Drilling waste is a mixture of drilling sewage, drilling fluid (drilling mud), drilling cuttings and dirty oil, and it is a fairly stable colloidal suspension system. It contains clay, weighting materials, various chemical treatment agents, sewage, dirty oil and drilling cuttings. The main chemical components harmful to the environment are hydrocarbons, salts, various polymers, heavy metal ions, barite and impurities in modified asphalt. These pollutants are high in chroma and oil. Every time a well is drilled in an oil and gas field, an abandoned mud pool must be left in the same place. An oil and gas field has thousands of wells and thousands of abandoned mud pools. The drilling waste in each mud pit ranges from several hundred cubic meters to several thousand cubic meters. These wastes are polluted by soluble inorganic salts, heavy metals and organic hydrocarbons (oily substances). If stacked or buried in the well site, once soaked by rain and washed by rivers, it will cause serious environmental risks to the surrounding soil, water source, farmland and air.

Preventive and control measures:

In order to do a good job in regional geological and hydrogeological investigation, it is necessary to make a good prediction of the geological structure and possible geological disasters in the proposed drilling area.

Engineering design should be carried out reasonably, and advanced drilling technology and targeted drilling methods should be adopted. If directional wells or cluster wells are used to drill in high-risk areas of geological disasters or sensitive protected areas that need to be avoided, exploration should be carried out before mining.

Strengthen wellhead sealing and shaft wall maintenance to ensure that blowout and shaft wall collapse do not occur (to prevent oily reinjection water from entering the groundwater aquifer to pollute groundwater), and timely block the shaft wall rupture.

Use high-quality and efficient (environmental protection) drilling mud to prevent downhole oil leakage and corrosion of drill pipes and equipment.

Cofferdams should be set around important storage tanks and devices where leakage accidents may occur, and the foundation layer should be treated with seepage control.

The drilling area is equipped with pollutant treatment facilities, sedimentation tank, regulating tank and accident emergency tank to treat drilling cuttings, drilling wastewater and drilling waste mud respectively, and those that can be comprehensively utilized can be utilized or reinjected as much as possible, and those that cannot be utilized can be solidified and buried in sanitary landfill, and the ecology can be restored after covering.