Publications

The gas-bearing sandstone reservoir was planned to be drilled laterally. The reservoir was suspected to have not only a lateral compartment but also a multilayer vertical compartment. Thus, the trajectory was planned to penetrate all lateral and multilayer vertical reservoir compartments before landing in the base reservoir layer. The heterogeneity of the thin laminated shale and sand reservoir cause a challenging task to achieve maximum reservoir exposure. Moreover, TVD thickness of the multilayer targeted reservoir ranges from 5 to 15 feet. Deployment of distance-to-bed boundary and density image while-drilling tool aided the well placement. In this study, two wells were drilled using a distance-to-bed boundary tool, combined with a real-time density image. The tool combinations were deployed to place the well in gas-bearing sandstone reservoirs. The estimated reservoir depth position was based on seismic. A geosteering operation was required for the landing on top of the reservoir and placed the well trajectory in the multilayer targeted sandstone reservoirs. Well-A; reservoir top was 13.95 feet deeper than prognosis. The targeted sandstone reservoir comprised of two layers, called the 1st sand lobe and the 2nd sand lobe. In this well, the thickness of the 1st sand lobe encountered in lateral wellbore trajectory was 6.3 ftTVD and such in the 2nd sand lobe was 15 ftTVD. The total reservoir exposure amounted at 95% (2,261 ftMD). Well-B; reservoir top was 5.4 feet deeper than prognosis. In this well, the thickness of 1st sand lobe encountered in lateral well-bore trajectory was 7.6 ftTVD and the 2nd sand lobe was 10 ftTVD. The inter-shale bed between 1st and 2nd sand lobe had 1.4 ftTVD. The total reservoir exposure amounted to 90% (1,844 ftMD). Based on this study, it can be deduced that combinations of distance-to-bed boundary and density image have been proven as an effective combination for optimum well-placement in a challenging sandstone reservoir. The achievements of up to 95% reservoir exposure in lateral wells have been considered as successful practice of operational and drilling excellence.