Dynamic Analysis Of Fish Impact Caused By Different Deformation Casing In Horizontal Wells

In recent years,with the continuous development of oil fields,the casing of oil wells in major oil fields has suffered varying degrees of damage.Due to the complex environment underground,casing damage is difficult to detect in a timely manner.During subsequent construction,drilling tools that are lowered or accidentally fall into the casing may become stuck at the damaged location of the casing,which is commonly referred to as "falling fish".When there are fish stuck in the deformation area,it will affect the progress of casing repair work.Therefore,before repairing the casing,the fish should be removed first.When the stuck point of the fish is located in the horizontal section of the horizontal well,it is difficult for conventional tools to remove the fish.Moreover,as the depth of the stuck point increases and the curvature radius of the wellbore increases,the frictional force between the casing and the fishing tool also increases,and the releasing force on the fish is smaller.Vigorous fishing has a poor releasing effect.Therefore,it is of great significance to conduct dynamic analysis of fish impact caused by different deformation casings in horizontal wells.In order to better implement the work of releasing fish stuck in horizontal wells,this article first derives the impact force and impact time of a certain type of hydraulic jar acting on the fish based on impact dynamics and elastic wave theory.Taking the reduced diameter deformed casing and fish falling as the research objects,considering the initial interference between the casing and the fish falling,the contact nonlinearity and dynamic characteristics between the casing and the fish falling,transient dynamic analysis method is used to establish a fish falling dynamic model and numerical calculation method in the reduced diameter deformed casing in a horizontal well.Impact dynamic analysis is conducted on the fish falling in the reduced diameter deformed casing with diameters of 108 mm,110mm,and112 mm,respectively.The impact forces obtained for the fish to detach from the clamping point are 680.9k N,563.0k N and 416.6k N,respectively.Taking elliptical deformation casing and fish falling as research objects,considering the initial interference between casing and fish falling,the contact nonlinearity and dynamic characteristics between casing and fish falling,transient dynamic analysis method is used to establish a fish falling dynamic model and numerical calculation method in elliptical deformation casing in horizontal wells.Impact dynamic analysis is conducted on fish falling in elliptical deformation casing with diameters of 108 mm,110mm,and 112 mm,respectively,The impact forces obtained for the fish to detach from the clamping point are 67.20 k N,62.70 k N and 55.30 k N,respectively.The research results can provide theoretical guidance for the implementation of seismic unlocking work underground.