| Recent years, most of China’s big oilfields have entered the middle and later period of oil exploitation. Geological conditions and physical property is getting worse, and reservoir permeability is getting lower. The effective reservoir stimulation is an effective means of exploitation of low permeability oilfield. Hydraulic jet fracturing technology is a stimulation technology developed in the late 1990, and now it is widely used by the major oil fields in our country. However, the conventional hydraulic jet fracturing technology which is commonly used in plain tubing will encounter many difficulties when drilling some complex wells, such as slim-hole wells, casing deformation wells, casing failure wells and so on. Research on small diameter tubing hydraulic jet fracturing technology is of great significance to the stimulation of the well.Based on the study area small diameter of 060.32 mm tubing hydraulic jet fracturing construction as an example, this paper optimizes the friction calculation formula, and carries on the simulation analysis of the liquid flow pipe and the nozzle by using Fluent software, then obtains the following achievements:(1) The optimization of friction calculation formula is more suitable to the study area of small diameter tubing friction calculation of hydraulic jet fracturing.(2) On the column of fluid in the simulation especially on analysis of coupling fluid flow, it finds that the pressure and velocity at coupling varies violently. The friction there is large and the festival hoop wears uniform.(3) On the nozzle of fluid flow simulation, pressure changes abruptly at the nozzle, which proves that pressure drop sharply.(4) From the site test of hydraulic jet fracturing in small diameter tubing (060.32mm), it shows that pressure is stable and the optimized formula is applicable.The results of this study provide the basis for the calculation of small diameter tubing friction and displacement prediction. |
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