Research On Full Spectrum Saturation Logging Interpretation Method

Many blocks in Dagang oilfield have entered the middle and late stages of water injection development,and the distribution of remaining oil is highly dispersed in both vertical and horizontal directions.Under the circumstances of high investment,high risk and difficulty in finding replacement reserves,comprehensive treatment of old areas and tapping remaining oil potential has become the most economical and feasible measures to control water and stabilize oil production in Dagang Oilfield.The purpose of this paper is to establish a set of comprehensive interpretation methods of full spectrum saturation logging in accordance with the geological characteristics of Dagang oilfield through theoretical research and experimental data,in order to provide accurate basis for tapping remaining oil potential in old oilfields,so as to more accurately and conveniently measure formation parameters and further improve the interpretation rate of data.Based on the core data of Dagang Oilfield,the principle and influencing factors including three conventional logging techniques,such as carbon-oxygen ratio logging,neutron lifetime logging and oxygen activation logging,as well as the dual logging mode of carbon-oxygen ratio and neutron lifetime,are deeply analyzed.The interpretation method of full spectrum saturation logging is presented by using numerical simulation chart.Empirical formulas and interpretation parameters were adjusted.Through quantitative and qualitative analysis,the criteria for distinguishing oil,water and gas reservoirs were defined.In the field application of six wells,the log interpretation results are in good agreement with the actual situation,which can be accurately and effectively judge oil-water interface,identify gas reservoirs,and distinguish watered-out zones.Through the modification of the empirical formula of full spectrum saturation logging and the reasonable selection of interpretation parameters,this paper establishes and perfects the interpretation method in accordance with the actual situation of Dagang Oilfield,which will provide strong technical support for the accurate determination of formation oil saturation,remaining oil enrichment areas and intervals in Dagang Oilfield.