惠民凹陷下第三系湖相沉积密集段特征

沉积密集段作为层序地层学理论中的一个重要概念，它控制着盆地生油岩层的分布和厚度。为了更好地研究生储盖组合关系，预测隐蔽油气藏，利用层序地层分析的基本原理和方法，对惠民凹陷进行了层序地层学研究，将其下第三系沙河街组二、三、四亚段划分为３种层序类型，确定出断陷初期型、强断陷期型和断陷后期型３种类型沉积密集段，每一层序又可进一步划分成低水位体系域（ＬＳＴ）、湖侵体系域（ＴＳＴ）、高水位体系域（ＨＳＴ）和下降体系域（ＦＳＳＴ）。

Turbidite Petroleum Geology Updates in the Deepwater and Subsalt Gulf of Mexico

The past six years （2008-2014） was a prosperous time for exploration and production in the dGOM （deepwater Gulf of Mexico）. Recent exploration and production activities can be divided into three major categories： drilling new wildcat wells, appraising and developing newly discovered fields and enhanced oil recovery of mature fields. Seismic imaging, complex geology, high pressure drilling, greater depth, and higher temperature are key challenges for the exploration and production of dGOM reservoirs. Complex geology includes salt-related structures and traps, reservoir compartmentalization, and the sequence stratigraphy of turbidite reservoirs. Turbidite sequence stratigraphy helps the asset team to fred the best target intervals. Sheet and channelized sandstones with good downdip aquifer support are preferred reservoir conditions. All the drilling, development and production challenges are related to high pressure, greater depth, higher temperature and lack of existing field analogs. Various IOR （improved oil recovery） methods are studied and applied in the development stage of the Wilcox fields, which have an average primary recovery factor of 10%-15%. With ideal tabular reservoir geometry and IOR methods, recovery factor of the Wilcox reservoirs can reach up to 42% of OOIP （origional oil in place） through the field life cycle.

Presence of carboxylate salts in marine carbonate strata of the Ordos Basin and their impact on hydrocarbon generation evaluation of low TOC, high maturity source rocks

The total organic carbon （TOC） in the marine source rock of the Ordos Basin mostly ranges from 0.2% to 0.5%. The industrial standard commonly states that the TOC value has to be no less than 0.5% （0.4% for high mature or over-mature source rock） to form large petroleum reservoirs. However, gas source correlation indicates that the natural gas in the Jingbian gas field does receive contribution from marine source rocks. In order to determine the effect of Carboxylate salts （or called as organic acid salts） on TOC in highly mature source rocks with low TOC value, we sampled the Ordovician marine source rock and the Permian transitional facies source rock in one drilled well in the southern Ordos Basin and performed infrared and GC-MS analysis. It is found that both kerogen-derived organic acids and carboxylate salt-conversed organic acids exist in both marine and transitional facies source rocks. The carboxylate salt-conversed organic acids mainly come from the complete acidification of carboxylate salts, which confirms the presence of carboxylate salts in the marine source rocks. Although the C16：o peak is the main peak for the organic acids both before and after acidification, the carboxylate salt-conversed organic acids have much less relative abundance ahead of C^6：o compared with that of the kerogen-based and free organic acids. This observation suggests that the kerogen-based and free organic acids mainly decarboxylate to form lower carboxylic acids, whereas the carboxylate salt-conversed organic acids mainly break down into paraffins. By using calcium hexadecanoate as the reference to quantify the kerogen-derived and carboxylate salt-conversed organic acids, the high TOC （〉2.0%） marine source rocks have low carboxylate salt content and the low TOC （0.2%-0.5%） marine source rocks contain high content of carboxylate salt. Therefore, for the marine source rocks with 0.2%-0.5% TOC, the carboxylate salts may be a potential gas source at high maturity stage.

Evaluation of hydrocarbon generation of the Xiamaling Formation shale in Zhangjiakou and its significance to the petroleum geology in North China

The semi-closed pyrolysis simulation system under constant pressure was conducted to explore the characteristics and mechanisms of hydrocarbon generation from Xiamaling Formation shale in Xiahuayuan,North China.The experiment results indicate the oil generated by the Xiamaling Formation shale in oil window should be classified as "aromatic-intermediate" type,whereas the decreasing of dry coefficient can be ascribed to the cracking of residual bitumen in source rock in the stage of high to post maturity.The amount of hydrocarbon gas generated from residual bitumen can be up to 1-2 m3 per ton rock in high to post mature stage by calculating hydrogen contents in the kerogen,the expelled hydrocarbon,and the residual hydrocarbon.This reveals the importance of residual bitumen as a gas source during high to post mature stage of the kerogen evolution,and also as the broad exploration prospect of these gases.This research highlights the attention should be paid to oil/gas reservoirs sourced from residual bitumen of organic-rich source rock in high mature stage,even the primary oil/gas reservoirs considered as the main exploration targets in middle-upper Proterozoic sediments of North China.