Evaluation For Down-hole Casings During Well Completion And Its Application

Well Completion is an important process of petroleum exploration and exploitation. The casing load condition during well completion is more serious than during drilling. Moreover stratum in exploratory well is indeterminacy, so the risk of the casing in completion well of exploration is increased. For that reason according to the casing combination and operation characteristics of deep well with high temperature and pressure and in view of weakness point which is concerned with well completion and hidden troubles in safety which may come forth, the remained strength of casing of completion well and the load and security during well completion are analyzed in this text, which can be used to direct the design and construction of well completion.The main works made are:(1) analysis of worn thickness and the remained strength of worn casing.(2) Analysis of mechanics characteristics of perforated casing.(3) Analysis of loads and safety of casings during well Completion.(4) Analysis of loads and stresses of casing under non-uniform stresses.(5) Analysis of loads and heat compounding of worn casing in the well with high temperature and high pressure.Works made in this paper may be the base for theoretical and technical supports for safety analysis of casing in completion well. Accordingly the analysis and calculation was made to direct safety analysis of casing of completion well of Longgang, Dina, Dabei which have high temperature and high pressure, thus the safety of operating and casing during well completion in extreme difficult plots above has been guaranteed.