Research On Solid-liquid Two Phase Flow Mechanisms And Application Technology Of Fracturing String In Horizontal Well

The horizontal well fracturing operation capacity and fracturing sand quantity increased with the oilfield deep development.Many problems such as the Bybass Crossover Sub(BCS)lopsided wear,the oil tubing broken,sand-up trouble which directly led to the fracturing string can't be fit for multistage fracturing operation or operation failure and waste the raw materials.The horizontal well multistage fracturing has become a "bottleneck" technical difficulty to restrict the horizontal well development and widespread application.Based on solid-liquid two phase flow characteristics in horizontal well fracturing string,the fracturing fluid adopts Euler's method,the haydite adopts Lagrange's method,considering the haydite's turbulence effect,the haydite relative fracturing fluid coupling effect set up the solid-liquid two phase flow mathematical mode inl horizontal well fracturing string.The wear and tear abrasion experiment with the horizontal well fracturing string material has been done by different angles,different sand ratio and rotational speed combined with the experimental data and determine the empirical constant to establish the scour wear model for this study.The established solid-liquid two phase flow model and the scour wear model have used to research the solid-liquid two phase flow and scour wear regularity in the horizontal well fracturing string,respectively simulate the normal fracturing operation situation,the structure of eccentric situation and perforated interval non-uniform flow condition to analyze the string damage reason.Using LDA test results and fracturing tools' scour wear visual testing after operation validate the inflow field velocity distribution to be accord with the fluid model is verified reliability.In horizontal well fracturing string pitch is apart from the law of grit in numerical simulation of analysis the liquid viscosity,particle diameter and flow rate affects the sand debris quantity to educe sand debris regularity in the different pitch to provide theoretical guidance for the fracturing operation.According to serious BCS lopsided wear structure,combining with the field abrasion operation develop the structure improvement scheme forward as three-way BCS,oblique section BCS and 10 hole diverting BCS.These different types of BCS used to numerically simulate,according to the result of simulation to be parameter optimization.The three-way BCS's flow uniformity and wear rate has a certain degree improvement with one eccentric hole and two eccentric holes,but in the structure of eccentric cases,the three-way BCS may be has the problem of the inner housing wear intensity within the two holes.The oblique section BCS inhibit the vortex near the plug position,flow pattern is improved obviously.The 10 holes diverting BCS is a good fluid diversion,but the through hole inside wall is wear more serious.The oblique section BCS and the 10 hole diverting BCS are assemblage which can have very good inhibitory vortex flow and fluid diversion effect,effectively improve the BCS wear resistance.This paper provides the effective methods to the two-phase flow pattern in horizontal well fracturing string and wear rule,concluded that the wear rules and sand sediment rules,provide effective theory basis to optimize the horizontal well fracturing string design and operation design.The technology of optimization can extended the service life of tools,improve the success rate of fracturing operation.Therefore,this paper's research increases the horizontal multistage fracturing operation technical maturity,provide technical means to expand the horizontal well fracturing scope of application,provide technical support for the maturing field stable production,the new oil field highly effective development and increasing ultimate recovery ratio.