Well-stimulation

A clear solution of aluminum citrate neutralized to pH 7 is used for in situ gelling of polymers in polymer flooding and well stimulation in enhanced oil recovery techniques (128—132). The citrate chelate maintains aluminum ion solubiUty and controls the rate of release of the aluminum cross-linker. 

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

Air and Gas. In the regions where air and natural gas are used as the principal drilling fluids, the potential oil and gas production zones usually have low pore pressure, or require well stimulation techniques to yield commercial production. In these production zones, air drilling (or natural gas drilling) is continued into the production zone and the initial produced formation fluids are carried to the surface by the circulating air or natural gas. This is nearly the same situation as in mud drilling, except that in air (or gas) drilling the transit time for the initial produced formation fluids to reach the surface is much shorter. In mud... 

The composition is useful as an additive for clearing stuck pipe in wellbores and as a fixer spacer for cementing pipe in wellbores. Another use of the composition is as a well stimulation fluid in oil and gas production wells, in which the composition is effective to dissolve filter-cake that blocks pores in the production formation. 

For worthwhile oil or gas well stimulation, the best proppant and fluids have to be combined with a good design plan and the right equipment. The selection of a proppant is an important factor in determining how successful the stimulation treatment can be. To select the best proppant for each well, a general understanding of available proppants is imperative. 

Polypropylene glycol, particulate hydrophobic silica, and a fatty acid methyl ester, or an olefin or linear paraffin as a liquid diluent, are proposed for well-stimulation jobs [357]. 

Z. R. Lemanczyk. The use of polymers in well stimulation performance, availability and economics. In Proceedings Volume. Plast Rubber Inst Use of Polymers in Drilling Oilfield Fluids Conf (London, England, 12/9), 1991. 

K. C. Taylor, H. A. Nasr-El-Din, and M. J. Al-Alawi. A systematic study of iron control chemicals used during well stimulation. In Proceedings Volume, pages 19-25. SPE Formation Damage Contr Int Symp (Lafayette, LA, 2/18-2/19), 1998. 

Chemicals of various types are used in every stage of drilling, completing, and producing oil and gas wells. This review describes these chemicals, why they are used, and recent developments. These chemicals include common inorganic salts, transition metal compounds, common organic chemicals and solvents, water-soluble and oil-soluble polymers, and surfactants. As existing fields become depleted, use of chemistry to maintain production via well stimulation, more efficient secondary recovery operations, and enhanced oil recovery become ever more important. 

Acids were an early exception to the no water rule. It was recognized that aqueous solutions of acids would inhibit swelling of clays and shales as well as dissolve any acid-soluble minerals contained in a formation. By 1933 commercial well stimulation with hydrochloric acid was of great interest. A whole separate methodology and treatment chemistry has since evolved around acidizing and fracture acidizing(54). Water emulsions, mainly emulsified acids, and gelled acids thickened with polymeric additives were applied early in the history of well treatment. 

Holditch, S.A. Ely, J. "Successful Deep Well Stimulation Utilizing High Proppant Concentration", SPE paper 4118, 1972 SPE Annual Meeting, San Antonio, October 8-11. 

Crema, S.C. Aim, R.R. "Foaming of Anhydrous Methanol for Well Stimulation", SPE paper 13565, 1985 International Symposium on Oilfield and Geothermal Chemistry, Phoenix, April 9-11. 

The migration of iron mineral fines, primarily hematite and magnetite, is a common occurrence in portions of the Appalachian Basin. The phenomenon often occurs after well stimulation and can result in the continuing production of iron mineral fines which pose a significant disposal problem. The migration of iron mineral fines through propped fractures can substantially reduce the fracture flow capacity. Many of these are mineral fines are native to the formation and are not formed by precipitation of acid-soluble iron salts present in injection waters during or after acidi-... 

Solutions of TKPP were mixed with aqueous fluids commonly encountered in drilling or completion of wells. Unlike saturated zinc bromide, concentrated TKPP solutions can be mixed in any proportion with fresh water with the only result being a decrease in solution density. Similar results were obtained with conventional oil field brines containing as much as 400 parts per million polyvalent cations, mostly calcium. Saturated solutions of calcium hydroxide also can be added to TKPP in any proportion without promoting precipitation as can concentrated hydrochloric acid solutions, conventionally used for well stimulation. The acid tends to generate a slight haze as the pH is reduced from 11.5 to approximately 8 however, this haze rapidly disappears as the pH is lowered by further addition of acid. 

Alderman, E.N., Mack, D.J., and Ousterhout, R.S. "Evaluation of Fracturing Materials for Optimum Well Stimulation," API paper 801 37J, 1961 Spring Meeting of Pacific Coast District, Los Angeles, May 11-12. 

Read, D.A. and Wells, G.L. "Measurement While Fracturing for Comparing and Optimizing the Performance of Well Stimulation Treatments," 1985 Proc. Annu. Southwest Pet. Short Course, 171 176. 

Agarwal, R.G., Carter, R.D., and Pollock, C.B. "Evaluation and Performance Prediction of Low-Permeability Gas Wells Stimulated by Massive Hydraulic Fracturing," J. Pet. Technol. (March 1979) 362-372. 

Near-well treatments, in which chemicals are injected into producing and sometimes injector wells, where they are intended to react with the reservoir rock. Well stimulation techniques such as acidization, for example, are intended to increase the formation s permeability. Alternatively, producing wells may receive squeeze treatments in which a mineral scale inhibitor is injected into the formation. In this case, the treatment is designed so that the inhibitor sorbs onto mineral surfaces, where it can gradually desorb into the formation water during production. 

The theme of this book is not a reformulation of theoretical physics, but an attempt to identify the theoretical ideas fundamental to chemistry and recast them in more familiar style. There is no doubt but, that the chemist of this century will have to be familiar with the concepts that appear to be new, even alien, at present. The philosophy that inspires this work is that specialization in science is detrimental in the long term. Specialization may well stimulate productivity in the short term, but this productivity becomes sterile in the absence of innovation, that depends on cross-pollenation, or the adoption of new theoretical models. 

A recent report from the U. K. deals with 1,4-bis(oxodihydropyridazin-yl)benzenes and congeners which are also potent phosphodiesterase inhibitors and inodilators [159], This investigation, together with computer-aided modelling studies on various phosphodiesterase III inhibitors [160], may well stimulate the rational design of additional pyridazine-derived inodilators. 

History-Explosive Fracturing for Well Stimulation", ProeSpring Meeting Mid-Continent District, Div-Production, API, Wichita, Kansas, April 8-10, 1970, pp 58-63 2)G.Cohn, Edit, Expls Pyrots 5(6), 1972 (Abstract)... 

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