Study On Coiled Tubing Annular Sand Fracturing Technology In The CBM Wells

The conventional hydraulic fracturing plays important roles in CBM application,Fracture proppant injection use more abrasive filling the annulus to avoid severe downhole tool wear.Limited to the performance of coiled tubing,ordinary tubing is mostly used to the annulus construction.In recent years,with continuous improvements of production,material,yield strength,other properties and increasingly wide range of applications in coiled tubing,which provides the premise that using coiled tubing fracturing in coalbed methane applications annulus sand fracturing process implementation.The coiled tubing is applied to the coal seam gas pressure fracturing,and under the condition of the hydraulic fracturing of coiled tubing,the fracturing operation is carried out by means of annular sand.The fracturing technology combines the advantages of the decentralization of the coiled tubing positioning column rapid construction,thin coal seam,annulus sand jet tool wear,avoid the advantages of large displacement construction operations to shorten the construction time etc.Coiled tubing annulus sand fracturing technology has a very broad application prospects in CBM application.According to conventional hydraulic fracturing,coalbed methane technology combines coiled tubing fracturing techniques with annulus sand fracturing process,carrying out on the process design.Tools for application process were designed,including fracturing string design,selecting a range of supporting tools and down hole tools structural design.Next,calculating the maximum depth of the coiled tubing into the coal seam,calculating the relationship between nozzle pressure and displacement,different fracturing fluid from the wellhead to the bottom of the pressure loss in coiled tubing and annulus fracturing fluid injection for the ground displacement and ground pressure providing the basis to determine.Then,using Fluent software to simulate the erosion situation annulus sand fracturing process on the outer wall of the inner coiled tubing caused and made a reasonable proposal.Finally,for the problems of thin coal seam of coiled tubing pinpoint,analysing problems existing in the existing positioner,improving the mechanical casing connection collar locator structure.ADAMS software is used to simulate the dynamic simulation of the positioning device,analysing the different positioning block angle,lower speed,different spring stiffness and other conditions to influence the positioning accuracy,to ensure continuous tubing to realize the accurate positioning of underground status to reference.