Formation plugging and pipe-stuck freeing technology for Well 205 in Turkmenistan Yashila block

In the Yashila block, Yuratun, Turkmenistan, the limestone reservoir is porous, where there are several pressure systems. During drilling in oil and gas layers, many complexities occurred frequently, such as mud loss, pipe sticking and overflow. Well 205 is the first exploratory well in this block reaching the design depth of 5 000 m. In this paper, the cause and treatment regarding to mud leakage and drill sticking are analyzed. The shut-in inverse method is used to control and prevent overflow and blowout. Moreover, stuck pipe-freeing soak, acid soak and injection of fresh water for reducing pressure are used to free the stuck pipe. In this way, the coexistence of mud leakage, drill sticking and overflow in Well 205 is addressed successfully. The conclusions provide good reference for subsequent exploration and development operations in this block.