苏北洪泽凹陷古近系生物地层研究

洪泽凹陷古近系地层发育齐全 ,介形虫、轮藻、孢粉化石丰富 ,根据其属种分布规律 ,建立了 E1 f— E2 s的 12个化石组合序列 ,论述了各门类化石组合特征及对比关系。在此基础上 ,结合岩、电性对比 ,确立了顺河次凹和管镇次凹综合柱状图、地层对比图以及可用于凹陷内地层对比的 7个岩电性特征段。得出本区古近系除三垛运动和吴堡运动造成不整合或假整合外 ,其余组、段间皆为整合接触的结论     

济源凹陷下第三系碎屑岩的成岩作用特征

根据砂岩铸体薄片、扫描电镜和Ｘ－衍射分析资料，研究了济源凹陷下第三系碎屑岩主要的成岩作用特征，并说明了压实作用、胶结作用和溶蚀作用是影响下第三系碎屑岩储集层孔隙结构的主要因素。     

东海西湖凹陷南端砂岩储层特征及其控制因素

本研究区始新统—中新统地层内大套砂质岩储层发育，砂层厚度为２—３０ｍ。分析结果表明：具有一定储集和渗透能力的砂层主要分布在井深１９００—３２００ｍ（Ｃ—１井、ＣＨ—１井深度可达３６００ｍ），即花港组和龙井组，岩性以细砂岩、粉砂岩为主，还有少量中砂岩。其中的细砂岩、粉砂岩具有粒度分选好，胶结物含量低（＜１０％）、孔隙、渗透条件好（φ为１０—２８％、ｋ为＜１—１８００×１０￣（－３）ｕｍ￣２）；以次生粒间扩大孔、粒内孔、铸模孔和粘土矿物中的微孔及少量原生孔为其储集空间。胶结物以粘土矿物为主，其次为碳酸盐和氧化硅胶结物。本区砂岩体储层物性除受原始地质条件、储集岩的成份、结构、埋藏深度等控制外，同时受成岩后生作用的影响，压实作用和胶结作用使其物性降低，而骨架颗粒（长石为主）和胶结物的溶蚀改善了其储集条件。     

Pressure evolution and hydrocarbon migration in the Baiyun sag, Pearl River Mouth basin, China

The Pearl River Mouth basin is one of the most important offshore basins in China. Petroleum exploration in the deep-water area is to start in the Baiyun sag in the basin. Due to the high cost of exploration in deep-water areas, the hydrocarbon migration and pressure evolution needs to be thoroughly probed before any actual exploration is to be done. Drilling results have indicated that the pore pressure is hydrostatic in shallow-water area. The mud diapirs found in the Baiyun sag indicate that there may be overpressure in the deep-water area. At present, little is known about hydrocarbon migration and pressure distribution in deep-water areas. On the basis of geological data from wells and basin modeling, the research comes to the following conclusions. (1) At least three episodic accumulations and releases of pressure had happened in the Cenozoic, which were closely related to the three regional tectonic movements: the Zhu-Qiong movement in the Late Eocene, the Nanhai movement in the Middle Oligocene and the Dongsha movement between the latest Middle Miocene and Late Miocene. The pressure release and associated hydrocarbon migration occurred primarily during the Dongsha movement, when most of the overpressure was released to hydrostatic pressure except for some overpressure in the deep-water area. (2) Both the measured pressure and the modeling results indicate that the pore pressure is hydrostatic pressure in the shallow-water area. Abnormally high pressure in the deep-water area is noted to be present. The difference of pressure distribution is caused by the lithologies, facies and faults. (3) The diapirs in the deep water cannot be driven by the overpressure because the maximum pressure is less than 9.0 MPa in the course of pressure evolution. (4) The fluids migrated to the shallow-water area and deep-water area along faults. Some faults connected the deep-water fans with the hydrocarbon source. Huge oil and gas fields may be formed in the deep-water area more favourably than in the shallow-water area. Translated from Earth Science-Journal of China University of Geosciences, 2006, 31(2): 229–236 [译自: 地球科学—中国地质大学学报]     

A study on the geochemical characteristics of natural gas and gas sources in the Bozhong sag

Natural gas is composed largely of hydrocarbon gas, especially wet gas in the Bozhong sag. The carbon isotopic composition shows that the gas is of organic origin. The carbon isotopic values of ethane indicate that the natural gas is dominated by mixed gas with minor coal-generated gas and oil-type gas. A gas-source correlation study showed that the source rocks of natural gas are those of the Lower Dongying Formation, the Shahejie Formation and the pre-Tertiary. The natural gas is characterized by multi-source and continuous generation in the study area, indicating that gas exploration potential is good in the Bozhong sag.     

辽河坳陷东部凹陷火山岩构造裂缝形成机制

研究区内最主要的次生裂缝是构造裂缝,是火山岩受构造应力作用后产生的裂缝。按规模构造裂缝可以分为区域构造裂缝与局部构造裂缝。局部构造裂缝包括与纵弯褶皱有关的裂缝、与横弯褶皱有关的裂缝和与断层有关的裂缝。构造裂缝反映出的应力场与区域或局部的应力场是一致的,同时不同级别、不同期次的断层活动过程也是局部或区域裂缝产生和叠加的过程。本区的区域构造裂缝的产生与整个辽河盆地新生代时期,受燕山运动、喜山运动、、幕的强烈影响过程中应力场的变化是一致的。构造裂缝的规模相对较大,在岩体中分布广、研究程度高、规律性强,且成组出现。火山岩要成为良好的储层,必须发育由后期构造作用产生的构造裂缝,将原生的孔隙连通起来,才能成为好的储层。因此,构造裂缝的形成机制对研究裂缝性储层具有十分重要的意义。     

西湖凹陷古近系平湖组泥质岩地球化学特征及其地质意义

西湖凹陷是东海陆架盆地重要的富生烃凹陷之一，平湖组是主要烃源岩和油气富集层系。为了探讨平湖组沉积期构造背景、源区性质及古环境，本文对平湖组泥质岩地球化学特征进行了研究。地球化学分析结果表明，平湖组沉积期同时具有大陆岛弧和活动大陆边缘构造背景。平湖组泥质岩的物源区母岩主要由上地壳岩石演化而来，并通过对比周围隆起区母岩特征，认为西侧的海礁隆起为西湖凹陷西部斜坡区平湖组沉积期的主要物源区，母岩主要以上地壳的长英质火成岩为主，并受到少量来自幔源岩浆和上地壳古生界变质岩系的影响，母岩类型主要为花岗闪长岩和英安质凝灰岩，少量安山岩和变质岩。泥质岩CIA分析表明，平湖组泥质岩的母岩经历了中等—强烈的风化作用，结合Sr/Cu值分析，推断西湖凹陷在平湖组沉积期古气候较为温暖湿润。微量元素和古盐度分析结果以及对盆地古地貌特征分析表明，西湖凹陷平湖组沉积期自北向南沉积背景有明显的地区差异性，北部（A- 1）沉积水体为淡水，主要发育河控三角洲沉积体系，而中部（A- 2）和南部（B- 1）表现为淡水和半咸水交替演化的特征，主要发育受潮汐影响三角洲沉积体系。平湖组泥质岩主要形成于含氧环境中。     

源外鼻状构造区油运移输导通道及对成藏的作用

尚家地区为一鼻状构造,位于三肇凹陷下白垩统青山口组一段油源区之外,其石油的成藏与分布主要受输导通道的控制。能否正确认识该区石油输导通道及对成藏的作用,对于指导该区石油勘探和丰富油气成藏理论均具重要意义。采用油源对比、典型油藏解剖和成藏模式的研究方法,对尚家地区石油输导过程进行了研究,将其划分为以下3个部分：① T2源断裂是三肇凹陷青山口组一段源岩生成石油向下伏下白垩统泉头组四段扶余油层、下白垩统泉头组三段杨大城子油层“倒灌”运移的输导通道;② 被T2—T2-2断裂沟通的砂体是扶余、杨大城子油层石油从三肇凹陷向尚家地区侧向运移的输导通道;③ T2—T1-1断裂是尚家地区扶余、杨大城子油层石油向上覆下白垩统姚家组葡萄花油层运移的输导通道。采用石油输导通道和石油分布之间匹配关系的研究方法,对尚家地区输导通道对石油成藏与分布中的作用进行了研究,得到T2源断裂越发育,三肇凹陷向尚家地区侧向运移的油源越充足;被T2—T2-2断裂沟通的砂体输导通道位置和能力控制着扶余、杨大城子油层和下白垩统泉头组二段石油的分布及富集程度;T2—T1-1断裂输导通道分布控制着尚家地区葡萄花油层的石油富集区域。