Water usage accounts for up to 25% of the total cost in hydraulic fracturing operations. Freshwater sourcing, transportation, treatment, storage and disposal of produced water negatively impact field economics and raise significant safety and environmental concerns. Developed to mitigate water management challenges, the xWATER Integrated Water Flexible Fracturing Fluid Delivery Service from Schlumberger allows operators to reuse up to 100% of produced water, thereby reducing or eliminating costs associated with water acquisition, conveyance, treatment and disposal.
The xWATER service provides a customized fracturing fluid solution specifcally engineered to enable the use of any available water rather than synthetically derived water that attempts to match the reservoir characteristics. This flexibility allows operators to use fowback or produced water from previous hydraulic fracturing jobs or nearby water sources, including brackish groundwater or seawater. The ability to reuse produced water by adding tailored fuids improves reservoir integrity and maximizes production as compared to freshwater.
The xWATER service is made possible by the latest advances in fluid chemistry, including salt-tolerant polymers and chemicals, scale prediction and mitigation, targeted water treatment technologies, and hardness-immune components compatible with saline matrices. Reusing produced water in tailored fluids reduces reservoir damage and can improve production as compared to freshwater. Preserving the fluids’ natural ability to stabilize clay also maximizes production. The xWATER service delivers significant savings (40%) in total water management cycle costs.
APPLICATIONS
1.produced water, brackish water, seawater, brinewater, or wastewater are readily available;
2.reshwater is scarce;
3.disposal or surface discharge is uneconomical;
4.environmental initiatives or regulations require water reuse;
5.transportation or conveyance costs are high.
BENEFITS
1.Reduces or eliminates water acquisition and disposal costs;
2.Minimizes water transportation or conveyance costs;
3.Maximizes use of alternative water sources, such as produced water, brackish water, seawater, and wastewater;
4.Optimizes the fracturing fluid system for the specific reservoir conditions;
5.Minimizes or eliminates the need for water treatment.
FEATURES
1.Characterization and identification of water quality, volumes, and total water management cycle 、costs to optimize economics and efficiencies;
2.Evaluation of reservoir effects to ensure positive impact to production;
3.Rapid economic feasibility assessment developed to compare current economics with optimized water management and operational scheme;
4.Tailored fracturing fluid engineered for operator’s specific water and fluid conditions
5.No operational upgrades;
6.Use of nonderivatized guar in most applications with no need for expensive fluid upgrades.
xWATER* integrated water-flexible fracturing fluid delivery service enables operators to use an engi- neered fracturing fluid customized for the available water, well conditions, and reservoir properties. The service eliminates and reduces sourcing, treatment, and disposal costs.
The xWATER service
Quantifies current total water cycle management costs
1.Enables operators to use all available water;
2.Requires little or no treatment;
3.Provides tailored fracturing fluids to work with the available water quality;
4.Demonstrates positive impact to production;
5.Ensures value is captured at key decision points in the water management cycle, which provide the greatest savings.
Integrated water management process
The xWATER service implementation and integration process begins with
1.Characterization of current water management costs and water quality parameters;
2.Modeling of reservoir damage mechanisms and water reuse infrastructure costs;
3.Creation of a fracturing fluid tailored to work with produced water or alternative water sources;
4.Implementation of fracturing treatment using same equipment without costly fluid upgrades, while integrating with the customer’s existing water management infrastructure;
5.Evaluation of reservoir effects to ensure positive impact to production.
Design of a tailored fracturing fluid
After completing the feasibility assessment, a customized fracturing fluid solution is engineered specifically to work with produced water or the most economic water source available. The use of produced water and other higher salinity waters for tailored fluids maintains reservoir integrity and maximizes production when compared to freshwater.
Reduced cost of water transportation
By reusing produced water, as well as other alternative water sources, xWATER service drastically reduces overall water transportation and conveyance costs. Eliminating the need for freshwater also minimizes water acquisition costs and conserves natural resources in water-scarce areas.
No need for disposal
As the well enters the production phase, the produced water is collected in centralized, on-site storage facilities, transported to new fracturing sites, then returned to storage after job completion—reducing transportation costs and eliminating the need for disposal.
xWATER Service Eliminates Disposal of 7.4 Million Gallons by Using 100% Produced Water
Minimize freshwater use and stimulation costs
Over the past several years, the Williston basin has experienced a quick and dramatic increase in activity that has resulted in some of the highest stimulation costs in the country, leading to increased interest in the use of produced and flowback water in fracturing operations.
The major challenges to using Williston produced water as a base fluid included dealing with the high concentrations of total dissolved solids (TDS), hardness ions (e.g., calcium, magnesium), and boron, as well as accommodating for the low pH and variability in water quality. The high concentrations of hardness cause traditional fracturing fluid systems to prematurely break down, but removing the hardness in the Bakken water would be cost-prohibitive (>USD 5/bbl by conservative estimates). Furthermore, boron was present in five times the concentration typically used to activate crosslinked fluid systems. In traditional fluids, this would unevenly crosslink the gel and hinder its ability to reliably carry proppant downhole.
Design a fracturing fluid for the well’s water
Rather than treating the water for the fluid requirements, Schlumberger engineered a fluid for the water conditions. Using xWATER service, the team developed a high-TDS friction reducer that was a one-to-one replacement for the friction reducer already being used in the Williston basin. Compatibility and friction loop testing proved it effective for handling the ultra- high TDS of Bakken produced water. The team then constructed a crosslinked system that would perform in 100% produced water without the significant cost increase or operational efficiency penalties of treatment or dilution.
The effects of mineral scale were modeled and managed for switching to a 100% produced water fracturing fluid to minimize the formation of solids downhole and maximize permeability.
After innovative design and lab testing, a suitable xWATER service was developed for field testing.
Maximize production with 100%produced water
Schlumberger successfully pumped six hybrid fracturing stages with more than 500,000 gallons of 100% produced water for the customer on a Bakken well in McKenzie County, North Dakota. Together, the systems used 7.4 million gallons of Bakken produced water in 65 stages, all with no freshwater use and no disposal. The wells using xWATER service yielded production equal to or better than offset wells using traditional freshwater systems.
The water supplied by the customer had not been diluted with fresh water and required no additional treatment to be compatible with xWATER service. This also eliminated secondary waste streams that are generated in treatment regimes. The customer saved an average of 650 truck trips per well.
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