Research On Reclamation Of Oil And Gas Field Drilling Sludge As Road Material

Our country is one of the major oil and gas production and consumption countries in the world.In the process of oil and gas exploration and exploitation,a large number of drilling sludge and other wastes will be generated,and there is a lack of effective resource utilization way.If the method of direct storage or landfill is adopted,it will not only occupy a large amount of storage space,cause a waste of resources,but also affect the ecological environment.In view of this,this paper aims to expand the way of resource utilization of drilling sludge.On the basis of chemical destabilization and pretreatment of drilling sludge in abandoned oil and gas fields,research is carried out on the road performance,durability and construction technology of cement,calcium carbide slag and lime stabilized drilling sludge,and explore the feasibility of filling roadbed and subbase with drilling sludge produced after sludge pressure filtration treatment.It provides theoretical support and technical reference for the application of drilling sludge in road engineering.Based on the field investigation and analysis of oil and gas field drilling operation area,this paper analyzes the water content,hazardous substance content and leaching toxicity of waste sludge from oil and gas field drilling.The results show that the waste drilling sludge belongs to the second class of general industrial solid waste,the chemical oxygen demand（COD）and p H of the leaching solution exceed the standard requirements.Four kinds of degumming agents,FeCl₃、PAC、Fe₂（SO₄）₃ and Al₂（SO₄）₃,were selected to carry out chemical degumming of drilling sludge.The COD and p H values of the leach solution of sludge after degumming and filtration were used as indicators to determine that PAC was the best degumming agent:The optimal dosage of PAC was 1%;The optimal PAC dosage of gas well sludge was 1.4%.After adding three times the dry weight of the sludge into the gas well sludge after pumping and filtration for half an hour,press filtration,wash twice,COD meets the requirements of the code,and can be used as resources.Further,the physical and engineering mechanical properties of drilling mud samples are analyzed.The results show that the CBR value and compressive modulus of gas well mud and oil well mud meet the requirements of the code for subgrade filling.Gas well mud and oil well mud can be directly used to fill the roadbed of through well road.Based on this,three kinds of inorganic binder stabilizing materials,cement,lime and calcium carbide slag,were selected respectively to analyze the unconfined compressive strength,California bearing ratio,compressive resilience modulus and freeze-thaw residual strength ratio of cement stabilized mud slag,lime stabilized mud slag and calcium carbide stabilized mud slag at different ratios.With the increase of cement,calcium carbide slag and lime content,the optimum water content,compressive resilience modulus,7d unconfined compressive strength and California bearing ratio of the stabilized mud slag increase gradually.The maximum dry density of calcium carbide slag and lime stabilized mud slag gradually decreases with the increase of lime and calcium carbide slag content,while the maximum dry density of cement stabilized mud slag increases with the increase of cement content.The freezing resistance of cement,lime and calcium carbide slag stabilized mud slag is poor,which is suitable for the area with light freezing damage.Considering the requirements of standard and economy,it is suggested to use 8%cement to stabilize the mud residue of oil well and gas well to fill the base.According to the dosage of breaking agent and the recommended value of the base mix ratio,the program controlled diaphragm filter press is used in the construction site to carry out the drilling sludge breaking and pressing test.The qualified drilling mud is used to build the test road,and its compacting degree,compressive strength and other road indexes are tested.The performance meets the requirements of the specification,and has good economic,social and environmental benefits.