Acids used fracture acidizing

Treatments using fracture acidizing of carbonates are conducted for the purpose of either bypassing formation damage or stimulating undamaged formations. 

Polyacrylamides are used in many other oilfield appUcations. These include cement additives for fluid loss control in well cementing operations (127), viscosity control additives for drilling muds (128), and fracturing fluids (129). Copolymers [40623-73-2] of acrylamide and acrylamidomethylpropanesulfonic acid do not degrade with the high concentrations of acids used in acid fracturing. 

The oil industry uses microencapsulated oil-field chemicals. For example, microencapsulated breaker is deHvered into a subterranean formation where it breaks the fracturing Hquid used to stimulate the recovery of fluids such as cmde oil or natural gas. Examples of breakers encapsulated include oxidi2ers, en2ymes, and various mineral or organic acids. 

Tetraalkyl titanates react with organic borates, B(OR )2, to give complexes of the general formula Ti(OR)4 B(OR )2, which are useful as catalysts and cross-linking agents (562). Mixtures of chelated organic titanates such as TYZOR TE and TYZOR LA with alkaU metal borates, such as borax, or boric acid can be used to produce shear-stable fracturing fluids (563). 

Tsai then applied thick films of the polyamic acid of PMDA and 4-BDAF to polished silver substrates and thermally imidized the films. The substrates were immersed into liquid nitrogen, causing the films to delaminate and XPS was used to examine the polyimide and silver fracture surfaces (see Fig. 33). The C(ls) spectra of the silver fracture surface were very similar to those of neat polyamic acid, indicating that imidization was inhibited by interaction of the polyamic acid with the silver substrate. This was evident from the observation of two peaks near... 

Rider and Amott were able to produce notable improvements in bond durability in comparison with simple abrasion pre-treatments. In some cases, the pretreatment improved joint durability to the level observed with the phosphoric acid anodizing process. The development of aluminum platelet structure in the outer film region combined with the hydrolytic stability of adhesive bonds made to the epoxy silane appear to be critical in developing the bond durability observed. XPS was particularly useful in determining the composition of fracture surfaces after failure as a function of boiling-water treatment time. A key feature of the treatment is that the adherend surface prepared in the boiling water be treated by the silane solution directly afterwards. Given the adherend is still wet before immersion in silane solution, the potential for atmospheric contamination is avoided. Rider and Amott have previously shown that such exposure is detrimental to bond durability. 

During well completion it is sometimes desirable or necessary to treat or stimulate the producing zone to improve permeability of the rock and to increase the flow of oil or gas into the casing. This may be accomplished by use of acid or by injection of fluid and sand under high pressure to fracture the rock. Such a trcatniciit usually improves the ability of the rock to allow fluid to flow through it into the well bore. At this point the drilling and completion phases have ended. 

The drill pipe itself can be used for formation evaluation (Drill Stem Testing— DST), well stimulation (fracturing, acidizing), and fishing operations. 

A low-molecular-weight condensation product of hydroxyacetic acid with itself or compounds containing other hydroxy acid, carboxylic acid, or hydroxy-carboxylic acid moieties has been suggested as a fluid loss additive [164]. Production methods of the polymer have been described. The reaction products are ground to 0.1 to 1500 p particle size. The condensation product can be used as a fluid loss material in a hydraulic fracturing process in which the fracturing fluid comprises a hydrolyzable, aqueous gel. The hydroxyacetic acid condensation product hydrolyzes at formation conditions to provide hydroxyacetic acid, which breaks the aqueous gel autocatalytically and eventually provides the restored formation permeability without the need for the separate addition of a gel breaker [315-317,329]. 

In addition to hydraulic fracturing, there are other stimulation techniques such as acid fracturing or matrix stimulation. Hydraulic fracturing finds use not only in the stimulation of oil and gas reservoirs, but also in coal seams to stimulate the flow of methane from there. 

Acrylics, A copolymer of 2-ethylhexylacrylate and acrylic acid is not soluble either in water or in hydrocarbons. The ester units are hydrophobic and the acid units are hydrophilic. An aqueous suspension with a particle size smaller than 10 p can be useful in preparing aqueous hydraulic fracturing fluids [776]. 

These properties were used to synthesize an organic cation (Table 17-10) with a higher efficiency as a clay stabilizer than the typical salts used in the oil industry to this point. These additives provide additional benefits when used in conjunction with acidizing and fracturing treatments. A much lower salt concentration can be used to obtain the same clay-stabilizing effectiveness [830, 833]. The liquid product has been proven to be much easier to handle and transport. It is environmentally compatible and biodegradable in its diluted form. 

M. E. Gonzalez and M. D. Looney. The use of encapsulated acid in acid fracturing treatments. Patent WO 0075486A, 2000. 

D. J. White, B. A. Holms, and R. S. Hoover. Using a unique acid-fracturing fluid to control fluid loss improves stimulation results in carbonate formations. In Proceedings Volume, pages 601-610. SPE Permian Basin Oil Gas Recovery Conf (Midland, TX, 3/18-3/20), 1992. 

Bone disease is a common manifestation of multiple myeloma. Bisphosphonates should be initiated in symptomatic patients with bone lesions to slow osteopenia and reduce the fracture risk associated with the disease. Pamidronate and zolendronic acid have equivalent efficacy in the management of osteolytic lesions, but because of relative ease of administration, zolendronic acid is used most frequently.43 The use of zolendronic acid decreases pain and bone-related complications and improves quality of life. The suggestion that bisphosphonates have direct antimyeloma activity, based on the ability to inhibit NF-kB signaling, remains controversial. Recent cases of osteonecrosis of the jaw have been a major concern. Risk factors are unclear, but osteonecrosis of the jaw is more common in patients receiving intravenous administration of bisphosphonates and having dental procedures performed. It is recommended that patients... 

The various fields of chemistry play an important role in the discovery and exploitation of oil and gas reserves. Improved drilling and well completion fluids, cement slurries, hydraulic fracturing and acidizing fluids to improve well productivity, various chemical additives to be used in these fluids, and chemicals for enhanced oil recovery are essential to the improvement of production economics and to an increase in recoverable hydrocarbon reserves. Chemistry will become increasingly important in future hydrocarbon production with the decreased likelihood of major onshore discoveries, increased discovery and production costs associated with deep offshore wells and Arctic frontier provinces, and the decline in drilling since early 1982. 

A breaker an enzyme (at T<140°F), strong oxidizing agent, or an acid, is used to depolymerize polysaccharides and break crosslinks such that viscosity declines at a controlled rate so that the proppant may be deposited in the fracture. Too rapid proppant dropout would cause a premature "sand-out" which prevents future extension of the fracture. Peroxydisulfates are the most frequently used breakers. Less reactive organic peroxides may be preferred for high temperature formations (85). 

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