Identification And Application Of Carbonate Reservoir’s Fluid Property In Lungu Area

In Lungu area of northern Tarim basin, the reservoir space types of the ordovician carbonate reservoirs are complicated with heavy heterogeneity, and all the reservoirs buried deeper. Due to the impact of hydrocarbon source rocks at different stages-the expulsion period, the oil reservoir experienced repeatedly migration-the filling process in the formation process of the oil reservoir, so it is extremely complex distribution of fluid in the vertical and horizontal. Therefore identify the reservoir fluid properties become more difficult, research of the oil and water distribution is unable to meet the need of oilfield development.In Identification of Carbonate Reservoir’s Fluid Property with well logging data, the predecessors’ research has some questions:the methods and models are very complex, for example, the parameters of the models were difficult to determine. Besides, some new methods have high expectations for the logging data, they usually need electricity imaging, sound or nuclear magnetic resonance imaging logging data. In practice, these well logging data cost higher than conventional logging, so the number of wells which were measured by these methods is less.Based in the research of lithology and reservoir types of ordovician reservoir in Tarim oil field, we firstly analyze the response characteristics of well logging in oil, gas, water, then we use apparent formation water resistivity of normal logging data and imaging material apparent formation water resistivity spectrum to identify the reservoir fluid properties. We made cross plots of the mean values and variances of apparent formation water resistivity of normal logging data and imaging material apparent formation water resistivity spectrum, from analyzing the effect of fluid property identification in carbonate reservoirs by this method, we discussed its boundedness. According to the fluid properties, we divided the oil-water interface of single well, then we analyzed the law of oil-water interface, finally, we analyzed the influence factors of the water-free producing period in research area.From using the result of fluid property identification by the logging data of LG7well area and determining oil-water interface, we found that the oil-water interface of LNX1well closes to LNX2well, so the two wells probably belong to the same oil-water unit whose oil-water interface is in depth of5404meters. There is no unified oil-water interface in LG7-9well area, every well have different oil-water interface, only the oil-water interfaces of LGXland LGX2are approximate, about in the5257.5meters, and the two wells should belong to the same oil-water unit. In LG7-11well area, only the oil-water interface of LNX3well which locates in5104meters can be seen. Overall, oil-water interfaces of LG7well area tend to increase along the NE direction. The test of LN54well shows the well only products oil and gas, and the oil-water interface can’t be seen from the logging data. The oil-water interface in the most of wells whose test result have water can be seen from the logging data, but the depth shows a larger difference without unified oil-water interface. The oil-water interface of few wells whose test result include water can’t be seen according to the logging data.From the reservoir production data of carbonate reservoirs in Lungu area of Tarim oil field, without considering nozzle size, the degree of reservoir development, porosity and drainage area, we can find that the water-free producing period of research area tends to become thicker when the thickness between weathering crust top and oil-water interface is bigger, the distant between oil layer and oil-water interface is longer and the thickness above oil-water interface is bigger. To delay water-free producing period, we suggest digging in the area with long distant between weathering crust top and oil-water interface and big thickness of oil reservoir, whilst insuring oil layers are enough distant from oil-water interface. The contour congruent map of the distant from oil layer to oil-water interface and thickness of oil reservoir can help to forecast the potential zone of oil accumulation.