Paper: Improving Return On Hydraulic Fracture Treatment Investment With Wireline Inputs

The Permian basin of west Texas is known for its low permeability reservoirs, earning it the reputation of "hard rock country." wells completed here require A significant percentage of the hydraulic fracture treatments in order to produce economic quantities of oil and gas. The hydraulic fracture treatment can represent a significant portion of the total well cost. In addition, the effectiveness of the treatment can be critical to the economics of the well. Too small a treatment can leave valuable hydrocarbons in the ground. Too large a treatment can be equallyinefficient and possibly ruin the well. Knowledge of the rock elastic properties and in-situ stress distribution is critical to determining the induced fracture geometry. With full sonic waveform data now available, the dynamic elastic properties of the rock can be directly measured. Poisson's ratio (v) can be directly obtained from the shear and compressional transit times. From the v/(1-v) relationship the horizontal stress component of vertical overburden stress can be obtained. When this is combined with pore pressure and bulk density data a relative closure stress value can be obtained. The final product is called the FracHite* log. As of this writing, over 450 wells have been evaluated with this technique. Several single-zone and multiple-zone field cases are presented here to illustrate the applications of the technique in the Permian basin. In addition, a 2D hydraulic fracture model is used in conjunction with actual decline curve data to illustrate the specific benefits of accurate hydraulic fracture height data. The case study utilizes data from a representative producing San Andres well in Ector County. An additional item of importance is the orientation of the hydraulic fracture. This is critical to designing an efficient drainage pattern in a field. It is now generally accepted that the hydraulic fracture follows a two-wing pattern dictated by the natural stress distribution in the rock. With the eight button Dual Dipmeter* and the FILMAP presentation this natural stress distribution can be mapped with an unprecendented degree of accuracy. the Dual Dipmeter, Nine Spraberry/Dean wells were evaluated using and the results are presented on a map of Midland and Martin Counties.