Safety Assessment And Analysis Of Coiled Tubing Hydraulic Jet Fracturing Pipe String

Coiled tubing hydraulic jet fracturing technology is anew and efficient horizontal well reservoir layer modification technology,which is safe,environmental protection,high efficiency,large displacement,low cost.After many years of continuous exploration and development,the technology has made an important breakthrough in the exploitation of oil and gas fields in horizontal wells.However,due to the characteristics of the coiled tubing is easy to be unstable and its rigidity is small,it can be difficult to work in the construction process,can not be entered and the pressure of tube wall is not enough and so on.Therefore,it is needed to analyze the safety problems that may arise in the operation of coiled tubing string,and to establish the safety evaluation process and the method for the mechanical analysis of hydraulic jet fracturing operation pipe string.It has important guiding significance for the promotion and development of the field safety operation of coiled tubing string in our country.In this paper,according to the borehole data of discrete trajectory fitting calculation,it determines the fracturing string in three-dimensional space state wells;Then according to the new type of hydraulic jet fracturing tool string for the four conditions,the specific situation is analyzed and establish the mechanical model of pipe string.Based on the finite element software analysis,the relationship between the pull down pressure and the actual pressure of the tool is analyzed,and the friction force of the pipe string tool string is calculated.According to the maximum tensile condition,friction condition and buckling deformation,the buckling analysis and maximum penetration depth analysis can be drawn and ensured the pipe string tool can get to the right place.Finally,according to the above theoretical analysis,the clearance safety check method and the comprehensive safety factor method,the four kinds ofworking conditions for the safety evaluation system can been established.Based on the mathematical and mechanical models and combined with the safety theory evaluation method,a safety assessment software for hydraulic jet fracturing of coiled tubing was established based on VB language.It realizes the two dimensional and three dimensional picture of the well trajectory and the stress calculation of the four working conditions,and it establishes the change curve of the mechanics index with the well depth.Through the safety evaluation analysis,it is judged whether the pipe string is safe under the condition of operation,and the position of the dangerous point and the buckling instability of the pipe string that are analyzed.Finally through the database to achieve the data storage and export,the follow-up design and construction can be guided.At the same time,according to the specific construction experiment and the construction data,in the preparation of software error analysis and calculation,the accuracy of the software can be ensured.