Analysis Of Seismic Facies And Study Of Reservoir Predition Of The Changxin Formation In The Fuling Area

Fuling area lies east of Sichuan basin. It is east of the Da chigan gas fields, west of Datianchi gas fields. According to paleomagnetic data, the Sichuan Basin was located in the low latitudes near the equator in the Changxing Period when the climate was warm and humid. The climate characteristic was one of the reasons for reef widely developed in the Permian. In the east of KaiJiang-LiangPing trough, many gas fields of reef flat were found, such as Puguang gas pool, huanglongchang gas pool, Gaofengchang gas pool etc. Meanwhile, in the west of KaiJiang-LiangPing trough, many gas fields of reef flat also were found, such as yuanba gas pool, longgang gas pool etc. Fuling area was west of KaiJiang-LiangPing trough in the Changxing Period. In the 2010, Well Xinglong 1 set of tests obtaining gas production 51.7×104m3 in the Changxing formation. To see the exploration prospects and comprehend reef flat development and distribution characteristics. On the guide of a multi-disciplinary theory, this thesis , with geology association with geophysics as the main line, according to drilling data, log data, seismic data and combining with the regional geological background, carry out to the single well analysis and well comparison which instruct seismic facies analysis and sedimentary distribution of the plane characterization. We analyze geophysical response characteristics of the reservoir using log data analysis with forward modeling technique. Also, union with seismic inversion and extraction of seismic attributes which are sensitive to reservoir development in the area, we carriy out reservoir prediction. In the end , we run comprehensive evaluation of reservoir and determination favorable exploration targets area.Through sequence analysis, the Changxing formation in the Fuling area is divided into 2 3rd-order sequence which all are mainly preserved transgression systems tract(TST) and high systems tract(HST), the thickness of TST is smaller than of HST. According to observation of the area outcrops, drilling lithology, lithology-electrical characteristics, the sedimentary facies in the study area was divided into carbonate platform, slope and continental shelf. In the TST of the 2 3rd-order sequence, the reef flat of platform and platform margin is not developed. But in the TST, the reef flat is developed, with open platform and platform margin gradually as the water moving to north and northeast. From seismic facies analysis, it's concluded that the area be divided into four categories regional seismic facies and five major local seismic anomaly including imbricated prograding structure, moniliform, stratigraphic overlap pinchout ,dome-shaped and wave. By combing with geology and seismic, we analyze geophysical response characteristics of the reservoir in the study area and propose for reservoir prediction method, it is that bonding with seismic facies ,we firstly confirm the favorable development zone of reef flat by sensitive seismic attributes, and then carry out impedance inversion and gamma inversion, and pick up the reservoir of reef flat on the impedance inversion section from which we remove mudstone, predict reservoir thickness of the 2 3rd-order sequence on the plane in the end.With taking into account the sensitive attributes and local small structures, Integrated seismic facies, sedimentary facies, impedance inversion and reservoir thickness prediction, we comprehensively evaluate and predict favorable zones of the study area. In the first circle round ,we think there are 4 favorable zones, including one typeⅠ, two typeⅡand one typeⅡ. In the second circle round ,we think there are 5 avorable zones, including two typeⅠ, two typeⅡand one typeⅡ.