Abstract: In order to solve the frequent pipe sticking in porous limestone reservoir formation in the Iranian Y Oilfield,based on the properties and pore pressure of F formation,the reasons and types of pipe sticking were analyzed.Different pressure systems are the main reason behind pipe sticking,and there is highly different pressure between the drilling fluid column pressure and formation pore pressure.According to the calculation formula of friction between the drill string and borehole wall,the following technical measures were suggested to prevent sticking:non-invasive drilling fluid system should be applied to seal near wellbore zone,separate drilling fluid column pressure from low pressure formation,and cut the differential pressure transmission;drilling fluid performance be optimized and mud cake quality improved to lower the friction factor between drill string and borehole wall;BHA should be simplified to reduce the contact between it and borehole wall;and separated plugging,well trajectory control and reducing static time of drilling tools in well should be taken as well.Pipe sticking has been eliminated after taking the aforesaid measures in F formation of 13 wells in Iranian Y Oilfield,marking the success in addressing pipe sticking prevention there.