Production damage mechanisms

There are several possible production damage mechanisms, depending on the type ofwell (oil or gas) and the formation characteristics. Such damage contributors include the following ... 

Productivity damage attributable to drilling or completion fluids results from three mechanisms ... 

The flowback of a proppant following fracture stimulation treatment is a major concern because of the damage to equipment and loss in well production. The mechanisms of flowback and the methods to control flowback have been recently discussed in the literature [ 1343]. To reduce proppant flow-back, a curable resin-coated proppant can be applied [1349]. The agent must be placed across the producing interval to prevent or reduce the proppant flowback. 

Spin trapping is an often-used technique in the study of possible radical production in biological systems (for reviews see Kalyanaraman, 1982 Mason, 1984 Mottley and Mason, 1989), particularly by the detection and monitoring of spin adducts of the hydroxyl and hydroperoxyl ( OOH) radicals in view of their relation to possible damage mechanisms. This is a large area of research which it is not possible to cover in a limited review, and the treatment will therefore be restricted to a discussion of the electron transfer properties of biochemical systems (for a review on the application of the Marcus theory to reactions between xenobiotics and redox proteins, see Eberson, 1985) and... 

The examples of hydroxyl radical addition products identified in single crystals of adenine and guanine base derivatives confirm that water can play an important role in the radiation damage mechanism. It should be noted that the new mechanism has attracted some criticism [38]. The main objection is that nonplanar geometries were calculated for the gas phase radicals whereas planar structures are expected experimentally due to the hydrogen-bonding scheme... 

Besides direct damage of the DNA strand, it is also possible for the surrounding water molecules to be involved in radiation damage mechanisms. The hydration layer of DNA consists of a primary layer (approximately 20 or 21 water molecules per nucleotide), which possesses properties different from crystalline ice upon freezing, and a secondary layer, which cannot be distinguished from bulk water upon crystallization. Upon irradiation of water, many different products can be formed ... 

Damaging mechanisms work mainly in two directions, namely a) local affection of mucous membranes and skin in the contact areas, provoked by the new irritative-destructive effect products formed by the interaction between the poison and the water component of the mucous secretions (for methylizocyanite etc.) b) blocking of the enzyme groups in brain and other specialised cells, which conduct the intracellular oxidation (cytochromoxidase) etc. 

Lytic enzyme systems provide a chemically mild, low-shear and catalytically specific alternative to mechanical cell disruption. Depending on the particular lytic system employed and its purity, the enzymes may be engineered to attack cell wall components alone, without product damage. The enzyme lysozyme, active against some bacterial cell walls, has been used to harvest bovine growth hormone granules from 12. coli (8), and a membrane-associated hydroxylase complex from . putida (11) use of other bacteriolytic enzymes from a variety of microbial sources have also been reported (3). 

Quan, Fangkai et al. 2012. Reservoir damage mechanism and system optimization of in-situ coalbed methane drainage and production. China Coalbed Methane 9(4) 42-44. 

In micromechanics (Muta 1982), tensor in Eq. 7.20 is defined as the eigenstrain, which is explicitly equivalent to the damage tensor in damage mechanics (Kachanov 1980). In seismology, the following tensor product is defined as a moment tensor,... 

---