| The study area N1 well block in is located in the southeast of the Ordos Basin.The Chang 6 reservoir of the Triassic Yanchang Formation is the main exploration and development layer in the study area.It mainly develops low porosity and ultra-low permeability reservoirs with strong heterogeneity.This type of low-permeability reservoir physical property interpretation model has low accuracy,and it is difficult to meet the need for accurate prediction of reservoir physical properties.On the basis of previous research results,this dissertation formulates a technical route based on actual data.It comprehensively utilizes data such as cores,cast flakes,scanning electron microscopy,image grain size,conventional logging and core test analysis,and applies petroleum geology,Sedimentology,reservoir geology,geophysical logging,etc.,and established a physical property interpretation model suitable for the study of Chang 6 reservoir geological conditions.It systematically describes and characterizes the physical property distribution characteristics and its main controlling factors.Research and discussion were conducted,and the research results have certain guiding significance for the next exploration and development work.Based on the core return,the core time scale logging method is used to select the sonic time difference(DT)and natural gamma(GR)curves,and the binary linear regression fitting method is used to establish a porosity interpretation model.The correlation coefficient R=0.91 13,the interpretation accuracy is further improved than the sonic time difference single factor interpretation model(R=0.8776);based on the porosity log interpretation parameters,from the perspective of the geophysical significance of each log curve,the natural gamma relative value(AGR)and natural potential are selected The relative value(ASP)and the microelectrode amplitude difference(RMN-RNL)were fitted by multiple regression to establish a permeability interpretation model.Through the test,the correlation coefficient R=0.8487.The model interpretation result is highly reliable and applicable.The study on the physical property distribution characteristics of Chang 6 reservoir in the study area shows that the effect of particle sortability of Chang 6 reservoir on porosity and permeability is greater than the particle size parameter;from the underwater diverted channel? the underwater diverted channel flanks? the diverted bay In the facies change,the porosity and permeability show a tendency to worsen,which reflects that the sedimentary microfacies change has a significant effect on controlling the physical property distribution of the reservoir.The porosity and permeability of the study area are well developed.High-quality reservoirs are mainly distributed underwater Above the thick sand body at the center of the diverting channel,the transition to the flanks of the river channel gradually reduces the thickness of the sand body and bifurcates,and its physical properties are correspondingly deteriorated.According to the calculation results of the evolution of porosity,the average loss of porosity during compaction is 66.08%,and the average loss of porosity caused by cementation is 22.34%.The compaction is responsible for the loss of porosity of Chang 6 reservoir in the study area.The most important factor.The low-amplitude nasal structure developed in the Chang 6 reservoir in the study area has an earlier formation time,is in a long-term inheritance and develops at a high structural position,and has a relatively shallow burial depth.The nasal structure can offset the impact of some overburden loads and the intensity of compaction Lower,retain more primary intergranular pores,coupled with high intensity of acidic fluid activity,secondary pores are more developed,the development area of low-amplitude nasal structures is a favorable area for physical property development,and has important control over the physical property distribution of the reservoir effect. |
PDF Full Text Request