Combined Real-Time Active Resistivity and Passive Magnetic Well Ranging Applications While-Drilling

As new wells are drilled in mature oilfields to sustain and enhance production, geosteering near existing wells presents an increasing challenge. The exact location of each wellbore is uncertain, and the spatial inaccuracies grow with the length of the well. Therefore, real-time well ranging while-drilling solutions are crucial for accurately determining distance and direction of nearby wells to prevent collision events. Besides anti-collision, well ranging supports critical applications such as well interception and borehole twinning for advanced geothermal systems. The ultra-deep azimuthal resistivity (UDAR) and the definitive dynamic survey (DDS) tools offer 3D sensitivity to metallic objects, such as casing and screens. A novel workflow, known as active resistivity ranging (ARR), was developed from UDAR measurements, enabling real-time computation of the distance and orientation of nearby wells. Similarly, an innovative method using DDS data was developed to provide a passive magnetic ranging (PMR) to geolocate in real-time these magnetic objects. Since both downhole tools can be configured in the same bottom hole assembly (BHA), the two ranging solutions can be combined and deployed simultaneously to detect any nearby well. This paper presents the novel methodologies behind these two well ranging workflows, where a real case study was performed in a high-angle producer well, located in the North Sea of Norway. The results of the real case study demonstrate how the combined use of these ranging solutions can accurately detect the presence of a nearby well with metallic completion screens, and then capable of determining its relative distance and azimuthal orientation with respect to the newly drilled borehole. This technological combination leverages two distinct physics methodologies, electromagnetics and magnetism, to provide a dual safety approach for the reduction of collision risks while drilling. Additionally, both solutions operate in real-time for near-parallel well scenarios in which the borehole trajectory can be either in a vertical or high-angle profile. Furthermore, ARR is the only ranging solution in the logging-while-drilling (LWD) domain capable of detecting an open-hole well filled with conductive fluid, thanks to the resistivity variation in comparison to the surrounding formations. The respective work reveals how this innovative combined ranging application can support the safe drilling of future wells within targeted zones that are currently prohibited due to the collision risks given the ellipse of uncertainty of the borehole surveys. Furthermore, the combined approach can go beyond the anti-collision solution, such as well twinning and interception application for relief well. Finally, it can be deployed in the renewable energy sector, e.g. the drilling of paired wells in the advanced geothermal systems (AGS).