This paper presents a simple method of designing a suspended fracture of a desired conductivity. The design balances volume, pump rate, and fluid loss to get the desired length. A sand schedule then is calculated to give the optimum flow capacity. The fluid and sand used to build the excess flow capacity in an equilibrium pack design are used to obtain better vertical coverage and deeper penetration.

The method is most applicable to low permeability reservoirs where the conductivity of an equilibrium pack is not needed. In this type of reservoir, the surface area of a fracture face will give up only a finite amount of fluid. It is not necessary for the fracture to have a greater flow capacity to the well­ bore than the formation has into the fracture. The design also can be applicable in some massive zones where the permeability is higher, but the cost to build an equilibrium pack is prohibitive. With a suspended pack design using the same amount of fluid, a deeper fracture with 100% vertical coverage can be obtained. In many cases, this produces a higher productivity increase with a lower cost.

The design centers on the sand concentration of the sand slurry in a finite number of segments along the fracture length. Using a compound-interest formula, the approximate amount of fluid that has leaked off in each segment is calculated. Then, with the final desired slurry concentration known, the sand concentration needed in each segment when pumped can be calculated.

The design is done in 10 easy steps with a program written for a TI-59 that will do almost all of the calculations included. The design is not applicable to every well, but where it does apply it can (1) give better vertical coverage, (2) get deeper penetration, (3) reduce costs for the same productivity increase, and (4) reduce the amount of load to recover.