A method of dislodging a tubular string or well equipment connected to the tubular string can include connecting a dislodging tool in the tubular string, so that a flow passage of the dislodging tool extends through the tubular string, deploying a plug into the dislodging tool, applying a pressure differential across the plug, thereby displacing the plug through a seat of the dislodging tool, and dislodging the tubular string or the component in response to the displacing. A dislodging system can include a dislodging tool connected as part of a tubular string, the dislodging tool including a flow passage and a seat configured to sealingly engage a plug deployed into the tubular string, and at least one of a jarring force, load, impact, shock wave, elastic strain release and pressure pulse being generated in the tubular string in response to displacement of the plug through the seat.

A release device for a jarring tool includes a collet positioned between the mandrel of the jarring tool and a trigger sleeve. At least one end of the collet is in contact with a precompressed spring via a bushing. In order for the jarring tool to operate, a force greater than the precompressed force of the spring must be applied to the mandrel so that the collet can move in axial direction against the spring thereby releasing the mandrel.

A release device for a jarring tool includes a collet positioned between the mandrel of the jarring tool and a trigger sleeve. At least one end of the collet is in contact with a precompressed spring via a bushing. In order for the jarring tool to operate, a force greater than the precompressed force of the spring must be applied to the mandrel so that the collet can move in axial direction against the spring thereby releasing the mandrel.

A horizontal drilling machine with an in-situ detection device, including a support frame, an armored cable, a steel pipe-straightening mechanism, a steel pipe-feeding mechanism, a motor, a power head, a drill pipe, a rotating chuck, a damper, a non-core drilling tool, the in-situ detection device, a fishing device and a thrust cylinder. The steel pipe-straightening mechanism, the steel pipe-feeding mechanism, the rotating chuck and the damper are sequentially fixed on the support frame from left to right. One end of the thrust cylinder is hinged with the support frame, and the other end is connected to the power head. The active drill pipe of the power head is connected to the drill pipe. An end of the armored cable is connected to the fishing device in the drill pipe, and the fishing head of the fishing device is connected to the spearhead of the non-core drilling tool.

A smart jarring system for freeing stuck equipment downhole is disclosed. The smart jarring system comprises a set of jars, at least one laser source and at least one laser receiver that corresponds to the at least one laser source. The laser receiver intercepts a laser beam that is emitted from the laser source. This interception helps determine when the set of jars fired and in which direction the set of jars fired. The smart jarring system further comprises one or more sensors selected from the group consisting of vibration sensors, temperature sensors, and torque/tensile sensors. These sensors are configured to diagnose downhole conditions and help free the stuck equipment downhole.

A smart jarring system for freeing stuck equipment downhole is disclosed. The smart jarring system comprises a set of jars, at least one laser source and at least one laser receiver that corresponds to the at least one laser source. The laser receiver intercepts a laser beam that is emitted from the laser source. This interception helps determine when the set of jars fired and in which direction the set of jars fired. The smart jarring system further comprises one or more sensors selected from the group consisting of vibration sensors, temperature sensors, and torque/tensile sensors. These sensors are configured to diagnose downhole conditions and help free the stuck equipment downhole.

A jar assembly for use downhole includes a housing, a piston assembly slidable within and selectively coupled to the housing, a mandrel assembly coupled on a lower end of the piston assembly, and an anvil coupled to an end of the mandrel assembly opposite the piston assembly. The jar assembly is deployed in a wellbore by a conveyance means that couples with the housing. A hydraulic circuit in the piston assembly activates a latch for decoupling the piston assembly from the housing; when decoupled, the housing slides downward and impacts the anvil to generate a jarring force. The jar assembly is re-cocked by raising it with the conveyance means.

A jar assembly for use downhole includes a housing, a piston assembly slidable within and selectively coupled to the housing, a mandrel assembly coupled on a lower end of the piston assembly, and an anvil coupled to an end of the mandrel assembly opposite the piston assembly. The jar assembly is deployed in a wellbore by a conveyance means that couples with the housing. A hydraulic circuit in the piston assembly activates a latch for decoupling the piston assembly from the housing; when decoupled, the housing slides downward and impacts the anvil to generate a jarring force. The jar assembly is re-cocked by raising it with the conveyance means.

A jar includes the following: a mandrel; an outer housing slidably disposed about the mandrel; a low pressure chamber having a first port and formed between the mandrel and the outer housing; a high pressure chamber having a second port and formed between the mandrel and the outer housing; a fluid passage between the first and second port; and a valve disposed in the fluid passage.

A jar includes the following: a mandrel; an outer housing slidably disposed about the mandrel; a low pressure chamber having a first port and formed between the mandrel and the outer housing; a high pressure chamber having a second port and formed between the mandrel and the outer housing; a fluid passage between the first and second port; and a valve disposed in the fluid passage.