Despite the lack of freshwater resources in the Arabian peninsula, fresh water is still used in unconventional-resource operations there. Seawater, however, is plentiful and could substitute for fresh water. The high salinity of seawater raises many chemical challenges in developing design criteria for fracturing fluids. This paper examines the chemistry of developing seawater-based fracturing fluids using two types of polymers as gelling agents and compares results to existing fresh-water-based-fracturing-fluid data under different conditions.

Introduction

The oil and gas industry faces many challenges, including the availability of fresh water for making fracturing fluids, especially in the Arabian peninsula and other arid regions.

Using seawater to make fracturing fluid can help address several obstacles and reduce costs. However, using sea­water to make fracturing fluids also poses several new challenges. The high salinity of seawater and its propensity for scaling, compared with fresh water, make it crucial to consider different factors and chemical properties that influence the process of developing fracturing fluid.

This paper presents issues that can arise when using seawater as a base to develop fracturing fluids with two different types of guar as the viscosifying agent—hydroxypropyl guar (HPG) and carboxymethylhydroxypropyl guar (CMHPG).