The Research On Easy Erosion Components Of String And Tools Under Layered Fracturing Technology

Hydraulic fracturing technology is one of the main development means to improv e the low permeability reservoirs and to increase production of oil and gas wells,An d layered fracturing technology can transform hierarchical partial pressure nonuniform,can give full play to each small layer of oil and gas well production capacity,have the low construction cost and good productivity features.but separate layer fracturing operation need downhole string and tools work long hours,especially with the fracturi ng operation displacement and the increasing number of sand content in the liquid,th e erosion of string joint,internal spline and the variable cross-section of tools is mor e and more serious,will cause tool failure,cause the failure of fracturing operation.Therefore,the erosion wear’s research of fracturing string and tools,for prolonging th e service life of the tubing string and tools,and reducing fracturing construction cost has the good economic efficiency and application prospect.In this article to downhole fracturing tools easy to erosion components have class ified three types of erosion structures,base on computational fluid dynamics theory an d the theory of material erosion wear,use the software of flow field simulation CFX,to study the sand mixing liquid’s flow field distribution regularity in the easy erosio n positions,and get the erosion wear rules of mixed fluid to the easy erosion structur es.Variable diameter structures are mainly to study structure diameter decrease,incre ase,and the diameter sudden from big to small and the diameter sudden from small t o big four structures.And the study get conclusions that:The diameter decrease structur e,the smaller the diameter of the structure change ratio and the greater the angle the erosion wear more serious.The diameter increase structure,the smaller the diameter o f the structure change ratio and the smaller the angle the erosion wear more serious;The greater the diameter change ratio of the diameter sudden from big to small struct ure,the more greater the erosion wear.When the diameter change ratio decreased 0.2,the maximum erosion wear rate increase about 10 times in turn,and it is mainly ha ve big effect to large diameter changes structure;The greater the diameter change ratio of the diameter sudden from small to big structure,the more greater the erosion wea r.When the diameter change ratio increased 0.2,the maximum erosion wear rate incr ease about 2 times in turn,and the length of the diameter sudden from small to big structure’s diameter change place to the erosion wear effect is not obvious.The axial k eyway structure study get conclusions that:When the axial key area ratio decrease,the more thickness of the key the bigger the erosion wear,and the bigger of axial key area ratio the smaller erosion effect of the key’s thickness;The erosion rate order of axial key’s angle from big to small is 60°,45°,30°,90°,round,and among them 30°,900°round’s erosion wear are similar.when area ratio is 0.05,the more keys the grea ter the erosion,when area ratio is 0.08,the number does not affect,when area ratio is 0.11,the less keys the greater the erosion.In the study of radial hole structure,whe n the opening area and displacement is same,as a whole,the square hole erosion is smaller than round hole erosion.The erosion wear rules of the above three kinds of structures and the erosion we ar rules obtained from field experiments are consistent,and according to these rules,t o the key components of Daqing oilfield downhole applications of new type sand blo wer structure do structure optimization design and erosion simulation calculation,and these research for layered fracturing provide reliable easy erosion structure and the ba sis of design and construction.