Optimizing Seawater Fracturing Fluid Rheology Utilizing Chelating Agents

Hydraulic fracturing is applied to enhance hydrocarbon recovery by creating conductive paths that bypass the near wellbore damage and alter the reservoir fluid flow. Hydraulic fracturing operations are necessary to stimulate tight and unconventional formations and the only economical way to extract hydrocarbons. A massive amount of freshwater is used for multistage hydraulic fracturing (MSF), which could reach half a million barrels per well. Freshwater is scarce, especially in the Gulf region, which makes MSF treatments expensive and non-sustainable. For instance, 5,000 to 10,000 wells are required to develop the Jafurah basin, which would consume 5 billion barrels (210 billion gals) of freshwater. The massive amount of freshwater required might restrain other important activities in the Kingdom (i.e., agriculture). Using seawater is a more viable, sustainable, and economical alternative. Unfortunately, the existence of high total dissolved solids (TDS) and the abundance of some monovalent and divalent ions in produced/seawater can degrade the fluid viscosity and result in formation and proppant pack damage. Hence, several costly and toxic additives have been used with seawater fracturing fluids to tackle these challenges. This research aims to replace freshwater with seawater, where the lowest number of additives will be used. These additives are chelating agents, polymers, crosslinkers, and breakers. These additives are cheap, safe, eco-friendly, provide high viscosity, and capture the ions of damaging potentials. The ultimate goal of this work is to eliminate the effect of seawater by removing its hardness and achieve high viscosity at harsh reservoir conditions. The first step of this research includes formulating and testing seawater fracturing fluids rheology at ambient and reservoir conditions using standard industry rheometers. Several analytical techniques (i.e., FTIR, NMR) will be used to test the compatibility of different additives. We will assess the interaction between the developed formulations and different types of rocks using the API conductivity cell.