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取自北海及近旁10个不同地区或油田的50口井中的约12000ft(3658m)的下第三系和白垩系深水砂岩储层的常规岩心研究表明,这些储层主要由块体搬运沉积物,尤其是砂质滑塌和碎屑流的沉积物组成。典型的浊积岩极罕见,不足全部岩心的1%。表征滑塌和碎屑成因的沉积特征包括上界面突变的砂层单元、滑塌褶皱、不整一、陡层(达 60°)、滑动面、剪切带、角砾状碎屑、碎屑挤入(injections)、漂浮状泥岩碎屑、面状碎屑组构、反粒序和中至高的基质含量(5%～30%)。许多储层段的岩心以前或者被解释为盆底扇,或者展现出特定的地震(如丘状)和电缆测井(如块状曲线外形)特征以及地层关系(如下超在层序底界面上),这些均表明其是层序地层框架内的盆底扇。这种模式预示,盆底扇主要由展布广且呈席状的富砂质浊积岩组成。然而,取自若干个这类盆底扇(包括Gryphon-Forth,Frigg和Faeroe地区)的长岩心(400～700ft)中具有上述地震和电缆测井特征的沉积相的标定表明,这些特征实际上几乎全部是由滑塌和碎屑流沉积物为主的块体搬运沉积物组成的。区分诸如碎屑流之类的块体搬运沉积物与浊流沉积物,对于预测储层的几何形态具有重要的意义。碎屑流具有塑性流动的流变学特征,会形成断续的、互不连通的砂体,它们的圈定比起浊流所形成的那些横向连续且相互连通的砂体来要困难得多,且经济意义亦差。我们的岩心研究结果强调了深水沉积体系的复杂性,并指出利用遥测资料(如地震和电缆测井)的模型产生的解释结果来预测具体的沉积相和沉积特征时要格外小心。常规岩心的过程沉积学(Process Sedimen-tological)解释是确定储层砂岩真正成因及其分布的基本依据。
Conventional core studies of about 12,000 ft (3,658 m) of Lower Tertiary and Cretaceous deep-water sandstone reservoirs taken from 50 wells in 10 different areas or fields in the North Sea and adjacent fields show that these reservoirs are mainly transported by blocks, Especially sediments of sandy slump and debris flow. Typical turbidites are extremely rare, less than 1% of all cores. Depositional features that characterize the origin of slides and debris include sandstone units with abrupt changes in the upper interface, slip-folds, irregularities, steep layers (up to 60 °), sliding surfaces, shear zones, brecciated debris, debris crowding Injections, floating mudstone debris, planar detritus fabric, antisarticle and medium to high matrix content (5% to 30%). The core of many reservoir segments was previously or interpreted as a basin fan, or shows the characteristics of specific earthquakes (eg, mounds) and cable logs (eg, patchy curvilinear profiles) and stratigraphic relationships ), All of which indicate that it is a basin fan in the framework of sequence stratigraphy. This pattern indicates that the pelvic fan is mainly composed of well-distributed sand-rich turbidite. However, the calibration of sedimentary facies with the seismic and wireline log features described above in the long cores (400-700 ft) taken from several of these basin fans (including the Gryphon-Forth, Frigg and Faeroe regions) suggests that these features are actually Almost all are composed of sediment-carrying sediment-dominated blocks of slump and debris flow. Differentiating between blocks such as debris flow handling sediments and turbidity flow sediments is of great importance in predicting reservoir geometry. Debris flow has the plastic flow of rheological characteristics, will form intermittent, interlinked sand bodies, their delineation than those formed by turbidity flow that is laterally continuous and interconnected sand body to be much more difficult, And economic significance is also poor. Our core study highlights the complexity of the deepwater sedimentary system and points out that caution should be exercised in predicting specific sedimentary facies and sedimentary features using the interpretation of models generated by telemetric data such as seismic and cable logging. Process Sedimen-tological interpretation of conventional cores is the basic basis for determining the true origin and distribution of reservoir sandstone.