In this paper, a Middle East field example is shown to illustrate the application of new advances in Logging While Drilling measurements. In addition to standard two mega-hertz multi-depth resistivity, neutron and gamma ray LWD measurements, azimuthal density and photoelectric factor (Pef) measurements were recorded. The real-time and recorded mode applications of azimuthal density and Pef are discussed in this paper.

Conventional LWD density measurements are circumferentially averaged. This technique will smear the density output at bed boundaries, especially in horizontal wells where the bed's relative angle to the well bore is high. Information from azimuthally acquired quadrant density measurements can be used to clearly detect and evaluate bed boundaries in deviated and horizontal holes. In this paper, it is shown how up and bottom densities are used to accurately locate bed boundaries and other geological features such as faults. For geosteering purposes, up and bottom density displacement was able to show if the bed was being entered from the top or bottom of the well bore. It was also possible to estimate structural dip in real-time.

Sixteen azimuthal density and sixteen azimuthal Pef sectors were recorded in downhole memory. Once these LWD data were retrieved from the BHA memory and image processing and image orientation was done, structural features such as fault, bed boundaries and formation heterogeneities were identified. True dip was computed from the density image. The compilation of this information allowed further evaluation of the geologic model of the carbonate gas-bearing reservoir.

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