif Gas, Laju Alir Gas terhadap Waktu, Skenario V ......... 63 Gambar V.56 Plot Water Cut Terhadap Waktu, Skenario V ...................................... 64 Gambar V.57 Plot Tekanan Reservoir, Skenario V ..................................................... 64 Gambar V.58 Oil Recovery Factor Reservoir, Skenario V ........................................ 65 Gambar V.59 Distribusi So Pada Awal dan Akhir Simulasi Skenario V .................... 65 Gambar V.60 Posisi Sumur Produksi, Workover, dan Injeksi Pada Skenario VI........ 66 Gambar V.61 Produksi Kumulatif, Laju Alir Minyak Vs. Waktu, Skenario VI ........ 67 Gambar V.62 Produksi Kumulatif, Laju Alir Air Terhadap Waktu, Skenario VI....... 67
Gambar V.63 Plot Kumulatif Gas, Laju Alir Gas terhadap Waktu, Skenario VI........ 68 Gambar V.64 Plot Water Cut Terhadap Waktu, Skenario VI ..................................... 68 Gambar V.65 Plot Tekanan Reservoir, Skenario VI ................................................... 69 Gambar V.66 Oil Recovery Factor Reservoir, Skenario VI ....................................... 69 Gambar V.67 Distribusi So Pada Awal dan Akhir Simulasi Skenario VI ................... 70 Gambar V.68 Posisi Sumur Produksi, Workover, dan Injeksi Pada Skenario VII ...... 71 Gambar V.69 Plot Tekanan Reservoir Setelah Dilakukan Injeksi, Pra Skenario VII.. 71 Gambar V.70 Produksi Kumulatif, Laju Alir Minyak Vs. Waktu, Skenario VII ....... 72 Gambar V.71 Produksi Kumulatif, Laju Alir Air Terhadap Waktu, Skenario VII ..... 72 Gambar V.72 Plot Kumulatif Gas, Laju Alir Gas terhadap Waktu, Skenario VII....... 73 Gambar V.73 Plot Water Cut Terhadap Waktu, Skenario VII .................................... 73 Gambar V.74 Plot Tekanan Reservoir, Skenario VII .................................................. 74 Gambar V.75 Oil Recovery Factor Reservoir, Skenario VII....................................... 74 Gambar V.76 Distribusi So Pada Awal dan Akhir Simulasi Skenario VII.................. 75 Gambar V.77 Posisi Sumur Produksi, Workover, dan Injeksi Pada Skenario VIII ..... 76 Gambar V.78 Produksi Kumulatif, Laju Alir Minyak Vs. Waktu, Skenario VIII ...... 76 Gambar V.79 Produksi Kumulatif, Laju Alir Air Terhadap Waktu, Skenario VIII .... 77 Gambar V.80 Plot Kumulatif Gas, Laju Alir Gas terhadap Waktu, Skenario VIII ..... 77 Gambar V.81 Plot Water Cut Terhadap Waktu, Skenario VIII .................................. 78 Gambar V.82 Plot Tekanan Reservoir, Skenario VIII ................................................ 78 Gambar V.83 Oil Recovery Factor Reservoir, Skenario VIII .................................... 79 Gambar V.84 Distribusi So Pada Awal dan Akhir Simulasi Skenario VIII ................ 79 Gambar V.85 Posisi Sumur Horizontal, Workover, dan Injeksi Pada Skenario IX..... 80 Gambar V.86 Produksi Kumulatif, Laju Alir Minyak Vs. Waktu, Skenario IX ........ 81 Gambar V.87 Produksi Kumulatif, Laju Alir Air Terhadap Waktu, Skenario IX....... 81
Gambar V.88 Plot Kumulatif Gas, Laju Alir Gas terhadap Waktu, Skenario IX........ 82 Gambar V.89 Plot Water Cut Terhadap Waktu, Skenario IX ..................................... 82 Gambar V.90 Plot Tekanan Reservoir, Skenario IX ................................................... 83 Gambar V.91 Oil Recovery Factor Reservoir, Skenario IX ....................................... 83 Gambar V.92 Distribusi So Pada Awal dan Akhir Simulasi Skenario IX ................... 84 Gambar V.93 Posisi Sumur Infill, Workover, dan Injeksi Pada Skenario X................ 85 Gambar V.94 Produksi Kumulatif, Laju Alir Minyak Terhadap Waktu, Skenario X . 85 Gambar V.95 Produksi Kumulatif, Laju Alir Air Terhadap Waktu, Skenario X ........ 86 Gambar V.96 Plot Kumulatif Gas, Laju Alir Gas terhadap Waktu, Skenario X ......... 86 Gambar V.97 Plot Water Cut Terhadap Waktu, Skenario X ...................................... 87 Gambar V.98 Plot Tekanan Reservoir, Skenario X .................................................... 87 Gambar V.99 Oil Recovery Factor Reservoir, Skenario X ......................................... 88 Gambar V.100 Distribusi So Pada Awal dan Akhir Simulasi Skenario X .................. 88 Gambar V.101 Posisi Sumur Infill, Workover, dan Injeksi Pada Skenario XI ............ 89 Gambar V.102 Produksi Kumulatif, Laju Alir Minyak Vs. Waktu, Skenario XI ....... 90 Gambar V.103 Produksi Kumulatif, Laju Alir Air Terhadap Waktu, Skenario XI..... 90 Gambar V.104 Plot Kumulatif Gas, Laju Alir Gas terhadap Waktu, Skenario XI...... 91 Gambar V.105 Plot Water Cut Terhadap Waktu, Skenario XI ................................... 91 Gambar V.106 Plot Tekanan Reservoir, Skenario XI.................................................. 92 Gambar V.107 Oil Recovery Factor Reservoir, Skenario XI ...................................... 92 Gambar V.108 Distribusi So Pada Awal dan Akhir Simulasi Skenario XI ................. 93 Gambar V.108 Plot RF Skenario-skenario yang dilakukan dalam Studi..................... 98
DAFTAR TABEL
Halaman Table III.1 Tahapan Perolehan Minyak .................................................................... 17 Table III.2 Kisaran Nilai Tegangan Antarmuka ........................................................ 22 Table III.3 Kisaran Nilai Sudut Kontak ...................................................................... 23 Table III.4 Rasio Sumur Produksi Terhadap Sumur Injeksi pada Pola Sumur........... 27 Tabel IV.1 Properti Model Geologi ........................................................................... .28 Tabel IV.2 Seleksi Properti Fluida ............................................................................. 29 Tabel V.1
Hasil Berbagai Metode Pengembangan Zona A Lapangan X ................. 97
