Abstract
The dynamic kill process is divided into two stages: “dynamic pressure stability” and “static pressure stability” stage in this paper. In dynamic pressure stability stage, sea water fluid was pumped into the well the initial killing fluid; Then in “static pressure stability” stage, pump into the weight liquid by quantified displacement based on “dynamic pressure stability” that can achieve complete killing effect, and control well kick effectively to drill efficiency.
In this paper, the multiphase multicomponent staged pressure control equation is established by considering the effect of shallow flow gas influx, meanwhile, it adopts the auxiliary equations such as velocity equation, density equation, and Herschel-Bulkley fluid rheological equation with yield value. The dynamical drilling tools flow pressure loss method is considered to improve the calculation accuracy of displacement. This paper solves the equation by the finite difference iterative method which should get the solution conditions firstly, then the initial and weight displacement are got.
This paper takes a deepwater well as an example by comparing and analyzing calculation results and the actual data which shows that it has a greater degree anastomosis with the actual construction site. The following conclusions are obtained: (1) Calculation accuracy is more precise and practical when using the Herschel-Bulkley rheological model and considering the dynamical drilling tools pressure loss calculation (2) The emphasis of finite difference iterative method are grid division and the boundary conditions determination. (3) The prevention of shallow geological disaster is more effective and the process is more delicate by dividing the progress into two stages.
With oil and gas area trend diverting from land to sea, from the superficial to deep, the drilling and mining condition is becoming more and more complex. The method proposed in this paper can not only solve the complex well kick in deepwater which can't be solved before, but also the multicomponent multiphase equation established make the control of shallow flow gas more subtly, and the calculation equations of high accuracy displacement built by stages make the kill process more systemic.
