Perhitungan Nilai Laju Alir Gas dan Flowing Bottom Hole Pressure Berdasarkan Pengukuran Melalui Orifice Meter untuk Uji Deiverabilitas dengan Metode Modified Isochronal Test Sumur CN-1 merupakan sumur gas yang akan dilakukan analisa uji deliverabilitas untuk perhitungan nilai Absolute Open Flow Potential (AOFP). Data yang tersedia pada sumur ini diperoleh dari hasil pengukuran melalui orifice meter. Data pengukuran di orifice meter dilakukan berdasarkan uji dari variasi ukuran choke yaitu 24/64 in, 32/64 in, 43/64 in, dan 64/64 in. data yang diperoleh di orifice meter untuk variasi ukuran choke adalah data wellhead temperature, upstream dan downstream pressure dengan static bottom hole pressure (Pws) sebesar 1055,5 Psia. Perhitungan nilai laju alir gas (Qg) dan Flowing Botton-Hole Pressure (Pwf) pada sumur CN-1 perlu dilakukan pada variasi ukuran choke untuk mendapatkan nilai C (konstanta deliverabilitas) dan n (faktor turbulensi). Berdasarkan hasil perhitungan, uji ukuran choke 24/64 in diperoleh Qg sebesar 2,107 MMSCF/D dan Pwf sebesar 1008,455 Psia. Pada uji ukuran choke 32/64 in diperoleh Qg sebesar 4,085 MMSCF/D dan Pwf sebesar 934,775 Psia. Pada uji ukuran choke 43/64 in diperoleh Qg sebesar 6,225 MMSCF/D dan Pwf sebesar 802,570 Psia. Pada uji ukuran choke 64/64 in diperoleh Qg sebesar 8,218 MMSCF/D dan Pwf sebesar 771,133 Psia. Nilai laju alir pada ukuran choke 64/64 in merupkan extended flow. Setelah nilai Qg dan Pwf pada variasi ukuran choke diperoleh, selanjutnya membuat kurva deliverabilitas metode Modified Isochronal Test. Dari analisa grafik diperoleh nilai C sebesar 1,101 dan n sebesar 0,6776 MSCFD/Psia. Dari nilai tersebut maka diperoleh nilai AOFP Sumur CN-1 adalah 13781,421 MSCFD. Calculation of Gas Flow Rate and Flowing Bottom-Hole Pressure Based on Measurement Through Orifice Meter for Deliverability Test Analysis with Modified Isochronal Test Method CN-1 well is a gas well that will be analyzed for deliverability tests to calculate the Absolute Open Flow Potential (AOFP) value. The data available on this well is obtained from measurement results through an orifice meter. Measurement data in the orifice meter is carried out based on tests of variations in choke sizes, namely 24/64 in, 32/64 in, 43/64 in, and 64/64 in. The data obtained from the orifice meter for variations in choke size is data for wellhead temperature, upstream and downstream pressure with a static bottom-hole pressure (Pws) of 1055.5 Psia. Calculation of the value of gas flow rate (Qg) and flowing botton-hole pressure (Pwf) on the CN-1 well needs to be carried out on variations in the size of the choke to get the value of C (deliverability constant) and n (turbulence factor). Based on the calculation results, the 24/64 in choke size test obtained a Qg is 2.107 MMSCF/D and a Pwf is 1008.455 Psia. In the 32/64 in choke size test, the Qg is 4.085 MMSCF/D and the Pwf is 934.775 Psia. In the 43/64 in choke size test, the Qg is 6.225 MMSCF/D and the Pwf is 802.570 Psia. In the 64/64 in choke size test, the Qg is 8.218 MMSCF/D and the Pwf is 771.133 Psia. The flow rate value on choke size 64/64 in is extended flow. After the Qg and Pwf values for choke size variations are obtained, then create a deliverability curve for the Modified Isochronal Test method. From the graphic analysis, it was obtained that the C value was 1.101 and n was 0.6776 MSCFD/Psia. From this value, it is obtained that the AOFP value of the CN-1 Well is 13781.421 MSCFD. Key words : Gas Flowrate, Pwf, Orifice Meter, Deliverability, AOFP
