Reservoir characterization is a main objective in oil and gas exploration, with permeability, thickness, skin factor, reservoir boundaries, production potential, and reservoir fluids as key values. However, sustainability currently plays an important role, which often translates to compliance with zero flaring requirements.
Traditional workflows integrating all the acquired data, from geophysical and geological to production, are cumbersome and require many workdays for the various domains. DTT analysis with such integration has been accomplished in the past; however, with the evolution of digital technologies and cloud computing, new advanced workflows are possible. These advancements enable rapid integration of subsurface data so that decisions can be made soon after logging. For instance, a decision to sidetrack a well or the decision to make a new appraisal can be fast-tracked. Declaration of project commerciality can be made only a few days after logging and can include integrated analysis of the tested reservoirs and history-matched models, providing a clear evaluation of reservoir performance.
The objective of this well was to confirm hydrocarbon presence and evaluate well productivity. The methodology adopted was to combine advanced petrophysical and dynamic reservoir measurements with integrated 3D modeling.
DTT performed with Ora™ intelligent wireline formation testing platform delineated the reservoir fluids with real-time results from the other wireline logs, including imagers to build a near-wellbore 3D reservoir model. Additionally, the Ora platform's built-in DTT capabilities eliminate flaring. This intelligent infrastructure-led exploration (ILX) solution enabled real-time visualization through Wellbore Insights on Delfi™.
DTT is a new generation of wireline formation testing that investigates high to low permeability and thicker reservoir packages with an increased radius of investigation (ROI) compared with traditional interval pressure transient testing (IPTT) by flowing faster and longer and by using higher resolution pressure gauges. DTT is not a replacement for drillstem testing (DST) but rather an approach to bridge the information gap between IPTT and DST, mainly used for greenfields, especially in multireservoirs where it is costly to test all potential zones.
Offset well data can be used to build a preliminary numerical model for a feasibility study in the target well. As soon as they were recorded, relevant logs such as nuclear magnetic resonance (NMR) and image logs were used to select pressure, sampling, and DTT points and to derive reservoir properties and facies description to update the numerical model. Innovative ILX workflows, from laminated sand analysis and resistivity to permeability anisotropy calculation, were deployed.
During the DTT acquisition, real-time monitoring and constant communication between parties were critical for an effective operation. In situ reservoir fluid data and pressure transient data were constantly analyzed and integrated into 2D and 3D space in an open and and collaborative digital cloud environment of the Delfi digital platform. 3D near-wellbore reservoir models were created using geological and petrophysical data, combined with some seismic information shared by the operator. Several realizations were produced and tested against the dynamic data to derisk the geological uncertainties.
The most representative near-wellbore 3D model that integrated all of this information was ultimately used to calibrate the petrophysical properties. This step essentially consisted of history matching the transient data using the most probable geological model and log properties. The calibrated numerical model enabled evaluating well deliverability, reservoir connectivity, and minimum hydrocarbons in place.
Gathering insights such as these typically takes weeks with conventional technology. By using intelligent ILX, the operator was able to understand key reservoir insights for field development within hours of data acquisition.
For more information, read IPTC-24454-MS.
