High-quality Hydrocarbon Source Rocks Research Articles

The Geochemical Characteristics of High Quality Hydrocarbon Source Rocks - A Case Study of Hailaer Basin

The distribution of high quality hydrocarbon source rocks plays an important role in the accumulation of oil and gas. As a result, the identification of geochemical characteristics of high quality source rocks is the key to discriminate the distribution of high quality source rocks accurately. By core observation and sample analysis, taking Wuerxun-Beier depression in Hailaer Basin as the target regions, we make accurate discrimination of high quality hydrocarbon source rock developmental characteristics and comparison with common source rocks. The research shows that: (1) the hydrocarbon expulsion efficiency in study zone is high due to the alternating deposits of high quality hydrocarbon source rocks and sandstones. The high quality hydrocarbon source rocks deposited in the reducing environment to strong reducing ones, whereas common rocks deposited in oxidizing environment to weak oxidizing ones. (2) the occurrence of organic matter of high quality hydrocarbon source rocks is mainly in stratified enrichment type. The organic matter develops parallel bedding or basic parallel bedding. However, the distribution of organic matter of common source rocks is porphyritic and heterogeneous, or interrupted lamellar. (3) the hydrocarbon potential of high quality hydrocarbon source rocks is more than ten times that of common source rocks. (4) the content of organic carbon in high quality source rocks is high and the content of chloroform asphalt A is relatively low, which reflects that the hydrocarbon expulsion efficiency of high quality source rocks in the sand-shale interbeds of study zone is high.

High quality source rocks in trough facies of Upper Permian Dalong Formation, Sichuan Basin

Source rocks in trough facies of the Upper Permian Dalong Formation of the Sichuan Basin were assessed by field observations and measurements in outcrop areas as well as from logging and core/cutting analysis from drilling sites. The results show that in the Dalong Formation, the black shale and sapropelite facies have an average TOC of 5.86%, with the maximum value up to 24.31%, making them high quality hydrocarbon source rocks. Dark cryptite, with a TOC of 0.77% (on average) is also a good hydrocarbon source rock. A dark silicate, with TOC of only 0.13% on average, has no potential to generate hydrocarbons. Since the source rocks are much evolved, the content of chloroform bitumen “A” extracts tend not to be high. The (S1+S2) value of source rocks in the Dalong Formation are low, with only 4.36 mg/g on average. The major macerals of Kerogen of the Dalong Formation are sapropels, averaging 71.5%. Kerogen is mainly Type II1, and a little belongs to II2. The flourishing of pelagic organisms during deposition of the Late Permian Changxing Formation, slow deposition rate of the Dalong Formation and an anoxic and calm deep water depositional environment are the key controlling factors for accumulation, preservation and generation of organic matter in this part of the basin. ： 通过四川盆地上二叠统海槽相大隆组露头区野外观察测量和钻井区测井及岩心、岩屑分析，对大隆组烃源岩进行评价。研究表明，大隆组黑色泥质岩、腐泥岩TOC平均值为5.86%，最高可达24.31%，是一套优质烃源岩；大隆组暗色泥晶灰岩TOC平均值可达0.77%，也是很好的烃源岩；大隆组暗色硅质岩TOC平均值仅为0.13%，不具备生烃能力。由于烃源岩演化程度较高，氯仿沥青“A”含量总体不高。大隆组烃源岩（S1＋S2）值总体也比较低，平均值仅4.36 mg/g。烃源岩干酪根显微组分以腐泥组为主，干酪根主要为Ⅱ1型，少量为Ⅱ2型。晚二叠世长兴组沉积期浮游类生物繁盛、大隆组沉积速率缓慢以及缺氧、安静的深水沉积环境是有机质富集、保存、形成优质烃源岩的主要控制因素。图6表2参12

Exploration potential of Chang 9 member, Yanchang Formation, Ordos Basin

Abstract New discoveries have been achieved in the exploration of the Yanchang Formation Chang 9 member. This article discusses the exploration potential of the Chang 9 member from the hydrocarbon source rock condition, reservoir condition, and the pattern of hydrocarbon generation and storage. The Chang 9 member develops high quality hydrocarbon source rock (the mean TOC is 4.36% and R0 is 0.66–1.01%), has superior hydrocarbon-offering capacity, and the total resources surpass 402 million tons of oil. Delta front subaquatic distribution channel sandstone and river mouth bar sandstone can be laterally connected as a complex and the main reservoir space is made up of the remnant primary pores. The reservoir capability is good. The member develops three types of plays: self-generation and self-storage, below-generation and above-storage, above-generation and below-storage. The exploration potential of the self-generation and self-storage is best with dark mudstone or oil shale as the source rock and sandstone as the reservoir.

Chemical variation from biolipids to sedimentary organic matter in modern oceans and its implication to the geobiological evaluation of ancient hydrocarbon source rocks

Understanding the dynamics of organic matter in modern marine water columns greatly favors the geobiological evaluation of hydrocarbon source rocks. Biolipids could make great contribution to petroleum hydrocarbons due to their comparable chemical components and the slightly refractory characteristics of biolipids during the microbial/thermal degradation. A variety of environmental factors such as temperature, CO2 and salinity could affect the biochemical contents in microorganisms. As a result, microorganisms living in a changing environmental condition might have a different contribution to the petroleum formation. Organic carbon flux is shown to bear a positive correlation with the primary productivity only within a certain range of biomass volumes in a specific biohabitat. Furthermore, organic matter is degraded much quickly in a water column with oxic conditions. Therefore, the anoxic condition, along with the enhanced biological productivity, would be one of the significant factors in the formation of high-quality hydrocarbon source rocks. The formation of biofilms and microbial mats favors the preservation of sedimentary organic matter by decreasing the degradation rate of organic matter. Identification of biofilms and microbial mats in sedimentary rocks will thus greatly help to understand the depositional processes of organic matter finally preserved in hydrocarbon source rocks.

High-quality hydrocarbon source rock in the Paleogene sequence of the Ping Chau Formation, Hong Kong

Although petroleum exploration is being conducted in the Hong Kong region, high-quality hydrocarbon source rocks have never been found in this area. The Ping Chau Formation is only Mesozoic-Cenozoic sedimentary rock exposed in Hong Kong and its surrounding areas. The hydrocarbon source rock of the Ping Chau Formation is very rich in organic matters, which has an average total organic carbon (TOC) of 1.9% and chloroform bitumen “A” range from 0.14% to 0.24%. The total hydrocarbon content varies from 880 to 1800 ppm and the transformation ratio is specific from 5 to 9. The index of pyrolytic hydrogen is up to about 600 mgHC/gTOC. These data demonstrate the characteristics of the high-quality hydrocarbon source rock. The lamalginite is the major maceral of the source rock of the Ping Chau Formation, and geochemical characteristics also suggest that the organic materials of the source rock are of type I and type II1, with abundant gammacerane, γ, β-carotane and C24 tetracyclic terpane, which indicate that it was formed in the salt water and brackish water sedimentary environment, and the source rock has evolved into a mature phase. The organic inclusions are found within calcite veins in cracks of the source rock, indicating that hydrocarbon has been generated and a secondary migration has happened. The source rock in the Ping Chau Formation is about 200–300 m thick, thus having considerable hydrocarbon potential. The discovery of the high quality hydrocarbon source rock in the Ping Chau Formation will certainly provide insight on hydrocarbon resource exploration in the South China Sea area.

High-quality hydrocarbon source rock in the Paleogene sequence of the Ping Chau Formation, Hong Kong

High-quality hydrocarbon source rock in the Paleogene sequence of the Ping Chau Formation, Hong Kong