The Pyrenees Field comprises a series of biodegraded 19° API oil accumulations reservoired in Early Cretaceous sandstones of the Pyrenees Member in the Exmouth Sub-Basin, offshore WA The reservoir comprises excellent quality, poorly consolidated shallow marine to deltaic sands. Variable thickness oil columns (some with associated gas caps), strong bottom water drive, and relatively viscous oil has necessitated the drilling of long (up to 2,000 m) horizontal wells to maximise reservoir exposure while geosteering well to within a few meters of the roof of the reservoir to maximise standoff from the OWCs. The field is covered by excellent quality 3D seismic data; however, pre-drill mapping for well path planning is complicated by the unconformable nature of the top reservoir boundary formed by the sub-cropping Pyrenees Member. Faulting within and localised velocity variations above the reservoir are also a challenge to pre-drill well planning. Cutting-edge geosteering tools have been used to achieve the desired well paths. The tools use azimuthal deep induction resistivity measurements to model and predict reservoir and fluid boundaries, taking advantage of the large resistivity contrasts between the overlying sealing mudstones of the Muderong Formation and the oil (and occasionally gas) bearing Pyrenees reservoir sands. This extended abstract discusses the application of the tools both in pre-drill well path planning and the real-time geosteering operation. Operations are managed between the rig and a sub-surface team located in a dedicated geosteering room onshore. Here real-time data is compared with planned well paths in 3D seismic and geocellular reservoir models and well path adjustments made to optimise final well placement.

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A development campaign offshore Australia, with a total of 15 laterals in a challenging geological environment, has been successfully completed by Quadrant Energy. The main objectives were to geosteer and place the well path at an optimum standoff from the oil/water contact (OWC), while drilling at the interface of the gas/oil contact (GOC), when present, and at 1-1.5m TVD from the reservoir top when not.The field is characterized by a series of transverse and longitudinal seismic and sub-seismic faults that bisect hydrocarbon-bearing sands which represent the greatest challenges in this development campaign. Evidence from exploration wells showed a thin column of heavy oil and a gas cap in the fault-bonded reservoir. A new multi-disciplinary methodology not only enabled Quadrant Energy to achieve its development objectives, but to develop a full subsurface picture of the Coniston field reservoir.The use of the Reservoir Mapping-While-Drilling (RMWD) combined with Bed Boundary Mapping Tool (BBMT) and Multi-Function LWD services enabled the laterals to be placed at 1-2m TVD below the reservoir top or gas cap, when present, even in highly faulted sections. In addition to this precise placement the extreme depth of investigation of the RMWD service, in conjunction with the real-time multilayer inversion capability, constantly mapped the OWC at a distance up to 19m TVD below the wellbore. While drilling, different qualities of reservoir sands were identified and enabled the extensions of the wells' TDs based on reservoir properties. The distance to boundary information, provided in real-time by the RMWD service, was used in real-time by the Quadrant Energy geology and geophysics team to update and validate the seismic model that provided increased confidence in the reservoir model and a more precise planning for future development wells. This paper will illustrate the use of the latest LWD RMWD technology in a challenging geological environment. The paper will explore the close collaboration, teamwork, and integration necessary to drive innovation and demonstrate the outcomes of this successful campaign which have not only exceeded the development goals, but have also generated a full 3D view of the reservoir.

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Middle East carbonates frequently are heterogeneous in nature, encompassing variable pore types, strong diagenetic overprints, variable wettability and fracture networks amongst other effects. Resistivity borehole images have long been an integral constituent to understanding their complexity and unlocking volumes. High resolution LWD resistivity images were first introduced in the 1990's, however as downhole environments became progressively more challenging, resistivity images suffered from the dynamic acquisition environment resulting in severely degraded images. The Al Shaheen field has been developed with Extended Reach Drilling (ERD) wells, and wells of 30,000 feet are commonplace. Early LWD resistivity image data suffered from excessive stick and slip, with approximately half of the wellbore suffering from poor quality image data, degrading with depth. The outer portion of the wellbore is prohibitive to impossible to access via conventional drill pipe conveyed tools, resulting in an absolute requirement for high quality LWD resistivity images. The new methodology redefines the acquisition and processing methodology, resulting in images unaffected by stick slip with a 100% success rate in the most challenging of ERD environments. This paper illustrates the improvements in logging while drilling images (LWD) and subsequent fracture network characterization as a result of implementing a new image acquisition strategy and processing algorithm. The paper explores the close collaboration necessary to drive the innovation to dramatically enhance existing technology, and demonstrates the results with comparisons of the LWD images using the old and new methodologies.