Forms of Mercury in Drilling Fluid Barite and Their Fate in the Marine Environment: A Review and Synthesis

Author(s):  
John H. Tefry ◽  
Joe P. Smith
2000 ◽  
Author(s):  
A. Saasen ◽  
M. Berntsen ◽  
G. Løklingholm ◽  
H. Igeltjørn ◽  
K. Åsnes

2021 ◽  
Author(s):  
Qingchao Li ◽  
Yuanfang Cheng ◽  
Ubedullah Ansari ◽  
Ying Han ◽  
Xiao Liu ◽  
...  

Abstract As we all know, development and utilization of clean energy is the only way for society to achieve sustainable development. Although natural gas hydrates is a new type of clean energy, uncontrollable hydrate dissociation and accompanying methane leakage in drilling operation threaten drilling safety and marine environment. However, dissociation range of natural gas hydrates around wellbore can't be reasonably and clearly determined in previous investigations, which may lead to the inaccurate estimation of borehole collapse and methane leakage. Then, the marine environment will be greatly damaged or affected. The purpose of the present work is to experimentally explore the dissociation characteristics of natural gas hydrates around wellbore in drilling operation, and analyze the influence law and mechanism of various factors on hydrate dissociation. It is expected to provide reference for exploring effective engineering measures to avoid the uncontrolled hydrate dissociation, borehole collapse and accompanying methane leakage. The experimental results demonstrate that acoustic velocity of hydrate-bearing sediment can be accurately expressed as quadratic polynomial of hydrate saturation, which is the theoretical basis for determination of hydrate saturation in subsequent experiments. Owing to the fact that hydrate dissociation is an endothermic reaction, hydrate dissociation gradually slows down in experiment. Throughout the experiment, the maximum dissociation rate at the beginning of the experiment is 8.69 times that at the end of the experiment. In addition, sensitivity analysis found that the increase of stabilizer concentration in drilling fluid can inhibit hydrate dissociation more than the increase in hydrate saturation. Hydrate dissociation was completely inhibited when the concentration of soybean lecithin exceeds 0.60wt%, but hydrate dissociation definitely occurs in the near-wellbore region no matter what hydrate saturation is. In this way, based on the requirements of drilling safety and environment protection, hydrate dissociation and accompanying methane leakage can be controlled by designing and adjusting the stabilizer concentration in drilling fluid.


Author(s):  
V.N. Esaulenko ◽  
◽  
S.S. Malov ◽  
I.V. Pavlova ◽  
◽  
...  

2020 ◽  
Vol 649 ◽  
pp. 125-140
Author(s):  
DS Goldsworthy ◽  
BJ Saunders ◽  
JRC Parker ◽  
ES Harvey

Bioregional categorisation of the Australian marine environment is essential to conserve and manage entire ecosystems, including the biota and associated habitats. It is important that these regions are optimally positioned to effectively plan for the protection of distinct assemblages. Recent climatic variation and changes to the marine environment in Southwest Australia (SWA) have resulted in shifts in species ranges and changes to the composition of marine assemblages. The goal of this study was to determine if the current bioregionalisation of SWA accurately represents the present distribution of shallow-water reef fishes across 2000 km of its subtropical and temperate coastline. Data was collected in 2015 using diver-operated underwater stereo-video surveys from 7 regions between Port Gregory (north of Geraldton) to the east of Esperance. This study indicated that (1) the shallow-water reef fish of SWA formed 4 distinct assemblages along the coast: one Midwestern, one Central and 2 Southern Assemblages; (2) differences between these fish assemblages were primarily driven by sea surface temperature, Ecklonia radiata cover, non-E. radiata (canopy) cover, understorey algae cover, reef type and reef height; and (3) each of the 4 assemblages were characterised by a high number of short-range Australian and Western Australian endemic species. The findings from this study suggest that 4, rather than the existing 3 bioregions would more effectively capture the shallow-water reef fish assemblage patterns, with boundaries having shifted southwards likely associated with ocean warming.


2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Suganjar Suganjar ◽  
Renny Hermawati

<p><em>Safety management in the shipping industry is based on an international regulation. It is International Safety Management Code (ISM-Code) which is a translation of SOLAS ‘74 Chapter IX. It stated that t</em><em>he objectives of the Code are to ensure safety at sea, prevention of human injury or loss of life, and avoidance of damage to the environment, in particular, to the marine environment, and to property.it is also</em><em> requires commitment from top management to implementation on both company and on board. The implementation of the ISM-Code is expected to make the ship’s safety is more secure. The ISM-Code fulfillment refers to 16 elements, there are; General; Safety and Environmental Protection Policy; Company Responsibility and Authority; Designated Person(s); Master Responsibility and Authority; Resources and Personnel; Shipboard Operation; Emergency Preparedness; Report and Analysis of Non-conformities, Accidents and Hazardous Occurrences; Maintenance of the Ship and Equipment; Documentation; Company Verification, Review, and Evaluation;  Certification and Periodical Verification; Interim Certification; Verification; Forms of Certificate. The responsibility and authority of Designated Person Ashore / DPA in a shipping company is regulated in the ISM-Code. So, it is expected that DPA can carry out its role well, than can minimize the level of accidents in each vessels owned/operated by each shipping company.</em></p><p><em></em><strong><em>Keywords :</em></strong><em> ISM Code,</em><em> </em><em>Safety management, </em><em>Designated Person Ashore</em></p><p> </p><p> </p><p>Manajemen keselamatan di bidang pelayaran saat ini diimplementasikan dalam suatu peraturan internasional yaitu <em>International Safety Management Code</em> (<em>ISM-Code</em>) yang merupakan penjabaran dari <em>SOLAS 74 Chapter IX</em>-<em>Management for the safe operation of ships</em>. Tujuan dari <em>ISM-Code</em> <em>“The objectives of the Code are to ensure safety at sea, prevention of human injury or loss of life, and avoidance of damage to the environment, in particular, to the marine environment, and to property”</em> dan  <em>ISM-Code</em> menghendaki adanya komitmen dari manajemen tingkat puncak sampai pelaksanaan, baik di darat maupun di kapal.  Pemberlakuan <em>ISM-Code</em> tersebut diharapkan akan membuat keselamatan kapal menjadi lebih terjamin. Pemenuhan <em>ISM-Code</em> mengacu kepada 16 elemen yang terdiri dari ; umum; kebijakan keselamatan  dan perlindungan lingkungan; tanggung jawab dan wewenang perusahaan; petugas yang ditunjuk didarat; tanggung jawab dan wewenang nahkoda; sumber daya dan personil; pengopersian kapal; kesiapan menghadapi keadaan darurat; pelaporan dan analisis ketidaksesuaian, kecelakaan dan kejadian berbahaya; pemeliharaan kapal dan perlengkapan;  Dokumentasi; verifikasi, tinjauan ulang, dan evaluasi oleh perusahaan; sertifikasi dan verifikasi berkala; sertifikasi sementara; verifikasi; bentuk sertifikat. Tugas dan tanggungjawab <em>Designated Person Ashore/DPA </em>didalam suatu perusahaan pelayaran<em>, </em>telah diatur di dalam <em>ISM-Code.</em>  Sehingga diharapkan agar DPA dapat melaksanakan peranannya dengan baik, sehingga dapat menekan tingkat kecelakaan di setiap armada kapal yang dimiliki oleh setiap perusahaan pelayaran.</p><p class="Style1"><strong>Kata kunci</strong> : <em>ISM Code</em>, Manajemen keselamatan, <em>Designated Person Ashore</em></p>


2016 ◽  
Vol 1 (1) ◽  
Author(s):  
F. Sadatfaraji ◽  
A. Bashir Bhatti ◽  
F. Behzadi ◽  
M. Khani ◽  
M. Khani

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