Analisis Pengaruh Stabilitas Meter Factor dan Ketidakpastian Hasil Pengukuran Turbine Flow Meter terhadap Estimasi Kerugian Finansial pada Custody Transfer

Maritza Kirana Anindita, Dr.-Ing. Ir. Awang Noor Indra Wardana, S.T., M.T., M.Sc., IPM. ; Ir. Kutut Suryopratomo, M.T., M.Sc.

2026 | Skripsi | FISIKA TEKNIK

Kegiatan custody transfer pada industri minyak dan gas menjadikan volume terukur sebagai dasar penetapan nilai transaksi, sehingga mutu hasil pengukuran memiliki konsekuensi ekonomi langsung. Turbine flow meter yang digunakan pada kegiatan tersebut memerlukan koreksi meter factor melalui meter proving karena karakteristik meter dapat berubah selama operasi. Praktik industri umumnya mengevaluasi mutu sistem pengukuran melalui pemenuhan kriteria repeatability, sedangkan besarnya ketidakpastian hasil pengukuran beserta implikasi finansialnya belum terkuantifikasi. 

Penelitian ini menganalisis stabilitas meter factor dan ketidakpastian hasil pengukuran turbine flow meter menggunakan sepuluh set laporan meter proving dan sepuluh transaksi custody transfer. Stabilitas meter factor dievaluasi menggunakan individual control chart, repeatability dinilai terhadap kriteria API MPMS Chapter 4.8, sedangkan ketidakpastian dievaluasi mengikuti JCGM 100:2008 melalui identifikasi komponen Tipe A dan Tipe B, penyusunan uncertainty budget, serta perhitungan combined dan expanded uncertainty. Nilai expanded uncertainty selanjutnya dikonversi menjadi estimasi kerugian finansial. 

Seluruh nilai meter factor berada di dalam batas kendali tanpa indikasi variasi penyebab khusus dan seluruh repeatability memenuhi batas 0,02%. Combined relative standard uncertainty diperoleh sebesar 0,011734?ngan kontribusi terbesar dari temperatur terhadap CTLM sebesar 84,356%. Derajat bebas efektif sebesar 818,04 menghasilkan faktor cakupan 1,96 pada tingkat kepercayaan 95%. Pada total volume 182981,16 kL, expanded uncertainty sebesar 39,02 kL setara dengan estimasi kerugian finansial Rp390.213.226.

Custody transfer operations in the oil and gas industry use measured volume as the basis for determining transaction value, so measurement quality carries direct economic consequences. Turbine flow meters used in such operations require meter factor correction through meter proving because meter characteristics may change during service. Industry practice generally evaluates measurement system quality through compliance with repeatability criteria, while the magnitude of measurement uncertainty and its financial implications remain unquantified.

This study analyses meter factor stability and measurement uncertainty of a turbine flow meter using ten sets of meter proving reports and ten custody transfer transactions. Meter factor stability was evaluated using an individual control chart, repeatability was assessed against the API MPMS Chapter 4.8 criterion, and uncertainty was evaluated following JCGM 100:2008 through identification of Type A and Type B components, construction of an uncertainty budget, and calculation of combined and expanded uncertainty. The expanded uncertainty was subsequently converted into an estimated financial loss.

All meter factor values fell within the control limits with no indication of special cause variation, and all repeatability values met the 0.02% limit. The combined relative standard uncertainty was 0.011734%, with the largest contribution from temperature affecting CTLM at 78.127%. An effective degrees of freedom of 818.04 yielded a coverage factor of 1.96. For a total volume of 182,981.16 kL, an expanded uncertainty of 39,02 kL corresponds to an estimated financial loss of IDR 390,213,226.

Kata Kunci : custody transfer, turbine flow meter, meter factor, ketidakpastian pengukuran, estimasi kerugian finansial