scholarly journals Pore structures and reservoir characteristics of volcanic rocks in the Carboniferous Batamayineishan Formation in Shuangjingzi area, eastern Junggar Basin

2021 ◽  
Vol 36 (5) ◽  
pp. 105-119
Author(s):  
Masab Ali ◽  
Bian Weihua ◽  
Yang Kaikai ◽  
Muhammad Sabeh Khan Panni

Junggar Basin is one of the largest sedimentary basins in Northwest China. Carboniferous oil and gas fields have been found in different areas in the eastern part of the Junggar Basin on a large scale, indicating that the Carboniferous rocks of the Junggar Basin have a huge potential for oil and gas exploration. This study focuses on the Batamayineishan Formation in the eastern part of the Junggar Basin, which contains volcanic rocks and pyroclastic rocks, aiming to investigate the reservoir characteristics and to identify the formation mechanism of the rocks of this formation. The majority of the existent reservoir space in the volcanic rocks of the Batamayineishan Formation is dominated by secondary pores and fractures. Using the methods of petrography, pressure-controlled mercury injection (PMI), and electron probe microanalysis (EPMA), the reservoir characteristics and diagenetic history of the volcanic rocks of the Batamayineishan Formation in the Shuangjingzi area were studied. A theoretical framework is established to provide favorable guidance for exploring Carboniferous volcanic rocks in the Junggar Basin. The results of mercury injection indicate that the average pore throat radius and porosity of the volcanic rocks are 0.068 µm and 6.62%, respectively. Permeability remains stable and does not show a significant change with an increase in porosity. Despite the high porosity, the permeability is relatively low, reflecting isolated and non-connected primary pores. The average value of permeability is relatively low (0.424×10-3 µm2), which typically suggests narrow micro-throats. Primary gas pores fill and develop amygdales on a large scale. In addition, the dissolution pores developed by dissolution and alteration also compensated for the decrease in the original gas pore volume.

2018 ◽  
Vol 22 (3) ◽  
pp. 169-174 ◽  
Author(s):  
Cunhui Fan ◽  
Qirong Qin ◽  
Feng Liang ◽  
Zenghui Fan ◽  
Zhi Li

Fractures in Carboniferous volcanic rocks located at Zhongguai Area (China) highly influence the accumulation and productivity of oil and gas. As such, the study of development periods and genetic mechanisms of tectonic fractures could throw useful information regarding the evaluation and development of that reservoir. Their tectonic origins caused high-angle and oblique shear fractures. The primary orientation of those fractures appears close to EW (270°±10°), NW (300°±15°), NE (45°±15°), and SN (0°±10°). At least four fracture generations can be found in Carboniferous volcanic rocks at Zhongguai Area. Combined with a tectonic evolution, they are based on the segmentation relationship of the fracture fillings, the thermometry measurement of the fracture filling inclusion, and the acoustic emission, as well. Affected by a new horizontal principal stress, the opening and permeability of nearly EW fractures are the best. In this way, a priority in the development of well's patterns should be considered close to EW fractures. The pressure change in the process of exploitation may damage the reservoir permeability of fractured volcano rocks severely. Accordingly, well patterns should be adjusted to dynamic changes of permeability happened during the oilfield development since some differences have been detected in distinct fracture sets. 


2018 ◽  
Vol 6 (2) ◽  
pp. T431-T447 ◽  
Author(s):  
Xiaoming Sun ◽  
Siyuan Cao ◽  
Xiao Pan ◽  
Xiangyang Hou ◽  
Hui Gao ◽  
...  

Volcanic reservoirs have been overlooked for hydrocarbon exploration for a long time. Carboniferous volcanic rocks of the Zhongguai paleouplift contain proven reserves of [Formula: see text]. We have investigated the volcanic reservoirs integrating cores, well, and seismic data, and the proposed volcanic reservoir distribution is controlled by the weathering function, fractures, and lithology. The weathering process makes the originally tight igneous rocks become good-quality reservoirs, and fractures play an important role in connecting different types of pores and act as reservoir space. Isolated and ineffective pores become effective ones due to connection among fractures. Only volcanic breccia can be good-quality reservoirs without any weathering function. The nonlinear chaos inversion controlled by weathered layers shows that the good-quality reservoirs are distributed in the top of the weathering crust and the structural high. Furthermore, fluid-detection attributes and background information prove that oil and gas are distributed along the paleostructural high. The objectives of this study were to (1) describe the characteristics of volcanic reservoirs and determine the controlled rules for reservoir distribution, (2) characterize the distribution of reservoirs and hydrocarbon, and (3) propose an effective workflow for hydrocarbon exploration in volcanic rocks combining geologic and geophysical methods.


2021 ◽  
Vol 9 ◽  
Author(s):  
Weiming Wang ◽  
Weihao La ◽  
Tanguang Fan ◽  
Xiongfei Xu ◽  
Yingnan Liu ◽  
...  

Self-jetting high-yield oil flow was obtained from Ma 67 and Ma 36 wells drilled in the volcanic reservoirs of the Haerjiawu Formation in the Santanghu Basin, China. This has shifted the prospectors’ attention to the Haerjiawu Formation from the Kalagang Formation, which is generally considered to have favorable physical properties. To further explain the geological reasons why oil flow can jet itself from the volcanic rocks in the Haerjiawu Formation with poor physical properties, this study carries out a systematic comparison on the microscopic pore structures of volcanic rocks through unconventional tests such as low-temperature nitrogen adsorption, high-pressure mercury injection, and constant-rate mercury injection based on the analyses of physical properties and minerals. The results obtained are as follows. The volcanic rocks of the Kalagang Formation have relatively high pore permeability. However, their micropores have a wide distribution range of pore size and feature highly meandering structures and strong heterogeneity. Meanwhile, small pore throats connect large pores in the volcanic rocks, resulting in a relatively high pore/throat ratio. All these are conducive to the occurrence of tight oil and gas but unfavorable for the flow of oil and gas. The volcanic rocks in the Haerjiawu Formation have relatively low volcanic permeability. However, small pores connect large pore throats in the volcanic rocks; thus, leading to a relatively low pore/throat ratio. Meanwhile, the volcanic rocks feature low meandering structures, strong homogeneity, and high connectivity. All these are favorable for the formation of tight oil and gas reservoirs. These assessment results also indicate that the assessment indices of tight volcanic reservoirs should not only include porosity and permeability. Instead, more attention should be paid to the microscopic pore structures, and it is necessary to analyze the charging and flow of tight oil from the configuration of pores and pore throats. This study not only explains the geological factors of the wells with self-jetting high-yield oil flow in the Haerjiawu Formation from the perspective of microscopic pore structures but also provides a new idea and comparison method for the assessment of tight reservoirs in other areas.


2012 ◽  
Vol 616-618 ◽  
pp. 100-103
Author(s):  
Fang Lu ◽  
Xin Jiang Du ◽  
Yan Zhou ◽  
Yang Yang Du

With the rapid development of national economy, combined with the construction of strategic reservation of petroleum in China, difficulty of large-scale energy storage and peak-shaving comes up. In recent years, the U.S. Department of Energy (DOE), the Bonneville Power Administration (BPA), the Pacific Northwest National Laboratory (PNNL) and a number of energy companies launched two projects in the Columbia Basin to evaluate the technical and economic feasibility of underground gas and wind power storage in basalt interflow aquifers. These projects reveal the potential of volcanic rocks in the underground energy storage areas. This paper briefly describes the new progress of study in underground gas storage (UGS), compressed air energy storage (CAES) and underground thermal energy storage (UTES) of volcanic rocks. We point out that depleted volcanic oil and gas reservoirs could be another complementary type of UGS and CAES, and volcanic rocks types should be included extrusive rocks and pyroclastic rocks. At last, volcanic energy storage technologies used in some domestic related areas of enlightenment is summarized to provide theoretical basis for building green, efficient and low-consumption economy.


M. J. Roobol Yesterday we heard how the large whales and seals were taken from Antarctica to provide oil for light and heating. This partly assisted us in attaining our present population level of 4000000000. So today we are even more dependent on natural gas and oil. The Weddell and Ross Seas appear to overlie large sedimentary basins which are a part of the shelf of the Antarctic Continent. These basins could well contain oil and gas deposits. Dr Adie’s description of the Antarctic Peninsula, of granodiorites and diorites intruding volcanic rocks, sounds an ideal prospect for porphyry copper deposits, while the many faults mentioned could prove to be the sites of other types of mineral deposits. Could Dr Adie tell us a little about B.A.S. efforts and plans for the exploration of these potential mineral deposits.


1992 ◽  
Vol 29 (10) ◽  
pp. 2249-2265 ◽  
Author(s):  
W. Mueller ◽  
J. A. Donaldson

Sedimentation in the Archean Abitibi greenstone belt occurred during four depositional episodes: (i) sedimentary cycle 1, 2730–2720 Ma; (ii) sedimentary cycle 2, 2715–2705 Ma; (iii) sedimentary cycle 3, 2700–2687 Ma; and (iv) sedimentary cycle 4, 2685–2675 Ma. Records of the first two sedimentary cycles are preserved in basins within the northern volcanic zone, whereas basins formed during the latter two sedimentary cycles are located within the southern volcanic zone of the Abitibi belt. Sedimentary cycles 1 and 3 represent deep-water facies, as indicated by turbidites, resedimented conglomerates, pelagic sediments, and ubiquitous iron-formations; subaerial deposits have not been identified. In contrast, sedimentary cycles 2 and 4 show a prevalence of fluvial to shallow-water marine and (or) lacustrine deposits. Tectono-magmatic influence on sedimentation during cycles 2 and 4 is documented by (i) the presence of numerous unconformities underlain by plutonic and volcanic rocks; (ii) locally voluminous shoshonitic and calc-alkaline volcanic rocks; (iii) abundance of plutonic detritus; (iv) rapid vertical and lateral facies changes; and (v) repetition of successions of large-scale (50–250 m thick) alluvial and shallow-water deposits. Sedimentary cycle 1 represents incipient arc basins dominated by volcaniclastic debris, whereas cycle 2 reflects unroofing of arc volcanoes down to the plutonic roots. The sedimentary basins of cycle 3 have been tentatively interpreted as basins connecting arc terranes, within which small extensional cycle 4 basins of the successor or pull-apart type developed. The sedimentary facies associations, the tectono-magmatic influence on sedimentation, the chronological basin evolution, and overall southward younging of the basins invite comparison with modern island arcs formed by plate-tectonic processes.


Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 6114
Author(s):  
Danping Zhu ◽  
Xuewei Liu ◽  
Shaobin Guo

The Hong-Che Fault Zone is one of the important oil and gas enrichment zones in the Junggar Basin, especially in the Carboniferous. In recent five years, it has been proven that the Carboniferous volcanic rock has 140 million tons of oil reserves, and has built the Carboniferous volcanic reservoir with a capacity of million tons. Practice has proven that the volcanic rocks in this area have great potential for oil and gas exploration and development. To date, Carboniferous volcanic reservoirs have been discovered in well areas such as Che 32, Che 47, Che 91, Chefeng 3, Che 210, and Che 471. The study of drilling, logging, and seismic data shows that the Carboniferous volcanic reservoirs in the Hong-Che Fault Zone are mainly distributed in the hanging wall of the fault zone, and oil and gas have mainly accumulated in the high part of the structure. The reservoirs are controlled by faults and lithofacies in the plane and are vertically distributed within 400 m from the top of the Carboniferous. The Carboniferous of the Hong-Che Fault Zone has experienced weathering leaching and has developed a weathering crust. The vertical zonation characteristics of the weathering crust at the top of the Carboniferous in the area of the Che 210 well are obvious. The soil layer, leached zone, disintegration zone, and parent rock developed from top to bottom. Among these reservoirs, the reservoirs with the best physical properties are mainly developed in the leached zone. Based on a comprehensive analysis of the Carboniferous oil and gas reservoirs in areas of the Chefeng 3 and Che 210 wells, it is believed that the formation of volcanic reservoirs in the Hong-Che Fault Zone was mainly controlled by structures and was also controlled by lithofacies, unconformity surfaces, and physical properties.


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