Abstract

In the Arabian Gulf, a rotary-steerable system utilizing "point-the-bit" technology decreased the well-construction cost in two Saudi Arabian offshore oil fields. Drilling offshore, in many (if not all) parts of the world, is an expensive adventure. "Point-the-bit" technology has successfully and consistently controlled capital expenditures for wells in these offshore fields and, in head to head comparisons, has cost less money when compared to the conventional drilling systems that had previously been used. When it comes to offshore operational costs, time is a nemesis. The application of "point-the-bit" technology as a way to help solve this problem by permitting the economical completion of a quality borehole will be discussed in this paper. A major concern has been that the phenomenon known as "hole-spiraling" which has created hole-quality issues. These issues range from tortuous paths, torque-and-drag frictional forces, key-seating or sump effects, and poor log responses to name just a few of the problems. Thus, when the quality of a borehole and the time it takes to drill it are considered less than desirable, the drilling process and its resultant effects increase well costs and reduce operational efficiencies.

Several case histories within two offshore fields will be presented in this paper. These case histories will show that having the capability to make adjustments to downhole drilling tools "on-the-fly" makes for better steering control and creates better hole geometries. Correctly applying "point-the-bit" rotary-steerable systems on these wells demonstrates the value-added potential of this technology.

Introduction

The price and/or cost to do business in the oil-industry for operations such as exploration, drilling, field-development, and production has continually increased over time. Even in the Middle East Region, where the cost to produce a barrel of oil is one of the lowest in the world (Fig. 1), drilling costs have naturally increased.1 This phenomena can be attributed to many factors that are connected to supply and demand which drive world market conditions. This trend to higher drilling costs is not expected to change anytime soon and is especially true when the work being performed is in an offshore environment.

Because, at times cost seems to be the over-riding factor in completing a well, the condition of the borehole could suffer as a result. Operators of wells in areas that present formation, structural, or integrity related problems would undoubtedly prefer not to have borehole quality problems to deal with. Problematic hole conditions, perhaps created unknowingly, allow situations to occur that makes mechanically drilling the hole very difficult.

In the past decade, considerable advancements in the drilling phase from within the drilling services segment of the industry have contributed to the reduction in operating costs for operators worldwide. Such advancements in drilling tool technology become even more important to the customer when every minute of every day is measured on the bottom line.

Rotary Steerable (RST) Systems have been part of the industry for a number of years with the most recent advancement being a "point-the-bit" system known as "Geo-Pilot"®.

Value Analysis

Value is measured in many ways and is both quantified and/or qualified differently between organizations. Value can be specifically measured with the use of Time and Hole-Quality as a function of deliverability to the bottom line. However, even these specific measures, discussed more below, can affect each other. For example, drilling too fast, or beyond the capability to keep the wellbore clear of cuttings buildup, may create a situation where more time to ream and condition the hole is required or worse yet lead to a stuck BHA problem.

Time Savings

For an operator, saving time on an offshore rig is very valuable. As a result, it can be very tempting to drill as fast as possible to reach TD in order to save time. However, doing so can lead to conditions that will increase time. Being focused on increasing ROP to the point of neglecting proper hole cleaning can lead to major stuck-pipe problems.

This content is only available via PDF.
You can access this article if you purchase or spend a download.