TECHNICAL FIELD

Disclosed are apparatus and methods for perforation. More specifically, embodiments related to apparatus and methods that incorporate lasers and shaped charges for perforation of reservoirs are provided.

BACKGROUND

Shaped charges are used to create perforates in wellbores. Current shaped charges have several limitations including control over the depth, orientation, geometry and shape of the tunnel. Such limitations are due to, in part, to when the reservoir stress overcomes the power of the shaped charges, effecting the perforated tunnel.

High power laser technology is a thermal based process where the high temperatures can melt, spall, or vaporize formation rocks, and at lower temperatures can weaken the formation. Laser technology has attracted the oil and gas industry for several years due to the unique properties of the lasers such as precision, reliability, control and cost. The advantage of the laser is that it penetrates all types of formations regardless of the hardness and stress orientation. Laser technology has several advantages including the ability to drill in different types of rock, drill different hole sizes, be precise in orienting the beam to create the hole, and it is stress and structure independent.

High power laser technology has the potential to be an alternative to current conventional shaped charge perforation guns, however, there is a challenge in delivering the energy from the surface to the target location. If the energy transport is via fiber optics there is more than 60% power loss such that the energy delivered to the target is low and will not be sufficient to create a large perforating tunnel.

SUMMARY

Disclosed are apparatus and methods for perforation. More specifically, embodiments related to apparatus and methods that incorporate lasers and shaped charges for perforation of reservoirs are provided.

In a first aspect, a method of using a hybrid tool to perforate a formation is provided. The method includes the steps of deploying a hybrid tool into a wellbore positioned in a formation, where the hybrid tool includes a swivel laser head and a shaped charge, activating a laser beam from the swivel laser head of the hybrid tool, drilling a tunnel with the laser beam such that the tunnel extends from the wellbore to a first point, where the laser beam operates at a drilling power between 2 kW and 6 kW, reducing a power of the laser beam at the first point to a heating power, where the heating power is less than the power to melt the formation, operating the laser beam at the heating power to increase the temperature at the first point such that a first spherical heat zone expands from the first point, increasing the power of the laser to the drilling power, drilling a second span of tunnel extending from the first point to a second point, reducing the power of the laser beam to the heating power, operating the laser beam at the heating power to increase the temperature at the second point such that a second spherical heat zone expands from the second point, where a volume of the second spherical heat zone is less than a volume of the first spherical heat zone, where the tunnel, first spherical heat zone, and second spherical heat zone form a thermal gradient, ceasing operating of the laser beam, and detonating the shaped charged aligned with a targeted perforation path with detonating cord, where the thermal gradient compensates for a stress orientation of a reservoir stress in the formation to produce a perforation that aligns with the targeted perforation path.

In certain aspects, the method further includes the steps of increasing the power of the laser to the drilling power, drilling a third span of tunnel extending from the second point to a third point, reducing the power of the laser beam to the heating power, and operating the laser beam at the heating power to increase the temperature at the third point such that a third spherical heat zone expands from the third point, where a volume of the third spherical heat zone is less than the volume of the second spherical heat zone, such that the thermal gradient further includes the third spherical heat zone. In certain aspects, the swivel laser head is below the shaped charge. In certain aspects, the swivel laser head is above the shaped charge. In certain aspects, the stress orientation is toward the surface. In certain aspects, the stress orientation is away from the surface. In certain aspects, the stress orientation is perpendicular to the hybrid tool. In certain aspects, the stress orientation is parallel to the hybrid tool. In certain aspects, the method further includes the step of determining the stress orientation from log data of the formation. In certain aspects, the method further includes the step of determining the targeted perforation path from log data of the formation.

In a second aspect, a hybrid tool for perforating a formation includes a swivel laser head configured to emit a laser beam, a shaped charge configured to detonate into the formation, and a body to hold the swivel laser head and shaped charge. In certain embodiments, the swivel laser head further includes a fiber optics cable configured to transmit the laser beam from a surface to the swivel laser head, a rotational wheel configured to pivot the swivel laser head, retraction wheels configured to stabilize the fiber optics cable as the rotation wheel pivots the swivel laser head, an optics assembly configured to shape and manipulate the laser beam from the fiber optics cable, and a sensor configured to transmit data to the surface.

