Application Elemental Capture Spectroscopy Logging To Lithologic Identification And Reservoir Evaluation In Igneous Formation

At present, oil and gas reservoirs is more and more complex. Using a variety of logging technology for the correct evaluation of the reservoir in the oil field exploration and development is very important. For the complex lithology reservoir consisting of multi-mineral, it is very difficulty to evaluate it.Mainly due to the type of elements is complex and measurement of the elements content is difficult. The relationship between elements and the mineral content of rocks has not yet been established.Conventional log projects alone can not obtaine the mineral elements of the reservoir, it must be combined with other special log projects, to achieve the purpose of Reservoir Evaluation.Elemental Capture Spectroscopy (ECS) log by the recording of the gamma spectroscopy of neutron inelastic scattering and capture gamma-ray spectrometry gamma-ray spectrometry, through the explanation spectra obtained solution formation elements. As a log method to detect the chemical element of formation, it plays an important role in lithologic identification and the calculation of mineral in igneous.In this paper, the use of ECS solution elements (Si, K, Fe, S, Ti, Ca) and Al-activated logging to be elements of Al and the oxide solution of a closed model of Na , binding the conventional logging to the lithological identification and reservoir evaluation studies.Using the oxide factor to getting the content of SiO₂,Na₂O and K₂O from the elements, according to the current international classification standards common igneous silicon - alkali classification for lithological division. It has been achieved in this paper. In addition, according to different response of igneous rocks to shape the chart of conventio- nal logging and lithologic discrimination. Element has been changed to mineral based on CIPW index mineral law. Than the mineral grouped into four section based on QAPF model, contrasting QAP chart for lithologic identification. Finally, lithologic identification getted the integrated interpretation above-mentioned.Matrix parameter of igneous rock such as density and neutron calculated on the basis of Schlumberger formula. The mineral grouped into four section based on QAPM model and building volume model, than porosity can be calculated. Mineral parameters are calculated from ECS log binding convention log. The result is satisfactory for the calculated porosity with the core porosity.Using the studies based on the above methods, calculating the actual data of three wells in Songliao Basin , received better effect.