Abstract

The continuation of deep drilling has expanded the application for directional drilling to near commonplace proportions. Since 1968, there has been a steady progression of improvements in deep directional drilling tools and techniques.

This paper will highlight six different types of directional drilling projects emphasizing the planning, equipment used, techniques, planning, equipment used, techniques, instrumentation, problems encountered and cost figures associated with each type of job. A list of some other deep directional drilling projects with objectives and results are listed at the conclusion of the paper. paper

Introduction

Many significant improvements in equipment and techniques used in directional drilling have been made since 1934 when Mr. H. John Eastman was summoned from California by The Humble Petroleum Company concerning their Alexander No. 1 Well at Conroe, Texas. Mr. Eastman proposed a plan to start a new well near the crater and by the use of mechanical deflectors would throw it within a 100' circle drawn around the bottom of the runaway well. The subsequent plan was followed and the wild well was killed.

Since the birth of control directional drilling, advances in equipment and methods have continued at an accelerated rate; nevertheless, greater than normal costs are still associated with directional projects. Cost of operating larger rigs and projects. Cost of operating larger rigs and providing supporting services axe increasing and providing supporting services axe increasing and exhibit no tendency to decline. As more deep structures are being explored, the applications have been increased for deep directional control. Increased directional drilling efficiency appears to be the one means available for reducing overall cost.

In the past three years several deep directional projects have been done with reasonable success and expense in the Delaware Basin, Western Oklahoma and the Panhandle of Texas. This paper will discuss several of these wells.

PLANNING KICK OFF POINT PLANNING KICK OFF POINT All directional wells have or should have ample planning to reach a bottom hole objective at a specified vertical depth.

Some of the more familiar applications for "deep directional drilling" in the Delaware basin, Anadarko basin and Western Panhandle are to sidetrack or straighten a crooked hole due to lease line problems, side-track an obstruction, or reentry to gain geological advantage by cutting across faults or by gaining more structure.

once the objective target has been defined, the next item for consideration is the Kick-off point or the depth at which the directional drilled section of the hole is to be started. It is very important that all factors be carefully considered in selecting the best kick-off point, whether it be off bottom or off a cement plug. The primary considerations are the amount of angle necessary to attain the desired deviation, the type of formation and the formation structure at this point.

Experience has shown that directional holes with 18 degrees minimum angle have a greater stability for holding desired direction once the angle and direction has been established. The maximum angle schedule plan should be greater than any formation bedding plane angle that is to be drilled. As a result fewer deflecting tool runs are required to correct the drift direction.

The mechanical characteristics of "deep control holes" generally are more difficult to control due to the smaller hole size; therefore, a certain amount of "leeway" should be considered in picking the kick-off point if applications permit.

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