Loss and Control in Vugular Reservoir Formations in Block Tahe

The carbonate reservoir in the middle and lower Ordovician formations have strong inhomogeneity,and the mud loss pressure could be zero or even less than zero,meaning mud loss into the reservoir formation will be very easy,resulting in a very severe damage to the reservoir.This paper discusses the characteristics of mud losses into fractured-vugular reservoirs and karst reservoirs,and the mud loss control in well TK1206 and well TK1231.It is shown that,based on the geology of the reservoir formation in Tahe,the drill-in fluid and LCM fluid used in Tahe are suitable for mud loss control in the fractured-vugular reservoirs and karst reservoirs.Presently it is common to complete the well in advance if karst formation is encountered.The optimization of LCM having low damage to reservoir formations and easy to remove,and the corresponding LCM mud formulations should be studied extensively,and more attention should be paid to the prediction of mud losses and the finding of new methods of well completion in mud loss zones.