Study On Properties And Preparation Technology Of Sintered Brick With Polysulfonate Drilling Cuttings Of Natural Gas

With the development of natural gas drilling in China,polysulfonate drilling fluid is widely used in complex deep drilling projects.The output of polysulfone drilling cuttings is huge,most of which are treated by air-dried landfill or solidified landfill,and only a small amount is reused,which increases the risk of environmental pollution,and causes waste of cuttings resources.In this study,polysulfonate drilling cuttings are used as materials to prepare sintered bricks,which solves the problem of cuttings disposal,and realizes the resource utilization of polysulfonate drilling cuttings.Based on the physical and chemical properties of polysulfonate drilling cuttings,this study compares the chemical composition,mineral composition,particle size composition and plasticity index of polysulfonate drilling cuttings and ordinary brick raw materials,and discusses the feasibility of using polysulfonate drilling cuttings to prepare sintered bricks.Based on the compressive strength,water absorption,bulk density and linear shrinkage of sintered brick,the effects of different polysulfonate drilling cuttings on the properties of sintered brick are analyzed,and the sintering mechanism of polysulfonate drilling cuttings sintered brick is clarified.Calcium lignosulfonate is added to sintered brick to increase the amount of polysulfonate drilling cuttings,and the sintering temperature and holding time are changed to improve the properties of sintered brick.The response surface methodology is used to determine the optimal preparation process parameters for the best performance of polysulfonate drill cuttings sintered bricks.The main results are as follows:1.The main chemical components of polysulfonate drilling cuttings are Ca O,Si O₂ and Ba O,in which Si O₂is one of the indispensable components for preparing sintered brick.Polysulfonate drilling cuttings ontain the same mineral components as ordinary brick making raw materials—quartz and muscovite,and their particle size composition and plasticity index meet the specification requirements of brick raw materials.However,the content of some chemical components in polysulfonate drilling cuttings does not meet the content requirements of brick making raw materials,and shale needs to be added for reinforcement.2.Sintered bricks are prepared with polysulfonate drilling cuttings,shale and coal gangue.After high-temperature sintering,the calcium disilicate,kaolinite and chlorite in the brick react and decompose to form new minerals—anorthite and hematite.With the increase of polysulfonate drilling cuttings,the compressive strength and bulk density of sintered brick decreases,and the water absorption and linear shrinkage increases.When the content of polysulfonate drilling cuttings exceeds 15%,the bulk density of sintered brick does not meet the requirements of bulk density of ordinary sintered brick.When the content exceeds 20%,the water absorption of sintered brick increases significantly,and the compressive strength decreases sharply,which is lower than the requirements of MU15.3.In order to improve the resource utilization rate of polysulfonate drilling cuttings,the performance changes of calcium lignosulfonate mixed with sintered brick are studied.It is found that different amounts of calcium lignosulfonate have different substitute effects on the properties of polysulfonate drilling cuttings sintered brick.With the increase of calcium lignosulfonate content,the increase range of compressive strength and bulk density of sintered brick first increases and then decreases.When the content of calcium lignosulfonate is 0.4%,the properties improvement effect of sintered brick is optimal,and the compressive strength,water absorption,bulk density and linear shrinkage of sintered brick with 25%polysulfonate drilling cuttings meet the requirements of ordinary sintered brick.4.The effects of sintering temperature and holding time on the properties of sintered brick are explored.When the sintering temperature reaches 1000℃,the compressive strength,water absorption,bulk density and linear shrinkage of modified polysulfonate drilling cuttings sintered brick reaches the comprehensive optimum.When the holding time is 1.5～2.5h,the properties of sintered brick change greatly.When the holding time is increased to 2.5h,the shrinkage degree of sintered brick is significant and the bulk density is high,which does not meet the relevant requirements in the specification.5.The preparation process of polysulfonate drilling cuttings sintered brick is optimized by response surface methodology.The content of polysulfonate drilling cuttings,calcium lignosulfonate,sintering temperature and holding time are taken as design variables,and the compressive strength and water absorption of sintered brick are taken as response values.The results show that the content of polysulfonate drilling cuttings,calcium lignosulfonate,sintering temperature and holding time have significant effects on the compressive strength and water absorption of sintered bricks.Through response surface methodology,the optimal preparation process parameters that can ensure the utilization rate of polysulfonic drilling cuttings resources and the properties of sintered bricks are obtained:the content of polysulfonic drilling cuttings is 27.5%,the content of calcium lignosulfonate is 0.5%,the sintering temperature is 1025℃,and the holding time is 121min.