Characteristics of Oil Sources from the Chepaizi Swell,Junggar Basin,China

So far there has been no common opinion on oil source of the Chepaizi swell in the Junggar Basin. Therefore, it is difficult to determine the pathway system and trend of hydrocarbon migration, and this resulted in difficulties in study of oil-gas accumulation patterns. In this paper, study of nitrogen compounds distribution in oils from Chepaizi was carried out in order to classify source rocks of oils stored in different reservoirs in the study area. Then, migration characteristics of oils from the same source were investigated by using nitrogen compounds parameters. The results of nitrogen compounds in a group of oil/oil sand samples from the same source indicate that the oils trapped in the Chepaizi swell experienced an obvious vertical migration. With increasing migration distance, amounts and indices of carbazoles have a regular changing pattern （in a fine linear relationship）. By using nitrogen compounds techniques, the analyzed oil/oil sand samples of Chepaizi can be classified into two groups. One is the samples stored in reservoir beds of the Cretaceous and Tertiary, and these oils came from mainly Jurassic source rock with a small amount of Cretaceous rock; the other is those stored in the Jurassic, Permian and Carboniferous beds, and they originated from the Permian source. In addition, a sample of oil from an upper Jurassic reservoir （Well Ka 6）, which was generated from Jurassic coal source rock, has a totally different nitrogen compound distribution from those of the above-mentioned two groups of samples, which were generated from mudstone sources. Because of influence from fractionation of oil migration, amounts and ratios of nitrogen compounds with different structures and polarities change regularly with increasing migrating distance, and as a result the samples with the same source follow a good linear relationship in content and ratio, while the oil samples of different sources have obviously different nitrogen compound distribution owing to different organic matter types of their source rocks. These conclusions of oil source study are identical with those obtained by other geochemical bio-markers. Therefore, nitrogen compounds are of great significance in oil type classification and oil/source correlation.

Distribution and Significance of Carbazole Compounds in Palaeozoic Oils from the Tazhong Uplift, Tarim

Carbazole compounds in crude oils from the Tazhong uplift of the Tarim basin have been fractionated and detected and successfully used to study petroleum migration and trace source rocks in the study area. Alkylcarbazoles have been found in large amounts in the oil samples analyzed and alkylbenzocarbazoles detected in a small concentration only in part of the samples, but alkyldibenzocarbazoles have not been found in oils. Based on the distribution of G1, G2 and G3 of C2-alkylcarbazoles, the ratio of C3-carbazoles to C2-carbazoles and the relative amounts of alkylcarbazoles and alkylbenzocarbazoles, one can know that the vertical oil migration in the Tazhong uplift is generally from below upward, i.e. from the Ordovician through the Silurian to the Carboniferous. Evidently, source rocks in the uplift should be lower Palaeozoic strata (Ordovician and Cambrian). This study shows that carbazoles are of great importance in the study of petroleum migration and source rocks.

Geochemical significance of pyrrolic nitrogen compounds in various kinds of crude oils from the Tarim Basin

This is a report of the differences in abundances of pyrrolic nitrogen compounds and distribution of alkylated carbazoles among various oils from the Tarim Basin. At the same time, their geochemical significance is discussed.

苏北盆地溱潼凹陷油气运聚模式

通过对苏北盆地溱潼凹陷不同构造带部分具代表性油藏原油的饱和烃、芳烃生物标志物和吡咯类含氮化合物分布特征的分析,结合油区构造研究和油源对比成果,讨论了研究区油气的运移方向与运聚模式。结果表明,研究区不同构造带原油中吡咯类含氮化合物分馏效应存在差别,处于断阶带南侧的成熟原油运移效应明显,来源于其西北侧的俞垛次凹始新统阜宁组二段烃源岩;断阶带北侧的原油运移分馏效应较差,推测其主要来源于北侧的储家楼次凹阜宁组二段烃源岩,以短距离侧向运移为主;内斜坡带原油主要来自于储家楼深凹阜宁组二段烃源岩,沿其构造带上倾方向自西南到东北方向,含氮化合物分馏效应明显;坡垒带与外斜坡带阜宁组三段原油成熟度偏低,吡咯类含氮化合物浓度较高,原油自东北向西南方向以短距离运移为主,主要来自于深凹的低熟烃源岩。不同构造带的油气成藏模式也不一致,断阶带为阶梯状断块油气聚集模式,内斜坡带与坡垒带主要分布受断层控制的断块—岩性油藏,外斜坡带为反向正断层垒块控油模式。

酒西盆地老君庙构造带油气来源的探讨

酒西盆地自从发现鸭儿峡、老君庙、石油沟及柳沟庄等油气田以来 ,大多数学者认为油气来自青南凹陷。经过对原油物性、含氮化合物、山前推覆体构造、已发现油气储量占油气资源的比例及近几年油气勘探进展的分析 ,认为老君庙与石油沟的油气中的较大部分应是山前推覆体之下掩埋的下白垩统烃源岩所生成。图 3表 1参

准噶尔盆地中部Ⅰ区块现今油气运移方向研究

根据石油成熟度梯度、原油中吡咯类含氮化合物丰度和异构体参数变化特征以及原油中高分子量正构烷烃的分布特征,结合车—莫古隆起的构造演化,探讨了准噶尔盆地中部Ⅰ区块油藏可能的油气运移方向。结果表明,研究区原油间运移分馏效应十分复杂,近期原油主要运移方向是由南向北,即油气是从南部的征1井区向沙1井、庄1井区运移。

运用原油吡咯类含氮化合物研究塔里木盆地塔中地区石油的二次运移

在塔里木盆地塔中地区的原油中分离和检测到咔唑类含氮化合物，并成功地将其应用于油气运移研究。烷基咔唑类化合物大量存在于所分析的样品中，苯并咔唑只在部分样品中检测到且含量小，而二苯并咔唑则未发现。根据C2烷基咔唑的G1、G2和G3结构类型的分布，C3－咔唑／C2－咔唑比值以及烷基咔唑与苯并烷基咔唑的相对含量可知，塔中地区石炭系C3油组的石油分别从北西和南东两个方向向塔中4号构造的高点侧向运移。研究还表明该区的原油可能经历了相当长距离的运移。

柴达木盆地跃进地区石油运聚特征研究

通过对柴达木盆地跃进地区烃源岩物质基础、原油地球化学特征的系统剖析,应用成熟度参数和含氮化合物参数揭示了研究区2个不同构造区的两种不同石油运移方式。提出跃进一号构造区尕斯库勒油田原油主要来源于北部的茫崖坳陷和红狮坳陷,石油自北向南运移,并具有多源注入-混合聚集成藏的特征;跃进二号构造中的原油则主要由南向北运移成藏,其中扎哈泉凹陷对该地区油藏的形成有重要贡献。