Sequence Architecture And Reservoir-Forming Rule Of Lower Cretaceous In Gaonan Region Of Nanpu Depression In Bohai Bay Basin

The previous research of the Gaonan region has become more and morefiner in recent years. After the reservoir evaluation of a batch of drilling wellsand from the determination of super face structure of oil layers to theimplementation of the description of effective reservoir sand distribution andfavorable lithology target, drilling results have reached a satisfactory level,moreover, they have expanded the demand of deeper exploration anddevelopment of fault zone of high south regions. The analysis shows that themiddle-shallow hydrocarbon reservoirs have been mainly controlled by thelow-grade fault and the distribution of low-grade fault so that it is necessaryto study the reservoir-forming rule more deeply. High south region is one ofthe key regions of Nanpu land, in which shallow layer is the key reservoir ofthe construction of oilfield development capacity, which has a great potentialto border and produce. In order to study further and carry out the research foreach oil group structure of major target and fault development characteristics,as well as determining structure accurately, we have carried out lithologicaltrap identification and reservoir prediction in combination of well data basedon the sequence framework to determine the favorable trap and advantagedreservoir development area. Moreover, we have carried out reservoir genetic feature and set up the pool-forming pattern for high south region as well asoptimizing the favorable exploration targets and offering a proposal for welllocation in order to provide high quality reserves block for productivityconstruction. For the sake of predicting the reservoir and provide a referencefor well distribution, we compared and divided stratified data and directionalwell trajectory once again along with computing and arranging data, settingup a database for researching area to carry out seismic sequence attributeanalysis and predict the distribution of the reservoir by means of dividing andcomparing the layer, researching sedimentary microfiches as well asanalyzing seismic sequence attribute for the middle-shallow layer of the highsouth region. We can get the following conclusion that Dongying Formationis a sedimentary association which is mainly composed by classic rocks. Ithas been formed by the fan delta which has forged ahead to lake basins. Thedevelopmental sedimentary fancies include fan delta, shore-shallowlacustrine delta, and semi-deep and deep lacustrine and subaqueousgravity-flow sedimentation. The high south region is a rollover anticlinewhich is caused by the development of Gaoliu Fault downthrown side.Synsedimentary and deposit faults and growth anticlines have controlled theancient topography at the same time. The ancient topography takes animportant role in controlling the high south sediment disposal system andsedimentation system in development and distribution. Dongying Formationfavorable reservoir sand body is the subsea river channel sand body, at thesame time the mouth bar sand body and the sublacustrine fan sand body. Thesubsea river channel sand body is the key component of Ed1. Thesublacustrine fan sand body is also an effective reservoir within Ed2and Ed3.