Characteristics Of Sandstone Reservoirs In The Third Member Of Xishanyao Formation In Hongtai Area,Tuha Basin

In this paper,the sandstone reservoir of the third member of the Middle Jurassic Xishanyao Formation in the Hongtai area in the eastern part of the Taipei sag in the Tuha Basin is the research target.Based on the previous research results,the well logging and logging are carried out by observing the core of the core.The comprehensive application of the data,combined with the test data of ordinary thin slices,cast thin sections,scanning electron microscopy,X-ray diffraction,mercury intrusion and physical properties,systematically studied the characteristics of the third member of the Xishanyao Formation sandstone reservoir in the Hongtai area,and revealed the Xishan Mountain in the Hongtai area.The sedimentary facies types and characteristics of the third member of the kiln formation and their distribution characteristics in the vertical and lateral directions are studied.The petrological and microscopic pore-throat structure characteristics of the third member of the Xishanyao Formation sandstone are studied,and the diagenesis characteristics are clarified.And the sequence of diagenetic evolution;on this premise,reveal the main controlling factors of high-quality reservoirs and establish reservoir evaluation criteria,and predict the distribution of favorable areas,and provide basis for future exploration and deployment.Comprehensive research shows:The third member of the Xishanyao Formation in the Hongtai area is dominated by medium-grained sandstones,which are lithic feldspar sandstones and lithic sandstones,followed by feldspar lithic sandstones and feldspar sandstones.Sorting,etc.,sub-circular-sub-angular shape,the whole of the debris particles are point-line contact,particle support,pore-contact cementation type,the overall maturity of the structure is characterized by medium-difference,and the composition is mature.A lower degree feature.The interstitials are mainly produced in the form of hetero-bases and cements.The cements include kaolinite,calcite and iron calcite.The content of pyrite is higher than that of silly;authigenic minerals such as siliceous,pyrite,chlorite and illite.Less development.The third member of Xishanyao Formation in Hongtai area is mainly a braided river delta-lake sedimentary system that develops shallow lake sub-facies,front delta sub-facies and delta front sub-facies,including underwater distributary channels and underwater diversions.Bay,estuary dam,pre-delta mud,front delta sand dam and shallow lake mud sedimentary micro-facies.On this premise,combined with reservoir physical properties,the study of the third member of the Xishanyao Formation sandstone reservoir shows that the macroscopic sedimentary facies control the development of effective reservoirs,which is the basis for effective reservoir development;The micro-phase sedimentary areas such as the diversion channel,the estuary dam and the front delta sand dam are in the micro-facies such as the diversion bay and the front delta mud.The reservoir sandstones of the third member of Xishanyao Formation in Hongtai area mainly have residual primary pores,intergranular dissolved pores,intragranular dissolved pores,intercrystalline pores,mold pores and cracks.The majority is the remaining primary pores and secondary dissolution pores.The porosity?q?is between 0.9%and 15.8%,the average value is 7.63%,the permeability?K?ranges from 0.05 to 52.8×10^-3?m ²,and the average value is 0.38×10^-3?m ²,which belongs to the low pore-extra low Infiltration reservoir.The data analysis of the pressure of the mercury in the third section of the Xishanyao Formation in the study area shows that the discharge pressure is relatively medium,the throat radius is small,the pores are relatively large,and the pore throat sorting is poor overall and the distribution is uneven.Poor connectivity.The reservoir capillary pressure curves are divided into three categories:Class I is low-discharge pressure-micro throat type,Class II is low-displacement pressure-micro-throat type or medium-discharge pressure-micro-throat type,Class III medium Discharge pressure-ultra-throat type.The compaction,cementation,dissolution and rupture of the third member of the Xishanyao Formation in the Hongtai area.Judging from the influence of diagenesis on reservoir physical properties,compaction acts as the largest diagenesis of reservoir physical failure,which causes irreversible reduction of sandstone pore seepage;chlorite,calcite,siliceous and high in cementation The development of cement such as slate has caused the clogging of pores and throats to destructively affect the reservoir properties.However,the production of early chlorite cement has improved the reservoir,and the later green mud The stone aggregates are filled in the pore throat to destroy the reservoir physical properties;while the feldspar,cuttings,quartz and other soluble components are dissolved,a large number of secondary dissolved pores are developed,which is good for reservoir physical properties;The development of action also further improves the physical properties of the reservoir.The diagenesis evolution study in the study area shows that the whole reaches the A-stage of the Medium diagenesis,and some wells can reach the B-stage of the Medium diagenesis.The comprehensive evaluation results of the third member of Xishanyao Formation in Hongtai area reveal that it mainly develops type I reservoirs,type II reservoirs,type III reservoirs and ineffective reservoirs;among them,type II reservoirs and type III reservoirs.Type I reservoirs are only partially distributed in the favorable reservoir area;while the main reservoir types of the II reservoirs and the III reservoirs are more favorable reservoir zones.