The ultrasonic assisted tungsten inert gas （U-TIG） welding is a newly developed arc welding method, which is aimed at improving the weld quality and efficiency. TIG welding and U-TIG welding of 2014 aluminum alloy w...The ultrasonic assisted tungsten inert gas （U-TIG） welding is a newly developed arc welding method, which is aimed at improving the weld quality and efficiency. TIG welding and U-TIG welding of 2014 aluminum alloy with 5 mm thickness were experimentally carried out in this paper. The microstructure and porosity of welded joints were analyzed. Compared with conventional TIG welding, the columnar crystals are changed into equiaxed crystals at the centre of weld zone and the grain of fusion zone in U-TIG welding is refined and equiaxed. The porosities of joint decrease after the ultrasonic was applied on the arc. The mechanism of crystal grain refinement is discussed in this paper and the reasons of porosity decrease in U-TIG welded joint may be due to the effect of acoustic streaming and cavitation, which need further research.展开更多
Carbonate rocks are important hydrocarbon reservoirs around the globe and in Southeast Asia a key one,particularly,is the Central Luconia province.Understanding the internal characteristics,distribution,geometry and l...Carbonate rocks are important hydrocarbon reservoirs around the globe and in Southeast Asia a key one,particularly,is the Central Luconia province.Understanding the internal characteristics,distribution,geometry and lateral extent of these rocks is essential for exploration and production success.Detailed work on Miocene carbonate reservoir facies,north of Bintulu,offshore Sarawak includes qualitative and quantitative analysis of photomicrographs and reservoir quality,considering especially microporosity.Stratigraphically,these carbonates are known as Cycles IV and V and are represented by eight major facies types(F-1 to F-8).They comprise:coated grain packstone(F-1)(av.Ф=3%,av.Kh=0.5 m D)(av=Average;?=total porosity,and Kh=permeability);massive coral lime grainstone(F-2)(av.Ф=14.7%,av.Kh=6 m D);oncolite lime grain-dominated packstone(F-3)(av.Ф=10%,av.Kh=4 m D);skeletal lime/dolo-packstone(F-4)(av.Ф=15%,av.Kh=4.6 m D);coral(platy)lime mud-dominated packstone(F-5)(av.Ф=4%,av.Kh=0.5 m D);coral(branching)lime-dominated pack-grainstone(F-6)(av.Ф=15%,av.Kh=1 m D);cross-bedded skeletal lime packstone(F-7)(av.Ф=20%,av.Kh=2 m D);and bioturbated carbonate mudstone/chalk(F-8)(av.Ф=8%,av.Kh=0.8 m D).Study of thin sections reveals that red algae,foraminifera,and corals are the dominant fossil components with a minor admixture of skeletal fragments of echinoderms,bivalves,bryozoans,and green algae.All parameters,e.g.,facies characterization,petrography,porosity–permeability value,and microporosity value were utilized to obtain a reliable reservoir quality.The microporosity value was quantified using digital image analysis software and is significant for recognition of good reservoir quality.Consideration of the presence of microporosity against the total porosity in the carbonate rocks has improved the correlation coefficient(R2)value,which has increased from 0.51 to 0.82.展开更多
文摘The ultrasonic assisted tungsten inert gas （U-TIG） welding is a newly developed arc welding method, which is aimed at improving the weld quality and efficiency. TIG welding and U-TIG welding of 2014 aluminum alloy with 5 mm thickness were experimentally carried out in this paper. The microstructure and porosity of welded joints were analyzed. Compared with conventional TIG welding, the columnar crystals are changed into equiaxed crystals at the centre of weld zone and the grain of fusion zone in U-TIG welding is refined and equiaxed. The porosities of joint decrease after the ultrasonic was applied on the arc. The mechanism of crystal grain refinement is discussed in this paper and the reasons of porosity decrease in U-TIG welded joint may be due to the effect of acoustic streaming and cavitation, which need further research.
基金Professor Dr.Deva Prasad Ghosh(Head:Centre for Seismic Imaging,Department of Geoscience,University Technology PETRONAS,Tronoh,Perak,Malaysia)for his support and economic assistance throughout the research under grant YUTP 0153AA-A14。
文摘Carbonate rocks are important hydrocarbon reservoirs around the globe and in Southeast Asia a key one,particularly,is the Central Luconia province.Understanding the internal characteristics,distribution,geometry and lateral extent of these rocks is essential for exploration and production success.Detailed work on Miocene carbonate reservoir facies,north of Bintulu,offshore Sarawak includes qualitative and quantitative analysis of photomicrographs and reservoir quality,considering especially microporosity.Stratigraphically,these carbonates are known as Cycles IV and V and are represented by eight major facies types(F-1 to F-8).They comprise:coated grain packstone(F-1)(av.Ф=3%,av.Kh=0.5 m D)(av=Average;?=total porosity,and Kh=permeability);massive coral lime grainstone(F-2)(av.Ф=14.7%,av.Kh=6 m D);oncolite lime grain-dominated packstone(F-3)(av.Ф=10%,av.Kh=4 m D);skeletal lime/dolo-packstone(F-4)(av.Ф=15%,av.Kh=4.6 m D);coral(platy)lime mud-dominated packstone(F-5)(av.Ф=4%,av.Kh=0.5 m D);coral(branching)lime-dominated pack-grainstone(F-6)(av.Ф=15%,av.Kh=1 m D);cross-bedded skeletal lime packstone(F-7)(av.Ф=20%,av.Kh=2 m D);and bioturbated carbonate mudstone/chalk(F-8)(av.Ф=8%,av.Kh=0.8 m D).Study of thin sections reveals that red algae,foraminifera,and corals are the dominant fossil components with a minor admixture of skeletal fragments of echinoderms,bivalves,bryozoans,and green algae.All parameters,e.g.,facies characterization,petrography,porosity–permeability value,and microporosity value were utilized to obtain a reliable reservoir quality.The microporosity value was quantified using digital image analysis software and is significant for recognition of good reservoir quality.Consideration of the presence of microporosity against the total porosity in the carbonate rocks has improved the correlation coefficient(R2)value,which has increased from 0.51 to 0.82.
