Research On Reservoir Sedimentology Of Qingshankou Formation In Qingnan-Heidimiao Area, South Of Songliao Basin

Qingnan-Heidimiao area located at the south of Changling depression, concretely , the south of Daqingzi well low uplift, the north of Heidimiao subdepression. The area tectonic relatively comparatively simply, is made up with depression and slope, don't have large scale tectonic zone, the faulted structure scales is smaller, the main direction is NNW. Oil geology and basin model study indicate: the area oil resources is three-four hundred millions ton, have further exploration value. But the exploration study degree is relatively low, there is no systematical reservoir research work..The paper based on drilling core observe,microscope identification,fractional analysis,well logging and seismic data analysis,scanning electron microscope,inclusion thermometry and mercury penetration experimentation measure etc, do the study of reservoir sedimentary facies,the transform model of sedimentary facies and seismic facies,the feature of distribution,the type of air space,pore configuration,reservoir physical property,the type of diagenesis,diagenetic stage and diagenetic evolution model, then made a research on mathematical statistics by choosinge the key parameters which were intimatly related to develope feature and evaluation of reservoirThere are two array modes of oil-generating-reservoir-caprock in Qingshankou formation:①,self-generation self-save array mode: take the case, the layer of first member and under stratum of second member ,the dark mudstone of themselves is generating rocks, and the condition of unboiled oil is relatively good, and the sand body of delta front facies and lake facies is the reservoir;②,down-generation up-save array mode: the layer of third member is the case. The fault is the main passageway of oil migratory, the oil-gas form the layer of the first member and the second member, from the under stratum to the sand body of the third member layer through the fault.The main sedimentary facies are delta face and lake face in Qingshankou formation of this area, including six subfacies,fifteen microfacies. And the most main sedimentary face is the delta front subfacies, formatted in the layer of the first member and the top of second member ;under water density current appear at the first member and the second member layer of hei 55 well,hei 100 well and hei 143 well, the scale is relatively small; the others subfacies appear at all of the members of Qingshankou formation. In the area of triaxial seismic, resumed the feature of sedimentary microfacies distributed in all the system tract. In TST, the microfacies are under water distributary channel,mouth bar,sand sheet ,and the sand body of under water distributary channel is the main sedimentary; In HST, in this district, the main microfacies is the mouth bar,and the sand sheet was the same and latter developed as mouth bar, but not the underwater distributary channel. In RST, the microfacies succeed the features of HST.Based on analysis of lithology characteristics, make sure that the reservoir rocks is feldspatite lithic sandstone and lithic arkose, the fuller is mainly mud,carbonate mineral,autogeny quartz and clay mineral. According to the research of sandstone diagenesis, have induction that the diagenesis of reservoir are machine compaction,pressolution,chemical cementation,metasomasis,denudation and clay mineral transform acting etc. And the denumation is the main diagenesis in this area. Diagenetic stage divide into syndiagenetic stage,early diagenetic stage and late diagenetic stage. Qingshankou formation is in the A2-A3 sub-stage of late diagenetic stage. Diagenetic evolution model indicate that: when the second,third member layer began to sediment, the first member layer was going into late diagenetic stage, when the second and third member layer began to sediment, the whole first member layer of Qingshankou formation had been in A1 sub-stage of late diagenetic stage; when Mingshui formation began to sediment, the whole Qingshankou formation was in A2 sub-stage; when it comes to paleogocene, the first member layer had been in A3 sub-stage, and the second and third member layers been in A2 sub-stage.The airspace type of reservoir in Qingshankou formation include two types: primary pore and secondary pore, the primary pore include intergranular pore and micropore, secondary pore include emposieu and fracture pore. The analysis of mercury penetration experiment characteristic parameter indicate that : the pore configuration in Qingshankou formation is under middle (ⅡB),under middle (ⅡB) and sub-bad(ⅢA).Based on core test data, established the forecast relation between porosity,permeability and acoustic travel time ,the result display: the average value of porosity in the third member is maximal ,is 13.91%; the average value of permeability in the first member is maximal, is 4.03×10-3um; 2 generally,the type of reservoir is low porosity low permeability. According to the analysis of correspond relations between microfacies and physical property, from under water distributary channel,mouth bar to sand sheet ,the physical property become more and more worse.Choose the parameter of physical property,lithologic character and pore configuration, including porosity(φ),permeability(K),carbonate(Cc),the max saturation of hydragyrum(Smax),the maximal value of J function(Jmax),the maximal radius of pore throa(tRa),average value radius of pore throa(tRp),relative separation factor(D),drainage pressure(Pcd),coefficient of sorting(Sp),ejection efficiency (Sp)etc,according to the results of obscure synthesis on reservoir: the first member of Qingshankou formation ,which evaluated value was 0.560,is the better reservoir of typeⅡ1;and the evaluated value of the second member was 0.533,it belongs to the type of middleⅡ2.however,in spite of larger porosity and permeability existing in the third member of Qingshankou formation, because of the worse hole structural ,the evaluated value is only 0.458,and the type of reservoir is worseⅢ.