RIASSUNTO
Abstract
The advent of highly deviated and horizontal well completions has created the need for a new line of service tools that do not rely upon gravity for the setting and retrieving of downhole tools. When using reeled tubing in downhole applications, in particular highly deviated or horizontal wells, frictional drag can limit the available forces required to set and pull flow controls, shift sleeves, shear pins , etc. As such, tools are needed that pins , etc. As such, tools are needed that take advantage of the pressure and flow capabilities of the reeled tubing to create an efficient system for servicing highly deviated ana horizontal wells in addition to conventional vertical wellbores.
Introduction
Reeled tubing equipment has been used for many years for various types of well servicing operations including sand washing with liquid or foam, unloading of wells with nitrogen or foams, fluid displacement, injection of paraffin or corrosion inhibitors, spotting paraffin or corrosion inhibitors, spotting acid, and even squeeze cementing. Reeled tubing sizes have increased over time with 1 1/4 in. (31.75 mm) OD tubing replacing 3/4 in. (19.05 mm) OD, and 1 in. (25.4 mm) OD tubing as the standard. Also, 1 1/2 in. (38.1 mm) tubing is currently available with 2 in. (50.8 mm) tubing undergoing development. This trend towards larger OD tubing not only improves the flow capacities due to increased circulating areas, it also results in greater strength tubing which is a plus for the transportation and manipulation of downhole tools in highly deviated and horizontal wells in addition to conventional vertical wellbores.
Such tools can be divided into three basic groups: the pressure activated tools for the setting and retrieval of downhole flow controls and bridge plugs; the heavyduty workstring which includes an accelerator, stem, and jars; and the complementary tools which includes reeled tubing connector subs, emergency disconnect subs, centralizers, and pressure holding knuckle joints. The heavyduty workstring and the complementary tools contain a flow thru ID and can be run in conjunction with the pressure activated service tools.
The use of these tools results in numerous benefits, particularly in highly deviated and horizontal wells where high axial loads cannot be achieved and conventional wireline methods cannot be utilized. These benefits include accurate and controlled setting of wireline subsurface flow controls, circulation with pulling tools allow washing and retrieving to be pulling tools allow washing and retrieving to be performed in a single operation, increased performed in a single operation, increased pulling capacity over conventional wireline pulling capacity over conventional wireline methods and expanded use of reeled tubing as well as standard wireline subsurface flow control equipment.
P. 631