Schlumberger

Case Study: At-Bit Azimuthal Gamma Ray Enables 90% Accuracy in Geosteering Wells in Marcellus Shale

Seneca Resources uses dip picking to improve production potential and identify faults in highly dipping formation

Challenge: Increase in-zone percentage to maximize production potential and identify faults in shale formation with high dips.

Solution:

  • Quickly interpret formation bed boundaries using iPZIG at-bit inclination, gamma ray, and imaging service with a customized drilling assembly.
  • Accurately geosteer with PayZone Steering well placement service in the unconventional shale formation.

Result: Placed well on target and achieved in-zone geosteering for more than 90% of the lateral length.

Increase in-zone percentage to maximize production potential

In a new drilling campaign in the complex Marcellus Shale, Seneca Resources wanted to achieve an in-zone percentage that was greater than it attained in the lateral sections of previous wells drilled in the same formation. Standard gamma ray measurements had proven insufficient for keeping the trajectory of certain wells within the target, and the operator wanted to find a better imaging solution to maximize production potential in the wells planned for the development.

Within this formation, the target is typically 10–15 ft wide with markers that look similar from above and below the target when using standard gamma ray. The first well was planned using available 2D seismic data, which showed the zone leveling off at approximately 90° and then curving up, adding to the difficulty of remaining in zone at the end of the interval.

Use advanced gamma ray measurements to geosteer with improved downhole insight

To geosteer within the lateral and stay in the target zone, Schlumberger recommended using the iPZIG at-bit inclination, gamma ray, and imaging service with azimuthal gamma ray to obtain real-time bedding measurements. The PayZone Steering well placement service was recommended for accurate geosteering to keep a higher percentage of the lateral in zone and achieve the highest possible production from each well.

Stayed within the zone more than 90% of the time with greater directional control

The in-depth information gained from the iPZIG and PayZone Steering services helped Seneca Resources correctly determine the position of the pay zone and direct accurate drilling, enabling the operator to stay within the target interval more than 90% of the time. Throughout the entire lateral, inclination was highly variable and ranged between 0.2°/100 ft and –1.8°/100 ft.

The iPZIG service positioned the azimuthal gamma ray and dynamic inclination measurements close to the bit, which enabled the operator to quickly adjust the well trajectory while navigating through critical hole sections and maintaining the wellbore in the target zone. During drilling, the geosteering team discovered that the pay zone was higher than planned and dipped down throughout the entire lateral section. When a fault was detected, the decision was made to TD the well. The iPZIG service provided greater directional control and the ability to make time-critical decisions to maximize in-zone exposure.


Download: At-Bit Azimuthal Gamma Ray Enables 90% Accuracy in Geosteering Wells in Marcellus Shale (0.33 MB PDF)

Related services and products

 
Request More Information

Maximize In-Zone Exposure with Greater Directional Control

iPZIG
PrevNextZoom1 of 1

Real-Time Data for Time-Critical Geosteering Decisions

iPZIG at-bit inclination and gamma ray image service
iPZIG service provides real-time, at-bit, 8- to 16-section image natural gamma ray and dynamic inclination measurements.
Visit iPZIG At-Bit Service page