Matrix stimulation fluids

Stimulation fluid is a treatment fluid prepared for stimulation purposes, although the term most commonly is applied to matrix stimulation fluids. Most matrix stimulation fluids are acid or solvent-based, with hydrochloric acid being the most common base due to its reaction characteristics and its relative ease of control. Matrix stimulation is a process of injecting a fluid into the formation, either an acid or solvent at pressures below the fracturing pressure, to improve the production or injection flow capacity of a well. 

Excessive acidization of a carbonate, especially in matrix acidizing, may create large voids, or caverns, extending from the wellbore into the formation. These voids may collapse, resulting in poorer productivity from perforations or in open-hole conditions. In extreme cases, void creation may result in buckled casing. Again, the problems associated with excessive reaction can be reduced or avoided with proper treatment design. Mild add or non-add stimulation fluid alternatives may be sensible. 

There are a wide range of possible channeling patterns or structures that can be created as acid reacts in carbonates under matrix conditions. The channeling structure depends on injection rate and acid reactivity with the rock, which is a function of the stimulation fluid properties and temperature. For each formation and its conditions, there will exist an optimum combination of acid (or reactive fluid) injection rate and degree of reactivity (or retardation). 

Wattiez R et al. Human bronchoalveolar lavage fluid protein two-dimensional database study of interstitial lung diseases. Electrophoresis 2000 21 2703-2712. Yanagida M et al. Matrix assisted laser desorption/ionization-time of flight-mass spectrometry analysis of proteins detected by anti-phosphotyrosine antibody on two-dimensional-gels of fibrolast cell lysates after tumor necrosis factor-alpha stimulation. Electrophoresis 2000 21 1890-1898. 

Certain human populations depend on dietary sources of vitamin D because of insufficient biosynthesis of the vitamin due to inadequate skin exposure to sunlight. The classic symptoms of vitamin D deficiency are rickets in children and osteomalacia in adults. 25-Hydroxyvitamin D3 is the major circulating metabolite in the blood, but the hormonally active form of the vitamin is 1,25-dihydroxyvitamin D3. The latter metabolite stimulates the intestine to absorb calcium and phosphate by two independent mechanisms and acts with parathyroid hormone to mobilize calcium, accompanied by phosphate, from the bone fluid compartment into the bloodstream. 1,25-dihydroxyvitamin D 3 is also involved in the formation of osteoclasts—giant cells that are solely responsible for the resorption of bone matrix (33). Resorption is an essential process for the development, growth, maintenance, and repair of bone. 

However, the chemist is often interested in transient free-radicals in the gas-phase or fluid solution. These may be trapped by rapid freezing or matrix isolation, but the advantages of single crystal studies are thereby lost. Fortunately the results derived from studies of radicals in single crystals have stimulated several groups to return to the problem of interpreting spectra from amorphous solids (Adrian et... 

FIGURE 6.10 The neuromuscular junction. The region of contact between one nerve and another nerve, or between a nerve and a muscle cell, is called a s)maptic cleft. The secretory vesicles are represented by circles in which acetylcholine is represented by dots. The nerve impulse provokes the entry of calcium ions (not shown) from the extracellular fluid into the nerve cell. Calcium ions act as a signal that stimulates the fusion of vesicles with the plcisma membrane, releasing acetylcholine into the extracellular fluid. Acetylcholine binds to membrane-bound proteins (acetylcholine receptors) on the plasma membrane of the muscle cell, resulting in stimulation of the muscle cell. Acetylcholinesterase of the neuromuscular junction catalyzes the destruction of acetylcholine in the moments after transmission of the nerve impulse. The enzyme is extracellular and is bound to proteoglycan, a molecule of extracellular matrix. 

In an attempt to improve the selectivity of local dopamine measurements in the complex extracellular matrix of brain fluid, an implantable enzyme-based dopamine microbiosensor has been constructed based on the immobilization of tyrosinase in a thin-film chitosan coating of carbon-fiber disc microelectrodes [357]. o-Dopaquinone, which is the product of the tyrosinase reaction with dopamine, was monitored via its reduction at the modified microelectrode surface. The application of these cathodic tyrosinase dopamine microbiosensors was reported for the continuous real-time in vivo visualization of electrically stimulated dopamine release in the brain of anesthetized laboratory rats. Remarkably, due to the cathodic potential the sensor response was not significantly disturbed by the presence of typical interferences such as ascorbic and uric acid, serotonin, norepinephrine, and epinephrine. 

A number of cytokines have been implicated in the pathology of inflammatory disease. In particular the role of IL-1 has been extensively investigated. In-traarticular administration of IL-1 induces inflammatory changes identical to those seen in some animal models of chronic arthritis (PIO). IL-1 has been shown to mediate cartilage matrix degradation, inhibit synthesis of proteoglycans, induce the breakdown of bone matrix, and stimulate PGEj synthesis (D5, D12, M40). More recently lL-6 and TNF have been shown to have many of the properties attributed to IL-1 and it remains to be established which cytokines exert an effect in vivo. Increased levels of all three of these cytokines, IL-1, TNF, and IL-6, have also been reported in the synovial fluid from arthritic joints (N12). 

The reactive foam exhibited good fluid-loss properties however, the gas phase of the foam was lost to the rock matrix at an extremely rapid rate. In an actual treatment stimulation scenario, the rapid loss of gas would result in the foam quality being depleted at a short distance into the fracture. The treatment would then essentially be reduced to a conventional add treatment with no real gain in production being accomplished. 

Foamed Matrix Acidizing. Matrix addizing is a stimulation treatment used to remove damage near the wellbore without deating a fracture. The process involves the injection of a reactive fluid into the porous medium at a pressure below the fracturing pressure. The fluid dissolves some of the porous medium and consequently increases its permeability. 

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