Source-Less Method Case Study: Integrated LWD NMR and LWD AzimuthalResistivity Application in Low Resistivity and Low Contrast Reservoir inBohai Bay

摘要

The use of radioactive source porosity measurements is strictly prohibited in Bohai Bay, China. As analternative, logging-while-drilling nuclear magnetic resonance (LWD-NMR) has been applied. In one block of the Bohai Bay field, it is a big challenge to identify and quantify hydrocarbon reservoirsections due to little resistivity contrast between reservoirs and water zones. LWD-NMR technologyand the azimuthal resistivity tool is able to solve this challenge. The low-gradient LWD-NMR tool notonly measured porosity also provide T2 distributions, which can be used for fluid type characterization.The azimuthal resistivity tool has a deep azimuthal resistivity measurement that can identify nearby bedboundaries, up to 5 m from the borehole, while drilling. This information is available in real-time to theoperator for decisions while drilling. The combination of the two measurements is capable of differentiatingphysical properties of the reservoir and providing information on fluid types. Thus, the operator can easilymake decisions to optimize the wellbore placement and perform an accurate petrophysical evaluation ofthe reservoir.