The Coarse-Grained Lacustrine Slope Apron Deposits in the Moliqing Area, Yitong Basin, Northeast China

Overlapping gravity accumulation bodies were formed on the northwestern steep slope of the Shuangyang Formation in the Moliqing fault depression of northeast China. This study analyzed in detail the spatial distribution of the lithofacies and lithofacies associations of these accumulation bodies based on more than 600 m of core sections, and summarized 12 major types of lithofacies and three types of lithofacies associations: (1) the proximal zone consists of gravelly debris flows dominated by alluvial channel conglomerates; (2) the middle zone is dominated by various gravity flow deposits and traction flow deposits; and (3) the distal zone is dominated by mudstones with intercalations of sandy debris and turbidites. Combining with the grain size cumulative probability curves analysis, we determined the transformation of debris flows to sandy debris flows and to turbidity currents in the slope zone of the basin margin, and further proposed a lacustrine slope apron model that is characterized by (1) an inconstant multiple source (line source), (2) an alternation of gravity flow deposits and traction flow deposits dominated by periodical changes in a source flood flow system, and (3) the transformation of sandy debris flow deposits into distal turbidity current deposits. This sedimentary model may be applicable to other fault depressions for predicting reservoir distribution.     

Three-dimensional reservoir architecture modeling by geostatistical techniques in BD block,Jinhu depression,northern Jiangsu Basin,China

To reduce or avoid some of the ambiguities in a heterogeneous reservoir, a fine three-dimensional model would be inevitably established with the application of geostatistical techniques. BD oilfield is a low-permeability fractured reservoir with many fracture types, which composes a multi-azimuthal fracture system, causing strong anisotropy and heterogeneity. Moreover, fracture provides not only accumulation space for oil and gas but also channels for migration of hydrocarbons and water dashing and thus plays a leading role in controlling BD reservoir production. With the continuous exploitation of oil in reservoir for more than 30 years, BD oilfield has currently stepped into high water cut stage, exposing many problems such as low oil recovery, poor exploitation stability, rapid oil production decline, and one-way water intrusion. Therefore, a detailed reservoir characterization, constructed to describe reservoir behavior under strong water drive in a well-developed fractured reservoir, is urgently needed. In this study, combined with three-dimensional geostatistical techniques, an accurate and efficient reservoir parameter model that occurs in a strong heterogeneous fractured reservoir has been constructed through stratigraphic correlation and sedimentary facies analysis. Hence, all the study presented above will be available for well location, remaining oil potential-tapping and oil recovery improvement during the later study work.     

Fine description of structure and sedimentary microfacies of Li32 block of Lijin oilfield,Dongying depression,China

Considering that available data in Li32 block is limited, log phase method and core analysis were used to divide sedimentary facies and sequence, the former is principal, and two short-term cycles, five middle term cycles, and fifteen short-term cycles were divided. Combined seismic interpretation with fault point and fault rod, the instantaneous phase profile explained small fault more clearly and accurately. The sever faults were analyzed, and integrated structure was constructed. Lithofacies in cored wells were observed; the grain-size probability curves mainly are suspension and jumping transport; grain size is mainly for the siltstone and fine sandstone; the color of mud in the second segment of Shahejie formation (ES2) is mainly gray–green, gray to dark gray, these reflect that sediment environment is delta front, which included underwater distributary channel, mouth bar, distal bar, and so on. Well data and structural maps were integrated to build 3D structure model and sedimentary microfacies model of Li32 reservoirs using stochastic simulations with geometry data. The integrated 3D geological model is a valuable tool of reflecting geologic body with great reality and can accurately represent and describe the complex reservoir heterogeneity.     

Environmental Effects of Water Product from Coalbed Methane Wells: A Case Study of the Songhe Well Group,Western Guizhou,China

Natural Resources Research - Based on water chemistry analyses of five batches of water product samples from eight coalbed methane (CBM) wells of the Songhe well group in the western Guizhou...     

流体性质转换机制在重力流沉积体系分析中应用初探

自1950年Kuenen发表"浊流形成粒序层理"一文至今,深水重力流研究取得了长足发展。然而,目前很多学者不仅对浊流理论分歧很大,而且对浊流概念、术语的使用也有不同的观点,这严重制约了重力流的分类及重力流沉积体系的识别。本文在重力流沉积过程和流态研究的基础上,提出了基于"流体性质转换"理论的重力流沉积体系分析方法。研究认为,重力流在形成、发展和消亡过程中不仅存在多个流体阶段,而且存在着多种流态之间的转换。这种流体发育的最终阶段特征决定了重力流沉积体系的形态与类别,而流态共存与转换的特性造成了深水紊流成因的浊积岩与其他流体成因的岩相共存的沉积特征。根据这一理论对牵引流—碎屑流成因的扇三角洲体系、浊流成因的近岸水下扇体系和碎屑流成因的斜坡裙体系进行成因分析与特征对比,阐述了"流体性质转换"理论在沉积体系识别中的作用。     

Sequence stratigraphic analysis and integrated 3D geological modeling of M1 block, Wenmingzhai oilfield, Dongpu depression, China

The M1 block is a typically complex fault-block oilfield, whose recovery has reached 30.5% through the twenty years waterflooding development. Remaining oil scatters very widely and the production between layers is in a high degree. However, many problems have been exposed at the same time which hinder improvement of the recovery rate and sustainable development of the reservoir. Hence, it is important to carry out basic geological research and form a comprehensive understanding of reservoir properties. However, few such studies have been conducted in China. In this study, work related to basic geological research was conducted based on high-resolution sequence stratigraphy, seismic interpretation technology and 3D visual geological modeling, and significant results were achieved. Three sequence orders and three types of interfacies in the stratigraphic architecture of M1 block were identified through seismic sections, logging curve characteristics and entropy spectrum analysis. Thirty-two short-term sequence cycles (fifth order), eight mid-term sequence cycles (fourth order) and two long-term sequence cycles (third order) were identified, followed by the establishment of a high-resolution isochronous stratigraphic correlation framework. Finally, a regional 3D geological model was established on the basis of these preliminary studies. The integrated 3D geological model is a valuable tool for reflecting geological bodies accurately, and it can accurately represent and describe reservoir heterogeneity.     

基于沉积相反演的砂砾岩体沉积期次精细划分与对比

砂砾岩体一般为多期发育、多次沉积的复合体,其内部结构非常复杂,对砂砾岩体沉积期次的精细划分与对比问题,国内外尚无很好的解决先例.本文提出了基于沉积相反演的砂砾岩体沉积期次精细划分方法.文章在岩芯观察和描述的基础上,用岩芯对成像测井资料进行刻度,建立研究区成像测并模式,并精确地识别出鲍马层序、高密度浊流序列和中扇辫状水道...