Evaluation study of nozzle design selection for hydraulic fracturing test on concrete,limestone and andesite with triaxial loading at the laboratory

摘要

Hydraulic fracturing is one of method to determine the in-situ stress,which can be done by analyzing the hydraulic pressure that could create a fracture on the borehole wall. One of the difficulty of the method is the packer system that isolate the interval test which should have design to overcome the pressure as high as the breakdown pressure in the interval test. The new method which conduct the test at the end of borehole, therefore the isolation is needed at one section had been studied at the laboratory. This research used three different nozzles to create various directions of fluid burst, which are vertical spray, horizontal spray (which is equivalent to the spray of packer) and a combination of vertical and horizontal spray.The effect from different types of nozzle to the result of hydraulic fracturing had been studied. This research tested hydraulic fracturing in three types of samples, which are concrete, limestone and andesite. The dimensions of those samples are (25× 25× 25) cm and cubical. Those samples were being subjected to triaxial loading during the hydraulic fracturing tests. Results showed that the most efficient type of nozzle that could initiate fracture in all of those samples is the nozzle that bursts a combination of vertical and horizontal spray.