Study On Oil Accumulation Law In Slope Area Outside Oil Source Area

There are some problems to be solved such as faults chatacteristics,distribution ofsandbody reservoirs,distribution rule of oil and water,and oil accumulation conditionsbecause of little acquaintance degree of geology Fan188-122block,which influencesubsequent develop and exploration.Therefore,it is extremely urgent to make geologyresearch by means of modern exploration technology and oil accumulation theory of slop areaoutside source.it is also of great significance to perfect oil accumulation rule in slope areaoutside oil source area.The paper analyzed structural features,fault geometric characteristics on the basis ofresearch on structure background of Songliao Basin with3D seismic interpretation of thearea.Fault activities took place during Early stage of Early Cretaceous,early stage ofQingshankou Formation deposition and late stage of Mingshui Formation deposition,which isproved by tectonic evolution history extension and extension rate.The area has a tectonictrend of NNE and is a monoclinic of high in high in southeast and low in northwest.There are6typical geometric characteristics in Fan188-122block:(1)Fault trend aremainly nearly NS,NS and litte NW.(2)It has a small fault density of0.317and a small faultscale which has a length from1to5km.(3) Faults in T2reflectors are usually dense.(4)Thereexist typically fold reversal structure.(5)Faults have typical segment growth traits.(6)Thereare lots of reverse faults.The whole contrat of265wells,3formations,117layers,40time units and540600times hasbeen done by well pattern,drilling fine contrast of3D seismic and well to well contrast andother methods.Fuyang oil layer in Fan188-122block is shallow river delta facies according tosedimentary setting and single well micro facies of with well log-ging curves.Futher more,2sedimentary subfacies including delta plain facies and delta front facies and10micro facieswere divided.The following is micro facies characteristics of Fuyang oil layer in the block:(1)It is proved that provenance is in the southwest and provenance systems and sand bodiesare NE by the research of40sedimentary time units micro facies.(2)Segmented growth partsof fault is the place where river going into the basin.(3)The research on sedimentary microfacies shows fuyang oil layer in Fan188-122block is shallow river delta sedimentary system:1)obviously shallo water.2)wide lake shoreline.3)There is mainly delta plain facies and delta front facies has a short deposition time.Sub facies in profile transition is gradual anddistributary channel microfacies rich which are primary reservoir of Fuyang oil layer.Verticalmicrofacies evolution shows FⅠ15,FⅠ2,FⅠ5,FⅠ22and FⅠ7are rich in sandstone,inwhich oil and gas mainly distribute.In the profile,oil primarily gather in FⅠ oil layer which is important developing layerand partly in FⅡ by the statistical result of distribution of oil and water. Reservoir profileshows the numbers of layers rich in oil get smaller from low to high. Oil mainly is rich inslope structure zone and there is little oil at the top of anticline,which shows oil source supplyin the area is short.Oil and water distribution in each time unit and the coincidence of densezone and reverse fault indicate oil mainly is rich in the footwall and micro anticline in densezone.The coincidence of channel sandbody and distribution of oil and water proves that oilmainly distribute in the range of channel sandbody.Three kinds of oil migration and accumulation modes are concluded by the analysis ofrule of oil and water distribution and accumulation controlling factors:1.Reverse fault andsandbody and dense zone migration and accumulation mode.2.Micro anticline and sandbodyand dense zone migration and accumulation mode3.Sandbody pinch out and dense zonemigration and accumulation mode.Finally on the basis of each comprehensive research have we predicted and optimizatedfavorable target area. Besides,well placement analysis and calculation of reserves have alsobeen done.