TY - THES

T1 - Antibuckling System in Sucker Rod Pumps

AU - Langbauer, Clemens

N1 - embargoed until null

PY - 2011

Y1 - 2011

N2 - About 85% of all artificially produced oil is lifted with sucker rod pumps. Sucker rod pumps are used to lift oil from almost depleted reservoirs, which means if the production with these pumps is uneconomic, often the well will be shut in and no further recovery is achieved. To increase the economic life time of an oil reservoir it is necessary to reduce the required number of maintenances and cost. An essential restriction for sucker rod pumps is buckling, which reduces the volumetric efficiency, increases erosion and initiates corrosion. This master thesis deals with analyzing the dynamic behavior of the sucker rod string, which is crucial in all investigations of the buckling behavior of the sucker rod string. An extensive literature study shows that the viscous damped wave equation, introduced by GIBBS in 1966, and its modifications are still generally used in the analysis of the dynamic behavior of the sucker rod string. Therefore a diagnostic model, applying the analytical solution of this equation, is programed in MATLAB to use the measured surface data and calculate the corresponding pump information. The influence of the damping coefficient and the selected number of Fourier Coefficients is visualized and additionally optimized to match best with measured pump data. The main task of this MATLAB program is to analyze the dynamic behavior within the critical sections of the sucker rod string and to apply a buckling criterion to investigate whether buckling occurs or not. Different measures to prevent buckling are presented and simulated with MATLAB. The output shows that a proper combination of sinker bars and a tensioning element with an intelligent selection of the overall sucker rod segments efficiently prevents buckling. Furthermore it is shown that the weight of the final designed rod string, including buckling prevention measures, can be less than the original composition, suffering under buckling.

AB - About 85% of all artificially produced oil is lifted with sucker rod pumps. Sucker rod pumps are used to lift oil from almost depleted reservoirs, which means if the production with these pumps is uneconomic, often the well will be shut in and no further recovery is achieved. To increase the economic life time of an oil reservoir it is necessary to reduce the required number of maintenances and cost. An essential restriction for sucker rod pumps is buckling, which reduces the volumetric efficiency, increases erosion and initiates corrosion. This master thesis deals with analyzing the dynamic behavior of the sucker rod string, which is crucial in all investigations of the buckling behavior of the sucker rod string. An extensive literature study shows that the viscous damped wave equation, introduced by GIBBS in 1966, and its modifications are still generally used in the analysis of the dynamic behavior of the sucker rod string. Therefore a diagnostic model, applying the analytical solution of this equation, is programed in MATLAB to use the measured surface data and calculate the corresponding pump information. The influence of the damping coefficient and the selected number of Fourier Coefficients is visualized and additionally optimized to match best with measured pump data. The main task of this MATLAB program is to analyze the dynamic behavior within the critical sections of the sucker rod string and to apply a buckling criterion to investigate whether buckling occurs or not. Different measures to prevent buckling are presented and simulated with MATLAB. The output shows that a proper combination of sinker bars and a tensioning element with an intelligent selection of the overall sucker rod segments efficiently prevents buckling. Furthermore it is shown that the weight of the final designed rod string, including buckling prevention measures, can be less than the original composition, suffering under buckling.

KW - sucker rod pump

KW - buckling

KW - antibuckling

KW - rod string analysis

KW - Pumpgestänge

KW - knicken

KW - Knickverhalten

KW - Pferdekopfpumpen

M3 - Master's Thesis

ER -