Vertical Survey Enhancements

Manage Depth Uncertainty for Multilateral & Horizontal Wells

Schlumberger MWD TVD optimization surveying gives an accurate picture of where a wellbore is going—at a significantly lower cost compared with other methods. As we push the envelope with LWD technology, tighter TVD tolerances are required to deliver on well production objectives. For multilateral or horizontal drilling, TVD optimization is critical to minimizing risk and maximizing efficiency with drilling engineering.

Depth uncertainty is the product of many common, and unavoidable, elements:

• natural discrepancies between wireline and drill pipe
• tide, heave, and pipe compliance
• tool movement and sag
• mechanical and thermal drillpipe stretch

Depth corrections for confidence in LWD data

Schlumberger high-definition surveying (HDS) methods make corrections using surface and downhole measurements to ensure accuracy in LWD measurements and precise agreement with wireline data.

• Measured Depth—Original wireline and drillpipe depth data can show differences in measured depth, but with proper correction they agree perfectly.
• TVD—A continuous inclination surveying method takes measurements again and again throughout drilling operations to provide the inclination and properly measure TVD regardless of sliding, rotating, vertical drilling, etc.
• Depth—Schlumberger TVD optimization provides absolute depth, relative depth, and reproducible depth.