Study On Leak Prevention And Plugging Technology Of Safe Density Window Of Drilling Fluid

The biggest problem of leakage prevention and plugging is the complexity and uncertainty of geological conditions,which makes it simple,convenient and intuitive to monitor the leakage layer in real time,the key to solve the problem is to evaluate the formation pressure,strength and the possibility of leakage in time and take simple and effective emergency measures.With the expansion of exploration and development field,the complexity of lost circulation increases and the difficulty of treatment increases.Therefore,this paper analyzes the existing techniques for dealing with lost circulation,and points out that there are still many problems in the existing techniques for lost circulation prevention and plugging,which can not fully meet the purposes of lost circulation prevention and plugging and reservoir protection,it is also necessary to develop new lost circulation plugging technologies and equipment in order to cope with the increasingly complex lost circulation accidents and to reduce or eliminate the complications,time delays and significant economic losses caused by lost circulation.In this paper,a series of pre-plugging technology is formed,which is based on the prediction of formation pressure,the definite geological data,the analysis of formation porosity and the selection of drilling-while-drilling non-permeable plugging agent.In addition,according to the existing extreme loss of drilling fluid situation,from the high-density drilling fluid,under-balance two extreme conditions,respectively,to carry out targeted lost circulation plugging technology research,expand the drilling fluid security density window.