FIELD AND BENCHMARK STUDIES OF LWD NUCLEAR TOOL RESPONSE IN HIGH ANGLE AND HORIZONTAL WELLS

摘要

With more and more high-angle and horizontal (HA/HZ) wells drilled for hydrocarbon exploration and exploitation, some significant differences have been observed between nuclear logs from vertical wells and logs from HA/HZ wells in the same stratigraphic section. These differences are noted even when the vertical and HA/HZ wells nearly intersect. Benchmark Monte Carlo simulations with generic LWD neutron and density tool specifications were conducted to understand these differences. The benchmark simulation cases include (a) bed boundary and depth of investigation effects; (b) azimuth and dip effects; ? oval-shaped borehole shape and cuttings effects; (d) thin bed or anisotropy effects.