The Importance of Understanding Reservoir Fluid and Reservoir Description in Pressure Transient Analyses Hari Karyadi Oetomo1, Hananya Wirianta1, Satriyo Nurhanudin Wibowo1, Onnie Ridaliani1, Djunaedi Agus Wibowo1, and Mohamad Romli
1 Teknik Perminyakan, Fakultas Teknologi Kebumian dan Energi, Universitas Trisakti, Gedung D, Kampus A, Jl. Kyai Tapa no.1, Jakarta, Indonesia.
2 KP3 Teknologi Eksploitasi PPPTMGB ^LEMIGAS^, Jl. Ciledug Raya kav. 109, Jakarta Selatan, Indonesia
Abstract
A development gas well penetrated carbonate build-up reservoir at a depth of around 8300 feet was tested for pressure transient analyses. After series of flow tests, the test was ended up with 42-hour pressure build-up test. Previously, the test analyses were carried out twice, and both showed that the wellbore storage are constant, with one constant pressure boundary. The first analysis has two porosity pseudo steady state model, while the second analysis has two-porosity slab model. In this paper, the analysis considers the effect of changing wellbore storage due to high condensate yield gas of 27 stb/mmscf, with dew point pressure of 2130 Psia, which is within pressure range during pressure build-up test. Fair^s method is used as changing wellbore storage method, since the compressibility in the wellbore became higher during the pressure build-up test- from two-phase became gas phase. The boundary in this paper is found to be two parallel faults, which is confirmed by the geological map. The permeability and the reservoir pressure results of the three analyses are very similar to each other, however understanding fluid behaviour and reservoir model would change the strategy in producing the well and further field development.
