Successful Application of Metal-Crosslinked Fracturing Fluid with Low-Polymer Loading for High Temperature Proppant Fracturing Treatments in Saudi Arabian Gas Fields — Laboratory and Field Study

摘要

For the past decade, Saudi Aramco has been successfully exploiting tight gas sandstone formations. These formations are routinely hydraulically fractured to enhance gas production, but as the development of the existing fields continues into deeper formations the exploration of new reservoirs emerges. New challenges are now being faced especially, considering that higher temperature is being encountered and the fracture fluids currently being used (based on borate crosslinker) are not stable enough to tackle the extreme conditions. Metal-crosslinked fracture fluids have long been the most popular class of high viscosity fracturing fluids. Primary fluids that are widely used are titanate and zirconate complexes of guar, hydroxypropyl guar (HPG), carboxymethyl hydroxypropyl guar (CMHPG), or carboxymethyl hydroxyethyl cellulose (CMHEC). Zirconium-delayed CMHPG are typically used for high temperature applications. These types of fluids provide high temperature stability with low polymer loading with the added benefit of salt compatibility. The proppant transport capabilities of the metal-crosslinked fluids are excellent. Zirconiumdelayed CMHPG fracture fluid is currently the preferred fluids due to its extraordinary stable characteristics for bottom-hole temperatures (BHTs) up to 375°F. This paper addresses the research, lab testing and successful application of a metal-crosslinked fluid used for fracturing operations of a high temperature (312～330 °F) tight gas reservoir in Saudi Arabia, with its post-treatment evaluation to optimally develop these reservoirs in harsh bottom-hole conditions.