Study Of Gasfield Fracturing Wastewater Recycling Technology

The fracturing process is a key initiative to increase production of oil and gas wells, widely used in every oilfield. Fracturing waste water does great harm to the surrounding environment, because of its complex and relatively stable internal components of pollutants, in the presence of the natural forces that are difficult to decompose, and bring enormous ecological environmental problems. And discharged after fracturing wastewater treatment is difficult and high costs, has become an important factor of sustainable development of oil and gas fields. Therefore, mixed fracturing fluids after fracturing wastewater treatment on oil and gas fields to reduce costs, environmental protection and conservation of freshwater resources are of great significance.In this study, Sulige gasfield fracturing wastewater as the research object, select the gasfield with a typical representative of the wellfield wastewater fracturing, analysis of fracturing wastewater pollution characteristics studied fracturing wastewater total iron, Ca2+, Mg2+, salinity, organic matter, boron ions influence on the formulation of fracturing fluid, and the corresponding elimination methods. The results indicated that Sulige gasfield fracturing wastewater has a high viscosity, high COD, high SS, high salinity, high hardness characteristics. Therefore, after lowering the viscosity of the fracturing wastewater, reducing the iron concentration, reduce organic matter, SS, calcium and magnesium ions can re-use treated reconstituted fracturing fluid.For gas fracturing wastewater high viscosity, high COD, high stability, the use of pre-oxidation of H2O2 and iron-carbon micro-electrolysis viscosity complete decomposition and transformation of organics, through subsequent hydrocyclone solid-liquid separation technology to complete the reduction of the fracturing wastewater COD, SS, Fe3+ and other pollutants. The results indicate that the process can be wastewater COD, SS, chroma, Fe3+ effectively removed. In the treated water fracturing fluid formulation resource utilization as the goal, to study the COD, Ca2+, Mg2+, Fe3+, B3+, TDS and other factors affect water resource utilization. For among the factors interaction mechanism proposed citric acid as Ca2+, Mg2+ masking agent, and the blending of Fe3+, B3+ ratio of sodium ion exchange resin to control TDS reaches the treated effluent formulated fracturing fluid resource utilization goals.Based on the above studies to determine the Pre-oxidation — Iron-carbon micro-electrolysis—Coagulation—Sedimentation—Adding masking agent fracturing wastewater treatment process, the design and development of an integrated gasfield fracturing wastewater treatment equipment, the equipment set pre-oxidation, iron carbon microelectrolysis, flocculation, sedimentation and other unit as one of fracturing wastewater regeneration treatment. Field experimental study in Sulige gasfield, to prove the practicability and feasibility of this process, recycling of wastewater fracturing Sulige gasfield wellsite providing technical support.