Geological Factors Analysis Of Casing Damage In Shengtuo Oilfield

Shengtuo Oilfield is a complex fault zone which is consist of manyoilyieldingstratum. Oilfield put into developed in 1964 and the firstdamaged casing well appeared in 1972. By august of 2005, the totaldamaged casing wells are 1316. Statistical analysis Shengtuo Oilfieldcasing damage main type and well type, casing easily damage layerlithology, depth of burial, depth of stratum. Each block well casingservice life and different development phase casing failure. Employrelevant geology materials, from two respects of lithologic character andfault to study the casing damage. The lithological aspect includes: findout the distribution of mud stone in threedimension,content, thicknessand burying depth, mudstone meet water creeping, the pore structuralchange of reservoir, mollification surface of mudstone and interlayer. Thefault aspect includes: the distribution rule of casing damage in plain, thecasing damage rule of different fault level, the relationship between faultand angle of bedding. Combine with the geological material, to calculatethe threedimention,nonlinearelastoplasticity stress and strainsimulation of casing in plastic stratum (mud stone stratum). According to ANSYS software, quantitative simulate the stress field and displacementfield change of the plastic (mud stone) stratum and inquire the mechanismof casing damage in plastic (mud stone) stratum. Through statisticalanalysis as well as quantitative simulation, known mudstone meet watercreeping, mollification surface of mudstone and interlayer, fault and angleof bedding increase formative asymmetry load are Shengtuo Oilfieldcasing damage major factors. Combine with the reservoir character ofShengtuo Oilfield, we put forward some advises and offer some offerencefor the casing damage ptotection and prevention.