| The fish-bone spur well is a method of hydrostatic rock breaking,using small diameter drill pipe to spray water to break rock,and realize orientation,fixed point and fixed length perforation.It is a high-performance and precise connection completion production technology for oil and gas reservoirs.Turning the stimulation into a part of the drilling operation,forming multiple branches in the reservoir,increasing the exposed area of the reservoir,without the need for casing,cementing,fracturing,etc.,is a kind of fracturing and natural production.Due to the large number of branches drilled at one time,how to improve the efficiency of jet rock breaking and the optimization of hydraulic parameters has become an important research topic.Firstly,based on the theoretical analysis of the characteristics of the jet structure,the drilling of the fish-bone spur well by the rotary jet rock breaking method is determined,and the rock breaking mechanism and process of the rotating jet are simulated.The results show that the maximum velocity of the flow field of the rotating jet is not at the axis,but at a certain annular position from the axis,the jet is obviously diffused,which makes the rock-breaking area enlarge and form a tapered hole,which has high rock breaking efficiency.And its diffusion angle,spray distance and jet velocity have a significant impact on the rock fragmentation area and rock breaking efficiency.Secondly,through the indoor rock breaking experiment,the structural parameters of the impeller,the impeller outlet angle,the blade length,the blade geometry,the inlet diameter,the outlet diameter and the diffusion angle,and the influence of the nozzle structure parameters on the jet structure characteristics and rock breaking effect were studied.Based on the comprehensive rock-breaking pore size and rock-breaking depth,the N11 B hydraulic drill with the best rock-breaking effect is determined as the optimal structure under the experimental conditions.According to the preferred hydraulic drill,the rock drop test,the abrasive type,the abrasive particle size,and the abrasive volume fraction are respectively considered for the rock breaking experiment,and the hydraulic parameters are preferred.At last,comprehensive rock breaking experiments were carried out through rocks of different lithologies(solid cement stone,diabase,granite and coarse sandstone),which provided a basis for further optimization of hydraulic parameters.Finally,based on the structure and drilling requirements of the fish-bone spur well,based on the rock breaking experiment in the hydraulic drill bit,the rock breaking speed is taken as the objective function,and the whole flow pressure consumption of the fish-bone spur well is considered comprehensively,and a set of fish bone spurs is designed.The calculation method of well hydraulic parameters,and the corresponding design software was compiled.In this paper,the combination of numerical simulation and experimental research is designed to design a rotating jet hydraulic rock-breaking drill bit,and through the indoor rock breaking experiment,the structural parameters of the hydraulic drill bit are optimized,combined with the ground pump pressure and displacement,and the fish-bone spur well.In actual situation,the hydraulic parameter calculation model was designed.The hydraulic parameter program of the fish bone spur well was compiled to provide technical support for the construction of the fish bone prick well. |
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