| As to fan-delta and braided river-delta the formers emphasize on dissecting sandstoneunderground and observing outcrop profile and have studied systematically sedimentarycharacteristic of fan-delta and braided river-delta according to lithofacies, well-logging faciesand seismic facies. In fact, the structure phenomena clarified by means of seism have sufferedalteration for several times, so they are not to represent primary situation. Despite manyinvestigators commit themselves to finding more means of reconstructing paleostructure toexplore controlling of paleostructure to sediment, they focus on the control action ofpaleostructure to driving and sealing of oil and gas migration and accumulation. The control ofpaleostructure to fan-delta and braided river-delta, adopted in this study, is relatively fewerinvolved. Shiwu faulted basin, about 1600km2, northeast of which is Dehui faulted basin, southwestof which is Liutiao faulted basin, lies in southeast of southeast uplift area in Songliao Basin,north west of the line of Changchun-Siping, southeast of the line of Changling-Shuangliao.Shiwu faulted basin is a dustpan-like basin controlled by arc-shaped west borderline trendingNNE, forming since late Jurassic. There are many faults in the faulted basin which are classifiedinto basal main faults, basal sublevel faults and cover faults according to scale and the action offaults in the basin evolvement. The base and cover can be divided into such three sets ofstructural successions as pre-faulted basal succession, sync-faulted succession and depressionsuccession after faulting. The research target of the paper is Shahezi and Yingcheng Formationof sync-faulted succession. The contents and results obtained are such follows. In terms of fan-delta theory domestic and abroad, it is believed that at the west slope ofShiwu faulted basin fan-delta with great thickness, narrow phase belt, quick phase change andcoarse or mixed lithologic characters developed because of strong activity of faults and enoughsource supplied. However, at the north slope and east gentle slope, braided river-delta developedas stratum ascending and source are both few. Therefore, the sedimentary thickness is small andplain facies belt and coastal transition is wide while delta front, turning to wide lacustrine facieswhen entering water, is narrow. The main difference of fan-delta and braided river-delta consistsin delta plain. 4By means of core observation, logging analysis and seismic interpretation, 15 types oflithofacies are identified and 7 lithologic assemblages is divided, namely braided channelmicrofacies, brainded branch channel microfacies, underwater channel microfacies, delta frontsand microfacies, fringe sheet sand microfacies, wide lacustrine microfacies and underwatergravity current microfacies. In addition, sedimentary microfacies characteristics of fan-delta andbraided river-delta are studied in detail in term of logging, seism etc. Sawtooth box-like logging and mid-high breadth sawtooth funnel-like, sawtooth funnel-like—box-like logging are main logging facies types used to respectively recognize braided channeland fan-delta front. In longitudinal direction geometrical shape of fan-delta is like wedge, andinner reflection configuration represents disorder or non-reflection, from middle to end thereflection, with poor continuity, behaves as oblique crossing foreset. So the variety of amplitudeis main character of recognizing fan-delta from seismic profile. In horizontal profile reflection ofseismic seems hillock. The lithologic characters of coastal and offshore lake facies,deep-middeep lake facies is mainly mudstone and siltstone. Spontaneous-potential loggingappears as low breadth sawtooth-like and tiny sawtooth flat. Turbidite is part of prodelta, loggingof which appears as high breadth sawtooth or finger-like. Spontaneous-potential logging ofbraided river delta plain appears like b...
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