Palynostratigraphical studies on some subsurface middle Albian–early Cenomanian sediments from North Western Desert,Egypt

The Kharita and Bahariya formations are of great importance for Egyptian economy. They are the target of the oil and gas exploration in the Egyptian Western Desert. The present study investigated the palynostratigraphy, palynofacies and spore coloration of samples from these two formations in Negelah-1 Borehole. The investigations were used to evaluate their thermal maturity and potentiality to generate the hydrocarbons. The identified palynozones are Afropollis jardinus Acme Zone (late Albian–early Cenomanian) and Araucariacites australis Acme Zone (middle Albian). The first zone is differentiated into two subzones, which are Elaterosporites klaszii Interval Subzone and Cretacaeiporites densimurus Interval Subzone. The palynofacies analysis revealed that the Kharita Formation was deposited in proximal near shore marine environment under oxic conditions. Whereas the lower part of the Bahariya Formation was initially deposited in proximal near shore dysoxic marine conditions and the environment of deposition getting more distal to inner shelf dysoxic to anoxic marine conditions in the younger upper part. The samples from both formations include gas prone type III and IV. The spore color observations indicated that the samples from both formations are immature to yield gas and are not effective hydrocarbon source.     

Pursuit formations with dynamic control gains

The paper presents a coordinated motion control law of multiple autonomous agents based on the pursuit strategy with dynamical gains. In particular, we are interested in the control law with no communication between the agents, that is, the leader's moving velocity is not known by the follower robots. Each follower only utilizes its local measurement of relative position information to keep a desired distance and a desired bearing with its neighbors according to a fixed topology. The paper proposes a modified follower's control law, in which each follower pursues its neighbor along the line of sight rotated by a constant offset angle with a dynamic control gain. The offset angle is designed to attain the specific bearing and the dynamic control gain is introduced for the purpose of achieving the desired distance to its neighbor. Then, all the agents make the same motion to the leader's in a steady formation. It is shown that, for the case of uniform rectilinear motion, the group of mobile robots converges to the exact formation specified by the offset angles and the distances no matter what the leader's velocity is, whereas for the case of uniform circular motion, the group of agents converges to an approximation of the formation attained in the rectilinear motion case when the leader's turning radius is much greater than the desired distances between neighboring robots. The effectiveness of the proposed technique and the obtained analytical results are demonstrated in simulations. Copyright © 2011 John Wiley & Sons, Ltd.     

Cutaneous sensory nerve formations as studied with impregnation techniques: Notes about a simple and reliable method

In spite of the modern immunocytochemical methods employed in the study of peripheral sensory nerve formations, silver impregnations are still frequently used. This paper describes and discusses in detail a simple “Cajal-type” silver impregnation method suitable for the peripheral and central nervous systems, which offers excellent results when used in the study of sensory nerve formations. Essential features are (a) the use of a pretreatment solution containing sodium tartrate and picric acid; (b) the short time needed for the whole impregnation process; (c) its simplicity, and (d) the ability to show the axonal elements of sensory nerve formations and other very thin nerve fibres too difficult to be demonstrated with immunohistochemical methods. Taken together, these properties allow this method to be included among the so-called “routine methods.” © 1996 Wiley-Liss, Inc.     

中国南方海相层系油气成藏组合类型与勘探前景

中国南方海相层系以志留系区域滑脱层为界,可分为上、下两个构造层,据不同地区上、下构造层形变特征与强度及其组合特征,可将其地质结构分为单层稳定、双层连续、双层断褶、单层叠瓦、双层冲滑、单层冲断和二元推覆等7种类型。印支以来多期沉降与隆升产生了"早降晚抬"和"早抬晚降"2大类6种形式的埋藏演化史类型。海相地层原始建造、后期构造运动改造与上覆陆相地层的叠加形成了原生型、改造型、再生型和后生型4种类型的成藏组合。其中原生型成藏组合油气保存条件好,勘探前景好。中、下扬子区再生型和后生型成藏组合具有一定的勘探前景。     

松辽盆地徐家围子断陷火山活动期次与烃源岩演化

徐家围子断陷在断陷期有3次较大规模的火山活动,营城期火山活动持续时间最长。火山活动加速了深层火石岭组、沙河子组、营城组3套主力烃源岩的成熟。烃源岩的埋藏史、热史和生烃史模拟计算结果表明,徐家围子断陷深层火石岭组烃源岩埋深1300 m的R_o值,在约1Ma 时间内迅速达到0.7%。沙河子组以及火石岭组烃源岩埋深约2600 m时,R_o值已经达到1%。泉头组沉积前,沙河子组及火石岭组烃源岩已进入生气高峰。青山口组沉积前,营城组烃源岩处于生气高峰,沙河子组以及火石岭组开始生成干气。此时,登娄库组二段和泉头组一、二段区域盖层业已形成,徐家围子断陷开始形成营城组-泉头组天然气藏。嫩江期末,由于边界断层的活动,营城组-泉头组天然气藏进行再分配。     

耐盐胶乳水泥浆体系的室内研究

胶乳水泥浆体系已广泛应用于大位移井、分支井、大斜度井、调整井和小井眼井等疑难井的固井,用以提高水泥浆的防气窜和控制失水能力,同时改善水泥石的胶结性能、韧性和防腐蚀能力.但是,由于盐的存在会使胶乳双电层的zeta电位降低,从而破坏胶乳的稳定性,导致胶乳在盐水中发生絮凝,因而限制了其在含盆岩层(盐层、盐膏层、盐水层)和水敏...     

海底天然气水合物成因影响因素探讨

自然界中的天然气水合物资源主要存在于海洋中,海底的自然条件是形成天然气水合物的基础.文章探讨了多孔沉积物、孔隙水成分等因素对天然气水合物形成条件的影响,分析了海底天然气水合物的成藏特性.     

中条山某公路隧道地下水环境问题探讨

以中条山某公路隧道为研究对象,从隧道区的地质环境、水文地质条件、地下水环境特征等方面入手,对隧道施工的可能突水来源进行了分析,主要探讨了公路隧道地下水环境相互转化关系,得出了相关结论并提出建议。     

Crystallization in a Barium-Containing Magnesium Aluminosilicate Glass-Ceramic

Crystallization in a Ba-containing magnesium aluminosilicate (Ba-MAS) glass-ceramic was studied using transmission electron microscopy. Ba-MAS slabs were hot-pressed at 1000°C to form dense glassy bodies, which were crystallized by further heating in air or argon between 850° and 1300°C. Heterogeneous nucleation of a metastable highquartz solid solution (μ-cordierite) occurred at crystallization temperatures below 1100°C, followed by dendritic growth; the interdendrite phase was Ba-rich silicate glass. The high-quartz solid solution generally acted as a precursor for the nucleation of the stable β -phase, which was the final crystallization product. Surprisingly, slower crystallization kinetics were observed in argon than in air. Further morphological changes at the higher temperatures and longer annealing, times resulted from a Rayleigh type instability, which led to breakup of the interdendrite silicate rods, and simultaneous polygonization of β -cordierite.     

东秋五井复合盐层钻井技术

论述了塔里木盆地第三系复合盐层的基本特征及对钻井工程的危害；通过东秋五井的钻井实践，总结出一套复合盐层钻井技术措施。