A preliminary screening and characterization of suitable acids for sandstone matrix acidizing technique: a comprehensive review

Matrix acidizing is a broadly developed technique in sandstone stimulation to improve the permeability and porosity of a bottom-hole well. The most popular acid used is mud acid (HF–HCl). It is a mixture of hydrofluoric acid and hydrochloric acid. However, one of the conventional problems in sandstone acidizing is that mud acid faces significant issues at high temperature such as rapid rate of reaction, resulting in early acid consumption. This downside has given a negative impact to sandstone acidizing as it will result in not only permeability reduction, but can even extend to acid treatment failure. So, the aim of this study is to provide a preliminary screening and comparison of different acids based on the literature to optimize the acid selection, and targeting various temperatures of sandstone environment. This paper has comprehensively reviewed the experimental works using different acids to understand the chemical reactions and transport properties of acid in sandstone environment. The results obtained indicated that fluoroboric acid (HBF4) could be useful in enhancing the sandstone acidizing process, although more studies are still required to consolidate this conclusion. HBF4 is well known as a low damaging acid for sandstone acidizing due to its slow hydrolytic reaction to produce HF. This would allow deeper penetration of the acid into the sandstone formation at a slower rate, resulting in higher porosity and permeability enhancement. Nevertheless, little is known about the effective temperature working range for a successful treatment. Considering the pros and cons of different acids, particularly those which are associated with HF and HBF4, it is recommended to perform a comprehensive analysis to determine the optimum temperature range and effective working window for sandstone acidizing before treatment operation. Prior to sandstone acid stimulation, it is essential to predict the feasibility of acid selected by integrating the effects of temperature, acid concentration and injection rate. Therefore, this manuscript has thrown light into the research significance of further studies

Environmental benefits of leaving offshore infrastructure in the ocean

The removal of thousands of structures associated with oil and gas development from the world's oceans is well underway, yet the environmental impacts of this decommissioning practice remain unknown. Similar impacts will be associated with the eventual removal of offshore wind turbines. We conducted a global survey of environmental experts to guide best decommissioning practices in the North Sea, a region with a substantial removal burden. In contrast to current regulations, 94.7% of experts (36 out of 38) agreed that a more flexible case‐by‐case approach to decommissioning could benefit the North Sea environment. Partial removal options were considered to deliver better environmental outcomes than complete removal for platforms, but both approaches were equally supported for wind turbines. Key considerations identified for decommissioning were biodiversity enhancement, provision of reef habitat, and protection from bottom trawling, all of which are negatively affected by complete removal. We provide recommendations to guide the revision of offshore decommissioning policy, including a temporary suspension of obligatory removal

Protein/Emulsifier Interactions

An important consequence of protein-lipid interaction is the effect on stability of the protein in solution as well as on its behavior at interfaces. Here we will discuss key aspects of protein aggregation and unfolding as well as the effects of protein structure (random coil proteins versus globular) that are relevant for our understanding protein-lipid interaction. The main types of emulsifiers are the (1) aqueous soluble, surfactant type and (2) lipids with low aqueous solubility. The monomer concentration as defined by cmc is an important parameter for the soluble lipids. For emulsifiers with low aqueous solubility the emulsifier self-assembly structure and its properties control the interaction with proteins. We will therefore summarize the main features of lipid self-assembly. It also allows us to define different plausible scenarios and principles and models for factors that control the interactions in real food (and Pharmaceutical) systems. For the food applications the fate of the lipid during digestion is important and therefore we will discuss some aspects of enzyme-catalyzed lipolysis in terms of the structural evolution. New products and concepts of using protein/emulsifier interactions will be exemplified by illustrating how food nanotechnology possibly can be used for the delivery of functionality