Fracturing Fluids For Deep-Hot Formations

Crosslinked gels are adequately stable at high fluid temperatures and have thus established their usefulness for fracturing high-temperature formations. However, in certain treatment situations, they may develop high friction pressure in tubular goods which can limit their injection rate. Furthermore, the rheological properties exhibit a time-shear history dependency that is quite difficult to predict. Two-stage gel systems have been very successful in providing a means to develop desired viscosity at downhole conditions without causing high tubular friction pressures. However, several currently available systems do not have the stability required for large volume treatments at temperatures above 250_F (120C). A fracturing fluid has been developed that solves many disadvantages and limitations of both crosslinked and two-stage gel systems. This is made possible by the use of a new delayed hydrating gelling agent. The fluid has the desired two-stage viscosity qualities and can be formulated to provide the desired viscosity throughout a treatment. In addition, the rheological properties of the new fluid system are highly predictable. This fracturing fluid system has been successfully tested in the field. Fluid design and treatment results will be presented.