What is horizontal drilling?

Horizontal drilling can be referred to as the directional drilling of an oil well in a horizontal direction rather than vertical. Since most oil wells are drilled in a vertical direction, horizontal drilling helps in stimulating the well in a different way to extract most of the produce from the reservoir. Horizontal drilling is also called as directional drilling or slant drilling and it usually intersects a vertical oil well to stimulate it and produce oil and natural gas. It is a common method to extract natural gas from Marcellus shale formation.

There are two types of oil well drilling – horizontal and vertical. Normally, wells are drilled in a vertical direction, i.e., drilled straight down into the rock formation. However, this traditional way of drilling oil well limits the complete extraction of the resources in the rock layer. Therefore, horizontal drilling, which is done intentionally in a horizontal direction in the earth’s depth, allows engineers to extract the energy sources from underground that are present in the horizontal layer. While the drilling process in the depth is carried in a horizontal direction, it initially begins in a vertical direction. From a straight vertical path, the drilling gets carried in a curve, ending in a horizontal position.

How Does Directional Drilling Work?

Directional drilling has been an integral part of the oil and gas industry since the 1920s. While the technology has improved over the years, the concept of directional drilling remains the same: drilling wells at multiple angles, not just vertically, to better reach and produce oil and gas reserves. Additionally, directional drilling allows for multiple wells from the same vertical well bore, minimizing the wells’ environmental impact.

Directional Drilling

Directional Drilling Source: Amerex Co.

Improvements in drilling sensors and global positioning technology have helped to make vast improvements in directional drilling technology. Today, the angle of a drillbit is controlled with intense accuracy through real-time technologies, providing the industry with multiple solutions to drilling challenges, increasing efficiency and decreasing costs.

Tools utilized in achieving directional drills include whipstocks, bottomhole assembly (BHA) configurations, three-dimensional measuring devices, mud motors and specialized drillbits.

Now, from a single location, various wells can be drilled at myriad angles, tapping reserves miles away and more than a mile below the surface.

Directional Drilling

Directional Drilling Source: Mackenzie Gas Project

Many times, a non-vertical well is drilled by simply pointing the drill in the direction it needs to drill. A more complex way of directional drilling utilizes a bend near the bit, as well as a downhole steerable mud motor. In this case, the bend directs the bit in a different direction from the wellbore axis when the entire drillstring is not rotating, which is achieved by pumping drilling fluid through the mud motor. Then, once the angle is reached, the complete drillstring is rotated, including the bend, ensuring the drillbit does not drill in a different direction from the wellbore axis.

One type of directional drilling, horizontal drilling, is used to drastically increase production. Here, a horizontal well is drilled across an oil and gas formation, increasing production by as much as 20 times more than that of its vertical counterpart. Horizontal drilling is any wellbore that exceeds 80 degrees, and it can even include more than a 90-degree angle (drilling upward).


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