Advances In Remote-controlled Drilling
Authors: Desbrandes R. , Morin P. 
Published: March 2010

For over twenty years, the Institute Francais du Petrole has researched remote-controlled drilling. As wells go deeper and are more slanted, and sometimes horizontal, such facilities are essential.

Control is by wireline transmission of bottom-hole data and control of downhole functions. There are three main components:–a directional unit (magnetic-accelerometer type);–a bottom-hole drilling parameters measuring unit (with various sensors to measure the required parameters, fully pressure compensated);–a variable-angle bent sub (rotation of the lower part of a sub around a tilted axis).

(Figure in full paper)

Operational results for the directional unit, and test data for the other components indicate satisfactory performance.

In the future besides marketing existing industrialized tools, the design of tools in diameters other than the 7%-in. selected for the prototypes will be undertaken and sensors for measuring logging parameters and safety parameters will be added.

Introduction

The earliest application of directional drilling was in boreholes which were in bad shape and required side-tracking because of fish in the hole. Remote-control methods are, therefore, particularly useful. Directional wells are also needed to intersect with and kill wild wells.

In 1962, the Institute Francais du Petrole launched a research· program in the area of telemetry and remote control(l). Directional drilling is now used on offshore platforms, to drill in faulted zones, in the presence of salt domes and in inaccessible terrain.

The remote-controlled drilling system designed by the Institute Francais du Petrole consists of the following components:A powerful downhole motor, capable of drilling the entire well, including the highly slanted part, with conventional or heavy drill stems.A wireline telemetry system permanently connected during drilling to the downhole sensors for measurement of the directional parameters, including borehole azimuth, drift and bent sub position. Mechanical parameters such as weight on bit, torque, pressures and temperatures inside the drill stem and in(Figure in full paper)the annular space, and motor r.p.m, are recorded. Logging parameters, including mud resistivity inside and outside in the annular space, true resistivity and natural gamma radiation of the formations, are also transmitted.A variable-angle bent sub controlled from the surface by the same conducting wireline used to correct the trajectory.Surface equipment designed to read, record and process the above.

Description of the System

The remote-controlled drilling system (Fig. 1) adapts to conventional drilling systems with downhole motors. A downhole motor may be of the turbine or of the positive-displacement type. A TELEPILOTE variable-angle bent sub controlled from the surface, a TELEVIGILE drilling parameter measuring sub, an orienting sub and an AZINTAC directional measurement sonde placed inside a nonmagnetic drill collar make up the detecting devices.

A single-conductor electrical cable runs through a lateral window sub into the annular space of the vertical or subvertical part of the borehole. A winch and conventional surface equipment are used to wind the cable. An electronic console equipped with a minicomputer performs data processing, display and recording.