Evaluation Method Of The Water Flooded Layers In Jiangsu Oil Field With NMR And Three-dimensional Quantitative Fluorescence Technologies

After more than 30 years of exploitation, the water flooding degree of Jiangsu oil field is serious and it is difficult to exploit. When accurately evaluating the water flooded layers with the well logging technology, the results are easily affected by salinity influence. But the nuclear magnetic resonance and the three-dimensional quantitative fluorescence are not affected. Based on the reservoir characteristics of the ZW oil field, WZ oil field and GJ oil field, the core experiment of water driving oil is designed, and the core samples with different water production rate are prepared. The experiment parameters of nuclear magnetic resonance and three-dimensional quantitative fluorescence are measured, and the water flooded response characteristics are analyzed. It shows that the water saturation, initial state movable water saturation and movable water saturation increase with the increase of water yield, but the oil saturation decrease and the saturation of mobile fluid remains unchanged; The oil concentration and the contrast level gradually decreased, but the best excitation wavelength, the best transmit wavelength, the fluorescence intensity and the oil index are basically unchanged. The sensitive parameters reflecting the degree of the water flooding of the two mud logging technologies are selected. Practical evaluation of the water flooded layers in Jiangsu Oilfield is directed by the experimental analysis results, and the η-Som chart and C-Oc chart qualitative identifying the flooded formations are established. Then the oil layers/weak water-flooded layers and middle/high water-flooded layers are distinguished. Well logging technology can accurately distinguish between the oil layers and the water flooded layers, making up for shortcomings of the mud logging technique in evaluating the oil layers and the water-flooded layers.Thus, this paper combines the well logging technology with the nuclear magnetic resonance and three-dimensional quantitative fluorescence technology. The response characteristics of well logging curves are analyzed after the formations flooded. Firstly using the acoustic time curve, the dry layers and production layers can be identified. Then with the(RFOC-RILD)-RILD chart, the oil layers and water layers can be distinguished with the water flooded layer. Combining the two logging technologies, the oil layers, weak water-flooded layers and middle/high water-flooded layers are distinguished reaching the three level of the interpretations of the water flooded layers. A comprehensive evaluation method for water flooded layers in Jiangsu oil field is established. Using the method to evaluate the well G26, well L7-11, well W2-73 and well G1-2A, the interpretation results are in agreement with the test results.