Abstract:

Currently, the well control in the drilling engineering design of onshore oil and gas wells mainly includes wellhead device, pressure test and well control requirements in conventional operation, and does not involve the calculation of the overflow quantity of shut-in. In this paper, kick tolerance is considered to be added to the design above, and a calculation method of kick tolerance is given. Combined with the drilling condition of ? 311.1 mm hole of well LJ-20 in gas field A in the Sichuan-Chongqing area, examples were applied to analyze how to add kick tolerance and assist the well control of overflow in drilling site. The calculation results showed that, with the given KI value, the deeper the hole was, the smaller the kick tolerance would be; while at the same depth, the kick tolerance also decreased with the increase of the KI value. Therefore, it is necessary to add the kick tolerance to the design. Thus, whether the shut-in operation with overflow is safe or not can be effectively judged. At the same time, further considering should be given to how to obtain the dynamic kick tolerance of shut-in which is more applicable in the field, so as to assist in safe drilling in the deep formations where pressure is difficult to be predicted accurately.

Key words: overflow, drilling engineering design, kick tolerance of shut-in, strength of kick tolerance