A green field located in the central part of Norwegian Continental Shelf is currently being developed by an NCS operator. Development drilling commenced in 2022, and the target reservoir is Heimdal sand deposited in deep marine environment during Paleocene age. Heimdal reservoir consists of the main sand as well as injectite sands above the main sand and is capped by Lista shale. Regional OWC exists within the reservoir, providing strong aquifer support.

Drilling horizontal wells in deep marine–injectite reservoirs presents significant challenges. These include abrupt roof-dip changes, uncertainty in sand body distribution and high lateral heterogeneity, all driven by complex depositional environments. Achieving sufficient reservoir contact at an optimum position in this environment can be very difficult, especially with unstable shale boundaries. The Lista shale is highly reactive with continuous exposure exceeding 40m MD often leading to wellbore collapse. Without advanced planning and technologies, these challenges can lead to low productivity, for example, short producer length, low NTG and early water production.

To overcome the challenges, an innovative solution with strategy and technology collaboration has been defined. A key technology enabler was the use of UDAR which coupled with advanced drilling products such as Wired Drill Pipe and Dynamic Drilling Surveys, improved drilling efficiency, allowing for up to 70 m/hr ROP. Faster execution reduced time-dependent risks associated with shale instability, enhancing the success rate of production string installation.

Tailor-fit strategy was implemented, involving horizontal pilot wells to acquire 3D reservoir mapping data. Information from 2D UDAR inversion revealed lateral variations in the resistive reservoir geometry and depicting direction with better sand development. Based on this data, control points in XYZ coordinates were selected to create the producer trajectory at the most optimal position, as close as possible to the roof and maximizing distance from OWC.

Through this innovative solution, the NCS Operator successfully drilled over 70 km of geosteered meterage utilizing UDAR multi-dimension technology across the 12.25" landing section, 8.5" horizontal pilot, and 8.5" horizontal producer intervals, achieving an average measured depth exceeding 1,000 meters per producer well section, with consistently high Net-To-Gross (NTG). As a result of optimal producer placement and maximized distance to OWC, production from the field in Q3 2025 reached ~77,000 BOPD with very low water cut (source: Norwegian Offshore Directorate).

We also share how 3D UDAR identified survey uncertainty in an extended-length well and helped to formulate solutions. We observed a discrepancy in data between pilot and producer well after drilling more than 1000m MD, where the Ellipse-of-Uncertainty grew towards TD. UDAR provided critical geological markers to better understand the relative location of the two wells.

UDAR Reservoir Mapping has proven to be a key technology for accessing hydrocarbon potential in geologically complex reservoirs, such as deep marine-injectite. This paper demonstrates how the application of UDAR enabled the NCS Operator to optimize field development in a green field project. Through a tailor-fit strategy to acquire Reservoir Mapping in horizontal pilot wells, producer wells were placed at the most optimal position to reduce attic oil, delay water breakthrough, and achieve extended reservoir contact with high NTG. This Green field project provides a valuable reference for similar projects in other locations on how the application of 3D UDAR enhances productivity and benefits operators in long-term cycle of the field life.