The sources of oilfield soil pollution are mainly from the invasion of drilling mud during oil and gas exploration, extraction, transportation and storage. If the contaminated drilling mud cannot be disposed of in a timely, reasonable and effective manner, serious pollution of the soil around the oil field will occur. As the main source of pollution, drilling mud contains pollutants such as petroleum, heavy metals, organic chemicals, chloride ions and other pollutants that enter the soil without treatment, which will not only cause great harm to the soil, but also to the environment. The content of trace harmful elements in the soil exceeds the background value, and the content is too high due to excessive deposition, so it is called “soil heavy gold pollution”. Five schemes for remediation of oilfield soil pollution:
1) Oil sludge thermal desorption method oilfield soil pollution remediation plan:
The sludge thermal desorption method to remediate oilfield soil pollution is based on an integrated solution of solid-liquid separation. Through sorting equipment, the stones, weeds, tree roots and other sundries in the contaminated soil are separated; the proportions of oil and water are different. Physical properties: water, oil, and mud sand are fully stratified through water temperature and chemical stirring. The oil floats on the top layer according to the specific gravity. The water layer is in the middle, and the mud sand settles at the bottom layer. Finally, it passes through three-phase separation equipment or oil-water separation equipment. And mud-water separation equipment to achieve the purpose of three-phase separation of water, oil and mud.
2) Bio-method oilfield soil pollution remediation plan:
Bio-method oilfield soil pollution remediation program: Bioremediation is a method that uses biological growth and metabolism to degrade and transform organic matter. It has the characteristics of safety, reliability, and low repair costs. This soil pollution remediation plan includes: key processes, remediation preparations, supporting equipment and other core technologies.
3) Physical method of oilfield soil pollution remediation plan:
The physical method of oilfield soil pollution remediation program refers to pollution control technologies such as the soil method, incineration method, physical separation method, solution leaching method, solidification stabilization method, thermal desorption method and electrodynamic method based on physical methods.
4) United Technologies Oilfield Soil Pollution Remediation Plan:
The composition characteristics of oil and secondary metabolism determine the difficulty and complexity of oilfield soil pollution remediation. Therefore, a single technology cannot solve the pollution problem well, and it is necessary to consider the combined use of various treatment technologies.
5) Remediation plan for soil pollution of oilfield by leaching method:
The leaching method for remediation of oilfield soil pollution is an in-situ remediation method, which is very similar and close to the technical principles of “water flooding” and “polymer flooding”. The water from the injection well flows into the soil contaminated area of the oilfield, so that the oil contaminants in the oilfield soil are flushed into the area that can be pumped out by the groundwater well under the accumulation and driving of the water. The extracted petroleum-contaminated groundwater and flushing water are treated by surface facilities, and the rinsing water is recycled and reused. After the treated wastewater meets environmental protection requirements, it is discharged. When choosing an oilfield soil pollution remediation plan, different soil pollution remediation plans should also be selected for the oilfield soil contaminated by light oil and heavy oil.
KOSUN- China Solids Control Leader&Drilling Waste Management Expert
Contact person: Lily Wang