This paper summarizes the work performed by EBN together with NuTech Energy Alliance for the Netherlands regional study, which aims to address the underexplored pay potential covering both onshore and offshore Netherlands. The paper provides the technical proceedures involved and the usage of available public domain well data for the Netherlands regional field study in order to fulfill the study's two main objectives. First main objective being to identify and analyze the shale play opportunities in unconventional reservoirs of the Lower Jurassic Posidonia Formation and the Namurian Geverik member as well as other shale & marl sections in the area. The second objective is to identify bypassed hydrocarbon opportunities in conventional reservoir sections through onshore and offshore Netherlands. The Netherlands regional study provides insight into reservoir potential, geological and petrophysical properties of all formations based on innovative petrophysical well data analysis that were applied to 116 representative wells across the area.

With the onset of offshore decommissioning resulting in an increasing number of permanent plug and abandonment (P&A) campaigns it is critical to manage these in a safe and cost-effective way. A robust methodology is important to manage the magnitude of wells in Norway to be P&A’d including the need to comply with Norsok Standard D-010 (Norsok, 2013). Many technologies have come to the forefront to aid with safe permanent well abandonment, with different criteria to be met, principally by verifying the integrity of the casing and cement barriers across the zones that are plugged. To inspect the cement barrier interval, spectral noise logging was utilized to investigate noise generated by flow in fluid and gas phases. A practical test in a controlled environment was required to document the sensitivity of the spectral noise logging techniques ability to detect liquid and gas flow for different annular cement quality scenarios. Full-scale barrier reference test cells were constructed to represent a range of cement defects such as gas channels, mud channels and de-bonded cement. These test cells have been utilized to evaluate the performance of well barrier verification technologies. The measurement resolution of spectral noise logs to detect flow behind casing was investigated by flowing water and gas through the different leakage paths. The flowrate range used for this experiment was between 1 and 1300 mL/min for water and between 1 and 24 L/min for gas (N2). The experiment was performed in a low noise environment to avoid ambient noise sources that might compromise the experiment. P&A regulations and recommended practices were considered when developing the test procedure. Controlled annular leakage rates of water and gas were established using barrier reference cells representing good cement, no cement, gas channels and micro-annuli. Spectral noise logging measurements were recorded using a memory based, commercially available logging tool and the results were analyzed. The data showed the spectral noise logging tool was able to detect the noise generated by low flowrates of water and gas through different leakage paths. The yard test results provide a basis for considering noise logging and its spectrum analysis as an alternative means or an addition to currently used cement bond logging technologies for cement barrier verification. The applicability of utilizing spectral noise logging as an additional proof of annular barrier integrity was demonstrated.

fax 01-972-952-9435. AbstractAchieving the objectives of drilling horizontal wells is greatly dependent on accurate placement of the drainhole in the reservoir. Careful pre-job planning using offset well data and seismic maps helps to reduce the uncertainty to some extent. However, the unpredictability of structural and stratigraphic variation between the planned and offset wells and uncertainty inherent in seismic data are always associated with horizontal well planning. The formation dips computed from seismic and offset wells are therefore prone to some degree of error.Advances in real-time data transmission technology have made it possible to transmit image data uphole while drilling, through improving the robustness of the real-time signal, signal bandwidth and data compression. Logging-whiledrilling (LWD) real-time azimuthal resistivity images can be used for accurate estimation of the dip and strike of formations intersected along the well trajectory. In addition, structural surprises such as faults can be detected, and remedial actions taken immediately. Such information is of great value in making geosteering decisions while drilling into reservoirs within structurally complex geology or in an area with sparse geological information. Using image data, trajectory adjustments can be made during drilling yielding optimal well placement.We descibe the use of real-time image interpretation during the drilling of two horizontal wells within a block bounded by major faults on the north and south, with a series of smaller associated faults, anticipated but not confirmed prior to drilling from existing data, in a carbonate field in United Arab Emirates. The image data provided crucial input to guide the well trajectory through the target reservoirs resulting in the wells objectives being achieved. In addition, the image data clarified the regional geology of the area around the wells, thus helping to update the geological model for better description of the structurally complex reservoir.

When an oilfield is exploited by simply producing oil and gas from a number of wells, the reservoir pressure in many circumstances drops quicker than normal impacting the production rates (Koning, 1988) and well performance. To maintain the pressures in the oil producing formations, waterflooding enhancement method is implemented by the Operators. This is achieved by drilling injection wells or converting the oil producing wells into injectors. The injection wells are located at carefully selected points in the oilfield so that the water displaces as much oil as possible to the production wells before the water starts to break through. A significant saving in an oilfield development can be obtained by reducing the actual number of injecting wells and increasing each of the injector wells' capacity for injection. Balancing the injection and produced volumes often involves injecting at high pressures leading to the fracture of the reservoir rocks along a plane intersecting the wellbore. This happens when injection pressure overcomes the rock stress and its tensile strength, thereby creating an induced fracture network. With continuous injection, these fractures start propagating into the reservoir and may reach the reservoir caprock. Continuing to inject further in such a fracture system may breach the top seal integrity of the caprock leading to uncontrolled out of zone injection. The study of evaluation of downhole fracture monitoring is divided into two parts. In this paper a downhole verification approach to identify the fracture initiation point(s) is the focus. It describes the planning, execution and interpretation of the downhole data. This includes spectral acoustic monitoring and modelling of the temperature responses to quantify the injectivity profile. In paper (Kohli, Kelder, Volkov, Castelijns, & van Eijs, 2021), the direct business impact and regulatory requirements are discussed by further integration of acoustic monitoring and temperature modeling data with detailed results from downhole measurements of fracture dimensions by means of pressure fall off tests. Combined, both studies form the integrated approach that the Operator took to meet the regulatory requirements proving that the fracture network propagation remains within the reservoir and that the top seal integrity is maintained.

fax 01-972-952-9435. AbstractAchieving the objectives of drilling horizontal wells is greatly dependent on accurate placement of the drainhole in the reservoir. Careful pre-job planning using offset well data and seismic maps helps to reduce the uncertainty to some extent. However, the unpredictability of structural and stratigraphic variation between the planned and offset wells and uncertainty inherent in seismic data are always associated with horizontal well planning. The formation dips computed from seismic and offset wells are therefore prone to some degree of error.Advances in real-time data transmission technology have made it possible to transmit image data uphole while drilling, through improving the robustness of the real-time signal, signal bandwidth and data compression. Logging-whiledrilling (LWD) real-time azimuthal resistivity images can be used for accurate estimation of the dip and strike of formations intersected along the well trajectory. In addition, structural surprises such as faults can be detected, and remedial actions taken immediately. Such information is of great value in making geosteering decisions while drilling into reservoirs within structurally complex geology or in an area with sparse geological information. Using image data, trajectory adjustments can be made during drilling yielding optimal well placement.We descibe the use of real-time image interpretation during the drilling of two horizontal wells within a block bounded by major faults on the north and south, with a series of smaller associated faults, anticipated but not confirmed prior to drilling from existing data, in a carbonate field in United Arab Emirates. The image data provided crucial input to guide the well trajectory through the target reservoirs resulting in the wells objectives being achieved. In addition, the image data clarified the regional geology of the area around the wells, thus helping to update the geological model for better description of the structurally complex reservoir.