Resistivity Variation Of Shallow Formation Water And Logging Response Characteristics Research In Dawanqi Oilfield

The burial depth of Kuqa formation in Dawanqi oilfield is shallow and the leach of surface water is significant.By using the analysis data of formation water and the Archie formula,this paper recalculates the resistivity of standard formation water,draws the chart of the vertical distribution of formation water resistivity and preliminarily studies the variation law of formation water resistivity.The distribution char shows the starting depth of the stable value of formation water resistivity in different well oilfield and the stable value is approximately 0.05?·m.However,the formation water resistivity in shallow varies fast vertically.It is easy to lead to the misinterpretation of the fluid properties in the reservoir,and greatly increase the difficulty in logging reservoir evaluation.So it is essential to look for new method to predict the formation water resistivity in shallow.The W-S model is suitable for Argillaceous Sandstone and can be used to predict formation water resistivity without being affected by the depth.Thus,on the base of analyzing the pore throat characteristics of shallow mudstones,this paper try to apply the W-S model to the shallow mudstones and to calculate the formation water resistivity.In order to verify the validity of the method,this paper establishes the W-S model of shallow mudstone by using the classic Geiger algorithm and the logging data,recalculates the oil saturation by the formation water resistivity from the model and verifies the recalculated oil saturation by the perforation and oil test data.Finally we apply the method to the X17 well in Dawanqi oilfield and the results are consistent with the perforation and oil test data.We also use The W-S model to reconstruct the chart which is designed to determine the fluid properties and verify it by the perforation and oil test data.In addition,we analyze the logging curves and summarize the logging response characteristics of different reservoirs,in particular to the characteristics of electric curves in different reservoirs.These methods can be used to determine the fluid properties both quantitatively and qualitatively and provide theoretical guidance and technical support for the accurate identification of fluid properties and the improvement of final interpretation accuracy.