Abstract: Hydraulic fracturing of earth formations from wells for producing gas or hydrocarbon liquids is carried out by extending the fracture to a predetermined length with clean or low proppant concentration fluids, then decreasing the rate of injection with low proppant concentration fluids to equal the fluid leakoff rate until the fracture tip is blocked or screened out. Alternatively, the proppant concentration could be progressively increased until tip screenout occurs. Injection rates are then increased, particularly in high permeability formations, to increase the fracture width.

Abstract: Certain wellbore fluid stimulation treatments may be monitored by a system including instrumented manifolds which may be connected between a base fluid source and a blending unit and between the blending unit and fluid injection pumps, respectively for measuring flow rates of the base fluid, the fluid additives and the fluid composition formed by the base fluid and the fluid additives. Instruments are also provided for measuring fluid temperature, pH, viscosity and flow behavior indexes (n', K') and fluid density. Quality control and determination of pressure losses in the wellbore together with modeling of stimulation treatments may be carried out by the continuous monitoring of parameters with the base fluid manifold and the mixed composition manifold.

Abstract: Certain wellbore fluid stimulation treatments may be monitored by a system including instrumented manifolds which may be connected between a base fluid source and a blending unit and between the blending unit and fluid injection pumps, respectively for measuring flow rates of the base fluid, the fluid additives and the fluid composition formed by the base fluid and the fluid additives. Instruments are also provided for measuring fluid temperature, pH, viscosity and flow behavior indexes (n', K') and fluid density. Quality control and determination of pressure losses in the wellbore together with modeling of stimulation treatments may be carried out by the continuous monitoring of parameters with the base fluid manifold and the mixed composition manifold.

Abstract: Friction pressure losses are obtained for non-Newtonian or generalized Newtonian fluids being pumped through conduits at high flow rates, such as in hydraulic fracturing of subterranean formations, by measuring friction pressure losses in a pipe viscometer under laminar flow conditions. The pipe viscometer includes a pump which supplies fluid to a continuous loop having three pipe sections of different diameter for measuring pressure drop at different flow velocities. Sets of data points of generalized shear stress and shear rate are measured for determining the consistency index (K') and the Power Law or flow behavior index (n').