Horizontal drilling is a core technology for reservoir development. This paper is an overview of today's horizontal drilling technology and a discussion of how the technology may be used in the future, The following technologies will be discussed:


Most horizontal wells drilled today are placed in the reservoir based upon reservoir or geological parameters. MWD logging tools are being used to guide the well path as the well is being drilled This paper will discuss the various logging sensors available and how they can be used for geosteering

Under balanced Drilling Systems

These systems are being developed to minimize formation damage and ensure that the maximum production potential of each horizontal well is realized. Under balanced drilling is being used primarily in pressure depleted reservoirs. This paper will review the different techniques being used and discuss the relative merits of each.

Multiple Lateral Wells.

These wells are being used to drain single reservoirs more efficiently and to drain multiple reservoirs. Use of multiple laterals can also reduce the number of surface locations, which lessens environmental impact and reduces overall project cost, The multiple laterals can be drilled using either open hole sidetracks, or newly developed casing systems that will permit controlled reentry into each of the laterals. This paper presents an overview of the types of wells being drilled today and discusses potential uses of the technology in the future

Short Radius Drilling Systems.

Short Radius Drilling Systems have been in use for many years. These systems have, however, had some significant limitations. New systems have been developed which include MWD tools for steering control, The development of composite fibre drills/ring components will permit the use of steerable systems for drilling the horizontal interval. This paper discusses the potential uses of short radius systems and how they will interface with other emerging technologies.

These emerging technologies enhance the production capabilities of horizontal wells making them more effective for oil recovery than conventional vertical wells. In addition to improved recovery, field development costs are often reduced since fewer wells are required to drain the reservoir. The above emerging technologies will have an impact on the number and type of horizontal wells drilled in the future.


Until 1994, the number of horizontal wells drilled in Canada had approximately doubled each year (Figure I). For 1995, approximately 900 to 1000 horizontal wells will be drilled, which is similar to the number drilled in 1994.

Most horizontal wells are development wells. When the number of horizontal wells drilled is compared to the number of development wells drilled, we notice that horizontal wells are becoming a larger percentage of the development wells. This would tend to indicate that horizontal drilling technology is becoming or has become a core technology for reservoir development.

Horizontal Drilling Trends

The following horizontal drilling trends have been observed:

  • an increase in build rates

  • a reduction in hole sizes

  • an increase in re-entry drilling

  • an increase in geosteering

The first three are related while the fourth is influenced by the first three.

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