Differential diagenetic evolution and hydrocarbon charging of the tight limestone reservoir of the Da’anzhai Member in the central Sichuan Basin, China

2020 ◽  
Vol 8 (4) ◽  
pp. T1007-T1022
Author(s):  
Jiao Su ◽  
Zepu Tian ◽  
Yingchu Shen ◽  
Bo Liu ◽  
Qilu Xu ◽  
...  
Keyword(s):  
Sichuan Basin ◽  
Large Scale ◽  
Depositional Environments ◽  
Carbonate Reservoir ◽  
Source Rocks ◽  
Petroleum Exploration ◽  
Porosity Reduction ◽  
Hydrocarbon Charging ◽  
Pore Evolution ◽  
Central Sichuan Basin

The tight lacustrine carbonate reservoir of the Da’anzhai Member, Lower Jurassic Ziliujing Formation, in the central Sichuan Basin is a typical tight oil reservoir, and it is one of the crucial petroleum exploration targets in the Sichuan Basin. The porosity of the limestone ranges from 0.5% to 2%, and the permeability ranges from 0.001 to 1 mD. The Da’anzhai limestone experienced multiple diageneses, including compaction, cementation, dissolution, and recrystallization. Different diageneses occurred in the burial process due to the various fabrics and depositional environments, eventually forming distinct rock types; therefore, the pore evolution and hydrocarbon charging characteristics are inconsistent. In our research, there are two stages of major maturation and hydrocarbon expulsion in the source rocks of the Da’anzhai Member. The first large-scale expulsion of hydrocarbon is oil-based and gas-supplemented, whereas the second expulsion is dominated by gas. Hydrocarbon-filling characteristics are different in different types of reservoir rocks. Compared with the bioclastic grainstone and crystalline limestone, we have considered that the argillaceous shell packstone and bioclastic packstone deposited in the shallow and semideep lake environment still contain residual intergranular pores, which have not become fully compacted and are partly filled with hydrocarbons. The presence of hydrocarbon fluid hindered the secondary porosity reduction and was helpful for reserve space preservation.

scholarly journals Sedimentology and geochemistry of Middle–Upper Permian in northwestern Turpan–Hami Basin, China: Implication for depositional environments and petroleum geology

2018 ◽  
Vol 36 (4) ◽  
pp. 910-941
Author(s):  
Jian Song ◽  
Zhidong Bao ◽  
Xingmin Zhao ◽  
Yinshan Gao ◽  
Xinmin Song ◽  
...  
Keyword(s):  
Depositional Environment ◽  
Saline Water ◽  
Depositional Environments ◽  
Source Rocks ◽  
Petroleum Exploration ◽  
Upper Permian ◽  
Late Permian ◽  
Humid Climate ◽  
Mountain Area ◽  
Volcanic Source

Studies have found that the Permian is another important stratum for petroleum exploration except the Jurassic coal measures within Turpan–Hami Basin recently. However, the knowledge of the depositional environments and its petroleum geological significances during the Middle–Late Permian is still limited. Based on the analysis about the sedimentological features of the outcrop and the geochemical characteristics of mudstones from the Middle Permian Taerlang Formation and Upper Permian Quanzijie Formation in the Taoshuyuanzi profile, northwest Turpan–Hami Basin, this paper makes a detailed discussion on the Middle–Late Permian paleoenvironment and its petroleum geological significances. The Middle–Upper Permian delta–lacustrine depositional system was characterized by complex vertical lithofacies assemblages, which were primarily influenced by tectonism and frequent lake-level variations in this area. The Taerlang Formation showed a significant lake transgression trend, whereas the regressive trend of the Quanzijie Formation was relatively weaker. The provenance of Taerlang and Quanzijie Formations was derived from the rift shoulder (Bogda Mountain area now) to the north and might be composed of a mixture of andesite and felsic volcanic source rocks. The Lower Taerlang Formation was deposited in a relatively hot–dry climate, whereas the Upper Taerlang and Quanzijie Formations were deposited in a relatively humid climate. During the Middle–Late Permian, this area belonged to an overall semi-saline water depositional environment. The paleosalinity values showed stepwise decreases from the Lower Taerlang Formation to the Upper Quanzijie Formation, which was influenced by the changes of paleoclimate in this region. During the Middle–Late Permian, the study area was in an overall anoxic depositional environment. The paleoenvironment with humid climate, lower paleosalinity, anoxic condition, and semi-deep to deep water during the deposition of the Upper Taerlang Formation was suitable for the accumulation of mudstones with higher TOC values.

THE EVOLUTION OF THE BERNIER RIDGE, SOUTHERN CARNARVON BASIN, WESTERN AUSTRALIA:IMPLICATIONS FOR PETROLEUM PROSPECTIVITY

2004 ◽  
Vol 44 (1) ◽  
pp. 241 ◽  
Author(s):  
A.M. Lockwood ◽  
C. D’Ercole
Keyword(s):  
Seismic Data ◽  
Large Scale ◽  
Sedimentary Basins ◽  
Early Carboniferous ◽  
Source Rocks ◽  
Petroleum Exploration ◽  
Large Igneous Province ◽  
Satellite Gravity ◽  
Tectonic Events ◽  
Carnarvon Basin

The basement topography of the Gascoyne Platform and adjoining areas in the Southern Carnarvon Basin was investigated using satellite gravity and seismic data, assisted by a depth to crystalline basement map derived from modelling the isostatic residual gravity anomaly. The resulting enhanced view of the basement topography reveals that the Gascoyne Platform extends further westward than previously indicated, and is bounded by a northerly trending ridge of shallow basement, named the Bernier Ridge.The Bernier Ridge is a product of rift-flank uplift prior to the Valanginian breakup of Gondwana, and lies east of a series of small Mesozoic syn-rift sedimentary basins. Extensive magmatic underplating of the continental margin associated with this event, and a large igneous province is inferred west of the ridge from potential field and seismic data. Significant tectonic events that contributed to the present form of the Bernier Ridge include the creation of the basement material during the Proterozoic assembly of Rodinia, large-scale faulting during the ?Cambrian, uplift and associated glaciation during the early Carboniferous, and rifting of Gondwana during the Late Jurassic. The depositional history and maturity of the Gascoyne Platform and Bernier Ridge show that these terrains have been structurally elevated since the mid-Carboniferous.No wells have been drilled on the Bernier Ridge. The main source rocks within the sedimentary basins west of the Bernier Ridge are probably Jurassic, similar to those in the better-known Abrolhos–Houtman and Exmouth Sub-basins, where they are mostly early mature to mature and within the oil window respectively. Within the Bernier Ridge area, prospective plays for petroleum exploration in the Jurassic succession include truncation at the breakup unconformity sealed by post-breakup shale, and tilted fault blocks sealed by intraformational shale. Plays in the post-breakup succession include stratigraphic traps and minor rollover structures.

The transformation effect of source rock-derived acidic fluid on carbonate reservoir from simulation experiments

2020 ◽  
Author(s):  
Qian Ding ◽  
Zhiliang He ◽  
Dongya Zhu
Keyword(s):  
Physical Properties ◽  
Source Rock ◽  
Carbonate Reservoir ◽  
Carbonate Reservoirs ◽  
Source Rocks ◽  
Petroleum Exploration ◽  
Hydrocarbon Generation ◽  
High Quality ◽  
Simulation Experiments ◽  
Deep Layers

<p>Deep and ultra-deep carbonate reservoir is an important area of petroleum exploration. However, the prerequisite for predicting high quality deep ultra-deep carbonate reservoirs lays on the mechanism of carbonate dissolution/precipitation. It is optimal to perform hydrocarbon generation-dissolution simulation experiments to clarify if burial dissolution could improve the physical properties of carbonate reservoirs, while quantitatively and qualitatively describe the co-evolution process of source rock and carbonate reservoirs in deep layers. In this study, a series of experiments were conducted with the limestone from the Ordovician Yingshan Formation in the Tarim Basin, and the low maturity source rock from Yunnan Luquan, with a self-designed hydrocarbon generation-dissolution simulation equipment. The controlling factors accounted for the alteration of carbonate reservoirs and dissolution modification process by hydrocarbon cracking fluid under deep burial environments were investigated by petrographic and geochemical analytical methods. In the meantime, the transformation mechanism of surrounding rocks in carbonate reservoirs during hydrocarbon generation process of source rock was explored. The results showed that: in the burial stage, organic acid, CO<sub>2</sub> and other acidic fluids associated with thermal evolution of deep source rocks could dissolve carbonate reservoirs, expand pore space, and improve porosity. Dissolution would decrease with the increasing burial depth. Whether the fluid could improve reservoir physical properties largely depends on calcium carbonate saturation, fluid velocity, water/rock ratio, original pore structure etc. This study could further contribute to the prediction of high-quality carbonate reservoirs in deep and ultra-deep layers.</p>

THE CAMBRIAN PALAEOGEOGRAPHY OF AUSTRALIA AND OPPORTUNITIES FOR PETROLEUM EXPLORATION

1982 ◽  
Vol 22 (1) ◽  
pp. 42 ◽  
Author(s):  
Peter J. Cook
Keyword(s):  
Continental Drift ◽  
Depositional Environments ◽  
Source Rocks ◽  
Petroleum Exploration ◽  
Time Intervals ◽  
Middle Cambrian ◽  
Reservoir Rocks ◽  
Essential Components ◽  
Potential Reservoir ◽  
Cooper Basin

As part of a larger project to re-evaluate the petroleum potential of Australia, it was considered necessary to produce a series of Cambrian palaeogeographic maps. This required the compilation and correlation of a large number of stratigraphic columns, the delineation of sedimentologlcally-significant time intervals, the production of data maps for these same time intervals, and the development of a Cambrian 'tectonic' map. This palaeogeographic study was not undertaken to establish precise exploration targets. However, it does provide new information on where many of the essential components are, what age they are, and why they are there, and as such is a valuable tool in the overall exploration and resource evaluation strategy.The six palaeogeographic maps finally produced illustrate events involving continental drift, tectonics, and climatic and sea-level variations, over a period of 70 million years. Together, these events produced marked changes in the palaeogeography and depositional environments, which in turn profoundly affected the type and distribution of sediments being deposited on and around the palaeo-continent during the Cambrian. Using the palaeogeographic maps and the data accumulated for the project, it is possible to demonstrate that organic-rich sediments, with the potential to be petroleum source rocks, were relatively common during the Cambrian, especially on the eastern cratonic margin during the Lower Cambrian (Officer and possible Amadeus Basins) and the Middle Cambrian (Georgina Basin). There may also be some suitable petroleum source rocks in the Ord Basin. Limestones and dolomites, some of which may constitute potential reservoir rocks, were deposited in a number of Cambrian intracratonic basins (Amadeus, Georgina Basins) and on the shelf (Cooper Basin). Cambrian sandstones in Australia are commonly poor reservoir rocks, but where they have been subjected to shore-line or shelf 'clean-up', for example during the Middle and Upper Cambrian on the northwest side of the craton (Bonaparte Gulf Basin), there may be some potential reservoir rocks. Some sandstones may also be present on the south side of the Cooper Basin. Fine-grained impermeable sediments (potential cap rocks) were deposited throughout the Cambrian, but evaporites were most common during the Early and lower Middle Cambrian. Synsedimentary tectonics may have produced structural and stratigraphlc traps, and a major phase of karsting occurred in the Cambrian. Therefore, the Cambrian of Australia is believed to have many of the prerequisites for the generation, migration and entrapment of hydrocarbons. Especially favourable areas for these features may lie to the southeast of the Georgina Basin and in the offshore region northwest of the Ord and Bonaparte Gulf Basins.

Late Accumulation of Kunbei Area in Qaidam Basin

2013 ◽  
Vol 690-693 ◽  
pp. 3549-3552
Author(s):  
Hui Shi ◽  
Hui Li
Keyword(s):  
Seismic Data ◽  
Qaidam Basin ◽  
Scientific Evidence ◽  
Source Rocks ◽  
Petroleum Exploration ◽  
Tibet Plateau ◽  
Hydrocarbon Generation ◽  
Long Distance ◽  
Hydrocarbon Charging ◽  
The Tibet Plateau

This paper is aimed to find out the main reason of late accumulation of Kunbei area in Qaidam Basin using geochemistry and seismic data and to provide scientific evidence to the potential petroleum exploration in this area. Reservoirs in Kunbei fault terrace zone originate from petreoleum generated by source rocks of E32 in Zhahaquan depression after N23(about 5.2Ma), which means a charcteristic of hysteretic hydrocarbon generation. Brine inclusions shows two hydrocarbon charging periods.The first charging most likely happens at N1 and the second begins at N21,continuing to Q.Two deformaton stages exist in the study area due to the Tibet Plateau uplifting. The accumulations of first stage have been damaged after Middle N1. The reservoirs of Kunbei zone at present are almost orignated from E32 in depression. Above all,the primary cause of late accumulation is due to long-distance effects of the Tibet Plateau uplifting.

scholarly journals Biomarker distributions and depositional environments of continental source rocks in Sichuan Basin, SW China

2020 ◽  
Vol 38 (6) ◽  
pp. 2296-2324
Author(s):  
Siqin Huang ◽  
Guosheng Xu ◽  
Fanghao Xu ◽  
Wei Wang ◽  
Haifeng Yuan ◽  
...  
Keyword(s):  
Sichuan Basin ◽  
Lower Jurassic ◽  
Upper Triassic ◽  
Depositional Environments ◽  
Source Rocks ◽  
Late Triassic ◽  
Ms Analysis ◽  
Continental Source ◽  
The Sichuan Basin ◽  
Tricyclic Terpanes

In order to study the distributions of the biomarker of the continental source rocks in the Sichuan Basin, 71 source rock samples were collected from the Upper Triassic-Lower Jurassic strata in different regions. The n-alkanes, isoprenoids, terpane, sterane, sesquiterpenes, caranes and aromatics in the extracts were analyzed in detail. GC-MS analysis has been conducted to analyze the biomarker of the continental source rocks. The results of GC-MS analysis indicate that the Upper Triassic source rocks are high in the content of extended tricyclic terpanes, pristane, phytane, gammacerane, C28 regular sterane and carotene. However, they are low in content of rearranged compounds. The ratio of Pr/Ph is less than 1, with the characteristics of tricyclic terpane C21 > C23. The Lower Jurassic source rocks are extremely low in content (even zero) of extended tricyclic terpanes, pristane, phytane, gammacerane, C28 regular sterane and carotene, and high in content of rearranged compounds. The ratio of Pr/Ph is more than 1, with tricyclic terpane C21 > C23. These characteristics are still preserved after maturation. Moreover, during the sedimentation of the source rocks of T3x2–T3x3 members, the supply of continental plants was low (TAR < 1, with regular sterane C27 > C29, 1-MP/9-MP < 1). The source rocks of T3x5 member were low in salinity (slightly low content of gammacerane and carotene), being different significantly from the other Upper Triassic source rocks. In addition, during the sedimentation of the source rocks of J1dn Member, the supply of continental plants was also low (regular sterane C27 > C29, 1-MP/9-MP < 1), being quite different from that of J1l member. Through analysis of the difference in biomarkers, it is indicated that the sedimentary environment had changed from anoxic and brackish water during the Late Triassic to oxygen-rich and freshwater during the Early Jurassic in the Sichuan Basin. During this process, the types of organic matters had changed for several times.

scholarly journals Basic characteristics and accumulation mechanism of Sinian−Cambrian giant highly mature and oil-cracking gas reservoirs in the Sichuan Basin, SW China

2017 ◽  
Vol 36 (4) ◽  
pp. 568-590 ◽  
Author(s):  
Bing Luo ◽  
Yu Yang ◽  
Gang Zhou ◽  
Wenjun Luo ◽  
Shujiao Shan ◽  
...  
Keyword(s):  
Natural Gas ◽  
Lower Cambrian ◽  
Sichuan Basin ◽  
Large Scale ◽  
Oil And Gas ◽  
Source Rocks ◽  
Burial Depth ◽  
Sw China ◽  
Accumulation Mechanism ◽  
Oil Cracking

Old Mesoproterozoic−Cambrian successions have been regarded as an important frontier field for global oil and gas exploration in the 21st century. This has been confirmed by a recent natural gas exploration breakthrough in the Sinian and Cambrian strata, central Sichuan Uplift, Sichuan Basin of SW China. However, the accumulation mechanism and enrichment rule of these gases have not been well characterized. This was addressed in this work, with aims to provide important guidance for the further exploration while enriching the general studies of the oil and gas geology in the old Mesoproterozoic–Cambrian strata. Results show that the gas field in the study area is featured by old target layers (Sinian–Lower Cambrian), large burial depth (>4500 m), multiple gas-bearing intervals (the second and fourth members of the Sinian Dengying Formation and the Lower Cambrian Longwangmiao Formation), various gas reservoir types (structural type and structural–lithologic type), large scale (giant), and superimposing and ubiquitous distribution. The giant reserves could be attributed to the extensive intercalation of pervasive high quality source rocks and large-scale karst reservoirs, which enables a three-dimensional hydrocarbon migration and accumulation pattern. The origin of natural gas is oil cracking, and the three critical stages of accumulation include the formation of oil reservoirs in Triassic, the cracking of oil in Cretaceous, and the adjustment and reaccumulations in the Paleogene. The main controlling factor of oil and gas enrichment is the inherited development of large-scale stable paleo-uplift, and the high points in the eastern paleo-uplift are the favorable area for ​natural gas exploration.

scholarly journals Quantitative fluorescence techniques for investigating hydrocarbon charge history in carbonate reservoir

2017 ◽  
Vol 35 (3) ◽  
pp. 356-375 ◽  
Author(s):  
Nian Liu ◽  
Nansheng Qiu ◽  
Jian Chang ◽  
Fangyu Shen ◽  
Xuefeng Ma ◽  
...  
Keyword(s):  
Eastern China ◽  
Carbonate Reservoir ◽  
Petroleum Exploration ◽  
Bohai Bay ◽  
Hydrocarbon Accumulation ◽  
Hydrocarbon Charging ◽  
Index Value ◽  
Buried Hill ◽  
Cutoff Threshold ◽  
Accumulation History

The quantitative grain fluorescence and quantitative grain fluorescence on extract have become effective approaches in the analysis of hydrocarbon evolution in clastic reservoirs recently. The cutoff threshold for differentiating current/paleo-oil and water zones is crucial to reconstruct accurately hydrocarbon accumulation history. However, the absence of theoretical study on the cutoff threshold in the carbonate reservoir has precluded their application and development. In this paper, we attempted to investigate the cutoff threshold by analyzing the quantitative grain fluorescence and quantitative grain fluorescence on extract parameters and spectra of the cores and natural carbonate outcrop samples in known current/paleo-oil and water zones revealed by the frequency of oil inclusions, formation test, logging analysis, etc. Based on this, the hydrocarbon charging history of the Suqiao Buried-hill Zone, Bohai Bay Basin, eastern China was reconstructed using the gotten threshold. Results show that the carbonate minerals fluorescing will lead to a higher cutoff threshold of quantitative grain fluorescence index value in the carbonate reservoir, while the threshold of quantitative grain fluorescence on extract intensity value is coincident with the corresponding value in the clastic reservoir. The quantitative grain fluorescence and quantitative grain fluorescence on extract data have unraveled a complicated hydrocarbon accumulation history in Suqiao Buried-hill Zone including oil charging before gas and paleo-oil loss due to the tectonism. The ascertained cutoff threshold in this study is of great significance for reconstructing accurately and effectively the complicated hydrocarbon charging history in the carbonate reservoir, which provides significant models for future petroleum exploration.

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