scholarly journals Evaluation of Favorable Shale Gas Intervals in Dawuba Formation of Ziyun Area, South Qian Depression

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Kun Yuan ◽  
Wenhui Huang ◽  
Xinxin Fang ◽  
Ting Wang ◽  
Tuo Lin ◽  
...  

A series of qualitative descriptions and quantitative analyses was used to determine the lithofacies characteristics and recognize the favorable shale intervals of Dawuba Formation in the Ziyun area of South Qian Depression. The qualitative descriptions include core description and scanning electron microscope (SEM) observation. The quantitative analyses include X-ray diffraction, total organic content analysis, vitrinite reflectance, maceral composition, porosity, and permeability, as well as gas and element composition. The Dawuba Formation could be divided into four members. In general, the shale in the first and third members showed similarly high organic matter content with most samples in range of 2–2.5% and higher brittle mineral content with a content of quartz 40.53% and 33.21%, respectively, compared with the other two members, as well as high gas content. However, the first member shale samples exhibited much higher porosity and permeability than the third member shale samples. Furthermore, the shale gas in the first member was chiefly composed of methane (average: 83.63%), while that in the third member mainly consisted of nitrogen (average: 79.92%). Hence, the first member should be regarded as the most favorable target.

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 635
Author(s):  
Shihu Zhao ◽  
Yanbin Wang ◽  
Yong Li ◽  
Honghui Li ◽  
Zhaohui Xu ◽  
...  

Tarim Basin is the largest Petroliferous basin in China, while its shale gas development potential has not been fully revealed. The organic-rich black shale in middle Ordovician Heituao Formation from Tadong low uplift of Tarim Basin has been considered as an important source rock and has the characteristic of large thickness, high organic matter content and high thermal maturity degree. To obtain its development potential, geochemical, mineralogical and mechanics research is conducted based on Rock-Eval pyrolysis, total organic carbon (TOC), X-ray diffraction (XRD) and uniaxial compression experiments. The results show that: (1) the TOC content ranges between 0.63 and 2.51 wt% with an average value of 1.22 wt%, the Tmax values are 382–523 °C (average = 468.9 °C), and the S2 value is relatively low which ranges from 0.08 to 1.37 mg HC/g rock (averaging of 0.42 mg HC/g rock); (2) the organic matter of Heituao shale in Tadong low uplift show poor abundance as indicated by low S2 value, gas-prone property, and post mature stage (stage of dry gas). (3) Quartz is the main mineral component in Heituao shale samples, accounting for 26–94 wt% with an average of 72 wt%. Additionally, its Young’s modulus ranges from 20.0 to 23.1 GPa with an average of 21.2 GPa, Poisson’s ratio ranges between 0.11 and 0.21 (average = 0.15); (4) the fracability parameter of brittleness index (BI) ranges between 0.28 and 0.99 (averaging of 0.85), indicating good fracability potential of Heituao shale of Tadong low uplift and has the potential for shale gas development. This study reveals the shale gas accumulation potential in middle Ordovician of the Tarim Basin, and beneficial for future exploration and production practice.


2013 ◽  
Vol 295-298 ◽  
pp. 2770-2773 ◽  
Author(s):  
Dai Yong Cao ◽  
Jing Li ◽  
Ying Chun Wei ◽  
Xiao Yu Zhang ◽  
Chong Jing Wang

Besides coal seam, the source rocks including dark mudstone, carbon mudstone and so on account for a large proportion in the coal measures. Based on the complex geothermal evolution history, the majority of coal measure organic matters with the peak of gas generation have a good potential of gas. Therefore, shale gas in coal measure is an important part of the shale gas resources. There are good conditions including the thickness of coal measures, high proportion of shale rocks, rich in organic matter content, high degree of thermal evolution, high content of brittle mineral and good conditions of the porosity and permeability for the generation of shale gas in Wuli area, the south of Qinghai province. Also the direct evidence of the gas production has been obtained from the borehole. The evaluation of shale gas in coal measure resources could broaden the understanding of the shale gas resources and promote the comprehensive development of the coal resources.


2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Ahmad Shobib

Cow manure can be used for making organic fertilizer because it contains nutrients such as Nitrogen (N), Phosphorus (P), and Potassium (K). Rice straw has a high C-Organic content. Adding straw compost will increase soil organic matter content. The study aims to determine the fermentation process that occurs so as to produce organic fertilize, know the effect of fermentation time and the effect of the composition of raw materials for cow manure and rice straw on the process of making organic fertilizer to the content of organic fertilizer according to SNI 7603 : 2018. The method use by aerobic fermentation is by mixing cow manure and rice straw and M-Dec bioactivators by comparison 3 : 1, 2 : 2,1 : 3 and fermentation time 7, 14, 21, 28 days. The parameters tested are C-organic, Nitrogen (N), C/N ratio, Phosphorus (P), and Potassium (K). The best quality organic fertilizer in the treatment of cow manure : rice straw with a ratio of 2 : 2 on the 28th day fermentation process namely C-organic content 34,63 %, C/N ratio is 25, macro nutrient content N+P2O5+K2O of 3,14 % that has met SNI 7763 : 2018. Keyword: M-Dec bioactivator, aerobic fermentation, cow manure, rice straw, C/N ratio


2005 ◽  
Vol 53 (1-2) ◽  
pp. 23-38 ◽  
Author(s):  
Rosebel C. Nalesso ◽  
Jean-Christophe Joyeux ◽  
Cintia O. Quintana ◽  
Evelise Torezani ◽  
Ana Clara Paz Otegui

The present work describes and analyses the structure of the macrobenthic epi- and infaunal assemblage of the estuarine system of Vitória Bay, South-eastern Brazil, from January 1998 to June 1999. Replicated sampling at intertidal and subtidal levels was conducted quarterly at ten stations. Intertidal and subtidal sediment composition was characterised. Water physico-chemical parameters were measured in situ. A total of 10,695 individuals, belonging to 144 taxa, were collected. Molluscs, crustaceans and polychaetes were the most abundant groups. The bivalves Anomalocardia brasiliana, Mytella guyanensis and M. falcata were the most abundant species. Locally, significant discharges of residential and industrial wastewater resulted in high organic content in the sediment (up to 30%) and low dissolved oxygen concentration in the water (< 1mg.l-1). Near the two entrances of the bay, high hydrodynamic activity and coarse sand reduced the detrimental effects of raw and treated sewage inputs. Species richness (S), diversity (H') and total abundance (A) decreased from outer-bay stations (22 < S < 72; 1.99 < H' < 2.85; 320 < A < 1737) towards inner-bay stations (2 < S < 45; 0.59 < H' < 2.67; 2 < A < 1317), where salinity and dissolved oxygen were lowest and organic matter content highest.


2020 ◽  
Author(s):  
Belén Oliva-Urcia ◽  
Ana Moreno ◽  
Blas Valero-Garcés

&lt;p&gt;Paleoenvironmental reconstructions from three mountaineous lakes located in northern Iberia are compared and completed with classical magnetic analyses in order to detect the influence of different processes on the record and preservation of magnetic properties. The lakes are located in the Cantabrian Mountains, Enol Lake, and in the Pyrenees, the Marbor&amp;#233; Lake and Basa de la Mora Lake and share a similar composition of their catchment areas, dominated by limestones. They present other different characteristics, such as in the organic matter content, being Enol the one with the highest organic carbon values. Redox indicator (Mn/Fe) is higher and more variable in Basa de la Mora Lake, whereas in Enol and Marbor&amp;#233; Lakes steadily increases towards the top of the sequences. New and revisited results from sedimentary cores unravel the significance of the magnetic changes respect to the geochemical and sedimentological variations found in the geological record.&lt;/p&gt;&lt;p&gt;The magnetic mineralogy present after analyses done in discrete samples (less than 500 mg) is magnetite in all samples, due to a sharp decrease at 120 K (Verwey crystallographic transition) and 580&amp;#186;C (Curie temperature of magnetite) in the thermomagnetic curves performed in the MPMS and the Curie balance respectively. No indication of neither pyrrhotite (phase transition at 35 K) nor siderite is observed. The high temperature thermomagnetic analyses show the presence and creation of magnetite during heating, see an increasing of induced magnetization forming a broad peak above 450&amp;#186;C in the heating curve. In addition, a subtle change in the induced magnetization is observed at around 300&amp;#186;C. All analyses related with coercivity indicate the predominance of low coercitive minerals (&amp;#8220;soft&amp;#8221;) as magnetite is.&lt;/p&gt;&lt;p&gt;The combination of geochemical, sedimentological and magnetic proxies suggest that in Enol Lake the magnetic signal may be dominated by the formation of new minerals in relation to redox processes favored by the higher presence of organic matter (6%organic content), whereas in Marbor&amp;#233; Lake, the increase of the magnetic signal toward the top of the sequence seems related to the oxic environment and the preservation of magnetite, since this lake is ultra-oligotrophic. In Basa de la Mora Lake, the source rock seems to play a role in the magnetic signal of the sequence.&lt;/p&gt;&lt;p&gt;These results indicate that diagenesis and changes in the redox conditions alter the concentration of magnetic minerals during the Late Pleistocene and Holocene and underlines their value as environmental and paleoclimate archives.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Acknowledgements&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;Funding for this research was provided by the Spanish Inter-Ministry Commission of Science and Technology through MEDLANT (CGL2016-76215-R) and DINAMO 3 (Ref CGL2015-69160-R) projects and by the European Commission (EFA056/15 REPLIM). The Institute for Rock Magnetism (IRM), the Instrumentation and Facilities program of the National Science Foundation of the Earth Science Division and the University of Minnesota are acknowledged for supporting visits and the free use of the facilities at the IRM, together with the both easy-going and expert guidance from the IRM staff.&lt;/p&gt;


2012 ◽  
Vol 246-247 ◽  
pp. 576-580 ◽  
Author(s):  
Bian Hong Zhou ◽  
Cheng Zhong Zhang ◽  
Jian Hua Gao

The four north-central Shaanxi OCPs observed surface concentration of farmland were analyzed via GC-MS and GC/ECD, respectively, Xi’an observation area 6.110 ng•g-1, Tongchuan observation area 0.817 ng•g-1, Yan’an observation area 3.018 ng•g-1, an observation area in Yulin 5.286 ng•g-1, respectively. Be observed over the same period in Xi’an concentration of OCPs in air 325.773 pg•m-3, where the concentration of particles OCPs 160.883 pg•m-3, the concentration of gaseous OCPs 164.890 pg•m-3.Xi’an urban air particles and gas field surface soil OCPs and the OCPs was correspondence between the basic components of content, indicating that much of Xi’an OCPs in the air of dust released from the soil. The results show that the observation area at the same time with different content of each component of different OCPs, DDTs maximum concentration, mainly in the form of p, p’-DDT, BHC, followed by HCHs, mainly in the form of β-HCH; air, gas-eous and OCPs There are two forms of particulate, HCHs gas content was significantly greater than the particulate phase, DDTs substances content of particles greater than the gas content; OCPs in soil content and the physical nature of the soil, HCB, Chlordane, TN+CN and soil organic matter Content showed a significant positive correlation, chlordane, endosulfan, EnSO4 and soil acidity was a significant positive correlation, HCHs, DDTs and soil acidity were some negative.


2018 ◽  
Vol 36 (6) ◽  
pp. 1482-1497
Author(s):  
Qiang Xu ◽  
Fengyin Xu ◽  
Bo Jiang ◽  
Yue Zhao ◽  
Xin Zhao ◽  
...  

We analyzed the tectonic evolution characteristics, sedimentary environment, geochemical characteristics, petrological characteristics, and gas-bearing properties of three mudstone sections of the Lower Paleozoic in Ningwu Basin, NE China, and determined the geologic characteristics and resource potential of the transitional facies shale gas. Geochemical analysis of the organic carbon content, kerogen macerals, and vitrinite reflectance of the shale samples showed that the total organic content was generally over 2.0%, the main organic type was type III, and the vitrinite reflectance values (Ro) were between 1.20 and 1.90%. Thus, the mudstones are good shale gas source rocks. The thickness of the three mudstone sections was approximately 30–70 m, and the average porosity was 3.10%. The pore types were diverse with good reservoir capacity. The shale gas resources of the Carboniferous-Permian transitional facies estimated by the volumetric method were approximately 2798.97 × 108–4643.09 × 108 m3. Through a comparison with shales in SW China, where shale gas has been successfully exploited, we determined the preferred criteria for favorable shale gas areas, as well as favorable areas for shale gas enrichment.


2016 ◽  
Vol 30 (1) ◽  
pp. 19-23 ◽  
Author(s):  
Ewa A. Czyż ◽  
Anthony R. Dexter

Abstract Soil bulk density was investigated as a function of soil contents of clay and organic matter in arable agricultural soils at a range of locations. The contents of clay and organic matter were used in an algorithmic procedure to calculate the amounts of clay-organic complex in the soils. Values of soil bulk density as a function of soil organic matter content were used to estimate the amount of pore space occupied by unit amount of complex. These estimations show that the effective density of the clay-organic matter complex is very low with a mean value of 0.17 ± 0.04 g ml−1 in arable soils. This value is much smaller than the soil bulk density and smaller than any of the other components of the soil considered separately (with the exception of the gas content). This low value suggests that the clay-soil complex has an extremely porous and open structure. When the complex is considered as a separate phase in soil, it can account for the observed reduction of bulk density with increasing content of organic matter.


Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3078 ◽  
Author(s):  
Zhuoying Fan ◽  
Jiagen Hou ◽  
Xinmin Ge ◽  
Peiqiang Zhao ◽  
Jianyu Liu

Estimating in situ gas content is very important for the effective exploration of shale gas reservoirs. However, it is difficult to choose the sensitive geological and geophysical parameters during the modeling process, since the controlling factors for the abundance of gas volumes are often unknown and hard to determine. Integrated interdisciplinary experiments (involving petrophysical, mineralogical, geochemical and petrological aspects) were conducted to search for the influential factors of the adsorbed gas volume in marine gas shale reservoirs. The results showed that in shale reservoirs with high maturity and high organic content that the adsorbed gas volume increases, with an increase in the contents of organic matter and quartz, but with a decrease in clay volume. The relationship between the adsorbed gas content and the total porosity is unclear, but a strong relationship between the proportions of different pores is observed. In general, the larger the percentage of micropores, the higher the adsorbed gas content. The result is illuminating, since it may help us to choose suitable parameters for the estimation of shale gas content.


2011 ◽  
Vol 52 (No. 12) ◽  
pp. 544-549 ◽  
Author(s):  
J. Pavlíčková ◽  
J. Zbíral ◽  
M. Smatanová ◽  
P. Habarta ◽  
P. Houserová ◽  
...  

A pot experiment focused on the study of factors influencing thallium transfer from contaminated soils into kale (green cabbage, Brassica oleracea L. var. acephala, variety Winterbor F1) was evaluated. Three different types of topsoils with naturally low content of thallium (heavy, medium and medium-light soil) were used for pot experiments. The soils were contaminated with thallium sulfate to achieve five levels of contamination (0, 0.52, 2.10, 4.20 and 5.88 mg/kg). There were six replicates for each combination (90 pots in the experiment). The first part of the experiment started in the year of contamination (2001) and continued in 2003. The soil samples and the samples of kale (leaves and stalks were sampled separately) were collected and analysed. Kale was found to be able to accumulate Tl without any influence on yield. The highest thallium concentration was found in the leaves of kale in the first year of the experiment and reached 326 mg/kg dry matter. Bioaccumulation factor (Biological Absorption Coefficient &ndash; BAC) was found to be over 80 during the first year of the experiment. In the third year the BAC was around 3 for the soil with the highest pH and the highest organic matter content but as high as 15 for an acid soil with the lowest content of organic matter and the lowest Cation Exchange Capacity (CEC) of soils. The content of thallium in the leaves of kale was found to be 7 to 10 times higher than in the stalks in the third year. In the first year this ratio was up to 18. From these findings it can be concluded that the ability of some plants of Brassicacea family, that are planted as common vegetables, to accumulate thallium is very high and can be a serious danger for food chains. Neutral soils high in CEC and organic matter are able to bind thallium more effectively than poor acid soils and the transfer of Tl into plants from these soils is substantially lower. The uptake of Tl from contaminated soils into kale can be very high and without any negative effect on the plant growth. The transfer of Tl into kale decreases with the time necessary to reach the equilibrium between the added Tl and the soil (ageing of a sample).


Sign in / Sign up

Export Citation Format

Share Document