High Quality Resevior Identifying Of Sequence SB21in Deep-water Area Of Baiyun Sag In Northern South China Sea Introduction Of The Author: Hu Lian, Male, Was Born In August1984, Whose Tutor Was Professor Xu

Baiyun sag is located in Zhu Ⅱ depression of the Pearl River Mouth basin,lying in deep-water area (water depth: more than200m) in the north of South ChinaSea. It has excellent oil and gas charging condition. In the last few years, a hugesystem of low-stand deep-water fans have been discovered with the application ofsequence stratigraphy theory. Its huge potential for oil and gas exploration wasalready been fully confirmed by well C3-1-1, first deep-water (water depth:1480m)exploration well in China which obtains natural gas discovery in the deep-water fanreservior. Owing to the discovery of C3-1-1, Baiyun Sag has become the focus ofdeep-water oil and gas exploration.In this thesis, applying theories of classical sequence stratigraphy, based onseismic data and constrained by well data, the author identifies the sequence boundaryof SB21, intepretates the delta and deep-water fan sendiment. Analyses therelationship between delta and deep-water fan, and the seismic response of reseviorwith complex cover strata based on rockphysics.Finally, the author implement thedepicting of high quality resevior and evaluating its porosity together with thepecentage of sand by using a geology constrainted seismic inversion Main progressand understanding obtained are as follows:1) the sendiment characteristics of SB21sequence boundarySandy delta prograde to the shelf break of SB21in this area,which provided asandy background sources feeding the deep water fan system downdip of slope.Thosefans are stacked lobes from multiple feeding channels.The scale of channels and fansAave tigAt connection with the dip of slope.The high angle slope of SB21ispropitious to develop large scale and sandy deep water fan reservior.2) The statistics of well logs data in Baiyun sag shows the characteristics of lowimpedance sand with high impedance shale only exist from1000m to3000m(Depth from Seafloor).the impedance is similar between sand and shale near the up and lowdepth limit,and even reverts if out of the range.Using ampletitude or inversion data toevaluating these reservior should be careful.The impedance of limely cover uponSB21resevior is extremely high.3) Reflection of reservior with carbonate cover changes.the seismiccharacteristics of resevior pinch out is a continuous top troughand a discontinuousbottom peak.The AVO type of resevior’s top reflection changes from type3to type4.4) Seismic inversion with geology condition constrain has much bettereffect.Inversion applies with the initial model based on the geology model carried outby sequence stratigrapAy and the regional velocity.It solved the problem of thedramatical lateral difference of impedance caused by the varying barried depth.5) Identifying the high quality reservoir by applying geophysics and sequencestratigraphy theory.Channel sands are constrained right inside the channel,which have well lateralseal condition.The upper ends of channels are a district of bypass,which is shalely;Thelower ends of channel in the south carry out some lobes that are consist of thin sheetsands(deep water fan).The channel sand and deep water fan ‘s porosity are nearly25%with70%VQUA,according to inversion.Those arguments had been proved by drilling,A34-2、A29-1showed greatconsistency between prognosing and actual result.