Reservoir Characteristics Of Yulou Oil Layer In J91 Block

The J91 block is located on the west slope of the west depression of the Liaohe fault depression,and is the secondary fault block of the Jin 45 block.It is located in the southwestern part of the Jin 45 block.The main target for development is the Yulou oil layer.This block of Yulou oil layer is developed in two layers of steam stimulation in the longitudinal direction of the building oil layer,and has entered the middle and late stages of high-level and inefficient production stages.The production effect is close to the limit of steam throughput,and the throughput method is about to be abandoned.At present,heavy oil conversion methods such as fire flooding and steam flooding are being tested.However,due to the sub-facies of the fan delta front sediment in the Yulou reservoir,the small-scale underwater distributary channel frequently oscillates.This results in the mutual superposition of the sand bodies between the underwater distributary channel sand bodies and the inter-channel sand bodies and the planar strips.This results in strong heterogeneity in the reservoir plane and longitudinal direction,making it impossible to use the planes and longitudinal directions of the reservoir.All of these factors have become the main factors restricting the expansion of the heavy oil conversion and development test.Targeting at the aforementioned research difficulties,the research into this topic required the collection of seismic,logging,geological and dynamic data first.Based on various grades of base-level cycles,fine stratum division was conducted to the target stratum,which was divided into twelve sublayers and twenty-nine monolayers.On the basis of previous descriptions and understandings and in combination with the collected data,the sedimentary facies model of the target stratum of the research was determined,and the features of various types of sedimentary microfacies were studied.In the end,the plane distribution and sedimentary characteristics of the classified twenty-nine monolayers were studied.Under the constraints of the study of sedimentary microfacies,the reservoir characteristics of the target stratum in this research was studies in five aspects,namely the petrological characteristics of reservoir,the pore structural features of reservoir,the rhythmic characteristics of reservoir,the development characteristics of barriers and interlayers,and three-dimensional characterization of reservoirs in each classified sublayer.The study on barriers and interlayers aimed to establish the log response characteristics of different types of barriers and interlayers,the criteria for physical,electrical and lithological properties,and determine the plane and longitudinal distribution rules of barriers and interlayers,which was of great significance for the description of the heterogeneity of reservoirs and the division of reservoir evaluation units.The establishment of three-dimensional model of reservoirs facilitated the observation of the sedimentary facies patterns and the variations of the physical space from a three-dimensional perspective,thus making the reservoir evaluation more intuitive.In the end,a comprehensive quantitative evaluation for the target stratum of the research area was conducted by selecting five parameters that can fully reflect the reservoir's influencing factors,such as the shaliness,porosity,permeability,reservoir thickness,and heterogeneity permeability variation coefficient.The clustering method was adopted to divide the reservoirs into Type-I,Type-II,Type-III and Type-IV.Finally,the comprehensive reservoir evaluation graph allowed a visual development of various types of reservoirms on monolayers.