Integrating lessons learned from over 20 years of one-trip tubing-conveyed perforating and Frac Pack/gravel pack applications Omar Mohamed Baker Hughes, Stan Davis Baker Hughes
Authors: Mohamed Omar Y. , Davis Stan 
Published: July 2010

The one-trip system was introduced to industry in the early 1980s; since then, many jobs have been performed worldwide. One-trip perforating and gravel-packing techniques have proven to save rig time and costs, and can be applied to hard and soft rock formations, offering operators some key advantages: As much as two days of rig time can be saved, at deepwater rates, and the new system enables operators to reduce fluid loss from the formation and completion time.

This paper addresses a new technology will describe the tools and procedures that have evolved over time to reduce related risks, such as:High underbalance - Excessive sand influx around gunsGun shock - Inability to unset perforating packer (mechanical shock) and pre-setting of gravel pack packer (pressure wave)Excessive fluid loss - Swab off of gravel pack packer elements when unsetting lower packer and repositioning assembly

The paper also describes the new version of the one-trip system and its advantages, which include:Integrates lessons learned from over 20 years of one-trip tubing-conveyed perforating and gravel packing applicationsIncorporates latest perforating and frac packing technologiesPerforating uses field-proven hydraulic bottom gun anchorsGravel packing uses frac tools designed specifically for frac pack applications

Introduction

One-trip tubing-conveyed perforating and gravel packing applications, utilized with Gravel packing and Frac packs is the method of sand control. Hence, underbalance perforating was needed to help ensure the cleanest possible perforation tunnels. With underbalance pressures, the problem of sanding up perforating guns increased risk. When using the conventional systems, expected sand production while tripping out of the hole with the perforating assembly and tripping in the hole with the gravel pack assembly. A clean trip is required to remove formation sand and any perforating debris from the wellbore. After the perforating event the well is monitored for losses. If loss rate is too high a pill would be prepeared and spotted after the clean out trip to help control the losses into the wellbore. Tripping back in the hole with the gravel pack assembly, the operator would tag unwanted formation sand and debris in the wellbore. In some cases this cycle would be repeated many times before reaching an acceptable depth with the gravel pack assembly. Earlier systems did not have the capability of isolating the gravel pack packer's hydraulic setting tool from the shockwave and any hydraulic pressures the system experienced during the perforating event being performed on the zone of interest. This shortcoming in the earlier versions sometimes would result in prematurely setting the gravel pack packer during the perforating even; necessitating fishing the entire assembly before the sand control operations could continue.

To address this problem the system incorporates the latest perforating and frac packing technologies, Perforating utilizes field proven Hydraulic Bottom Gun Anchor; Gravel packing utilizes the FRAC platform tools designed specifically for frac pack applications;.