Conservation of Fresh Water with Groundbreaking Substitutes

Ground water from water supply wells is ordinarily used as the base fluid for well stimulation. The water consumption per stage during well stimulation can be significant. Preserving the groundwater resources by providing its substitute to carry out major upstream operations is perceived with a great priority. The objective of this paper is to demonstrate several ground water conservation schemes that were proven at the field during hydraulic fracturing treatment. Primarily, the water quantity and quality of evaporation pond at the gas plant has been evaluated for re-use opportunity for hydraulic fracturing operations with favorable geochemical composition. The boiler blowdown, produced, brackish and storm water are collected at the pond. Secondly, a novel technology was introduced for distilled produced water which is purely a water management technology aiming to desalinate produced water by transforming its ionic properties to deliver a high value end-product. Finally, seawater was nano-filtered to reduce sulphate content from 4000+ ppm to less than 500 ppm to use as base for stimulation fluids. Once the geo-chemical analysis of one of the alternative water sources is found satisfactory, various types of fracturing fluids (i.e., zirconate crosslinked gel, visco-elastic surfactant based fracturing fluid system, various acid blends etc.) were formulated. Intensive rheology, scaling and core flooding tests were performed on theses fluid systems to assess the fluids stability, compatibility and the formation damage level at the reservoir conditions. The ground water substitute-based stimulation fluids sustained viscosity values above the minimum requirement of 300 centipoise at 100 1/s shear rate for longer than the pumping time and then broke into the level of linear gel. The core flooding results showed high retained permeability indicating minimal formation damage. These stimulation fluid systems have been successfully trial tested in the high temperature carbonate reservoirs replacing ground water by 100%. The acid blends formulated with ground water substitutes and standard corrosion inhibition package for high temperature didn't show any signs of incompatibility such as fluid phase separation, flocculation, or precipitation at the reservoir conditions. The ground water substitutes are measured as resources instead of waste streams. The distilled produced water technology has a custom designed dynamic vapor recovery system that is capable of removing salt from hypersaline oilfield produced water. Recycling, retreating and re-using them with careful evaluations of chemistry and recipes allowed to manage well stimulation activities in a much better environmentally friendly way without compromising the stimulation effectiveness and well performance.