Effectiveness formation damage

However, production engineers have been reluctant to use particle bridging because of the possibility of particle transport into the formation, resulting in formation damage and/or costly and often ineffective stimulation treatments. A particle bridging fluid has been developed that quickly and effectively controls fluid loss in a wide range of permeabilities and pore diameters [916]. 

Formation damage caused by clay migration may be observed when the injected brine replaces the connate water during operations such as water-flooding, chemical flooding including alkaline, and surfactant and polymer processes. These effects can be predicted by a physicochemical flow model based on cationic exchange reactions when the salinity decreases [1665]. Other models have also been presented [345,1245]. 

J. L. Elbel, R. C. Navarrete, and B. D. Poe, Jr. Production effects of fluid loss in fracturing high-permeability formations. In Proceedings Volume, pages 201-211. SPE Europe Formation Damage Contr Conf (The Hague, Netherlands, 5/15-5/16), 1995. 

Table II. Formation Damage Effected by Clear Well Fluids...

McLeod, H.O., Jr. "The Effect of Perforating Conditions on Well Performance," SPE paper 10649, 1982 SPE Formation Damage Control Symposium, Lafayette, March 24-25. 

Alaond, s.U. and Bland, U.E. "The Effect of Break Mechanism on Gelling Agent Residue and Flow Impairment in 20/40 Mesh Sand," SPE paper 12485, 1984 Formation Damage Control Symposium, Bakersfield, February 13-14. 

Uojtanowicz, A.K., Krilov, Z., Langlinais, J.P. "Study on the Effect of Pore Blocking Mechanisms on Formation Damage," SPE paper 16233, SPE Production Operations Symposium, Oklahoma City, OK, March 8-10, 1987. 

In the simulations, a significant fraction (about 50% to 80%) of the alkali present in solution is consumed by reactions near the wellbore with the reservoir minerals (as shown in Reaction 30.6 for the NaOH flood), mostly by the production of analcime, paragonite, and dawsonite [NaAlC03(0H)2]. In the clastic reservoir considered, therefore, alkali floods might be expected to cause formation damage (mostly due to the precipitation of zeolites) and to be less effective at increasing oil mobility than in a reservoir where they do not react extensively with the formation. 

Wat, R. M. S, K.S. Sorbie, A. C. Todd, R Chen and R Jiang, 1992, Kinetics of BaSC>4 crystal growth and effect in formation damage (SPE paper 23814). Proceedings Society of Petroleum Engineers International Symposium on Formation Damage Control, Lafayette, Louisiana, February 26-27, 1992, pp. 429-437. 

Mechanism of Action A fungistatic antifungal that interferes with cytochrome P-450, an enzyme necessary for ergosterol formation. Therapeutic Effect Directly damages fungal membrane, altering its function. 

Mecfianism of Action An imidazole derivative that inhibits synthesis of ergosterol (vital component of fungal cell formation), damaging cell membrane. TAerapeMtIc Effect Fungistatic may be fungicidal, depending on concentration. 

Much as liquid water is essential for life, frozen water, ice, is frequently lethal, especially if ice formation occurs within the cell. Upon formation of ice, loss of liquid water may impair or preclude the four basic water-related functions listed above. In particular, the structures and the activities of macromolecules and membranes may be severely damaged. In fact, the harmful effects of ice formation are due to a suite of physical and chemical effects. Physical damage from ice crystals that form within a cell can lead to rupture of membranes and the consequent dissipation of concentration gradients between the cell and external fluids or between membrane-bounded compartments within the cell. Ice formation in the extracellular fluids also can lead to damage to membranes as well as to lethal dehydration of the cell, as water moves down its concentration gradient from the intracellular space to the now depleted pool of liquid water in the extracellular space. Dehydration of the cell not only deprives it of water, but also leads to harmful and perhaps lethal increases in the concentrations of inorganic ions, which remain behind in the cell. Because the activities and structures of nucleic acids and proteins are affected by the concentrations of ions in their milieu, dehydration is expected to lead to perturbation of macromolecular structure and metabolic activity. It should come as no surprise, therefore, that with rare exceptions such as the fat body cells of certain cold-tolerant insects (Lee et al., 1993b Salt, 1962), ice formation within cells is lethal. 

Peroxynitrite, like other oxidants, reacts with proteins, first oxidizing cysteine methionine and tryptophan residues (A7). The reaction products are sulfones, carbonyl moieties, and dityrosines (K23, M29). Formation of protein hydroperoxides and protein fragmentation was also observed (B7, G6). Nitric oxide induces oxidation of methionine residues, thus effecting oxidative damage to proteins (Cl 1). It also reacts with Fe-S clusters of aconitase (D15), though in most cases it is difficult to assess whether these effects are produced by the NO itself, or rather by a more reactive secondary product such as peroxynitrite (C5). At physiological... 

Formation damage. Precipitation and dissolution can cause changes of permeability and caving. Such effects are no doubt in operation in the instances of injecting hydrochloric and sulfuric acids into carbonate aquifers or sandstone cemented by calcite. 

Although only a limited amount of experimental data is available on the effect of temperature, it is apparent that a modest change in temperature has only a minor effect on the process. When a large change in temperature is involved, as may be encountered in thermal oil recovery processes, the temperature effects can be more pronounced. However, at temperatures involved in thermal recovery operations, other formation damage mechanisms, such as mineral dissolution and reprecipitation and colloidal iron plugging, may also be involved. 

Radiation effects A vast material has been collected, about the formation of free radicals by ionising radiation and by photolysis in chemical and biochemical systems. The treatise [20] dealing with studies of primary radiation effects and damage mechanisms in molecules of biological interest is also a valuable source of information of ENDOR spectroscopy in solids. Specialised treatises of radiation effects in sohds involve studies of inorganic [21] and organic systems [22], radiation biophysics [20], radical ionic systems [23], radicals on surfaces [24], and radicals in sohds [25]. 

Similar results were obtained using 0.8 and 5.0 pm filters. The residues change filter pore sizes resulting in a polymer filtercake buildup that controls fluid loss. Viscosity measurements would not have been able to separate these different effects. Design of efficient breaker systems require information of this type to maximize fluid return and minimize fracture and formation damage. 

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