A Study On Compatibility During Afflux Of Drilling Wastewater Into Gathering System In Longdong Oilfield

Located in the Qingyang district of Gansu province, LongDong oilfield is a typicallow permeability oil field which is attached to Changqing oil deposit. In order toguarantee the oil production, the drilling wastewater poses a great threat to environmentdue to its complex composition and hardness of degrading.Based on the problems caused by drilling wastewater, this study analyze thecomposition and morphological characteristics of the pollutants which draws theconclusion that the contribute factors and their proportion of COD are SS(32.41%),petroleum contaminants(25.35%), inorganic pollutants(12.83%) and viscosity(9.36%),respectively, while the other substances amounts for20.05%of the total. This study alsoshows that the heavy metal of drilling wastewater is not the key pollutant.Based on the characteristic of drilling wastewater including small amount and hardto collect, this study suggests the research ideas of importing and collecting of drillingwastewater as well as proposing the treatment technology including peroxidation,coagulation, sedimentation, hyperfiltration and catalytic ozonation on the basis ofnumerous previous research.This study demonstrates that there are six control indexes including COD, SS,chrominance, oil content, viscosity of the influence factors of drilling wastewater andthe compatibility of importing system, and the system will function well and will notbring adverse effect for original system when the total content of COD is below3000mg/L, the SS is less than10mg/L, the chrominance is less than or equal to80times after treatment, the oil content is below100mg/L, the pH is between6.5~8.0and theviscosity of treated water is less than or equal to1.3mpa.s.