Abstract: A risk assessment-based design method for a deep complex formation wellbore structure includes: (1) preliminarily determining casing layers and setting depths; (2) calculating to obtain the risk coefficients of each layer of casing; (3) analyzing and coordinating, according to the principle that a shallow casing shares more risks and a deep casing shares less risks, the risks of each layer of casing: determining whether the risk coefficients of each layer of casing are greater than a safety threshold value K; checking the setting depth: if the safety coefficient of an ith-layer casing satisfies RNi>K, selecting a casing layer with the minimum safety coefficient from upper casing layers, and deepening the setting depth h of the casing layer; and (4) repeating the steps (2) to (3) until the casing risk coefficients of each layer of casing are less than the safety threshold value K.

Abstract: A risk assessment-based design method for a deep complex formation wellbore structure includes: (1) preliminarily determining casing layers and setting depths; (2) calculating to obtain the risk coefficients of each layer of casing; (3) analyzing and coordinating, according to the principle that a shallow casing shares more risks and a deep casing shares less risks, the risks of each layer of casing: determining whether the risk coefficients of each layer of casing are greater than a safety threshold value K; checking the setting depth: if the safety coefficient of an ith-layer casing satisfies RNi>K, selecting a casing layer with the minimum safety coefficient from upper casing layers, and deepening the setting depth h of the casing layer; and (4) repeating the steps (2) to (3) until the casing risk coefficients of each layer of casing are less than the safety threshold value K.

Abstract: The present invention discloses a drilling speed improvement device capable of producing both hydraulic pulse and impact vibration. The device has a pressure transfer rod that is arranged at an upper end of a lower joint. A spring chamber is formed among a drill body, the pressure transfer rod and the lower joint. A spring is arranged in the spring chamber. A communicating hole is formed in the drill body. A piston is arranged at an upper end of the pressure transfer rod. A pressure bearing head is arranged at an upper end of the piston. A pressure bearing base is arranged on the inner side of an upper joint. Drill bit impact loads and drilling fluid pulse jets are modulated by the longitudinal vibration energy of a drill stem, the rock breaking efficiency of a drill bit is improved by both dynamic and static loads, and harm caused by vibration of the drill stem is reduced.

Abstract: The present invention discloses a drilling speed improvement device capable of producing both hydraulic pulse and impact vibration. The device has a pressure transfer rod that is arranged at an upper end of a lower joint. A spring chamber is formed among a drill body, the pressure transfer rod and the lower joint. A spring is arranged in the spring chamber. A communicating hole is formed in the drill body. A piston is arranged at an upper end of the pressure transfer rod. A pressure bearing head is arranged at an upper end of the piston. A pressure bearing base is arranged on the inner side of an upper joint. Drill bit impact loads and drilling fluid pulse jets are modulated by the longitudinal vibration energy of a drill stem, the rock breaking efficiency of a drill bit is improved by both dynamic and static loads, and harm caused by vibration of the drill stem is reduced.