泡沫质量和环空返速对泡沫携岩能力影响的数值模拟

Numerical simulation of effect of foam quality and annulus velocity on cuttings carrying capacity

尽管泡沫钻井具有较强的携岩能力,但在水平井钻井过程中,环空内依然存在岩屑传输困难的问题,有效降低或消除岩屑床是成功钻进的关键。根据质量守恒定律和动量守恒定理,运用计算流体力学软件FLUENT求解器,针对环空中泡沫和岩屑的混合流动过程进行了数值模拟,得到了偏心环空中不同泡沫质量和环空返速条件下岩屑床高度的变化规律,并与常规钻井液的携岩能力作了对比。研究结果表明:泡沫钻井液具有较强的携岩能力,在水平段所形成的岩屑床高度低于常规钻井液条件下的岩床高度,泡沫质量和环空返速对岩屑运移具有较大影响。

Although foam drilling has a good capacity of transporting cuttings, but in horizontal well drilling, there also exists a problem in cuttings transportation in the annulus. To efficiently reduce or clear up cuttings - bed is critical to successful drilling. According to the mass conservation law and the momentum conservation theorem, the mixed flow of the foam and cuttings in the annulus is stimulated by using the method of computation fluid dynamics of FLUENT software. So the variation rules of the foam quality in the eccentric annulus and the height of cuttings - bed at annulus velocity are obtained. Also the rules are compared with the cuttings carrying capacity of conventional drilling fluid. Research results show that foam drilling fluid has strong cuttings transporting capacity, and the cuttings - bed in horizontal sections is lower than that under normal mud conditions. The foam quality and annulus velocity exerts great effect on cuttings transportation.