Tone Kråkenes - Emerson Process Management
The industry is looking for fast, easy-to-use, powerful reservoir management solutions to improve performance and production, and reservoir modeling is moving into this crucial phase of drilling developments in well correlation, well planning, local model updates, and the ability to incorporate real-time drilling data.
The end result is a rapid model updating workflow running on a continuous basis as new well data is gathered, ensuring the most correct model is always available for reservoir management decisions to maximizing reservoir performance.
Reservoir modeling software can hold all the data about the reservoir – including seismic and well data, as well as both static and dynamic reservoir models.
Such modeling programs, however, traditionally are used to calculate volumes and to estimate production, with other software programs used for operational activities such as well planning and optimizing the well path while drilling. This separation often results in barriers between different specialist and in delays updating the reservoir model.
The benefits of an integrated tool for all these activities in one program are potentially huge. With one common platform, both the speed and quality of the decisions can be improved.
Latest developments in reservoir modeling
A reservoir model is a numerical description of a reservoir. The key inputs are the interpretations from the seismic, the faults, and the top and base of the reservoir, in addition to well logs. Together, these provide details on the quality of the rocks, such as porosity, permeably, and the presence of hydrocarbons.
The reservoir modeling tools have the functions offshore operators need to further interpret and analyze this data and to build a numerical 3D model representing these interpretations. The model describes the extent of the reservoir, the quality of the reservoir, the potential subdivision of the reservoir, and where the hydrocarbons are. From this, the model can calculate volumes and simulate production.
The workflow manger can store each step in the modeling process as a job. This opens a new world of more efficient work processes relating to how easily and quickly models can be updated as new data arrives. It also aids in the vital area of uncertainty evaluation.
The model is only an interpretation of the available data, so as more data becomes available, the interpretation of the reservoir can change dramatically. Using the most recent data and the latest interpretations when drilling can be the difference between success and a low-producing offshore well.
One enabler for rapid model updating is WITSML (Wellsite Information Transfer Standard Markup Language), the industry standard for transmitting data. WITSML has improved the ability to transfer data in real time between service and oil companies, helping provide minute-by-minute updates on well positions and log data. Furthermore, WITSML is a public domain standard that also has enabled software companies to develop real-time applications independently.
Using WITSML, a real-time geosteering method has been developed where the continuous flow of data can be integrated seamlessly into the model. In this way, initial well planning can be extended to help adjust the well path during drilling.
Real-time well correlation
The benefit of incorporating real-time data into reservoir modeling is improved when combined with the improvements in well correlation, which makes picking and tracking the geology simpler, faster, and more adaptable. With a new well correlation tool, log responses in different wells can be compared using ghost curves, with the ghosts resized and mirrored to reflect changes in the geology or well path orientation.
For the planned well, a synthetic log response can be calculated by combining log responses from the neighboring wells and the model. This synthetic log response then can be compared with the real log response from the well being drilled. This tool often can improve job of hitting the target
Reservoir engineers, for example, might want to see how the new data from the well being drilled affects the flow of the reservoir. To this end, a local adjustment of the 3D grid, such as the stretching or compression of the grid to reflect thicker or thinner reservoirs, can be carried out, making it faster and easier to update the simulation model.
The physical properties such as porosity and permeability also can be adjusted locally to incorporate the latest data are into the model. This is achieved with the smallest adjustments possible while ensuring that the model matches the new data.
