Oil potential in arthit field using time lapse neutron and mud log characteristic

Abstract

Mud logging is used to determine gas and oil in a reservoir while it is drilled by directional measurements. Mud log and electrical log data are combined to evaluate the producing potential of oil for a formation. The objective of this research is to identify a type of fluid in a reservoir by using carbon component, LWD (Logging while drilling), and WL (Wireline) neutron porosity data. If LWD-LW separation is present because of the difference in the porosity data that is measured while drilling and after drilling, a sand reservoir is interpreted to show the existence of gas. Since hydrocarbons that have five atoms of carbon are main components of oil, a reservoir that contains high proportion of this hydrocarbon would also have oil. Therefore, this characteristic is used to determine oil in a reservoir. Based on the results in 7 wells, the LWD-WL separation in time lapse neutron technique is more accurate to identify gas sand than using only wireline log data. However, C5 component, which is a characteristic of mud log, is inaccurate to identify types of fluid in sand reservoir. Due to the small numbers of well samples as well as lacking of oil reserve in the Arthit field, the data used to identify oil by using mud log characteristic is limited.