Drilling Company of Jilin oilfield

Problem

Curing process is the most common process method in China, which adds curing agent such as ferrous and aluminum-based inorganic salt to the waste drilling fluid compounding with adequate cement, coal ash, and lime, etc., and then mixes these agents by the "hook machine". The inorganic salt is used to absorb degraded organic pollutants, after mixed they will turn into consolidation plate matter with certain strength, and then covered with a layer of soil of 50-80 cm thick, so as to complete the process of pollutant control and land recycling. However, this process method has following problems: 
1) From technical aspect, the curing process is not unified and mature; the quality of curing agent and adding ratio are different; hazardous substances are not fully cured; heavy metal loss and secondary pollution are very common.
2) Most existing mud pits of Jilin Oilfield have a great quantity of wastewater at the surface, which requires more curing agents, and thus improving the curing cost greatly.
3) From the management aspect, the construction supervision is not in place, some construction parties cheat in work and cut down materials and reduce the ratio of curing agent to saving cost. As a result, the mud pit cannot cure for years and such events as sink of vehicle and oxen and horses often occur. In addition, mass petitions have occurred occasionally.

Pollutant

Waste drilling mud and its superstratum filtrate

Solution

1) For solid-liquid separation, add dedicated gel breaker to the wastewater layer and the mixed layer of the mud pit, and use the pretreatment and centrifugal process to separate solid from liquid.
2) For liquid process, use oxidation pond to process the liquid (sewage) obtained after solid-liquid separation, so as to meet the water quality standard for farm irrigation or standard for oilfield reinjection water.
3) For solid use, the solid obtained after solid-liquid separation and the sand bed (low liquid content) in the mud pit shall be cured by adding adequate gel breaker, adsorbent and consolidation agent such as cement, coal ash and quick lime, etc., and then can be used for road building. Pave the wellsite road by using specialized facilities.

Achievement

Treatment capacity: 20 m³/h
Standard of output water: Oil content < 50 mg/l  pH：6~9