| The west slope Zone of the north Songliao Basin broadly speaking refers to the axisof the West part of Qijia-Gulong sag, including secondary structure unit: West part ofQijia-Gulong sag、Longhupao-Daan terrace、Taikang uplift zone、West overlap Etc., theexploration area is27299km2.The amount of oil resources of the west slope Zone of the north Songliao Basin isabout11.62~16.56million tons, total proven oil geological reserves is1761milliontons(contain Fulaerji oilfield), oil area is21.3km2, the geological reserves of the naturegas is49.95×108m3，the gas area is58.9km2，that prove the west slope has great oil and gasexploration potential, but that have large difference between the quantity of oil and gasresources totality.In addition, the west slope of the north of Songliao basin is one of the low degreeexploration block of Daqing oilfield. In addition to reserves have3D seismic work area,the rest are in2D seismic area earlier or no seismic area coverage; In addition to the outerregions of the reserves have less drilling; and in addition to the Saertu reservoir, the otherreservoirs have no major breakthrough,but the exploration potential is comparativeobjective.Wells in some non structure developed area also have the show of oil and gas,indicates that the exploration of stratigraphic and lithologic oil and gas reservoirs havegreat prospects.This paper makes full use of logging data、core data and well-seismic combination of seismic facies analysis technology, determine the distribution of each third levelsedimentary sequence facies in study area.In the constraints of the regional sequence stratigraphic framework, using theoptimized back stripping method restorated the various sedimentary periodpalaeogeomorphology of the objective layers in the study area, in the third-order sequencestratigraphic units drawed paleogeomorphogloic map of each sedimentary period, analysisof morphological characteristics, especially the formation of sedimentary slope break belt,and the distribution of location and slope.At last, in sequence stratigraphic frameworks, combined with the characteristics andthe sedimentary facies distribution law of the structural slope break belt,used the controlprinciplestratigraphic traps formed "Two surfaces and Three belts"(That is Unconformitysurface controlling sand、The lake flooding surface controlling reservoir、The stratigraphiconlap Pinchout belt controlling sand、The slope break belt controlling sand dispersionsystem), To the research main line is slope belt control layer,facies, reservoir,to reveal theconfiguration of the relationship between the "Faces and The distrabution of sand " and"Two surfaces and Three belts".The combination of structural and sedimentary、regional research and key zone, Onthe basis of analyse known oil and gas traps, determination the development strata andplane distribution location of formation lithologic trap, analysis of the types of lithologicstratigraphic traps, From what has been discussed above, the paper may finally draw theconclusion as below:Established sequence stratigraphic framework of a objective interval the thirdsection of Quan period-Nenjiang period. The objective interval is divided into threesecond-order sequence the third section of Quan period, the fourth section of Quan period~Qingshankou period and Yaojia period~Nenjiang period. The fourth section of Quanperiod~Qingshankou period is divided into four third-order sequence SQ2、SQ3、SQ4、SQ5; The middle of Yaojia period is a third-order sequence SQ6. Upper Nenjiang period isdivided into two third-order sequence the lower part of the Nenjiang SQ7and the upper part of the Nenjiang SQ8. Based on the third-order sequences, we restored the depositionalperiod structure palaeotopography of the third sequence SQ3, SQ4, SQ5, SQ6, SQ7-LST+TST which inside the west slope region Qingshankou period. Results indicate that there issignificantly slope break in the depositional period of Qingshankou period and Yaojiaperiod and the vertical slope break is gradually slowing.The main development of the types of sedimentary facies in the objectiveinterval is determined.There are several major developmental deposition of river-floodplain, delta, slump turbidite fan, shallow lake and semi-deep lake facies in theobjective interval; Analysis of sedimentary facies composition and distributioncharacteristics of sedimentary system in rise of the third-order sequence and fall of;Pointed out that pour off with a sharp front turbidite fan delta and delta-front is animportant area of ithologic reservoir exploration.The western slope of Songliao Basin in northern delta front development,numerous stratigraphic and lithologic traps associated with delta-front type.Thispaper analyzes the structure of the delta front sand body and nose structure flank, fault andother composite formation-lithology, fault-rock, sandstone trap which are the main typetraps in the objective interval. The leading edge of the objective interval in the southerndelta relatively steep terrain slope and waves on the lake delta front sand under theprevious conditions for the transformation of delta front slump, moving to the lowerslopes of a certain scale slump turbidite fan, decentralized turbidite sand body issurrounded by lacustrine mudstones around, easy to form lithologic traps. To third-ordersequence as a unit, based on the study geomorphological evolution and its relationshipwith the depositional system configuration on the west slope were found SQ3-LST+TSTfluxoturbidite favorable area, SQ3-HST fluxoturbidite body and northern delta frontstratigraphic and lithologic traps favorable area, SQ4fluxoturbidite favorable areas andSQ7-HST side delta front sand traps favorable lithology super area.In summary, this study concluded that the understanding of the two innovation:This study practice as the continental sequence stratigraphy in the world the largestknown continental basins in western slope area application, through the use of the study area the existing seismic、drilling Etc. exploration and production data, established highresolution sequence stratigraphic framework of the Quantou Formation-lower Nenjiangformation., and on this basis, using the combination of well and seismic technology toidentify different sedimentary bodies, the two major exploration and four types of targetwas found, and ultimately identify favorable lithologic traps. In the study area for the firsttime using the Paleogeomorphology restoration technology, Qingshankou and Yaojiagroup was identified two level slope belt in the study area, after detailed analysis that theslope belt distribution of the different lithologic body have the corresponding controlfunction.This paper takes the sequence stratigraphy theory as the guide, established ofisochronous stratigraphic frame, in this framework, the sequence stratigraphy andsedimentology combined, structural geology and Sedimentology combined, analysised ofthe components of depositional system in the process of base level cycle evolution, therelationship of configuration between interfacial properties evolution and sedimentarybody,discusses paleogeomorphology slope belt development characteristics and sandcontrol principle, research the western slope zone of lithologic stratigraphic trap formationconditions and distribution regularities. Conclusion this paper to find favorable lithologytraps、the formation and the stratigraphic-lithologic traps, to open up a new prospect foroil and gas exploration in the west slope have very important practical significance. |
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