Metamorphic and geochronological evolution of Paleoproterozoic high-pressure ultra-high-temperature pelitic granulite, Chicheng, northern Trans-North China Orogen

2021 ◽  
pp. 106237
Author(s):  
Dingding Zhang ◽  
Patrick J. O'Brien ◽  
Hans-Peter Schertl ◽  
Xudong Ma ◽  
Zhonghua Tian ◽  
...  
2017 ◽  
Vol 36 (3) ◽  
pp. 343-368 ◽  
Author(s):  
Cyril Lobjoie ◽  
Wei Lin ◽  
Pierre Trap ◽  
Philippe Goncalves ◽  
Qiuli Li ◽  
...  

Tectonics ◽  
2013 ◽  
pp. n/a-n/a ◽  
Author(s):  
Thomas Bader ◽  
Leander Franz ◽  
Lothar Ratschbacher ◽  
Christian de Capitani ◽  
A. Alexander G. Webb ◽  
...  

2020 ◽  
Author(s):  
Jianying Feng ◽  
Yu Zhang ◽  
Suping Wang

<p>In 2018, severe meteorological drought occurred in the southwest of Northeast China, the  east-central of Inner Mongolia and the east of North China. Drought shows obvious regional and stage nature .In early March, mild to moderate drought appeared in North China, followed by severe drought in parts of northern and eastern of Hebe province. After the middle of April, the drought was alleviated obviously, and the drought in the southwest of Northeast China began to show signs. In  early May, there was mild to moderate drought in the central and eastern part of Inner Mongolia, and the drought in Northeast China developed. From June to early August, severe drought and above occurred in parts of Liaoning province , Inner Mongolia and North China. In mid-August, in addition to Liaoning province and North China, there were scattered light to moderate drought, drought relief in the northern China. In early September, the drought in North China increased and the range spread northward, and there were droughts of different degrees in the whole North China.In winter, there is only mild drought in North China.</p><p>The drought in this region has affected the agricultural production in different degrees. Spring sowing is blocked in the east of Inner Mongolia and the west of Northeast China, and high temperature in summer leads to the development of drought, corn and rice and other crops are adversely affected.</p><p>From spring to autumn, the precipitation in most parts of the drought disaster  area is less than 10-40%, and the temperature is higher than 1-2 ℃. The lack of precipitation and abnormal high temperature accelerated the loss of surface water, which resulted in the occurrence of drought in this area.</p><p>In spring of 2018, the middle and high latitudes are generally controlled by flat air flow, which is not conducive to the establishment of trough ridge, making the northern dry area lack of favorable precipitation conditions; in summer and autumn, the existence of Baikal Lake high-pressure ridge, resulting in circulation patterns that are not conducive to the precipitation conditions in the northern dry area. Among them, the obvious flat air flow in spring and the obvious high pressure ridge in summer are the main reasons for the outstanding drought in spring and summer in the northern arid area.</p>


2021 ◽  
Author(s):  
Jianhua Wang ◽  
Jiaqi Zhang ◽  
Lili Yan ◽  
Rongchao Cheng ◽  
Xiaoxiao Ni ◽  
...  

Abstract Oil-based mud (OBM) is the first choice for complex deep wells due to its advantages of high-temperature resistance, good lubrication and borehole stability. But barite sagging under ultra-high temperature during the long-time stationary completion operation may lead to serious problems in ultra-deep wells, for instance, pipe sticking, density variation and well control problems. In this paper, the influence of high-temperature and high-pressure (HTHP) on the performance of oil-based completion fluid was studied, and a model of rheological parameters was established with HTHP static sag law. The barite sagging stability was evaluated by a high temperature (220°C) and high pressure (100MPa) sag instrument. The results indicated that RM6 value and static shearing force were the main factors of affecting the settlement stability. The viscosity of the completion fluid significantly decreased with the increase of temperature, but increased with the increase of pressure. In addition, the relationship was also studied between HTHP rheology and atmospheric pressure rheology at 50°C. The results showed that when RM6 value was kept above 10, the sag stability factor (SF) of oil-based completion fluid was less than 0.52 at 190°C for 10 days, which proved a good high-temperature sag stability. Furthermore, the anti-high temperature property of oil-based completion fluid was improved through enhancing the temperature-resistance of the additives. And the high-temperature-resistant organic soil was introduced to raise the RM6 value and the static shearing force. Based on these solutions, the barite sag under high temperature of the oil-based completion fluid was prevented during drilling and completion operation in ultra-high temperature wells. The oil-based completion fluid was successfully used in Well Keshen 17 (175°C,7475 m) in Kuche piedmont structure and TT 1 well (210°C,6500 m) in Sichuan basin. The casing run smoothly, the oil-test operation was completed smoothly for 15 days, and no barite sag happened. It testified that the oil-based completion fluid had excellent of high-temperature sag stability. Therefore, this oil-based completion fluid is expected to be used widely in ultra-deep wells.


2006 ◽  
Vol 2006.1 (0) ◽  
pp. 189-190
Author(s):  
Ryuji SIRAKAWA ◽  
Yoshihisa HARADA ◽  
Takayuki SUZUKI ◽  
Kazumi HIRANO ◽  
Tokuo TERAMOTO

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