Establishing communication between the wellbore and hydrocarbon-bearing formations is critical to ensure optimal production. Laser is a new technology that utilizes the power of light to perforate rocks. The technology is non-damaging, safe (non-explosive), and affords precise control over the perforation's geometry (size and shape). The process creates an enhanced tunnel that improves the flow and increases production. The technology has been successfully demonstrated in the lab environment. The results are used to develop a field deployment strategy. In the field, the laser source will be mounted on a coiled tubing unit on the surface and transmitted downhole via optical fibers. Downhole, the beam is out-coupled and directed to the target using an optical bottom hole assembly (oBHA). This tool combines optical and mechanical components to control the beam and produce multipole shots per foot as needed to create the desired perforation network. High-power laser perforation is the next new intelligent perforation generation that will change current well perforation.
Laser-rock interaction drives in the transformation of electromagnetic energy into thermal energy. This results in a highly localized and controllable temperature surge that can melt or vaporize the rocks. These properties make the technology a unique alternative to current perforation techniques based on shaped charge guns. The thermal process induced by the laser enhances the flow properties of the rock, especially in tight formations. Laser perforation has been tested on all types for rocks including unconventional tight sands. This has been proven through extensive pre- and post-perforation characterization over the last two decades.
This work presents the development and evolution of the high-power laser tools for subsurface applications. These tools provide innovative and non-damaging alternatives to current downhole technologies. In the lab, the laser technology has been proven to improve the flow properties; thus, it can improve communication between the wellbore and formation. To achieve this efficiently in the field, it is necessary to develop different tool designs and configurations, manufacture prototypes, conduct extensive tests, and optimize each part before upscale for field operations.
The laser source is mounted in a coil tubing rig at the surface; the coil contains the optical fiber cable used to convey the energy to the downhole tool. The tool combines mechanical and optical components to transform, control, and direct the laser beam. The design and configuration of each tool assembly varies depending on the targeted application. For example, the perforation tool converts and splits the beam into several horizontal beams; whereas the drilling tool emits a straight beam with controlled size for deeper penetration. They also incorporate purging capabilities to circulate fluids to clean the hole from the debris and carry the cuttings. The entire assembly must be made to fit in slim holes as small as four inches. And finally, ruggedized to operate in a complex environment with high pressure and temperature.
The technology improves reach and provides versatility in a compact and environmentally friendly manner. For example, it is a waterless technology when it is used for fracturing, and a non-explosive based perforation when it is used to perforate. The unique features of the technology enable a precise, controlled, and oriented delivery of energy in any direction, regardless of the reservoir stress orientation and magnitude. Thus, it enhances reach to produce from pay zones that are bypassed by current conventional technologies and practice. The motivations to search alternative technologies are the advancement of technologies, including high power lasers, and the need to enhance several applications in deeper wells in an environmentally friendly manner.