Fracture advantages

Information supplied by flaw visualization systems has decisive influence on fracture assessment of the defect. Results of expert ultrasonic examination show that in order to take advantage of AUGUR4.2 potentialities in full measure advanced methods of defect assessment should be applied using computer modelling, in-site data of material mechanical properties and load monitoring [4]. 

It is of great advantage, however, to have available a second cylinder similar to, but much shorter than, C, and of wider internal bore. When the pellet has been formed inside C, the plunger S is released and the shorter cylinder inserted between C and the base B. The plunger S is again screwed down, and the pellet is thus slowly forced out of C into the shorter cylinder below. In this way the pellet, even if originally firmly fixed in C, can be removed without risk of fracture... 

The double torsion test specimen has many advantages over other fracture toughness specimen geometries. Since it is a linear compliance test piece, the crack length is not required in the calculation. The crack propagates at constant velocity which is determined by the crosshead displacement rate. Several readings of the critical load required for crack propagation can be made on each specimen. 

Interactions Between Fracturing Fluid Additives and Enzyme Breakers. Despite their advantages over conventional oxidative breakers, enzyme breakers have limitations because of interferences and incompatibilities with other additives. Interactions between enzyme breakers and fracturing fluid additives including biocides, clay stabilizers, and certain types of resin-coated proppants have been reported [1455]. 

The formation of calcium carbonate (CaCOs), calcium sulfate, and barium sulfate scales in brine may create problems with permeability. Therefore it is advantageous that newly made fractures have a scale inhibitor in place in the fracture to help prevent the formation of scale. Formulations of hydraulic fracturing fluids containing a scale inhibitor have been described in the literature [1828]. 

One advantage of fracturing with hydrocarbon gels compared with water-based gels is that some formations may tend to imbibe large quantities of water, whereas others are water-sensitive and will swell if water is introduced. 

From 1958 to 1970 inorganic salts such as CaCl2(53,55,56), MgCl2(57), KC1(55-58), hydroxyaluminum chloride(59-63), and zirconyl chloride(64-67) were introduced and found acceptance as clay protection additives. Each salt has its own peculiar set of advantages and disadvantages. It is now routine to include 2% KC1 by weight of water as a clay treatment chemical in nearly all fracture waters. 

Coulter, G.R. and Wells, R.D. "The Advantages of High Proppant Concentration in Fracture Stimulation," SPE paper 3298, 1971 SPE Annual Meeting, New Orleans, October 3 6. 

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