Abstract

Since its introduction in 1949, hydraulic fracturing has played an ever increasing role of importance to the oil industry. Today many fields are commercially successful only because of these techniques. Without hydraulic fracturing some producing horizons would be bypassed. In particular, some large offshore fields with high investments require some sort of fracturing to increase production rates to economically required levels. This paper will briefly discuss fracturing techniques, equipment, chemicals, fluids, and other design parameters as applied in the past. As far as the fracturing of today is concerned, the paper will discuss design parameters including, but not limited to, fluids and fluid selection and their effects on fracturing propagation and proppant transport. Also it will discuss the effect of invading fluids into the formation matrix near the fracture face and how to help reduce fluid retention. Further, it will examine proppant selection and concentrations as related to production improvement.

It is of utmost importance that a proper frac design consider the formation being stimulated when making fluid and proppant selections. There are numerous scientific core analyses methods available. The paper will discuss how fluid and proppant selections are made, and what types of core tests can be obtained.

Addditionally at present, many frac jobs are preceded with a so called minifrac. With the aid of a computer, in many instances, the outcome of a frac job may be more accurately predicted and significant information can be gained as to how the formation is going to behave towards the fluid. Fracture closure pressure, fluid loss coefficient and fluid efficiency are among other information it provides. With this information, important changes can be incorporated into the frac design, if well parameters so require. The paper will discuss available equipment and their capabilities to pump propping agents (at present exceeding 18 lb/gal concentration) and what the industry will be desiring in the future for pumping and proppant handling capabilities.