Extended Reach Drilling
Encyclopedia
Extended Reach Drilling(ERD) is directional drilling
Directional drilling
Directional drilling is the practice of drilling non-vertical wells. It can be broken down into three main groups: Oilfield Directional Drilling, Utility Installation Directional Drilling Directional drilling (or slant drilling) is the practice of drilling non-vertical wells. It can be broken down...

 of very long horizontal wells. The aims of ERD are:
  1. to reach a larger area from one surface drilling location, and
  2. to keep a well in a reservoir for a longer distance in order to maximize its productivity and drainage capability.


Today’s challenges in ERD are hole cleaning, managing the mechanical loads on the drill string and managing downhole pressure. There is even the cost issue to consider.

Definition

Early ERD-well definitions related wells to those that exceeded some step-out/vertical-depth ratio (often 2:1). However, for most highly deviated wells in deepwater environments, this definition clearly does not fit. Some methods have evolved to categorize wells according to their stepout within different vertical-depth ranges. ERD wells then can be described conveniently as shallow, intermediate, deep, and ultradeep. Other variants are associated with operating in deep water and high-pressure/high-temperature environments. Currently, there is no generally accepted ERD-well definition.

What exactly determines a well to be "extended reach" varies over time and location with the development of technologies and of experiences .
  • On 28 January 2011 the world’s longest borehole was drilled at the Odoptu field, Sakhalin-I
    Sakhalin-I
    The Sakhalin-I project, a sister project to Sakhalin-II, is a consortium to locate and produce oil and gas on Sakhalin Island and immediately offshore, in the Okhotsk Sea, from three fields: Chayvo, Odoptu, and Arkutun-Dagi....

     with a measured total depth of 12,345 meters (40,502 ft) and a horizontal displacement of 11,475 meters (37,648 ft).
  • Maersk Oil Qatar had the previous world record in a well with a measured depth of 40,320 ft (12,290 m) including a horizontal reach of 35,770 ft (10,900 m) in the Al Shaheen Field offshore Qatar.

New developments and innovations

New technologies emerge that claims to be pushing the existing boundaries of ERD. One of these is the Reelwell Drilling Method, a drilling method solving problems for challenging wells, particularly suited for long reach wells. This innovation aims at multiplying the distance drilled by conventional ERD methods.

There are several companies offering Extended Reach Drilling services, operations and equipment;

Related Topics

  • Underbalanced drilling
    Underbalanced drilling
    Underbalanced drilling, or UBD, is a procedure used to drill oil and gas wells where the pressure in the wellbore is kept lower than the fluid pressure in the formation being drilled. As the well is being drilled, formation fluid flows into the wellbore and up to the surface...

  • Well drilling
    Well drilling
    Well drilling is the process of drilling a hole in the ground for the extraction of a natural resource such as ground water, natural gas, or petroleum...

  • Drilling fluid
    Drilling fluid
    In geotechnical engineering, drilling fluid is a fluid used to aid the drilling of boreholes into the earth. Often used while drilling oil and natural gas wells and on exploration drilling rigs, drilling fluids are also used for much simpler boreholes, such as water wells. Liquid drilling fluid...

  • Lost circulation
    Lost circulation
    Lost circulation can be one of the more serious problems that can arise during the drilling of an oil well or gas well. Circulation is said to be lost when the drilling fluid, known commonly as "mud", flows into one or more geological formations instead of returning up the...

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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