Research On Microscopic Pore Structure And Characteristic Study On The Performance Response Of Different Diagenesis Facies Of He 8 Reservoir In Su 48 Block

The formation and distribution are obviously“phase-controlled” in the Sulige gas field which is a typical lithologic reservoir.The development of micro-nano pores and serious wellbore effusion are difficult to develop.Therefore,it is of great practical significance to clarify the influencing factors of different diagenetic rocks relative to microscopic pore infiltration characteristics and production dynamic response characteristics.In this paper,the He 8 reservoir of Su 48 block in Sulige area is taken as an example to study the characteristics of micro-pore throat structure and the regularity of gas-water distribution of different diagenetic facies based on the theories of sedimentary petrology,oil-gas reservoir geology and reservoir physics and research methods of qualitative,quantitative,image and non-image.Firstly,the reservoir-forming background,provenance and sedimentary microfacies of the study area are elaborated.Secondly,the differences in diagenesis,diagenetic stage and characteristics of the reservoir are analyzed.The naming of diagenetic facies and logging parameters characterization are also realized.By using X-ray diffraction,cathodoluminescence,scanning electron microscopy,casting slice,high pressure mercury injection,constant rate mercury injection,nuclear magnetic resonance and gas-water phase infiltration experiments,the qualitative and quantitative characterization of micro-nano pore structure and seepage characteristics of different diagenetic facies are carried out,and the main controlling factors of pore permeability and micro-occurrence characteristics of gas-water distribution of reservoirs are clarified.Finally,through the study of performance response characteristic of different diagenesis facies,a certain geological basis could provide for finding favorable areas.The main understandings obtained from study are as follows:(1)Based on pore types,authigenic clay minerals and diagenetic strength parameters,the diagenetic facies in the study area are divided into four types: the log response characteristics of medium compacted,quartz weak enlarged,intergranular pore and dissolution facies are low GR,high AC,medium-low RLLD,low DEN.The response characteristics of the medium compacted,kaolinite cemented,intergranular pore and dissolution facies are low GR,medium-high AC,medium RLLD,low DEN.the log response characteristics of the medium-strong compacted,carbonate cemented,microporous phase are medium-high GR,medium-low AC,high RLLD,medium DEN;the log response characteristics of the strong compaction,medium cemented,dense phase are high GR,low AC,low RLLD,high DEN.(2)The phase with moderately compacted,"quartz weakly increased,intergranular pore,dissolution belongs to high quality diagenetic facies.The characteristic parameters are: the plane porosity is 3.49%,and the average throat radius is 1.607?m.The discharge drive pressure is 0.34 MPa and the pore-throat ratio is 112.08;The irreducible water saturation is low,the conventional dominant phase is gas phase and the gas-water two-phase co-infiltration area is 2.8% on average;The types of pore combination are mainly intergranular pores-dissolved pores and dissolved pores-intergranular pores.(3)The medium-decomposed,kaolinite cemented,intercrystalline and dissolution facies is the favorable diagenetic facie in study area.Its characteristic parameters are: the face ratio is 3.11%,the average throat The channel radius is 0.9625?m,the discharge pressure is 0.59 MPa and the pore-throat ratio is 168.762;The irreducible water saturation is medium,the conventional gas phase dominant type and the gas-water two-phase co-infiltration area averages 2.12%.The types of pore combination are mainly intergranular pore--dissolved pore and dissolved pore-intergranular pore.(4)The Medium-strong compacted carbonate cemented microporous phase is a good diagenetic facies.Its characteristic parameters are: the face ratio is 1.44%,the average throat radius is 0.706?m,the discharge drive pressure is 1.61 MPa and the pore throat ratio is 215.66.The irreducible water saturation is high,the conventional water phase dominant type and the average area of the gas-water two-phase co-infiltration zone is 1.3%.The types of pore combination are mainly intercrystalline pore,dissolved pore and microporous-dissolved pore.(5)The Strong compaction medium-density dense phase facies has the worst quality.Its characteristic parameters are: the face ratio is 0.73%,the average pore radius is only 11?m,the average throat radius is 0.512?m,the discharge drive pressure is average 3.01 MPa and the pore throat ratio is 259.567;the movable fluid saturation Less than 20%,the maximum irreducible water saturation,the conventional aqueous phase dominant type and the gas-water two-phase co-infiltration area averages 0.5%,the pore type is mainly microporous.(6)It is shown that the quality of diagenetic and production characteristics has a good relationship.The best diagenetic facies has a medium-high production and the production rate is stable.The better diagenetic facies has a low production and the production is also stable with a rise in water production in late production cycles.The average diagenetic facies has a low production and the time of stable production is long.The gas-water interference in the worst diagenetic facies is strong and the production is low,sometimes even zero.