Seawater Based Fracturing Fluid: A Game Changer in Hydraulic Fracturing Applications in Saudi Arabia

Abstract

Abstract Hydraulic fracturing activities in tight gas wells in Saudi Arabia have been exponentially increasing to meet domestic demand for natural gas. During each fracturing stage, up to 125,000 gallons of groundwater is currently being used. The need to reduce groundwater usage during fracturing treatments has been set as a priority, and alternative water sources for fracturing applications that can significantly reduce groundwater usage have been intensively explored. One such alternative water source is seawater as a base fluid for hydraulic fracturing. The primary challenge for this application is the tendency for scale precipitation due to the high sulfate content in seawater and its potential incompatibility with formation water. Without proper prevention and mitigation measures, this scale precipitation can induce formation damage and reduce the fracture conductivity. To minimize scaling tendencies, an in-house multidisciplinary team has performed extensive collaborative research to identify a scale inhibitor appropriate for Arabian Gulf seawater and formation water. Scale precipitation can be further mitigated by filtering the seawater with a nanofiltration system to dramatically reduce the sulfate ion as well as lower the calcium and magnesium ions. The successful application of seawater-based fracturing fluid in Saudi Arabia opens up the door to minimizing consumption of groundwater in hydraulic fracturing operations. Millions of gallons of groundwater could be saved and development of sustainable water resources could be achieved. This paper will describe the optimization of a scale inhibitor and fracturing fluid system, the selection of the nanofiltration system, and the first field applications of the seawater based fracturing fluid system in high-temperature gas wells in Saudi Arabia.