Model for planning well control operations involving an induced fracture.

摘要

This dissertation presents a numerical simulator for designing a dynamic kill of an underground blowout. The simulator consists of three sub-programs: a reservoir model, a wellbore model, and a fracture model.;Previously published procedures have modeled the fracture by assuming a constant pressure in the wellbore at the depth of fracture. This assumption has sometimes led to unrealistic results. In this work, a hydraulic fracture model is coupled with the reservoir and wellbore model using a system analysis approach.;The hydraulic fracture model is based on a pseudo-3D model with some modifications introduced to more accurately model the extension of the fracture and to account for the use of a two-phase fluid. To obtain a more accurate prediction in the fracture model, an experimental procedure was planned to measure the leak-off volume inside the fracture for drilling mud and gas, and a correlation based on experimental data was presented. The correlation uses three parameters, (spurt loss volume, pack buildup factor, and equilibrium Darcy flow velocity coefficient), to determine the leak-off volume.;Simulations of underground blowouts were run, and these simulations showed significant differences between the current and the proposed models for some cases. The results show that, with the proposed model, well control can be achieved with lower pumping rates than indicated with conventional models. These lower pumping rates can be important since the time and cost of gathering the required pumping equipment and, in some cases, drilling additional relief wells is greatly dependent on the pumping rates required to overcome the blowout.;Also, the proposed model can be used as a tool for verifying the applicability of the shut-in procedure in shallow wells when controlling a blowout.