Characteristics and favorable area prediction of Ordovician buried-hill carbonate reservoirs in the Bozhong 21–2 tectonic belt,Bohai Bay Basin,China

Based on core data, thin section and logging, this study investigates the basic characteristics and occurrence regularities of the Ordovician buried-hill carbonate reservoir in the Bozhong 21-2 tectonic belt. Results show that the reservoir lithology is primarily limestone, followed by dolomite, dolomitic limestone or limey dolomite, and silty mudstone. The reservoir spaces are primarily composed of secondary porosity. These reservoirs can be divided vertically into weathered-crust karst reservoirs and inner dissolution-type reservoirs. The distribution of reservoirs is controlled chiefly by karstification. The high karst units in the study area are favorable for the development of the two reservoir types.     

FACIES HETEROGENEITIES IN A RAMP CARBONATE RESERVOIR ANALOGUE: A NEW HIGH‐RESOLUTION APPROACH FOR 3D FACIES MODELLING

In contrast to the conventional view that facies distribution patterns on carbonate ramps are relatively simple, outcrop analogue studies point to a high degree of internal facies complexity. Depending on the diagenetic overprint, this complex pattern may result in reservoir compartmentalization due to the presence of interflow baffles. The often subseismic scale heterogeneities may not be included in conventional reservoir modelling. In order to evaluate how facies heterogeneities in shoal reservoirs can be modelled realistically, this paper presents a facies modelling workflow which includes a new approach to the design of training images for multiple‐point statistics (MPS). The workflow was developed in the course of a reservoir outcrop analogue study of a Ladinian (Middle Triassic) coquinadominated shoal complex in SW Germany which was deposited on an epicontinental, gently inclined carbonate ramp. The data set was based on an intensive field study and includes 3D facies and sequence stratigraphic analyses of the largest shoal complex in the Quaderkalk Formation (Upper Muschelkalk). This several metre thick shoal complex represents a subseismic scale, bioclast‐rich reservoir analogue and has a very heterogeneous facies pattern. Integrating 1D facies logs and sequence stratigraphic trends from tens of outcrop sections and cores, two nested 3D geocellular facies models were produced: (i) a large‐scale (30 × 30 km) model based on truncated Gaussian simulation (TGS); this formed the basis for (ii) a smaller‐scale (10 × 10 km), more detailed model based on multiple point statistics. In addition, a new approach for training image design was developed to honour small‐scale sequence stratigraphic trends and lateral facies patterns observed in modern analogues. Compared to facies patterns in modern analogues, the large‐scale model presents geologically‐feasible facies distribution patterns and geometries, and in addition shows a vertical facies distribution which is similar to the observed sequence stratigraphic architecture of the outcrop data‐set used. Due to the new training image design, the final small‐scale model has a distribution pattern of facies heterogeneities which looks similar to modern facies distributions in the offshore UAE and thus represents a valuable method of producing realistic reservoir facies models. The modelling workflow and the new approach for training image design presented will help to reduce uncertainties in the understanding and modelling of subsurface reservoirs by using a systematic combination of outcrop data and modern analogues, with the consistent application of sequence stratigraphic principles. In addition, this study emphasises the importance of careful training image design, derived from modern analogues, which can be used as realistic inputs in order to optimize multiple point simulations, and which may be applied to producing bioclastic reservoirs such as those located on the Arabian Plate or offshore Brazil.     

THREE‐DIMENSIONAL SEISMIC GEOMORPHOLOGY OF PALEOKARST IN THE CRETACEOUS MACAÉ GROUP CARBONATES,CAMPOS BASIN,BRAZIL

Three‐dimensional seismic data from an oilfield in the Campos Basin, SE Brazil, was used to characterize a karstified unconformity surface at the top of the Albian – Cenomanian Macaé Group. Macaé Group carbonates underwent intense karstification associated with subaerial exposure during a period of some 10 to 15 Ma resulting in the development of canyons, valleys, sinkholes and cave systems. The carbonates host commercial oil accumulations at a number of important oil fields. Understanding how the karstification process has affected the carbonates' reservoir properties is essential for future exploration, not only to improve recovery rates but also to avoid drilling‐related issues such as thief zones. In this context, this study aims to characterize the top‐Macaé Group paleokarst system by investigating the morphology of the associated reflectors recorded on seismic data, together with endokarst features in the underlying carbonate succession such as cave systems and collapse structures. The top‐Macaé Group seismic horizon can be divided into two principal geomorphological domains: highlands, characterized by abrupt relief with well‐developed erosional features; and lowlands, marked by a smoother topography. Collapse sinkholes occur in both domains and take the form of closed circular depressions. The study of endokarst features from an analysis of amplitude anomalies (bright spots) indicates the presence of heterogeneous cave systems. The interpreted data contributes to a better understanding of the spatial distribution of the paleokarst system in the Macaé Group carbonates and may assist with future hydrocarbon exploration in the Campos Basin.     

超临界CO_2中苯酚氧化羰基化反应产物的分析

采用气相色谱-质谱联用技术,对超临界CO2中苯酚氧化羰基化反应合成碳酸二苯酯(DPC)的产物进行了定性分析。分析结果表明,与以二氯甲烷为溶剂的苯酚氧化羰基化反应不同,在超临界CO2中该反应的主要副产物是o-亚苯基碳酸酯。通过对反应物系的分析认为,这是由于苯酚首先在Cu化合物的催化下发生邻位氧化反应得到邻苯二酚,邻苯二酚再与超临界CO2发生羰基化反应得到o-亚苯基碳酸酯。采用气相色谱并利用外标法对反应混合物中的DPC和苯酚进行了定量分析,DPC和苯酚的外标曲线相关系数分别为0.998 36和0.999 03,方法的标准偏差分别为8.9%和7.7%,回收率分别为94.3%~105.3%和92.0%~105.0%。该方法重现性好,适用于超临界CO2中苯酚氧化羰基化反应产物DPC和反应物苯酚的分析。     

离子液体中K_2CO_3/CH_3I直接催化合成碳酸二甲酯

利用高压间歇反应釜,考察了K2CO3/CH3I催化CO2与甲醇直接合成碳酸二甲酯(DMC)的反应规律,得到最佳的反应条件:反应温度363K、反应压力3.6M Pa、反应时间8h、m(甲醇)∶m(CH3I)∶m(K2CO3)=12∶2.3∶1。液相产物中DMC含量随K2CO3用量的增加几乎呈直线增加,因此可以在较低的反应压力下获得较高的DMC收率。另外,利用离子液体溴代1-乙基-3-甲基咪唑盐[Em im]B r对CO2的溶解特性,研究了离子液体[Em im]B r对K2CO3/CH3I催化CO2与甲醇直接合成DMC反应规律的影响。实验结果表明,在反应温度低于393K、反应压力高于4.0MPa的条件下,离子液体[Em im]B r可以加快反应速率,对反应具有一定的促进作用,但不能改变反应的最佳条件和整体规律性。甲醇、CH3I、[Em im]B r、K2CO3的最佳质量比为12∶2.3∶1.6∶1。     

Cu基络合物催化甲醇液相氧化羰化反应

针对甲醇液相氧化羰基化法合成碳酸二甲酯(DMC)工艺,开发了新型Cu基络合催化剂(CuB rnLm)。对CuB rnLm催化剂的活性及其稳定性进行了研究。实验结果表明,采用该催化剂,甲醇转化率和DMC选择性较高;元素价态和物质结构分析表明,CuB rnLm催化剂循环使用5次后仍保持较好的稳定性。采用正交设计和中心响应曲面法设计实验,并使用S tatistica软件进行统计分析,寻求出反应的主要影响因素,并得到优化的工艺条件:反应温度100~110℃、反应压力3.0~3.5M Pa、反应时间4~6h、CuB rnLm催化剂质量浓度(以甲醇的体积计)0.15~0.20g/mL。在此工艺条件下,甲醇转化率可达23%以上,DMC的选择性为96%~98%。     

PdCl_2/Cu-HMS催化乙醇氧化羰基化合成碳酸二乙酯

制备了含Cu的介孔杂原子分子筛Cu-HM S和PdC l2/Cu-HM S催化剂,考察了其催化乙醇氧化羰基化合成碳酸二乙酯(DEC)的反应性能。通过X射线衍射、X射线光电子能谱、电感耦合等离子体原子发射光谱、红外光谱的表征表明,Cu离子以高度分散的状态进入HM S分子筛骨架,并保持了良好的介孔结构的有序性,同时PdC l2的负载在一定程度上提高了Cu-HM S分子筛的介孔规整度。通过催化剂活性的考察发现,载体表面的Pd与骨架中Cu之间的协同作用有利于该反应体系活性中心的形成,PdC l2/Cu-HM S催化剂表现出较佳的活性,DEC选择性达100.0%、乙醇转化率为5.1%、DEC时空收率达到110.50g/(L.h)。助剂的加入在不同程度上提高了PdC l2/Cu-HM S催化剂的活性,其中四乙基溴化胺(TEAB)的效果最佳,TEAB的最佳负载量为n(TEAB)∶n(Pd)=12∶1,产物DEC的时空收率达到187.93g/(L.h)。     

MnCl_2/活性炭催化合成正丁基氨基甲酸甲酯

通过对不同活性组分的筛选,开发出活性炭负载氯化锰(M nC l2/AC)催化剂,用于碳酸二甲酯(DMC)和正丁胺甲氧羰基化反应合成正丁基氨基甲酸甲酯(MBC)。考察了M nC l2负载量对M nC l2/AC催化剂催化性能的影响及反应温度、反应时间、催化剂用量和原料配比对反应的影响。实验结果表明,适宜的M nC l2负载量为0.2mm ol/g;适宜的反应条件为:n(DMC)∶n(正丁胺)=3,催化剂的质量分数为5%,反应温度80℃,反应时间7h。在此条件下,正丁胺能完全转化,MBC的收率达到96.5%。探讨了不同载体负载的M nC l2催化剂的催化性能,发现中性载体有利于甲氧羰基化反应。     

利用神经网络的LM算法确定碳酸盐岩声波孔隙度

确定碳酸盐岩声波孔隙度是测井解释中的一个难题，传统方法是利用平均时差公式经过适当校正或使用声波、中子、密度等两种以上的测井资料求取，在具体使用中误差较大且很不方便。为此，基于Levenberg—Marquardt算法，提出一种确定碳酸盐岩声波孔隙度的神经网络方法，主要步骤包括：样本信息的预处理、网络结构的设计、采用LM算法的网络学习训练、碳酸盐岩声波孔隙度的确定。仿真实验和比较分析表明，该方法快速稳定，其结果与真实值吻合程度高。     

SEISMIC FACIES ANALYSIS BASED ON 3D MULTI-ATTRIBUTE VOLUME CLASSIFICATION, DARIYAN FORMATION, SE PERSIAN GULF

Interpretation of recently acquired 3D seismic data from the adjacent Sirri C and D oilfields in the SE Persian Gulf indicates that a 3D interpretation of seismic facies is crucial to resolve the internal stratal geometries of the Aptian Dariyan Formation. This carbonate formation passes southward into the Shu'aiba Formation, a prolific reservoir rock of similar facies in the UAE. Lack of exposures and limited cored intervals have forced reliance on the seismic data for evidence of the depositional environment and the internal architecture of potential reservoir rocks. The progradational nature of the Dariyan Formation and the occurrence of carbonate build‐ups within it make this stratal geometry complex. The complex internal heterogeneity of the build‐ups and presence of seismic noise make mapping of the build‐ups in 3D space using conventional seismic interpretation tools difficult, despite the availability of high‐quality 3D seismic data covering the area. The high quality seismic and limited well data from this field is one of the few datasets of this kind presented in the literature. A procedure for the hierarchical multi‐attribute analysis of seismic facies using Paradigm's Seis Facies software is used in this study to provide a 3D interpretation of the stratal patterns. Principal component analysis reduces the noise and redundant data by representing the main data variances as a few vector components in a transformed coordinate system. Cluster analysis is performed using those components which have the greatest contribution to the maximum spread of the data variability. Six seismic attribute volumes are used in this study and the result is a single 3D classified volume. Important new information obtained from within the Dariyan Formation gives new insights into its stratigraphic distribution and internal variability. This method of processing seismic data is a step towards exploring for subtle stratigraphic traps in the study area, and may help to identify exploration targets.