Abstract
Wellbore obstructions are a common dilemma and typically must be removed as they can severely restrict a well’s production capability and have proven to be very costly. For instance, scale formation will eventually result in lower yields and well failure, while a fish left in a well can hamper future wellbore operations.
The thru-tubing well intervention impact hammer was designed to dislodge fish or scale from a wellbore, by delivering an upward or downward impact force. The tool is activated by flow, in combination with compressive or tensile force, depending on the required impact. In operations that require bi-directional forces, both the single-acting up (SAU) and single- acting down (SAD) can be used concurrently on the same bottom-hole assembly (BHA). This paper describes the performance of "fluid activated impact hammers" for fishing operations. Case histories of recent field results are also discussed which illustrate the efficient removal of wellbore obstructions in deviated wells. This enables the well to be put back on production quickly and saves cost.
The impact hammers are utilized in various applications, such as shifting sleeves, shearing pins, breaking disks, assisting with fishing operations and scale removal; in fact, any application where high frequency localized impacts are required. The tool’s impact force can be adjusted to accommodate the specific parameters of an operation. Its maximum capacity is up to 80,000 lb (36,000kg) per impact depending on tool size. The impact hammers enable operators to cost-effectively remove a wireline-retrievable packer (WRP), where conventional wireline techniques have failed and jars had proved impractical. The design allows adjustment of the impact force by manipulating the tension or compression weight on the tool. This maximizes operational efficiency, by enabling the impact hammer to function in numerous situations and the individual up and down hammer components enable the BHA design to accommodate specific jarring direction.
