Horizontal Well Split-fracture Drillable Bridge Plug Technology Research

At present, with the growth of human resources for oil and gas depletion, and further development of oil and gas field exploration and development, low permeability reservoirs, shale gas, tight oil and unconventional oil and gas will become the mainstream of oil and gas energy in the future. According to statistics,our country has proven reserves of low permeability reservoirs nearly 60 million tons and already spent nearly 3 billion tons, nearly 50% of proven reserves of low permeability which is difficult to adopt due to the low productivity and poor efficiency, so non-conventional layer (above) for fracturing technology needs implementing to reconstruct the reservoirs. Drillable bridge plug layer fracturing technology with such advantages:without restrictions of fracturing stratified layers, simple tool strings, not easy to cause sand-sticking, quick lifting of closure, and smooth wellbore for facilitating the subsequent landing of process tubing strings after drilling and milling bridge plugs, so it is currently used at home and abroad as shale gas and other unconventional oil and gas reservoir. In addition, it has become a main reservoir reconstruction technology and significant yield increase has been achieved. Among them,drilling composite bridge Plug and speed drilling and grinding shoes is the key tool, so packer tools and rapid lifting of reliability and security is a prerequisite to the success of the bridge plug staged fracturing. The production of foreign advanced composite materials is at high-level, and drilling composite bridge plug technology is pretty mature, so they are in a technological monopoly position. Prepared with them, domestic drillable composite bridge plug and speed drilling and grinding shoe research started late, and bridge plug production technology is not yet mature, but to meet the domestic unconventional oil and gas exploration and development, it becomes an urgency to develop autonomous drilling and grinding of the high efficiency and high pressure sealing capability new shoes Super drilling and grinding speed drill composite bridge plug. So the paper work and make such conclusions:Based on the above background, the writer focusing on the specific conditions for Jiaoshi oilfield shale gas well casing, creatively designed a drillable complex bridge plug and shaped cutting edge speed drilling and grinding shoes, and improved the matching of its construction technology.In the design process of the tool, the paper according to the research situation and application of research about composite bridge plug and speed drill grinding shoes at home and abroad. collect and digest a variety of patents and literature related to structural dimensions of composite bridge plugs. At last, the design scheme was set up and the corresponding technology was consummated. By studying the bridge plug, casing, the interaction mechanism of grinding shoes, the writer creatively designed a drilled composite bridge plug with a dual-slip and anti-cones projecting structure. Besides, based on stochastic theory, cutting edge shaped diamond grinding speed shoes were designed. The tool embodies some strengths:apparent preventing sudden failure effect, greatly-enhanced bearing and sealing capability, fast milling lift, and be able to adapt 70-90MPa fracturing well type. Based on SolidWorks, structure design, three-dimensional solid modeling and virtual prototype of tool parts were stimulated to achieve the working principles with reasonable structures.Based on the use of large deformation finite element theory of incompressible rubber test data processing and simulation conducted, the paper focuses on the influence of the various structural parameters of the bridge plug cones on the sealing performance of the sealing system.; a few structural parameters optimum level orthogonal analysis, the maximum contact stress assessment standards, and to determine the relationship between the primary and secondary impact of structural parameters and optimal fit; and cones outburst control structure were optimized, anchoring system established finite element simulation model, tipped kava and milling performance comparison, milling and structural parameters to optimize the design of kava. At the same time, the writer analyzed the cutting mechanics of the cutting speed drilling and grinding shoes, using finite element analysis software to build simulation models and analyzing the model validation of finite elements. Therefore, cutting evaluation index of the cutting teeth is for sure. Besides, the writer explored the cutting depth of the cutting teeth, cutting speed and other cutting efficiency of the cutting teeth influence law, and comparative analysis of three cutters at different cutting depth, and cutting speed cutting. It has certain guiding significance for the drilling parameters.