O One of the methods to determine the parameters and characteristics of a gas reservoir is the Pressure build-up test analysis. The parameters produced in the gas well test are permeability (k), skin (s). Apart from the Pressure build up test, the analysis that is usually carried out is the Deliverability Test. The parameters generated from this Deliverability Test are the values of n, C and absolute open flow potential (AOFP).The RM well is a gas well that has undergone a Pressure build up test and a Deliverability Test. Pressure build up analysis is done manually and with the help of software. Manually the pressure build up analysis was carried out using the Horner method and the pressure-squared (P2) approach. The results obtained using manual calculations are the RM Well permeability of 24.2 mD, and there is a skin factor of 2.42. While the analysis of pressure build up using software obtained the results, namely the wellbore model of Constant Wellbore storage, and the type of Homogeneus reservoir, as well as the boundaries of the Rectangel reservoir. Formation characteristics based on software analysis on the RM Well are permeability values of 23.7 mD, skin of 2.38. After that, a Deliverability Test is carried out with a type of Flow-after flow analysis which aims to find out the Absolute Open Flow Potential (AOFP) price. The results of the Deliverability Test analysis using Software are worth 19214.5 MSCFD and for manual calculations are worth 21340.8 MSCFD which are used to determine the productivity of gas wells.