Calculation Of Equivalent Circulating Density Of Deep-water Drilling Under Kick Conditions

In deepwater drilling,the distribution of wellbore temperature and pressure has a great influence on the equivalent circulation density of drilling fluid.When gas kick occurs,the calculation of ECD will be more complicated.To study the temperature model and calculate equivalent circulating density of deep-water drilling under gas kick,it has great significance to control the kick of deep-water drilling,simultaneously it help us achieve the safe and efficient development of deep-water drilling.Firstly,this paper studies the causes of kick in deepwater drilling.Based on the theory of multiphase flow,the gas kick modes are studied,and some characterization phenomena are analyzed such as drilling discharge,density,pump pressure,etc.The bottomhole flow pressure and flow distribution of two-phase flow calculation method are calculated in gas kick.Then based on engineering thermodynamics,heat transfer and computational fluid dynamics,the wellbore temperature model and the annulus temperature model during gas kick is solved by analytical method.At the same time,the model of calculating the equivalent static density is selected,The calculation formula of the power law fluid tube and the annulus laminar flow pressure is given,to calculate the equivalent circulating density of gas kick in the annulus.Finally,according to the obtained model and density calculation formula,Visual Basic is used to compile the software for “temperature and pressure simulation of deep water drilling during gas kick”.