Petroleum Source Rock Characteristics of the Lower Tertiary Formations in the Ereğli-Ulukışla Basin,Southern Central Anatolia,Turkey

Abstract

Potential source rocks in the Ere?li-Uluk??la basin include Campanian-Maastrichtian limestones and marls, Upper Paleocene-Lower Eocene deep-marine shales, and Middle-Upper Eocene continental slope deposits, including shales and sandstones. Organic geochemical analyses and palynofacies observations show that the organic components in Upper Paleocene-Upper Eocene sediments are mainly coaly and woody, with minor herbaceous and algal-amorphous-like organic matter, indicating that they are terrigenous (mainly Type III and Type IV kerogen). The organic carbon content of these rocks ranges from 0.04 to 0.73%, and they have marginal source rock quality for oil generation. A plot of HI versus T-max values implies that the Upper Paleocene-Lower Eocene samples are in the early stage of oil generation, while the Middle-Upper Eocene samples are thermally immature. The pristane/phytane ratio for Tertiary samples corresponds to a transition from anoxic to oxic depositional conditions.     

The Amount of Organic Matter,Kerogen Type,and Source Rock Potential of Bituminous Shales (Beydili,Nallıhan/Turkey)

Potential source rocks west of the central Anatolia basin, in Beydili/Nall?han (Turkey) include Paleocene-Eocene oil shale. Organic geochemical analyses show that the organic components in oil shale are of mainly algal-amorphous organic matter, indicating that they are marine (mainly type I–II kerogen). The organic carbon content of Beydili rocks ranges from 1.35 to 11.12 wt%, Göksarl?k Tepe rocks 1.06 to 13.8 wt%, and Kepeztepe rocks 1.55 to 11.31 wt% They have source rock quality for oil generation. The Paleocene-Eocene oil shale is in the early stage of oil generation. The redox conditions of depositional environment in three different areas have a transition period from oxic to anoxic.     

Source rock potential of the Sayındere formation in the Şambayat oil field,SE Turkey

Upper Campanian–Maastrichtian Say?ndere Formation, located in southeastern Turkey, composed of pelagic limestone which was deposited relatively deep marine. In this study, well samples of the Say?ndere Formation were analyzed by Rock-Eval pyrolysis and the oil sample from this unit were analyzed by GC, and GC-MS to assess source rock characteristics and hydrocarbon potential. The TOC values of the Say?ndere Formation samples range from 0.34 to 4.65?wt.% with an average of 1.14?wt.% and organic matter have good TOC value. Hydrogen Index (HI) values range from 407?mg HC/g TOC to 603?mg HC/g TOC and indicates Type II kerogen. T_max values are in the range of 434 - 442?°C and indicate early-mid mature stage. The Say?ndere samples have fair to good hydrocarbon potential based on TOC contents, S2, and PY values. According to the HI versus TOC plot, most of the samples have good oil source. The oil sample contains predominant short-chain n-alkanes and plots in marine algal Type II field on a Pr/n-C17 versus Ph/n-C18 cross-plot indicating anoxic environment. Biomarker analysis shows that the deposition of oil source rock is carbonate-rich sediments.     

The Sedimentary System and Evolution of the Early Tertiary in the Sunda Basin, Indonesia

1.Introduction The Sunda basin covers about7,000km2.Its maximum thickness at the depocenter is around16,000feet(5,000m).It has a north-south direction strike(Fig.1).The basement rock is believed to be Cretaceous granodiorite,metabasalt,mica schist and limestone(Tonkin and Himawan,1999).The basin began to take the shape at the Paleocene-early Oligocene,due to the collision of the Indian plate with the Eurasian plate(Hall,1997;Howells,1997).This collision produced the major NW-SE stress s…     

Sedimentary Characteristics and Evolution of Asri Basin,Indonesia,in Early Tertiary

1.Introduction The Asri basin is oval in shape,covering about2500km2from north to south.The maximum thickness at the depocenter is around18,000feet(5,500m).It is adjacent to the Hera basin in the west and to the Sunda basin in the southwest(Fig.1).Now it is under the Java sea.The basement consists of granites,granodiorites,marbles,schists and quartzites(Tonkin and Himawan,1999).In the early Tertiary,the eastern side of the basin was a steep slope controlled by syn-rifting,and the western s…     

Reservoir characterization of the Odovician oil and gas pools in the Tahe Oilfield, Tarim Basin, Northwest China

About 88. 1% of the proven reserves in the Tahe Oilfield in the Tarim Basin of Northwest China are trapped in Ordovician carbonate reservoirs. These reservoirs are formed by unconnected and interconnected networks of karstic porosity forming a heterogeneous and complex reservoir system. Oil, water and gas characteristics vary significantly in different portions of the Ordovician reservoir. There is no uniform oil/water contact in the field, adding to its complexity.An acid fracture treatment is beneficial in 76% of the wells, stimulating nonproductive wells and enhancing production in other wells by fracturing into unconnected reservoirs and enhancing flow pathways with acid. Acid fracture treatments should be a standard procedure for developing this and similar oil fields.     

Exploration Area and Potential of Natural Gas in Junggar Basin

Junggar Basin, located in Northern Xinjiang between Altai and Tianshan Mountains, is the second largest basin in China with its sedimentary area being about 130,000 square kilometers. A group of caprocks are developed over Carboniferous of the basin, including the Permian, Triassic, Jurassic, Cretaceous, Paleogene, and Neogene, among which the biggest sedimentary caprock is 15,000 meters thick. The formation and accumulation of oil and gas in the basin can be characterized by multistage and multisource after undergoing multiperiod structural movements such as Late Hercynian, Indosinian, Yanshanian, and Himalaya, etc.     

Direction and Potential of Exploration for Natural Gas in Qaidam Basin

Qaidam Basin is a large Meso-Cenozoic interior basin, which is surrounded by Qilianshan Mountains, Altun Mountains, and Kunlun Mountains, and with its geographical area, area of sedimentary rock, and maximal sedimentary thickness being 250 thousand km^2, 121 thousand km2, and 17.2 thousand meters respectively. The natural gas resources is sufficiently abundant in the basin. It is estimated that the total oil and gas resources is 4.65 billion tons at present, of which natural gas resources is 2500 billion m^3.[第一段]     

Characteristics of Guang’an Xu6 Tight Gas Reservoir in the Middle of Sichuan Basin,China

Tight gas reservoirs have been researched nearly 50 years and become more and more important in the future with the increasing consumption of nature gas. In this study, the characteristics of Guang’an tight gas reservoir, which lies in the middle of Sichuan Basin, China, was analyzed. This reservoir is a typical tight gas reservoir. First, the porosity and permeability of it are low. Second, it has high water saturation and diffused boundaries. Third, it does not have an obvious seal. Fourth, it does not have a clear gas-water contact. Fifth, it has geologic “sweet spots,” close to source rock. Sixth, it has normal reservoir pressure. According to the actual conditions of Guang’an tight gas reservoir, a new reservoir accumulation model is established, which integrates the knowledge of conventional and unconventional reservoir, and which can explain the special phenomenon that tight gas reservoir can produce water and have normal pressure.     

Formation and Accumulation of Hydrocarbons in the Central Uplift,Dongying Depression

1. Introduction The Central Uplift discussed is located in the center of the Dongying Depression, Bohai Bay Basin, which is one of the most important petroliferous areas in China. It borders the Lijin Sag in the west and south, and is bounded by the Niuzhuang and Minfeng sags in the east and northeast respectively. There are multiple source rocks providing oils for the Uplift, with different types of hydrocarbon genesis due to the special geological background (Liu, et al., 2004). The Up…     

An Optimum Model for Speeding Exploration and Development-the Development Concept Design of the Carboniferous Reservoir in Datianchi Structural Belt in Sichuan Basin

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Diagenesis and Its Effect on Reservoir Quality of Silurian Sandstones,Tabei Area,Tarim Basin,China

The diagenetic processes of the Tabei sandstones in the Tarim Basin include compaction, cementation (quartz overgrowths, calcite, clay minerals and a minor amount of pyrite), and dissolution of the feldspar and calcite cement. Porosity was reduced by compaction from an assumed original 40% to about 22.1%. Cementation reduced porosity to 26.6%. The Tabei sandstones lost a little more porosity by compaction than by cementation. Quartz cementation, especially syntaxial quartz overgrowth, is a major cause of porosity-loss in many reservoirs in moderately to deeply buried sandstone. Calcite cementation played a key role in the porosity evolution of sandstones. At the early stage of burial, the early calcite cement occupied most of the pore spaces resulting in significant porosity. On the other hand, some primary porosity has been preserved due to incomplete filling or the presence of scattered patches of calcite cement. In addition to calcite, several clay minerals, including illite and chlorite occurred as pore-filling and pore-lining cements. The pore-lining chlorite may have helped in retaining the porosity by preventing the precipitation of syntaxial quartz overgrowths. Illite, which largely occurred as hair-like rims around the grains and bridges on the pore throats, caused a substantial deterioration of penetrability of the reservoir. Calcite cement dissolution was extensive and contributed significantly to the development of secondary porosity.     

Further Recognition of Petroleum Exploration Potential of Marine Carbonates in Western Tarim Basin

A series of significant discoveries in marine carbonate rocks show great petroleum exploration potential in the Tarim Basin. However, the oil and gas fields discovered in the carbonate rocks are mainly distributed around the Manjiaer Sag in the eastern Tarim Basin. Some explorations occurred and no oil or gas field was discovered around the Awati Sag in the western Tarim Basin. Information from wells and outcrops reveals that there are excellent oil and gas source rock conditions around the Awati Sag. Transformed reef-shoal reservoirs could be formed in the Ordovician carbonate rocks with paleo-geographic background and hydrothermal conditions. Therefore, it is necessary to make a systematical study and overall evaluation of the potential of the periphery of the Awati Sag in terms of source rock evolution, resource potential, high-grade reservoir formation and distribution, and main factors controlling hydrocarbon migration and accumulation.     

Significance of Coal Seam in Recognition of Sequence Boundaries and Systems Tract of the Jurassic in East Fukang Slope, Junggar Basin, China

1. Introduction The East Fukang Slope is located in the east of the Changji Sag and on the junction of the middle-south of the Zhangbei Fault-fold Zone and the Baijiahai Salient in the northeast of the Junggar Basin, Northwest China, with an area of about 5,000 square kilometres (Fig. 1). When the Jurassic was deposited, a huge slope with a north-south dip was formed, which consisted of the Wucaiwan Sag, front of the Kelameili Mountain piedmont, the Baijiahai Salient and the East Fuka…     

Fouling and Antifouling of Depetanizer in Ethylene Units

Factors affecting fouling of depentanizer in ethylene units were explored through study of the composition of pyrolysis gasoline,C5 distillate and fouling deposits from the depentanizer while taking into consideration the processing parameters.A variety of antifouling measures,in particular the injec-tion of a special anti-fouling agent into the C5 gas phase pipeline and the C5 distillate reflux pipeline were introduced.Commercial evaluation test of a multifunctional anti-fouling agent,the RIPP-1404 anti-fouling agent,was also described.     

Characteristics of the lower part of the Xiaganchaigou Formation in the Mabei-Ⅶ structure in the northern margin, Qaidam Basin

基于岩心、测井资料及普通薄片、铸体薄片、扫描电镜、X衍射、物性和压汞等化验分析资料,研究了柴达木盆地马北8号构造下干柴沟组下段砂岩储层特征.结果表明:该套储层的储集空间以原生粒间孔为主,夹少量次生粒间孔,储层物性好,排驱压力和饱和度中值压力较低,孔喉半径较大且分选性中等,歪度粗,孔隙结构参数总体较好.储层质量受沉积相和成岩作用的综合影响,其中,辫状河河床及滩坝沉积区为最有利储层发育区,加之压实作用较弱、成岩早期的中等胶结作用和比较普遍的溶蚀作用有利于原生孔隙和喉道的保存及部分次生孔隙和喉道的发育.利用储层物性及压汞等参数,将马北8号构造下干柴沟组下段储层划分为Ⅰ、Ⅱ、Ⅲ类储层,其中Ⅰ、Ⅱ类储层在目前的技术条件下是增储上产的首选储层.     

Existence and implications of hop-17（21）-enes in the lower Cretaceous of the Saihantala Sag, Erlian Basin, China

C31- to C35-hop-17(21)-enes are identified by gas chromatography-mass spectrometry (GC-MS) analysis to exist as double isomers in most samples of the Aershan Formation and members 1 and 2 of the Tenggeer Formation from well SH3. Comprehensive organic geochemistry and organic petrology study indicates that algae and bacteria are the main biological source of lower Cretaceous sediments in the Saihantala Sag, and this is in accordance with the existence of hop-17(21)-enes. The similar distributions of hop-17(21)-enes and hopanes of these samples indicate that hop-17(21)-enes were transformed into hopanes through hydrogenation during diagenesis processes. The existence of hop-17(21)-enes means that not only the formation of organic matter is related to an anoxic environment and a biological source of algae and bacteria, but also hop-17(21)-enes are direct indicators of hydrocarbon rock at an immature to low-maturity stage. High hydrocarbon conversion ratio, algae and bacteria source and a high abundance of organic matter suggest that the Saihantala Sag has the potential to generate immature to low-maturity oil, which may be of great significance for oil exploration in the Erlian Basin.     

To Reinforce the Research and Exploration of Deep Basin Gas Trap����the speech made at the symposium on Deep Basin Gas trap in Shanganning Basin

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Organic richness,kerogen types and maturity in the shales of the Dakhla and Duwi formations in Abu Tartur area,Western Desert,Egypt: Implication of Rock–Eval pyrolysis

The objective of this study is to assess the organic material for petroleum potential and characterize the relationships between organic material, thermal maturity, and the depositional environments. This is done using “14” samples from the shales of the Dakhla and Duwi formations in Abu Tartur area. The samples have been analyzed using the geochemical method of Rock–Eval pyrolysis. The analysis shows that the total organic carbon content lies between 0.56 and 1.96 wt%. It also shows that kerogen is a mixture of type II and III that is dominant, and is deposited in the shallow and restricted marine environment under prevailing reducing conditions. This type of kerogen is prone to oil and oil/gas production. The geochemical diagrams show that all the studied samples have good thermal maturation. The Dakhla and Duwi formations which have been divided into all zones are mature (have T_max over 435 °C), and have organic carbon content located at the oil window (T_max between 435 and 443 °C).     

Characteristics of Oil and Gas Accumulation in Yong’an-Meitai Area of the Fushan Depression, Beibuwan Basin, South China Sea

The Yong’an-Meitai area is the focus of the present exploration in the Fushan Depression, Beibuwan Basin, South China Sea. All oils from this area are geochemically characterized by higher Pr/Ph ratio, higher proportion of heavy molecular weight hydrocarbons, and higher proportion of C29 regular steranes, which indicate that the organic matter of source rocks might have been deposited in an oxidizing palaeoenvironment and be dominated by higher plant organic matter input. The oil from E3w2 (the second member of Weizhou Fm. of the Oligocene) has a much higher density, relatively higher Pr/nC17 and Ph/nC18 ratios, and a “UCM—unresolved complex mixture” on gas chromatograms, which indicate that it has been slightly biodegraded. CPI and other terpane and sterane isomer ratios suggest they are all mature oils. The timing of oil charging in E3w2 and E2l1 (the first member of the Liushagang Fm. of the Eocene) determined by the homogenization temperatures of fluid inclusions and thermal evolution history are from 9-3 Ma and 8-3 Ma, respectively. Thus, the interpretation of E3w2 as a secondary reservoir is unlikely. The timing of oil charging is later than that of hydrocarbon generating and expulsion of Liushagang Fm. source rocks and trap formation, which is favorable for oil accumulation in this area. All molecular parameters that are used for tracing oil filling direction decrease with shallower burial depth, which suggests vertical oil migration. The widely occurring faults that penetrate through the source rocks of the Liushagang Fm. may serve as a fine oil charging conduit.