Numerical simulation analysis of dual laterolog response of fracture-cavity reservoir in horizontal wells
Caves are the main reservoir space of fracture-cavity carbonate reservoirs.Due to the strong heterogeneity of carbonate reservoirs,it is essential to correctly understand the response law of dual laterolog of fracture-cavity reservoir for the accurate evaluation of fractures and caves by using dual laterolog data.Based on the equivalent model of fracture-cavity formation,numerical simulation of dual laterolog response was conducted by using the 3D finite element method combined with COMSOL software,and the effects of cave size,cave filling compound and matrix on dual laterolog response were analyzed under horizontal well conditions.The analysis results show that:1)The characteristics of dual laterolog responses are completely consistent for caves filled by a single layer when the borehole passes through at different angles;2)With the increase of cave radius,the apparent resistivities of deep and shallow lateral logging decrease rapidly,and the deep lateral resistivity value is significantly higher than the shallow lateral resistivity value;3)The deep and shallow lateral logging responses increase with the increase of the matrix resistivity,the increased amplitude of shallow laterolog response with matrix resistivity becomes smaller;4)For caves filled by double-layer,the deep and shallow dual laterolog resistivities are greatly affected by well inclination angles at the filling interfaces;the deep lateral resistivity increases with the increase of well deviation angle in the low resistivity medium side,and decreases with the increase of well inclination angle in the high resistivity medium side;the shallow lateral resistivity decreases with the increase of well inclination angle in high resistivity medium,while the shallow lateral resistivity is affected by cave sizes and well inclination angles in low resistivity medium,which becomes more complex.Under the condition of a horizontal well,the resistivities of deep and shallow dual laterolog can not distinguish the resistivity of different filling compounds but reflectthe resistivity of a single medium between the two kinds of filling compounds.
万方数据
维普
