Acid treatment categories

There are three general categories of acid treatments  

In acid washing, the objective is simply tubular and wellbore cleaning. Treatment of the formation is not intended. Acid washing is most often performed to clean out scale and other debris restricting flow in the well. 

In matrix acidizing, the acid treatment is injected at matrix pressures or below formation fracturing pressure. In fracture acidizing, all (or at least a signiflcant portion) of the acid treatment is intentionally pumped above formation fracturing pressure. 

Matrix acidizing has application in both carbonate and sandstone formations. In sandstone formations, matrix acidizing treatments should be designed primarily to remove or dissolve add-removable damage or plugging in the perforations and in the formation pore network near the wellbore. 

Quite often, acid will form predominantly single wormholes from limited numbers of perforations, without significant branching. That is the case with strong acids, such as HCl. Weaker acids, such as carbox)dic acids (e.g., acetic add), and retarded acid systems tend to create more branching of wormholes, which is desirable but only to a certain extent. Retarded acid systems include viscosified acids (e.g., polymer- or surfactant-gelled acid, emulsified acid, and foamed acid) or chemically retarded (surfactant-retarded) acid. The nature of wormholes created depends on injection rate, temperature, and formation reaction characteristics as well. 

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If an unsaturated dicarbonyl precursor is available, no oxidant needs to be added a synthesis of the perchlorate of pyrylium itself, shown below, falls into this category careful perchloric acid treatment of either glutaconaldehyde, or of its sodium salt, produces the parent salt. (CAUTION potentially explosive). 

The oils were separated into saturated and aromatic fractions, which were then analyzed by suitable mass spectrographic methods. Table 16-9 shows the composition of these fractions by molecular type. Since the original lubricant stocks had been refined by solvent extraction or acid treatment, it is not unexpected that the bulk of the aromatics fall into the two-ring rather than the higher ring category. The sulfur compounds found in commercially extracted lubricant stocks become part of the aromatic fraction in an analytical separation by silica gel. 

Need must be based on both existing damage and potential damage that can be caused by the acid treatment. Once the absolute additive needs are identified, additive types can be considered. Selecting by type limits choices to about 13 categories. Within each category, there are many choices, with varying effectiveness and cost. 

Solvent Treatment. Solvent processes can be divided into two main categories, solvent extraction and solvent dewaxing. The solvent used in the extraction processes include propane and cresyHc acid, 2,2 -dichlorodiethyl ether, phenol (qv), furfural, sulfur dioxide, benzene, and nitrobenzene. In the dewaxing process (28), the principal solvents are benzene, methyl ethyl ketone, methyl isobutyl ketone, propane, petroleum naphtha, ethylene dichloride, methylene chloride, sulfur dioxide, and iV-methylpyrroHdinone. 

Cationic Starches. The two general categories of commercial cationic starches are tertiary and quaternary aminoalkyl ethers. Tertiary aminoalkyl ethers are prepared by treating an alkaline starch dispersion with a tertiary amine containing a P-halogenated alkyl, 3-chloto-2-hydtoxyptopyl radical, or a 2,3-epoxypropyl group. Under these reaction conditions, starch ethers are formed that contain tertiary amine free bases. Treatment with acid easily produces the cationic form. Amines used in this reaction include 2-dimethylaminoethyl chloride, 2-diethylaminoethyl chloride, and A/-(2,3-epoxypropyl) diethylamine. Commercial preparation of low DS derivatives employ reaction times of 6—12 h at 40—45°C for complete reaction. The final product is filtered, washed, and dried. 

Diuretics are one of the dmg categories most frequendy prescribed. The principal uses of diuretics are for the treatment of hypertension, congestive heart failure, and mobilization of edema fluid in renal failure, fiver cirrhosis, and ascites. Other applications include the treatment of glaucoma and hypercalcemia, as well as the alkafinization of urine to prevent cystine and uric acid kidney stones. 

The anion-exchange reactions of ionic liquids can really be divided into two distinct categories direct treatment of halide salts with Lewis acids, and the formation of ionic liquids by anion metathesis. These two approaches are dealt with separately, as quite different experimental methods are required for each. 

Only one procedure in this category emerged from the present survey. Thus treatment of 1,2-benzenediamine (372) with 3,3-bis(trifluoromethyl)-5-oxazolinone (373, R = H) in ethyl acetate containing a trace of acetic acid at room temperature for a short time afforded 2(l//)-quinoxalinone (374, R = H) in 92% yield 3-methyl- (374, R = Me), 3-isopropyl- (374, R = Pr"), 3-phenyl- (374, R = Ph), and 3-benzyl-2(l//)-quinoxalinone (374, R = CH2Ph) were made similarly in 60-80% yield. ... 

The ionization of benzoic acids in water at 25° was used by Hammett as the standard reaction for the original qp treatment (2a). This reaction and several analogous reactions, e.g., ionization and ester saponification rates of benzoic acids, cinnamic acids, and phenylpropiolic acids, gives ap correlations of relatively high precision. Taft and Lewis classified such reactions in an A category (2f). Reexamination of these A reactions, as well as additional analogous data which have become available subsequently, provided eight reaction series of data of apparently comparable reliability. In the para position, each of these sets of data meets the necessary condition of a minimal basis set... 

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