Improving the Effectiveness of Multi-Stage Hydraulic Fracturing in Horizontal Wells by Fracture Height Restriction

Abstract

The cost-effective development of low-permeability hydrocarbon formations of small thickness requires horizontal wells with multi-stage hydraulic fracturing (MS-Frac). The presence of higher or lower layers that are water-saturated and weak barriers to height growth imposes a restriction on the desirable geometry of the fracture to prevent a breakthrough into a flooded interval. Combining several methods of fracture height restriction and controlling such height can improve the efficiency of multi-stage hydraulic fracturing. The first technology to control the effective pressure was based on changing fracturing fluid rheology and resulted in a decrease in the net pressure and the fracture height. The main treatment buffer utilized a hybrid fluid design. The second technology used to limit the height of the fracture was based on creating artificial barriers inside the fracture that restrict height growth. In this case, a special mixture of proppants was pumped before the primary proppant-laden fracturing main stage. The construction of a horizontal well with a multizone completion implies the possibility of carrying out small volume multistage fracturing to prevent breakthrough into a water-saturated interval, creating an effective drainage zone. For the first time in the given field, MS-Frac was performed using combined technologies and techniques for fracture height growth restriction. The operations demonstrated successful results of horizontal multizone well treatments, where the rheology and fluid rate control methods were used to restrict the fracture geometry growth, and proppant slugs were used to create artificial barriers to arrest the fracture height growth.