Publications

“Nasir” field is one of the mature oil and gas producers in “Lancang Kuning” Basin. The field is both structurally and stratigraphically complex. These complexities control the fluid flow in the reservoirs. “Laksamana” sand in “Nasir” field consists of 2-3 sand lobes that are filled by gas cap, oil reservoir, and water. Most of wells penetrate to “Laksamana” sand but not all of them were filled by hydrocarbon due to stratigraphy framework. The previous interpreters viewed this sand interval as one reservoir system, and mapped one fluid contact which extended across the entire field. This interpretation could not explain observations such as the apparent presence of oil above gas. In this paper, stratigraphy framework interpretation using flow units or facies units is developed to assess fluid contact analysis, presence of hydrocarbons, and connectivity of sands. Fluid contact analysis was done by using a combination of existing data, such as: marked logs, sidewall core, petrophysical analysis, pressure data, and production data. Re-interpretation based on simple flow unit correlation better explains the observations. The apparent contradictory occurrence of oil over gas can be explained in terms of flow unit connectivity. The overall sand interval is broken into discrete flow units with barriers in-between that isolate individual sand reservoirs. This analysis has resulted in the identification of targets for further field development. It identified opportunities such as new zone behind pipe (NZBP) zones of bypassed oil. Furthermore, it is identified candidates for pilot project to drill a Horizontal Well on a location where the gas and oil reservoirs are in discrete sand bodies.