Innovative Process Empowers Resource-Based Disposal of Shale Gas Development Waste Fluid
In shale gas resource development, fracturing is a key technology. This technique injects fluid into the wellbore at high speed through surface high-pressure pump units, using the high pressure accumulated at the bottom of the well to fracture the rock of the target gas reservoir, thereby forming flow-conducting fractures. To prevent the fractures from closing as the pressure falls after pumping stops, proppants (such as quartz sand) with a density far higher than that of the formation are mixed into the fracturing fluid. These proppants enter the fractures with the fluid and remain there long-term, effectively keeping the fractures open and significantly improving gas flow efficiency. In this process, the liquid flowing back from the formation to the surface is called fracturing flowback fluid; its composition is complex, covering organic matter, dissolved salts and many other substances. If discharged directly without proper disposal, it poses a potential threat to the surrounding ecological environment.
Hydraulic fracturing operation site
To address the treatment difficulties brought by the complex composition of the flowback fluid, we have developed a new high-efficiency treatment process relying on our own core products and technical advantages. The specific process is shown in the figure below:
Process flow diagram of fracturing flowback fluid treatment
The process has many outstanding features: the overall flow is simple; the main equipment adopts a skid-mounted design, supports vehicle-mounted mobility, and enables operation wherever the well is; the core unit CDOF (Ozone Catalytic Oxidation Flotation Integrated Unit) is patented technology equipment with rapid and thorough oxidation reactions, capable of efficiently breaking gel and reducing viscosity; another key unit CDFU (Cyclonic Dissolved Air Flotation) is also a patented product of the company, capable of quickly and efficiently separating and removing oils and suspended solids; the process can effectively remove calcium, magnesium, boron and other ions, and the produced water quality meets the requirements for reuse in fluid preparation; the overall system residence time is only 1/5 of that of traditional processes and the footprint is reduced to 1/3; the complete set of equipment operates in a closed and automated manner, with the advantages of safety, environmental protection and simple operation.
Application case of fracturing fluid treatment at an oilfield in Xinjiang
CDFU (Cyclonic Dissolved Air Flotation):As a new generation of green and efficient vertical-tank flotation separation equipment, it innovatively integrates cyclonic centrifugal separation, ultrafine bubble generation and dissolved air flotation technologies. Through the synergy of multiple technologies, this equipment can achieve efficient and rapid separation and purification of floating oil, emulsified oil, suspended solids and other pollutants in the wastewater.
CDOF(Ozone catalytic oxidation flotation integrated unit):This integrated patented device originally combines multiple ozone catalytic oxidation, hydraulic cavitation and cyclonic flotation technologies; it is China's first and internationally leading high-efficiency integrated oxidation and flotation treatment unit. It can efficiently and quickly remove petroleum substances, suspended solids, colloids, chemical oxygen demand (COD), bacteria and other pollutants from the wastewater. The device consists of an oxygen production system, an ozone generation system, an efficient ozone dosing system, multiple catalytic reaction systems and a cyclonic dissolved air flotation system.
Comprehensive wastewater treatment project for fracturing fluid and drilling fluid at an oilfield in Africa
