Comprehensive Overview of Oilfield Fracturing Flowback Fluid
1.1 Sources
Fracturing fluid breaker fluid flowed back from the wellbore after fracturing operations:
The degraded fracturing fluid flowed back from the well pipes after fracturing operations is a main source of fracturing flowback fluid. To improve the permeability of reservoir rock, high-pressure fluid (i.e., fracturing fluid) is injected into the well during operations. After the fracturing fluid enters the formation, the macromolecular polymers in it (such as guar gum) gradually decompose under formation temperature, forming degraded fluid. After completing the fracturing function, these degraded fluids return to the surface together with crude oil, water and other impurities in the formation, forming fracturing flowback fluid.
Remaining original gel fluid (base fluid):
The original gel fluid (base fluid) that does not enter the formation during preparation is also one component. Before injection, fracturing fluid needs to be prepared, during which various chemical additives, such as preservatives and degradants, are added to adjust the viscosity and stability of the fracturing fluid. After operations, part of the original gel fluid that did not enter the formation will flow back to the surface together with the degraded fluid.
Large amounts of well-flushing wastewater from active-water well flushing before and after operations:
Active-water well flushing before and after fracturing operations produces a large amount of flushing wastewater. To remove impurities and residues in the well pipes, active water is usually used for cleaning. This large amount of wastewater is also included in the scope of fracturing flowback fluid.
Other sources:
In addition to the above main sources, fracturing flowback fluid may also be mixed with other fluids, such as formation water or rainwater. These fluids may seep into the fracturing fluid during operations and finally flow back to the surface together.
1.2 Characteristics
Complex composition:Fracturing flowback fluid contains various pollutants, including oil, suspended solids (SS), guar gum and various chemicals; these pollutants are numerous in variety and high in content.
High viscosity, severe emulsification:The viscosity of fracturing flowback fluid is high and the degree of emulsification is high, making separation difficult. The viscosity of some fracturing flowback fluids can reach 10-20 mPa-s; severe emulsification makes the discharged fracturing wastewater viscous with an irritating odor.
Large fluctuations in water quality and quantity: the water quality and quantity of fracturing flowback fluid often fluctuate considerably, placing high demands on the shock resistance and stability of treatment equipment.
High treatment difficulty:Because fracturing flowback fluid contains many types of organics in large amounts, with high COD (chemical oxygen demand), TDS (total dissolved solids) and TSS (total suspended solids), it is difficult and costly to treat.
1.3 Conventional processes
1.4 Process disadvantages
Poor treatment results:Fracturing flowback fluid contains many types of organics in large amounts, including high concentrations of guar gum and macromolecular polymers, which are difficult to remove effectively by conventional processes. Especially for high-viscosity, severely emulsified flowback fluid, conventional processes often fail to achieve ideal oil-water separation.
High treatment cost:Treating fracturing flowback fluid requires large amounts of chemicals, such as flocculants and oxidants, which are costly.
At the same time, the treatment process also consumes a large amount of energy, such as electricity and steam, further increasing treatment costs.
Large footprint:Conventional treatment processes often require the construction of large-scale sedimentation tanks, filtration tanks and other facilities, occupying a large area. For regions with tight land resources, this may become an important factor limiting application.
Low degree of automation:Conventional treatment processes mostly rely on manual operation, with a low degree of automation.
This not only increases operational difficulty and labor costs, but may also lead to unstable treatment results.
Great environmental impact:
Conventional treatment processes may generate large amounts of wastewater and waste residue during treatment; if not handled properly, they may pollute the surrounding environment. Especially for fracturing flowback fluids containing harmful substances, conventional processes may not completely remove the harmful substances, posing potential environmental risks.
Poor technical adaptability:The water quality and quantity of fracturing flowback fluid fluctuate greatly; conventional processes may not adapt to such changes. When water quality or quantity changes, the treatment process may need to be adjusted or additional equipment added, increasing treatment difficulty and cost.
1.5 SINOKLE process
SINOKLE Technology takes its CDOF and CDFU patented technologies as the core treatment equipment, combined with high-efficiency filtration and fine filtration methods, to achieve rapid and efficient treatment of fracturing flowback fluid while ensuring effluent quality meets the customer's on-site treatment standards.
Based on long-term production practice in oil and gas field development, Shenzhen SINOKLE Company has formed a comprehensive solution based on full life-cycle analysis of water resources in oil and gas field development, focusing on the treatment and comprehensive utilization of fracturing flowback fluid. The company has independently developed a number of patented technologies for the recovery and reinjection treatment of fracturing flowback fluid, adaptable to different customers and various water quality needs.
Technical indicators:
Application examples:
