Particle bridging effect

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]. 

Mangenot, S., Raspaud, E., Tribet, C., Belloni, L., and Livolant, F. (2002) Interactions between isolated nucleosome core particles A tail-bridging effect Eur. Phys. J. E 7, 221-231. 

Air-entrained pastes possess a higher viscosity than pastes with little or no air content, mainly because of the bridging effect of cement particles by air bubbles increasing the structure of the system. 

Concentrated particle suspensions may also show a yield point which must be exceeded before flow will occur. This may result from interaction between irregularly shaped particles, or the presence of water bridges at the interface between particles which effectively bind them together. Physical and chemical attractive forces between suspended particles can also promote flocculation and development of particle network structures, which can be broken down by an applied shear stress [2]. 

The effect of TP particle size is controversial. While crack pinning is favored by small particles, large particles can promote particle bridging. 

I. Particle size vs. chain length and dissociation property of the polymer For flocculation of coarse particles, bridging by organic polymers is very effective, especially that by the nonionic polymer. Inorganic electrolyte and surfactants do not have high flocculation efficiency. 

Bridging effects. A definite interaction is involved in this process that may include mutual diffusion or "alloying" between the substance of the particle and the surface. Liquid/solid bridging may be involved at the interface that invokes capillary forces. 

As far as heat exchanger fouling is concerned it is the long range forces that are of prime importance since they are responsible for bringing the "particles" and surface into initial contact. In this respect a general discussion of adhesion is acceptable whereas the bridging effects and short term forces will be very specific to a particular condition. 

MPam / could be attributed entirely to crack wake effects, including frictional sliding, SiC particle bridging and plastic deformation of alloy bridges, rather than to changes in the crack-tip profile. Anderson [96] measured Kic in four-point bending for both a base composite and a SiC-reinforced composite and obtained 7.8 and... 

Problems are usually encountered when pressure systems designed to operate at reasonable levels of particulate concentration are fed with dilute suspensions at the start of filtration. Low concentrations of sohds prevent the bridging effect which ensues when concentrated swarms of sohds are directed towards the pores in the filter medium. This effect is discussed quantitatively elsewhere in this Chapter. Failure to bridge the cloth pores will lead to deposition of particles inside the fabric. 

Values for and r] are reported in Table 4.8 below for depositions on plain pore monofilament cloths. These are calculated using nominal and mmimnni values of the cloth pore required for bridging. In equations (4.19) and (4.20) the constants Ks and Kf can be considered a measure of the bridging effectiveness of flie particle/pore combination in this req>ect K or ATp represents the pore/particle size ratio for bridging at unit concentration/particle flux re ectively. 

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