Application

UYa jar intensifier is used in conjunction with hydraulic jar to maximize impact forces during stuck-related remediation.The jar intensifier enchances impact force and reduces strain on fishing string, especially when operating in shallow and extended-reach wells.

Design

The jar intensifier consists of a body, a mandrel, a sub and a set of sealing elements. The mandrel is thread connected to the sub, having a box tool joint, on the upper end and washpipe on the lower end. Chevron packing is installed between mandrel shoulder and washpipe.The body consists of four parts that are thread interconnected. The mandrel has splined section engaged with matching splines in the upper part of the body. This allows torque to be transmitted through the tool. Lower part of the body ends with a pin thread. 
Inner chamber of the jar intensifier is filled with special silicon fluid of high compressibility index. All connections are packed off with seal rings. The jar intensifier is filled with fluids through ports, covered with threaded plugs. The jar intensifier is made up on the fishing string immediately above the drill collars, while hydraulic jar is installed immediately below the drill collars. Initially, the jar intensifier is closed (with interacting ends of the sub and body 2 brought together). As a strain is pulled on the string to actuate the jar, mandrel travels upward and stores energy by compressing silicone fluid. The jar intensifier acts as hydraulic fluid spring. When hydraulic jar trips, the strain acting on the jar intensifier and the string above the hydraulic jar drops down for a short period of time, while body of the jar intensifier, under force of compressed fluid, travels upwards, delivering additional upward impulse to the drill collars. The impulse is delivered to the stuck point through hydraulic jar.

Benefits

• provides means to store the required energy immediately above the jar and drill collars to effectively offset the loss of stretch in or drag on the running string;
• accelerates the drill collars and jar until a blow of high impact is stuck;
• cushion the shock of the running string as it rebounds after each jarring stroke, reducing shock-damage to the tool and running string to minimum;
• functions as a hydraulic fluid spring the tool and allows to get by without employment of excessive number of drill collars in specific case than would otherwise be possible, i.e. at shallow operating depth.