Drilling fluid technologies for pipe sticking prevention of standard well in Halahatang Block

The second-stage open hole section of the standard well in Halahatang Block is 5 200 m long and there is complex pipe sticking of different degrees in the second-stage hole section, which seriously hinders rate of penetration (ROP) improvement and productivity construction in this block. Taking Well HA9-13X as an example, this paper analyzed the causes of pipe sticking in different segments of second-stage hole section and put forward the corresponding drilling fluid technologies and measures as follows. First, higher drilling fluid viscosity is the cause of the pipe sticking in Cretaceous and the strata above it. And it is recommended to adopt the drilling fluid technology of “lower viscosity, finite inhibition, high fluid loss and strong plugging” combined with the large-displacement turbulent carrying sand to prevent pipe sticking. Second, mud shale slough is the cause of pipe sticking in Jurassic, Triassic and Permian. And in order to prevent pipe sticking, it is recommended to change the drilling fluid into the whole cationic system before drilling into Jurassic and introduce the film forming and plugging agent FDM-1 for plugging enhancement and slough prevention. Third, the traditional “solid-liquid” lubricating method is adopted in the directional hole section to prevent backing pressure, but its application effect is not remarkable. 0.3%-0.5% tailored vermiculite is added. The friction resistance is reduced effectively by 200-300 kN by changing the contact mode between drilling tool and borehole wall. In this way, the backing pressure and pipe sticking problems of directional long open hole section are solved. The field application shows that the drilling fluid based pick sticking prevention measures which are formulated specifically for different hole sections effectively ensure the safe and fast drilling of the second-stage long open hole section in Halahatang Block, avoid complex downhole accident of pipe sticking and shorten the drilling cycle.