模拟环空流动状态的堵漏试验装置设计

对比分析了缝板窄槽流动、室内建立井筒环空和搅拌器搅拌3种动态漏失模拟方法,发现这3种方法并不适用于堵漏剂室内效果评价。鉴于此,结合井筒工作液实际流动状态,将井壁剪切速率作为流动相似准则,建立了环空水力学模型并优化计算,设计出剪切速率达到100~1 000 s^-1且能够真实模拟环空流动状态的堵漏试验装置。采用分体式人造岩心漏失模块,解决了漏失模块与地层物性相差大的问题。在裂缝性漏失试验中,API堵漏试验仪为静态评价方法,不能准确反映井筒工作液的真实状况,而堵漏试验装置可以模拟地层压力、温度和钻井液在井筒中的螺旋运动状态等条件,因此能够准确评价堵漏材料的适用性和封堵效果,优选出适合现场的堵漏剂和防漏堵漏钻井液。研究结果表明该装置能够准确评价堵漏剂的封堵效果。

Design of Lost Circulation Control Test Device Simulating Annulus Flow

The three dynamic lost circulation simulation methods of narrow groove flow of the slit plate, indoor- build wellbore annulus and agitator stirring were analyzed and compared. It is found that these three simulation methods are not practical in the indoor evaluation of the lost circulation materials. On this basis, combined with the actual fluid flow state of the wellbore, taking the shear rate at the wellbore wall as the flow similarity criterion, the annulus flow hydraulic model is established and optimized. The lost circulation test device that could simulate real annulus flow state with shear rate to 100 .1 000 s_1 is designed. The split-type artificial core module which is convenient for observing the sealing condition addresses the great difference between the leakage module and the formation physical property. In the fracture loss test, the API lost circulation test device is a static evaluation device, which can not accurately reflect the real condition of the fluid in the wellbore. The new developed lost circulation test device can simulate the formation pressure, temperature and the spiral flow state of the drilling fluid in the wellbore. Therefore, it could more accurately evaluate the suitability and sealing effect of the lost circulation materials, and help to select preferable lost circulation prevention and control materials and drilling fluids.