Successful Field Trial of a Novel Abrasive Jetting Tool Designed to Create Large Diameter-Long Cavities in the Formation to Enhance Stimulation Treatments

Abstract

Gas exploration wells are being drilled in high pressure and temperature environments targeting low permeability and high fracture gradient formations that push the envelope of conventionally used technologies. Thus, conventional perforating techniques are often not sufficient to break down the formation during fracturing operations in this type of wells.A novel system, specially designed to enable hydraulic fracturing in challenging producers was successfully field-tested. The system includes an anchor, a multi-cycle incrementing and stroking tool (MCIST), and a jetting sub with multiple nozzles. The anchor is used to prevent axial motion of the jetting head while jet cutting, which overcomes the long-standing problem of tubing stretch due to pressure changes and vibration during abrasive perforating operations. With the anchor as a depth reference base, the MCIST changes length upon command from the surface and uses sequential jetting to create a series of evenly spaced perforations in the casing, with corresponding large diameter longitudinal slots in the formation, in a controlled and evenly spaced fashion. The tool design and testing process, details about the field trial experience as part of a stimulation treatment, and the excellent post-stimulation results achieved are discussed in the paper.

Successful Implementation of Abrasive Perforation in Highly Deviated HP/HT Gas Well

“…These nozzles create a high velocity stream estimated at 600 fps that can perforate through tubulars, cement sheath, and formation rock. The slot shape and dimensions (2) are directly related to several factors. These factors are the nozzle size, pumping rate, jetting time, nitrogen pumping rate, back pressure exerted against the jet, differential pressure across the nozzle, solid concentration of the slurry, and stand-off between the abrasive jetting tool and the casing or open hole.…”

“…Pervious experiments (2) show that the longer the jetting time, the higher the slot's penetration and dimensions. They also show that exceeding 30 minutes jetting time is not recommended as additional penetration beyond this time is negligible.…”

“…The weep hole effect (2) , created by slightly moving the non anchored abrasive slot cutting tool, will also help to achieve deeper penetration, faster cutting rate, and larger hole size.…”

“…Abrasive slot cutting (2) , which cuts through the casing, cement and formation, was proposed as an alternative solution. An adequate design to optimize the slot placement and penetration is therefore critical to minimize the skin, initiate flow after abrasive slot cutting, and optimize production after matrix stimulation.…”

Design, Application, and Implementation of Well Intervention Services within a Deep HP/HT Tight Gas Exploration and Appraisal Project

“…This abrasive fluid is jetted against the targeted area and is able to erode the tubular, cement, and formation interface resulting in connectivity between the wellbore and reservoir superior to the connectivity that can be achieved with explosive perforating. The benefits of abrasive jet perforating when compared to conventional explosive perforating techniques is well documented within the industry (East et al 2005;McDaniel et al 2008;Solares et al 2009;Curtino et al 2011). 3.…”