Experimental Study on Hydraulic Pulsed and Cavitating Jet Drilling Technique in Deep Wells of Tahe Oilfield

Factors such as low hydraulic energy utilization efficiency and ROP,high drilling cost,etc.severely hindered the speed of petroleum exploration and development in Tahe Oilfield.In view of the real conditions of Tahe Oilfield,and drilling formation,BHA,and drilling parameters of the second drilling section φ241.3 mm wellbore,hydraulic pulsed and cavitating jet drilling were employed to increase ROP.Using conventional drilling tools and composite drilling tools,hydraulic pulsed and cavitating jet drilling technique modulates pulsed jet and cavitating jet to change flow field and rock stress state at the bottom of hole,and raise ROP.The technique had been applied 5 times in 4 wells in Tahe Oilfield.Under normal pumping pressure,flow rate and drilling fluid density,applied well depth reaches up to 6 162 m.The net drilling time of single set of drilling tool exceeded 260 h,the ROP in the applied well intervals was 33.3%-74.3% higher than adjacent wells which were similar in conditions.Field tests indicated that hydraulic pulsed and cavitating jet technique had a good adaptability to sandstone and mudstone formation of Cenozoic,Mesozoic and Palaeozoic group and different,together with PDC bit,it could enhance ROP by a large margin.