Key Takeaways
- Wellbore drilled nearly parallel to the ground surface.
- Boosts production by increasing reservoir exposure.
- Ideal for thin or hard-to-reach reservoirs.
- Enables drilling under cities or protected areas.
What is Horizontal Well?
A horizontal well is a drilling technique where the wellbore deviates from vertical at an angle of at least 80 degrees, becoming nearly parallel to the surface to better access oil, gas, or groundwater reservoirs. This method improves production by exposing more of the reservoir rock than traditional vertical wells.
Horizontal wells are commonly used in conjunction with capital investment projects due to their increased efficiency and complexity compared to vertical drilling.
Key Characteristics
Horizontal wells have distinct features that set them apart from conventional vertical wells:
- Directional drilling: The well transitions from vertical to nearly horizontal to maximize reservoir contact.
- Extended lateral length: Some wells can extend thousands of feet laterally within the target formation.
- Increased production: Exposure to more rock can boost output up to 20 times compared to vertical wells.
- Use of mud motors: Specialized tools enable precise steering and rotation of the drill bit independent of the drill pipe.
- Application in shale plays: Often combined with hydraulic fracturing to unlock low-permeability resources.
How It Works
The drilling process begins with a vertical section from the surface to a kickoff point above the reservoir. At this point, a mud motor replaces the drill pipe rotation, allowing the bit to gradually curve into a horizontal orientation within the target formation.
Real-time data analytics guide the drill string to maintain precise inclination and direction, extending the wellbore laterally to maximize reservoir exposure. Horizontal wells can be either blind (ending within the reservoir) or continuous (exiting at another surface point), depending on the geological and operational goals.
Examples and Use Cases
Horizontal wells have become vital in various energy and environmental applications:
- Oil and gas: Companies like ExxonMobil and EOG Resources use horizontal drilling extensively in shale formations to enhance production.
- Environmental remediation: Horizontal wells improve groundwater extraction and vapor removal efficiency, often outperforming vertical wells by several times.
- Energy investments: Investors seeking exposure to innovative drilling technologies may consider best energy stocks that include firms specializing in horizontal drilling.
Important Considerations
While horizontal wells offer significant advantages, you should consider higher upfront costs and technical challenges compared to vertical wells. Effective project management and thorough understanding of subsurface geology are critical to realize expected production gains.
Additionally, the success of a horizontal well often depends on integrating advanced data analytics for real-time decision-making and adjusting drilling parameters to optimize well placement and performance.
Final Words
Horizontal wells significantly increase production efficiency by maximizing reservoir exposure, making them a valuable technique in resource extraction. To fully assess their potential benefits for your project, consider running detailed cost-benefit analyses or consulting with drilling experts.
Frequently Asked Questions
A horizontal well is a drilling technique where the wellbore deviates from vertical at an angle of at least 80 degrees, often becoming nearly parallel to the ground surface. This approach allows better access to oil, gas, or groundwater reservoirs compared to traditional vertical wells.
The drilling starts vertically from the surface to a kickoff point near the target reservoir, then curves using a mud motor to steer the drill bit horizontally. This lateral section can extend thousands of feet within the reservoir to maximize exposure and boost production.
Horizontal wells increase reservoir contact by exposing more rock, which can boost production rates up to 20 times higher than vertical wells. They also allow access to thin, fractured, or hard-to-reach reservoirs and enable drilling under urban or protected areas without surface disruption.
Horizontal wells are widely used in oil and gas extraction, especially in shale formations combined with hydraulic fracturing. They are also employed for environmental remediation, accessing multiple reservoirs from one pad, and installing utility lines under sensitive areas.
Yes, horizontal wells are used for groundwater extraction, vapor removal, and air sparging, often proving about five times more efficient than vertical wells. For example, they have been successfully applied to remediate contaminants like vinyl chloride in a shorter timeframe.
Directional drilling uses a mud motor, a hydraulic motor powered by drilling fluid, attached to the drill bit to rotate it independently of the drill pipe. Real-time measurements of inclination and direction guide the drill string to achieve precise horizontal placement.
The horizontal leg of a well can extend thousands of feet within the reservoir, with advanced cases reaching over 8,000 feet. This length helps maximize reservoir exposure and improve production efficiency.
No, besides oil and gas, horizontal wells are also used for environmental remediation, installing utility lines under rivers or buildings, and relief wells for pressure control. Their versatility makes them valuable in various industries where traditional vertical drilling is limited.
