Reducing Costs With Well Tractors for Horizontal Wells
Authors: Hallundbaek Jorgen 
Published: October 2008

ASTRACT

The Well Tractor is a new concept for a down hole tool that significantly reduces operation costs for servicing horizontal wells. The Well Tractor is a cost effective alternative to the very expensive and time consuming conventional drill pipe conveyed operations. The Well Tractor is capable of pulling coiled tubing and/or wireline horizontally beyond 10,000 ft. The Well Tractor is capable of pullingmore. than 25,000 fit of coiled tubing and/or wireline into a highly deviated well. Furthermore the tool is designed for pushing other tools into the hole, e.g. logging tools, video cameras. The lateral reach capacity with coiled tubing is therefore increased considerably. Time consuming production logging operations of horizontal wells utilising jointed pipe can be carried out by the Well Tractor as a wireline job.

The Well Tractor is used for cleaning, setting and pulling of plugs, operating sliding sleeves, open holelogging, running of production logs, drilling, perforation guns, cement bond logs etc.

The Well Tractor with modular power source is designed in two versions. A fluid driven version for coiled tubing operations and an electric driven version of the Well Tractor for wireline operations.

INTRODUCTION

Drilling and completing horizontal wells is becoming increasingly more common. With the conventional drill pipe operations and the currently available drilling and completion technology it is possible to drill and complete wells with a horizontal reach of 23,917 ft - Statoil C2 on the Statfjord field'. The problems occur when considering these wells for Coiled Tubing and wireline services. Many of the horizontal and deviated wells can not be serviced with Coiled Tubing. The Coiled Tubing will helically lock up due to the well profile and length. Logging the horizontal extended reach wells can be equally difficult, very time consuming, and expensive with todays drill pipe conveyed logging method. Horizontal open hole drilling with coiled tubing has also proven to be difficult as it is not possible to establish enough weight on bit.

The Well Tractor can solve all these problems because it is able to pull coiled tubing and/or wireline into the horizontal well while pushing other tools. By fitting the Well Tractor with a positive displacement motor and a drill bit it can be used for drilhg operations. When moving forward it generates tremendous weight on bit. In this set up the Tractor can be used for horizontal drilling, to make side-track holes or vertical slimhole drilling.

The Well Tractor has been developed to meet the demand for new technology that will enable the oil industry to achieve maximum well performance even from hard to reach wells and to comply with the always existing need to bring down costs and rig time.

DESCRIPTION OF THE TECHNOLOGY

In general the Well Tractor is designed for use in very long horizontal and highly deviated extended reach wells. Horizontally the Well Tractor pulls coiled tubing and/or wireline beyond 10,000 ft. The Well Tractor is capable of pulling more then 25,000 R of coiled tubing hire line into a highly deviated well.