The gamma ray-neutron Log interpretation methods applicable in Rantau Oil Field are described here with informations and several examples.A linear relationship is verified between the gamma ray values and SP values at the water bearing formations in this field, and the writer Concludes that gamm ray log is available to determine the shale percentage in this field.The porosity of the shaly formation can be derived successfully by using the combination of gamma ray and neutron values.The detection of gas bearing formation is possible by the cross plot of the porosities derived from the neutron log vs. the porosities derived from the Micro log, the open hole neutron vs. the cased hole neutron, and the dual spacing neutron.