有机缓释微乳酸解卡剂的制备及其性能影响因素

Preparation and Affecting Effects of a Slow-Releasing Organic Microemulsified Acid Pipe-Freeing Agent

针对当前钻井用解卡剂存在反应速度过快,容易发生漏失,从而导致解卡失败的问题,优选表面活性剂和酸液类型及其配比,制备出有机缓释微乳酸解卡剂最优配方:AQAS∶NP=2∶1,正丁醇∶正辛醇=1∶1,水相∶油相=23∶77,助表面活性剂∶表面活性剂=1∶3,乙酸∶氢氟酸=3∶1,体系为W/O型微乳酸,该配方酸液的包埋率为23%。在地层影响因素中,温度对其性能的影响显著,在高温高压下,酸液释放速度迅速增加;在钻井液处理剂因素中,加重剂、黏土和超细碳酸钙对微乳酸影响最大,微乳酸完全破乳,形成悬浊液。通过现场5口井试验发现,该解卡剂可解除黏附卡钻、沉砂卡钻和掉块卡钻多种类型卡钻事故,一次解卡成功率为100%。

Drilling pipe-freeing agents presently in use have some problems that need to be solved,for example,the reaction rate of the pipe-freeing agents is too high which is easy to result in loss of the spotting fluids into formations and thus failures of the pipefreeing operation.A slow-releasing organic microemulsified acid pipe-freeing agent has been developed to deal with this problem.Surfactants and acids were carefully selected to prepare the pipe-freeing agent.The optimized composition of the pipe-freeing agent is as follows:AQAS∶NP=2∶1,n-butanol∶n-octanol=1∶1,water phase∶oil phase=23∶77,secondary surfactant∶primary surfactant=1∶3,and acetic acid∶hydrogen fluoric acid=3∶1.The pipe-freeing agent is a water-in-oil(W/O)microemulsified acid,and the embedding rate of this pipe-freeing agent is 23%.Formation factors remarkably affecting the performance of the pipe-freeing agent is temperature.At high pressure high temperature,the release rate of the acid is increasing.Drilling fluid factors greatly affecting the performance of the pipe-freeing agent include weighting agent,clay and ultra-fine calcium carbonate.The microemulsified acid can completely lose its emulsion stability and turn into a suspension by the weighting agent,clay and ultra-fine calcium carbonate used in the drilling fluid.Field application of this pipe-freeing agent on five wells has shown that it can be used to free stuck pipes of many types such as pressure-differential pipe sticking,pipe sticking by settling drilled cuttings and bridging etc.,and the success rate of first try in freeing the stuck pipes is 100%.