Harmless treatment method for drilling wastes of oil and gas fields

Abstract

The invention provides a harmless treatment method for drilling wastes of oil and gas fields. The harmless treatment method comprises the steps that solid-liquid separation of waste drilling fluid is conducted, a water treatment agent is added in the solid-liquid separation process, and liquid water directly returns to drilling mud of the oil and gas fields to be reused after mechanical reinforcement to the solid-liquid separation is conducted; collecting equipment is adopted for collecting solid wastes such as rock debris and residual mud in waste mud; the collected solid wastes are placed in a mixer, and a solidification enhancement treatment agent comprising a RDH-1 solidification agent and a RDH-2 solidification agent is added into the mixer, so that the solidification enhancement treatment agent and the solid wastes containing a certain amount of water are mixed fully and evenly. The harmless treatment method is capable of effectively transferring harmful ingredients in wastes to substances small in harm or harmless substances, or reducing the leaching rate of the wastes, adjusting the PH value of a leaching solution of a solidified body of the waste mud and decreasing chemical oxygen demand (COD) and the chroma of suspended solids (SS), so that heavy metal ions contained in the treated solid wastes meet the requirement of a discharging index which environmental protection allows.

Description

technical field [0001] The invention relates to the technical field of waste treatment, in particular to a method for harmless treatment of drilling waste in oil and gas fields. Background technique [0002] Domestic oil and gas fields use drilling mud to carry solid particles and powders such as cuttings to the ground during drilling, and then carry solid particles and powder in the mud through solid control equipment (such as vibrating screens, desanders, desilters, centrifuges, etc.) Formation materials such as drilling cuttings are separated from the mud. The separated drilling cuttings and the mixture of waste mud, drilling additives, petroleum, high molecular organic matter, water and salt are called drilling solid waste. For every oil and gas well drilled in China, the total amount of drilling waste is about 500-800 cubic meters. my country's oil and gas fields can produce hundreds of millions of cubic drilling solid wastes every year, and these solid wastes have no...

AI Technical Summary

Problems solved by technology

[0009] The disadvantages of this treatment process are: (1) PH value, chemical oxygen demand COD, chromaticity, turbidity SS, various heavy metal ions, organic matter, oil and other harmful pollutants in the waste drilling fluid of oil and gas fields , has not been effectively treated by environmental standards and harmless treatment; (2) After decades of natural drying and simple landfill, the drilling waste treated by this method will still cause serious pollution to surface water and affect the mud The ecological environment around the pool pollutes the living, growing soil and water sources of animals and plants; (3) The mud pool that is naturally dry, covered with soil, and not solidified will become a rotten mud pond after encountering heavy rainfall and stagnant water , will fall into people and animals, causing serious life danger to the surrounding people and animals

[0011] The disadvantages of this treatment process are: (1) use a large amount of water treatment agent to treat water in a special tank first, and then use mechanical equipment to strengthen the waste water produced by solid-liquid separation. The waste water produced by this method is pre-mixed A large number of water treatment agents (such as those that adjust PH value, reduce COD, heavy metal ions, chroma, petroleum and other harmful components) must be treated twice to make the water quality meet the requirements of mud reuse water quality standards, greatly improving the quality of water. Significantly increased the cost of equipment, chemicals, manpower and material resources for secondary water treatment

(2) After the solid-liquid separation, the waste sludge should be piled up in the storage yard first, and after natural drying, other materials can be added for secondary solidification treatment, which increases the cost of equipment, manpower and material resources

[0012] Moreover, the current environmental protection treatment and recycling treatment are relatively disconnected in the process of oilfield waste mud treatment. The reason is that all the inorganic reinforcing materials in the market are highly alkaline. When ensuring strength, the pH value exceeds the range of environmental protection standard values, and the two cannot be unified.

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