초록 ▼

A surface controlled subsurface safety valve for deep well service. Communication of control fluid to the subsurface safety valve is controlled by a pilot valve at a subsurface location in close proximity to the safety valve. Responsiveness of the subsurface safety valve to decrease in control fluid

A surface controlled subsurface safety valve for deep well service. Communication of control fluid to the subsurface safety valve is controlled by a pilot valve at a subsurface location in close proximity to the safety valve. Responsiveness of the subsurface safety valve to decrease in control fluid pressure is thereby increased and the safety valve\s closure speed is also increased. The pilot valve controllably communicates pressurized control fluid to open the safety valve and allows control fluid to be displaced into the flow path through the safety valve during valve closure.

대표청구항 ▼

A surface controlled subsurface safety valve comprising: a. safety valve housing means with a fluid flow path therethrough; b. valve closure means associated with the safety valve housing means and adapted for movement between a first position opening the flow path and a second position closing the

A surface controlled subsurface safety valve comprising: a. safety valve housing means with a fluid flow path therethrough; b. valve closure means associated with the safety valve housing means and adapted for movement between a first position opening the flow path and a second position closing the flow path; c. control chamber means adapted to receive control fluid from the well surface and to shift the valve closure means from its second position to its first position when the pressure of fluid within the control chamber is greater than a preselected value; d. resilient means for urging the valve closure means to shift from its first position to its second position when the pressure of fluid within the control chamber is less than a preselected value; e. a pilot valve means having a first position allowing communication of control fluid from the well surface to the control chamber when the pressure of control fluid within the pilot valve exceeds a preselected value and blocking fluid communication between the control chamber and the flow path; f. the pilot valve means having a second position blocking communication of control fluid from the well surface with the control chamber and allowing fluid within the control chamber to communicate with the flow path; g. the pilot valve means comprising a first valve means and second valve means; h. the first valve means having a first position blocking fluid communication between the control chamber and the flow path when the valve closure means is in its first position and a second position allowing communication between the control chamber and the flow path; i. means for biasing the first valve means towards its second position allowing communication of fluids between the control chamber and the flow path; j. means for biasing the second valve means towards a position blocking communication of control fluid from the well surface through the pilot valve means to the control chamber; and k. control fluid pressure above a first preselected value shifting the first valve means to its first position and control fluid pressure above a second higher preselected value overcoming the biasing means of the second valve means to allow control fluid communication with the control chamber.