Study On The Enrichment Regularity Of Chang 2 Reservoir In The Southern Area Of Haojiaping,Ansai Oilfield

This thesis takes the Chang 2 oil-bearing formation of the Haojiaping South Area of the Xingzichuan Oilfield in Ansai area as the research object,and focuses on the study of the Chang 2 main oil-bearing stratum in the area.The purpose is to conduct an overall study and form a unified study on the key oil-producing blocks in the Ansai area.understanding.Therefore,this time,based on the deep exploration of the Chang 2 oil layer group,the Chang2 main oil layer as a background,through the study of the sedimentary facies of the study area,the sedimentary facies development and distribution law;sand body structure analysis and distribution law;reservoir Comprehensive analysis and other research,so as to obtain the basic laws of oil and gas enrichment in the study area.Based on the core data,particle size analysis and logging data,through the comprehensive analysis and research of more than 600 wells,the structural characteristics,sedimentary facies and sand body distribution rules,reservoir characteristic reservoir distribution,etc.of the study area are discussed in depth.The relevant laws and main controlling factors of reservoir enrichment.The thickness of the Chang 2 stratum is between 110m and 140m.The top surface structure of the sand body shows that the structural form has a certain degree of inheritance.It is dominated by the western inclined monoclinic structure,and the nasal structure is developed,mainly in the near-west direction.In general,the central apricot 4014 well-Xingfu156-5 well-Xing 24-4 well-Xing 4007 well developed a stable nose-like bulge structure,and the length of the Chang 2 oil layer gradually increased compared with other layers.During the Chang 2 deposition period,the river sedimentary system was developed,and the braided river subfacies were mainly developed.The microfacies types of the braided channel and the floodplain were identified on the logging curve.The Chang 2^1-3 reservoir is mainly distributed in the Hao 899 and Hao 897-3 well areas,and the oil-bearing areas are2.25km² and 0.59km^2,respectively.The Chang 2² reservoir is mainly distributed in the Hao902,Hao 900,Hao 899,Xing 6090,and Xing 4015 well areas.The reservoir lithology is mainly light gray,gray,gray-green fine-grained feldspar sandstone.Most of the reservoirs in the study area are mainly composed of river sand dam sandstone and river flood sandstone formed by river sedimentation.The porosity of the reservoir is mainly in the range of 12.0%¹6.0%.The reservoir permeability is mostly distributed in the range of 2.0¹0.0×10^-3?m2.The overall homogeneity is strong,and the reservoir has low porosity and low.The characteristics of permeability.The reservoir type belongs to the low permeability layer to the ultra low permeability layer reservoir.According to the evaluation criteria,the Chang 2 oil layer group is a special low permeability-medium preference reservoir.Distribution characteristics and regularity of the Chang 2 oil-bearing reservoir in the southern area of Ansai Haojiaping:the main sand belt of the river and the floodplain controls the reservoir distribution;the oil and gas along the main sand belt is stepped up,and the oil-bearing horizon gradually changes to form a compensatory accumulation..The main controlling factors affecting the distribution of Chang 2 reservoir are:?1?the river and river floodplain sand bodies provide favorable reservoir conditions for oil and gas enrichment;?2?the important role of nose-like uplift structure for oil and gas enrichment and formation;?3?The influence of lateral occlusion and upward tilt on oil and gas enrichment.The three factors jointly control the hydrocarbon accumulation and form a good configuration relationship,which constitutes a favorable area for oil and gas enrichment.The reservoir type is a massive structure-lithologic reservoir.