Acidizing Damage Mechanisms

Use of incompatible additives or improper mixing procedures Reprecipitation of acid reaction products Loss of near-wellbore formation compressive strength Formation of emulsions Formation of sludge Water blocking Wettability alteration 

Use of acid additives that are incompatible with one or more other additives or incompatible with the formation or formation fluids can cause damage, sometimes irreversibly. This problem can be eliminated with proper additive selection (see chapter 6) and quality control practices (see chapter 16). 

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Water blocking and wettability alteration are related acidizing damage mechanisms, especially useful in sandstones. In tight formations, water that is introduced to the formation may be retained by capillary forces. Gas or oil production rates may be severely impaired. Proper selection of surfactant additives is necessary to avoid water blocking. This is quite often difficult to assess without the benefit of core flow testing with a representative formation core. 

Propose a mechanism which explains how strong acids damage the chemical structure of polyesters. 

This mechanism is of importance in radical induced amino acid damage catalyzed by copper ions. The study of the decomposition of transients with a metal-carbon -bond containing two potential leaving groups (both an amine and a carboxylate group) at the p position of the carbon centered radical is of special interest. It was reported that the intermediate formed with the amino acid 2-methylalanine with cupric ions decomposes via p-carboxyl elimination whereas the intermediate formed with cuprous ions decomposes via p-amine elimination (102). 

Inhibition of bile acid transport More than 100 medicaments can cause intrahepatic cholestasis. In this case, the canalicular transport mechanisms are impaired. The retained bile acids damage the cells. 

Damaging mechanisms. Dioxin and difiiran injure the patients by provoking local irritative and ulcerous processes on the skin and mucosa contact surfaces, as well as severe disorders of the substances metabolism in the brain, myocardum and liver cells on the basis of enzyme failure and suppressed RNA and amino-acid groups interaction. 

The DNA-electrochemical biosensor is a very good model for evaluation of nucleic acid damage, and electrochemical detection is a particularly sensitive and selective method for the investigation of specific interactions [2-6]. The interpretation of electrochemical data can contribute to elucidation of the mechanism by which DNA is oxidatively damaged by hazardous compounds, in an approach to the real action scenario that occurs in the living cell and without using animal tests. 

The report examines the extent of environmental damage in the Community and in certain other European countries that may be attributable to acid pollutant emissions within Member States. The study assesses the evidence for possible causal effects and considers the physical chemical and biological processes which have been suggested as damage mechanisms. 

There is an urgent need for more field experimentation work to assess the degree and location of possible damage and/or yield loss to susceptible crops. Better understanding is needed of the principal pollutant damage mechanisms for spruce and fir trees, and the responses of different catchment areas to changes in acidity of precipitation and to liming. 

Hydrochloric acid can result in pitting and stress corrosion cracking. Carbon steels can tolerate a relatively high corrosion rate during hydrochloric acid cleaning, provided an inhibitor is added, because cleaning operations are short and other damage mechanisms are not a factor. 

The threshold of acidity for damage and pain may be different. A higher acidity is likely needed for damage to the epithelial cells compared to the acidity required for stimulation of the pain fibers. This is probably because the epithelial cells have acid recovery mechanisms (such as NaVH" or anion exchange) mostly absent in the pain fibers. Dependent on the location of the pain fibers and access thereto of H% individuals will have different sensitivities to luminal acidity. The therapeutic aims of acid control may vary, being elevation of mean diurnal pH for healing of erosions or prevention of acidic excursions for symptom relief or both. 

In any discussion about acidizing, organic deposits and their removal must be discussed. The deposition of organic material is a common damage mechanism, and its possible presence in an oil well that is a potential stimulation candidate must always be explored. This chapter briefly addresses organic deposition problems and solutions. 

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