Abstract

This paper discusses a technique for the completion and servicing of oil and gas wells while under pressure which can prevent formation damage caused by exposure to kill fluids. Operational procedures and actual field examples of completions and workovers performed with this technique are discussed, performed with this technique are discussed, and the necessary equipment is described in detail.

Introduction

Running and pulling pipe under pressure has been used to prevent permanent damage caused by kill fluids to certain formations by eliminating their use during the workover or initial completion. Recent trends show the increasing development and use of methods to run and pull pipe under pressure. These methods include the use of reeled tubing, hydraulic workover or "snubbing" units, and now, a hydraulic rig-assist technique. The hydraulic rig-assist technique has been developed to allow completions or workovers to be safely and routinely performed under pressure while working in conjunction with pressure while working in conjunction with conventional workover or drilling rigs. It quickly adds to the rig, and provides the capability to perform completion or workover operations with pressure on the wellhead. This affords the completion specialist leeway in his techniques with the ability to work under pressure. The equipment needed for the use of this technique comes in the form of a highly mobile unit that is modular in design, is compact, and can be rigged up quickly.

Performance features of this new concept Performance features of this new concept are:Rig up times: typically 1.5 hours. Running Speeds: average 1000 ft(304.8m) per hour for 4000 foot(1219.2m) deep wells. Pipe can be moved at rates of 60joints per hour when the pipe is‘heavy’.

The hydraulic rig-assist unit can be broken down into smaller components for shipment, if necessary, due to its modular construction. However, this greatly reduces its economic advantages due to reassembly time required at the well site.

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