https://orcid.org/0000-0003-4057-1468
Abstract
Horizontal wells with multiple hydraulic fractures have been used widely in the oil and gas industry. In published literatures, hydraulic fractures are assumed to be fully penetrating the formations. Recent studies have shown that partially penetrating fractures are more likely to occur rather than fully penetrating fractures
The purpose of this study is to formulate an analytical model describing the pressure behavior of a horizontal well with partially penetrating hydraulic fractures. This model is used to develop a technique, based on pressure and pressure derivative concept, for interpreting pressure transient tests and forecasting productivity of the well. The fractures in this study were assumed to propagate in an infinite homogenous porous system. Further more, the fractures were assumed to be vertical and inclined. Six main flow regimes can be observed for hydraulic fractures: linear, early radial, second linear, intermediate radial, third linear or elliptical and pseudo-radial flow. Early radial flow represents the radial flow around each fracture may develop for the cases of small penetrating rate. Intermediate radial flow is expected to develop for the case of wide spacing between fractures. Third linear flow may develop for the case of high number of fracture with short spacing between them.
Tiab's Direct Synthesis (TDS) technique has been applied using the plots of the pressure and pressure derivative curves. Several unique features of the pressure and pressure derivative plots of partially penetrating fractures models were identified including the points of intersection of straight lines for different flow regimes. These points can be used to verify the results or to calculate unknown parameters. Equations associated with these features were derived and their usefulness was demonstrated. A step-by-step procedure for analyzing pressure tests is included in this paper and illustrated by several numerical examples.
