Research On Logging Evaluation Method Of Low-resistance Oil Layer In L Oilfield

With the increasing demand for oil in society,the current exploration and development goals have changed from the simple high-amplitude structural reservoirs in the past to complex reservoirs,unconventional reservoirs,and subtle reservoirs.Low resistivity reservoirs are one type of subtle reservoirs.Since the resistivity of the low resistivity reservoirs is close to or even lower than that of the water layer,it often causes misjudgment or omission,which brings great difficulties to the exploration and development.In the regional L oilfield of this study,the J3 and J4 reservoirs are the low resistivity reservoirs.Therefore,on the basis of analyzing the genetic mechanism of low resistivity reservoirs,it is necessary to establish evaluation methods and standards which are suitable for low resistivity reservoirs in L oilfield.It can improve the coincidence rate of logging interpretation,and provide technical support for the subsequent development of oilfields.Based on the above background,this paper comprehensively uses geology,core,well logging,drilling fluid logging,and oil test data to carry out research on four properties'relations of reservoirs,and summarizes the lithology,physical properties,oiliness and electricity characteristics of J3 and J4 reservoirs in L oilfield.On the basis of comprehensive consideration of sedimentation and structure,focusing on the actual situation of L oilfield,this paper analyzes the characteristics,classification and formation mechanism of low resistivity reservoirs of J3 and J4 reservoirs in L oilfield.It concludes that the reasons for the resistance reduction of low resistivity reservoirs in the study area are mainly high formation water salinity and high irreducible water saturation.In addition,the pyrites of J4 reservoir also has a certain impact on resistivity.Based on the analysis of genesis,combined with petrophysical experimental data,the reservoir logging evaluation parameter layered model is established,and the characteristic response curves of the low resistivity reservoirs are selected according to the genetic mechanism.Combined with geological and well logging data,this study mainly used resistivity ratio method,AC*RT(sound wave and resistivity product)-?GR intersection graph method,movable water analysis method,resistivity-porosity correlation analysis method and wavelet multi-wave method.The above analysis method comprehensively identifies the reservoir fluid properties in the study area,and interprets the 12 well test wells in the study area.The identification results are consistent with the test oil,and the feasibility of the above methods is verified,indicating that the identification method has high precision.The remaining 24 wells in the study area were explained in detail,and 51 layers of interpretation results were modified,including 12 low-resistance oil layers,which provided a reliable technical support for fluid identification in the study area.Through the research of this paper,it is expected to improve the effect of oilfield production and development.This study provides a practical and feasible method for the identification and evaluation of fluid properties of low resistivity reservoirs in L oilfield.