Method and Apparatus to Isolate Well Pressure While Connecting Tubing to Tubing - Telescopic Threaded Type
Publication Date: 2015-Jul-16
The IP.com Prior Art Database
This paper describes a new apparatus and method for connecting two different types of work strings, in particular Jointed Tubing and Coiled tubing. The advantages of the method of using combined strings of Jointed Tubing and Coiled Tubing in the process of stimulating long horizontal oil wells are well known in the industry. The method is facilitated by a special Safety Valve installed between the two types of work strings. This valve protects personnel from well pressure while making up or braking down the connection between the two work strings.
The two basic components of this Safety Valve assembly are a Flapper Valve, and a Sliding Sleeve. The apparatus is operated by manipulating the Sliding Sleeve in two positions: (1) Sliding Valve retracted, allowing the Flapper Valve to check/stop any incoming fluid from the well formation; (2) Sliding Valve extended, holding the Flapper open and at the same time protecting it from erosion of the pumped fluid which is mixed with sand. The current equipment involves actuating this Safety Valve with hydraulic pressure either with a hand pump at the surface, or by placing the Safety Valve between two Blow Out Preventers (BOPs).
Description of the proposed improved design
The designed proposed in this paper is a telescopic threaded actuation type. The Figure 1 below is mostly self-explanatory. The Flapper is open/closed by simply rotating the Sleeve. A Lock Nut locks the valve in open/closed position. The extended or shorter length of the tool is a positive visual indication whether the Flapper is open or closed.
Figure 1. Curent and proposed design of Safety Valve
The proposed design is an alternative to the design used currently, with the following advantages:
- No hydraulic pump needed on location.
- Faster actuation
- Fewer seals.
- Potentially shorter overall length.
- Positive locking in open/close position and positive visual determination whether the valve is open/closed.