Papers by Keyword: Volcanic Rock

Abstract: Phosphorus contamination in aquatic system was a widespread problem in Zhejiang province due to the excess use of detergent, agrochemicals and other organic phosphorus chemicals. Volcanic rock, an adsorbent with porous structure and large surface area, was applied for phosphorus removal in wastewater. The results showed that the phosphorus removal rate and equilibrium time had positive correlation with the initial phosphorus concentration, while the volcanic rock particle size could also affect the adsorption performance as volcanic rock with smaller particle size used to have a larger cation exchange capacity and higher surface area. Both Langmuir adsorption and the Freundlich adsorption happened throughout phosphorus removal process, showing the strong capacity and capability of volcanic rock as absorbent for phosphorus wastewater. It is promising to use volcanic rock in phosphorus water/wastewater purification systems due its large quantities and accessibility in nature.

Abstract: Since the discovery of business flow in volcanic rocks of Yingcheng formation, the deep volcanic rocks of Songliao basin have become another advantaged target for oil-gas exploration. To reproduce the the development process of oil-gas generation, migration and accumulation, accurately calculating the oil-gas accumulation time is a very important work. To minimize the error, we must seriously study the regional tectonic evolution history and recover the eroded thickness. According to the actual situation of the study area, trend method can be used to recover the top eroded thickness of volcanic rocks in Yingcheng formation. Finally we get the maximum eroded thickness in the basin is between 120 m to 240 m, located in the southeastern basin.

Abstract: The main accumulating rock types of Yingshan Fault Depression in Songliao Basin were various volcanic lava and volcanic breccias, and the accumulating spaces included primary and secondary two kinds. Though the primary accumulating spaces took the small proportion, they provided favorable conditions for paulopost reconstruction. The development and evolution of volcanic rock accumulating spaces can be divided into four stages. The first is the forming stage of primary accumulation spaces, and the secondary is weathering and leaching stage. These two stages are dominated by construction. The third is shallow burying and structural fracture developing stage, with coexisting of construction and destruction, but dominated by construction. The fourth is deep burying stage, which is dominated by destruction.

Abstract: The rock structure information is a very important feature in the complex lithology identification. However, conventional logging response characteristics of the rock structures are very weaker, resulting that the recognition rate of complex lithology is very low in conventional logging. With the help of imaging logging data with accurate, intuitive structural characteristics of the rock, the volcanic structure is analyzed in electronic imaging logging data in this paper. First, several structural characteristics of volcanic rock are introduced. Then, several texture features are extracted based on image processing method. Finally, imaging logging response characteristics of different volcanic structures are analyzed by means of histogram, and some texture features of imaging logging are chosen to identify volcanic structures in the cross-plot method. Real data processing analysis results show that texture features extracted from electrical imaging logging is effective to distinguish the structures of volcanic rocks.

Abstract: The volcanic reservoir of Yingcheng Formation in Xujiaweizi Faulted-Sag of Songliao Basin was systematically studied by analyzing the data of the core and cast thin slice. It was founded out that all effective reservoir underwent six diagenetic stages. That is why porosity evolution and physical property of those rocks were different from each other. The organic acid dissolution and CO₂-bearing acidulous water dissolution,was the most useful diagenesis to the formation of effective reservoirs, secondary porosity developed mostly in the silicic volcanic rocks, which were easily dissolved by organic acid. Primary porosity system, faults and fractures, top/bottom unconformity surfaces of volcanic rocks are the key factors to dissolution.

Abstract: This paper based on the field outcrop ,core data, logging data , physical property data and testing data to research the weathering crust of the deep volcanic in xujiaweizi depression. Take red clay layer that developed on the top of volcanic rock as the identification mark, and take the logging response characteristics of volcanic rock weathering crust as division standard, to research weathering crust of volcanic rock. Results show that recognized 31 wells that developed volcanic rock weathering crust of deep K₁yc¹ and K₁yc³ volcanic of xujiaweizi depression that mainly distributed in Xuzhong and Anda region. Find that the main components of weathering crust are composed of rhyolite, volcanic breccia and tuff, and divide out dissolution and disintegration belt that are in conformity with the actual gas reservoir exploration position.

Abstract: Research on volcanic rock diagenesis have important reference value in volcanic rock secondary pore formation, evolution and reservoir prediction. Using the core data, flakes, imaging logging, geochemicals analysis and lithologies-lithofacies characteristics of Yaoyingtai area in Yingcheng Formation, Changling fault depression, we research on the volcanic rock diagenesis, reservoir space types, characteristics and relationships. The results are shown that: The research area mainly develop volcanic rock mantle thermal liquid alkali metasomatism and other 11 diagenesis types, and base on diagenesis formation mechanism and the effects of the reservoir spaces, which is divided constructive and destructive.

Abstract: In order to study the chemical composition of volcanic rock and physical properties in Hainan province, used the method of X-ray fluorescence, analysises on its chemical composition, and researched the physical properties of volcanic rocks including density test, porosity test, acoustic test, resistance test. The results showed that: the volcanic rock is tholeiitic at the cavity of lava area in Hainan province, P-wave velocity and S-wave velocity would change with the changing of porosity.

Abstract: Volcanic lithology and lithofacies are important factors to control the formation of volcanic reservoir. It is a challenge for geologists and petrophysicist to identify lithofacies in the borehole by using well logs. According to the reservoir characters of Daqing volcanic reservoir in Songliao basin, five lithofacies and fifteen su-facies have been recognized through the drilled core analysis of lithology, texture and structure. The relationship between conventional well logs and volcanic lithology can be established by calibrating with core analysis which can be used to identify the rock composition by the established cross-plots. From the FMI measurement, the differences of resistivity values caused by volcanic rock texture and structure can be showed in the image clearly. It shows that four kinds of textures and five kinds of structure can be identified with FMI image. As the volcanic lithofacies marks, specific volcanics lithology, texture and structure corresponds to the specific lithofacies and sub-facies. So lithofacies distribution can be evaluated effectively with the model of volcanics texture and structure combined with rock composition. The results of study indicate that the composition, texture and structure characteristics of the volcanics can be identified by conventional log with FMI measurement, which is important to the further volcanic reservoir exploration and production.

Abstract: The Early Permian volcanic-sedimentary sequences of Ongniud Banner consist mainly of andesite, rhyolite, perlite, volcanic breccia, tuff, tuffaceous sandstone, siliceous rock. Rock assemblage and sedimentary formations indicate that are of fore-arc basin sedimentary feature between subduction zone and island arc in Early Permian. The volcanic rocks from Elitu Formation have SiO₂=50.23%~74.83%, Mg^#=6.21~49.54, Na₂O+K₂O=5.27%~10.73%, Na₂O/K₂O=0.36~4.17, belonging to high-K cal-alkaline (HKCA)~shoshonite (SHO) series. The volcanic rocks are characterized with (La/Yb)_N=5.52~9.89, moderate - intense negative Eu anomalies, LILE enrichment such as Ba, Ra, K, Th and HFSE depletion such as Ta, Nb, P, Ti, and indicating that magma could be formed in the tectonic setting of the island arc and active continental margin related to the plate subduction. R1-R2 diagram also indicates that volcanic rocks were generated at syn-collision or post-orogenic period, perhaps representing the mid-later subduction stage of the Palaeo-Asian Ocean Plate and North China Plate. Taken together, the authors suggest that the region was located still in the Palaeo-Asian Ocean, rather than the intracontinental taphrogenic trough in Early Permian.