Abstract

Drilling horizontal laterals in unconventional reservoirs can be quite challenging, particularly when the goal is placing the lateral in a specific part of the pay zone with minimal undulations. While drilling a lateral, the wellbore is typically steered using radial gamma ray measurements. Sometimes focused gamma ray measurements are also taken both on the high side and low side of the wellbore. The ability to collect real-time gamma ray logs for both the upper and lower half of the wellbore while rotary drilling proves to be especially beneficial to the horizontal drilling operations. This is especially true considering that typically greater than 90% of the footage in a lateral is drilled in the rotary mode.

This presentation discusses the research and development activities leading to a new logging while drilling motor (LWDM) which collects data while-rotating azimuthally focused gamma ray and wellbore inclination about six feet from the bit. The data is then electromagnetically short-hopped up to the measurement while drilling (MWD) system and then transmitted to surface using either electromagnetic or mud-pulsed MWD telemetry systems. Prior to the development of this new technology, azimuthally focused data was acquired by taking stationary gamma ray measurements up and down at each connection along with projected and at times corrected wellbore inclination measurements.

This presentation also features a onshore mid-continent unconventional gas horizontal case study showing how an operator is using this near bit azimuthal gamma ray technology to enhance both geological well placement accuracy and drilling performance.