新型高分子中空微珠的制备及现场应用

Development and Field Application of a New High Molecular Weight Hollow Micro Beads

前期研发的聚苯乙烯中空微珠作为钻井液减轻剂在现场应用中易团聚,极易与钻屑吸附而被固控设备除去,导致钻井液密度逐渐升高。为解决聚苯乙烯中空微珠存在的吸附、团聚问题,从壳体本体性质、表面改性入手,优化设计出具有双层结构的高分子中空微珠,室内优化WF单体、催化剂、发泡剂、表面改性剂、防静电剂等关键材料的加量,并采用喷雾干燥装置制备出了SMHPS-2型高分子中空微珠。室内研究表明,制备出的高分子中空微珠微观形貌呈圆球颗粒,表面致密光滑,粒径均小于100μm,平均密度为0.31~0.32 g/cm^3,抗压达50 MPa,抗温达90℃,具有良好的抗研磨性、分散稳定性,自身不团聚,且与钻屑无吸附效应。锦111井的现场试验表明,基液中加入4%SMHPS-2型高分子中空微珠减轻剂可将密度降低0.04 g/cm^3,且与固控设备具有良好的适应性,无吸附、团聚现象,具有良好的抗剪切能力。

Hollow plastic microbeads made of polystyrene previously developed are easy to agglomerate when used as a lightweight agent in field drilling fluids,and are thus easy to be bond with drilled cuttings,thereby being removed by solids control equipment and resulting in a gradual increase in mud weight.To solve these problems,efforts have been done on the modification of the body and surface of the microbeads,giving birth to high MW polymer hollow beads with a double-layer structure,SMHPS-2.WF monomer optimization and the determination of the concentrations of critical materials such as catalyst,foaming agent,surface modifier and antistat were performed in developing SMHPS-2,which were dried with spray drying.Laboratory study showed that the particles of SMHPS-2were in round shape with smooth and dense surfaces.SMHPS-2had particle sizes less than100μm,average density between0.31and0.32g/cm3,compressive strength of50MPa,and remained stable at90℃.Particles of SMHPS-2were resistant to abrading,stable in a dispersion,and did not agglomerate by themselves,and did not adhere to drilled cuttings.In field application in the well Jin-111,addition of4%SMHPS-2in a base fluid reduced the density of the base fluid by0.04g/cm3.SMHPS-2showed good adaptability to use with the solids control equipment and superior resistance to shearing;no adhesion and agglomeration were observed during drilling.