Advancing Wellbore Safety with Pulsed-Neutron Sourceless Logging While Drilling Technology

Summary The increasing complexity of drilling high-angle wells through depleted reservoirs introduces significant risks, including differential sticking and bottom-hole assembly (BHA) loss. Traditional Logging-While-Drilling (LWD) tools using radioactive sources exacerbate these challenges due to stringent abandonment regulations and safety hazards. To address this, a sourceless LWD platform employing a pulsed neutron generator (PNG) has been developed, delivering comprehensive formation evaluation measurements such as bulk density, neutron porosity, elemental spectroscopy, and sigma, alongside resistivity, gamma ray, and ultrasonic caliper data. A key advancement is the accurate sourceless density measurement achieved through improved modeling of capture and inelastic signal interactions. Field application in a 1,600-ft interval with mixed lithologies demonstrated strong consistency with offset data and highlighted operational benefits. When the BHA became stuck, fishing and abandonment efforts and time were significantly reduced compared to radioactive-source tools. Additional advantages include cost savings on well isolation, deeper logging capability, and elimination of radioactive handling risks. This technology enhances safety across all operational stages while maintaining robust reservoir characterization. By integrating geoscience, drilling, and HSE priorities, the sourceless LWD platform represents a major step forward in mitigating wellbore risks without compromising data quality.