Oil casing drilling is a new oil and gas drilling method, which is of great practical significance to the efficient development of oil and gas fields. Surface driven casing drilling, no matter top driven or rotary driven, must transfer torque by rotating downhole casing string to achieve rock breaking drilling.
Therefore, in casing drilling, casing string as a drilling string will be subjected to tensile, pressure, bending, torsion, vibration and other loads, according to the casing wear law, combined with API5C5 physical test size requirements, through finite element calculation and analysis method, The ultimate residual compressive strength and ultimate residual tensile strength of casing with outer surface wear defects after drilling are studied, uniform wear conditions and eccentric wear conditions of casing are obtained respectively, and the critical length of casing casing with outer surface wear defects during casing drilling is given, as well as the formulas for calculating the residual compressive strength and residual tensile strength of casing string under different failure criteria are given. It lays a theoretical foundation for designing and calculating casing string of casing drilling. The factors influencing the extrusion strength of TP130TT152.4mm 16.90mm new casing have important guiding significance for the correct selection of this kind of casing.
The influence of wall thickness inhomogeneity, ellipticity and non-uniform load on casing extrusion strength is calculated and analyzed by finite element method. The calculation results show that the casing still has high extrusion resistance under the action of non-uniform external extrusion load. Under the action of hydrostatic pressure, the compressive strength of the casing decreases with the increase of wall thickness non-uniformity and ellipticity.
The damage of oil casing is mainly concentrated in salt formation. Due to the limitation of process conditions and product conditions, the salt section oil casing is basically remelted, and the average service life is only about 5 years. The casing wear of ultra-deep well is an important engineering problem that needs to be solved urgently in the exploration and development of oil and gas resources in western China. The following are two important casing wear prediction methods, which identify the main development direction of casing wear research in deep and ultra-deep Wells.
- The alloy electrode has good activation performance and can reach large discharge capacity after 1 to 4 charge and discharge cycles. The large discharge capacity of the alloy electrode, Cmax, is increased to 399.2mA h/gx = 0, and is replaced by Al. With the increase, the hydrogen absorption and desorption platform pressure of the alloy electrode decreases, and the hydrogen absorption lag increases. At the same time, annealing treatment can significantly improve the cycle stability of the oil sleeve alloy electrode. After 60 charge and discharge cycles, the capacity retention rate of the alloy electrode (the maximum value of S60 is 76.7% x = 0.1).
- Using DC magnetron sputtering ion plating technology, the oil film was crystallized under metal induction to prepare aluminum-silicon and nickel-silicon films. The samples were annealed at different temperatures by vacuum annealing furnace and X-ray diffractometer, and the phase structure of the annealed films was analyzed. The results show that the crystallization effect of L induced silicon films is good, followed by that of copper and nickel induced silicon films is poor. At 400℃, the crystallization effect of L-induced silicon film is good, and the average grain size of silicon increases with the increase of annealing temperature. The greater the internal stress of copper-silicon thin film, the more obvious the formation of silicon thin film.
