Handheld scanner helps increase life of hydraulic fracturing tools
October 23, 2010
By Mary Del
A major manufacturer of hydraulic fracturing tools for the oil and gas industry is using NVision’s handheld laser scanner to increase the performance and life of its products by gaining a clearer picture of erosion patterns. The company previously used ultrasonic sensors to measure discrete points in a gridded pattern after erosion testing with proppant. The handheld scanner provides a much clearer understanding of erosion patterns by measuring millions of points and providing a comparison of the geometry before and after testing with colour deviation models showing the amount of material that has been eroded in each area of the tool. This information helps engineers gain an intuitive understanding of tool performance, which in turn helps improve design and substantially increase tool life.
Hydraulic fracturing involves pumping a fracturing fluid into a well bore at a high enough level of pressure to cause the formation to crack, enhancing the flow of oil and gas from the formation to the well. A slurry material called proppant, which commonly consists primarily of sand or ceramic material, is then injected into the fracture to prop it open, thereby increasing the flow of formation fluids. However, the proppant is highly abrasive and erodes the casing and tools. After they have eroded to a certain point, the equipment needs to be replaced, which is expensive in terms of labour and tool cost, and it also delays the completion process.
The tool manufacturer ran tests of different tool geometries and materials in an effort to extend tool life. Typically, these tests involve pumping large volumes of proppant through the tool and measuring the resulting wear. Normally these measurements are performed with an ultrasonic scanner that determines the thickness at each point where a measurement is taken. The problem with this approach is that it’s impossible to measure enough points to get a complete picture of the tool’s geometry. Engineers working on the tool design know in which areas the erosion has occurred, but lacking knowledge of the complete geometry makes it difficult to fully understand the erosion patterns.
After some investigation, the manufacturer decided to perform the erosion measurements with the NVision HandHeld Scanner. The scanner is mounted on a mechanical arm so it can move freely around tools of any size. The mechanical arm keeps track of the scanner’s location so all data is collected within the same co-ordinate system. As technicians inspect the tool, the scanner generates a point cloud consisting of millions of points, each with x,y,z co-ordinates and i,j,k vectors. The laser scanner also provides accuracy to a few thousandths of an inch. Integrated software that comes with the scanner is used to convert the point cloud to an STL polygon mesh. Reverse engineering software then converts the STL data to a surface model. At different phases during the process, the surface models are compared to the original model, illustrating erosion and wear patterns of the tool.
The accuracy of the HandHeld Scanner and the ability to visualize the wear caused by the proppant has helped the manufacturer improve both the geometry and the materials of its tools. As a result, the manufacturer has implemented the design changes necessary to significantly increase the performance and life of its hydraulic fracturing tools.