Norway

Vol. 226 No. 4

New workflow capabilities integrate seismic to simulation activities

Sequential interpretation workflows, where the geophysicist passes interpreted horizons and faults to other asset team members (who then reload the data into their own separate applications), result in routine inefficiencies. Data are often duplicated, and valuable time is lost. Mistakes can be made, and team knowledge is inherently lost during every step of the process.

Technology developed in Norway overcomes these challenges by integrating multiple disciplines into a scalable, collaborative environment. Schlumberger Petrel* workflow tools are integrated Windows-PC software for seismic interpretation through reservoir simulation. All processes help to develop/ refine the same earth model.

The Petrel workflow tools seamlessly integrate seismic to simulation processes.

Common environment and management capabilities automatically capture workflows and knowledge, as work progresses. This eliminates information mismatch or exchange loss when using individual applications. It is the basis for integrating new data and rapidly updating earth models, lowering overall E&P risk.

By linking geophysics, geology and reservoir simulation in the same workspace, users can collaborate across disciplines, manage multiple development scenarios and introduce reservoir dynamics to everyone. This provides, consistent reservoir understanding for asset valuation. It leads to better predictions when forecasting oil in place, reservoir performance, and capex/ opex needs.

Apache Corp. selected this software as its primary reservoir modeling workflow tool. Schlumberger and Apache are also in an alliance, to work together on emerging technologies and workflow streamlining. The tools will interface directly with Apache’s OpenWorks** corporate data stores via OpenSpirit,*** avoiding any data migration. Apache will replace various interpretation packages with the new tools, enabling full seismic-to-simulation workflows within a single application.

“In both new assets and older fields, leveraging technology is a key element to profitability and adding value for our shareholders,” said Apache CEO Steve Farris. “New insights and efficiencies from technologies within the Petrel suite of workflow tools provide significant potential benefits to companies like ours.”

All data, such as seismic, wells horizon and fault interpretation, are organized into folders, for quicker data location in large projects. A case management system organizes all reservoir simulation runs, including volumetrics reports for detailed uncertainty projects. Spreadsheet layouts are used in many activities, such as analysis of mis-tie errors between 2D lines, or when setting up velocity models for domain conversion.

These workflow tools help to extract hidden information more quickly, and the patented “Ant Tracking” algorithm significantly accelerates fault interpretation. This results in a 3D volume that presents superior fault delineation, and automatically extracts fault surfaces by using intelligent search algorithms, 3D visualization and a stereo net tool.

The software provides a suite of seismic attributes that, in tandem with data analysis and crossplotting tools, helps asset teams understand how they relate to reservoir properties. 3D neural network technology enables quick differentiation of patterns in multiple seismic attributes that may indicate hydrocarbons.

The static reservoir model has become the focal point of data integration for geology and geophysics, but it is not the final product. Flow predictions based on the static model provide good approximations of initial, expected production rates and pressures during various operations. However, these predictions are rarely accurate for longer time periods, as changes occur when reservoir fluids are produced or injected. The ideal solution is to derive performance forecasts by using a dynamic earth model that evolves with the reservoir.

Reservoir engineering tools allow ECLIPSE* reservoir simulation models to be created and run within the integrated environment. This allows changes in seismic interpretation, or geological models to easily flow through to the simulation model. The impact of these changes on output rates or reserves can then be evaluated in a fraction of the time previously possible.

For example, Pioneer Natural Resources sought to improve drilling location accuracy and quality in the mature, geologically challenging West Panhandle Red Cave Amarillo Uplift of North Texas. Finding the right sand and reservoir quality had been hit-or-miss, and Pioneer was searching for a solution to predict those “sweet spots” of reservoir quality sand with greater probability.

Thus, Pioneer chose NuTech Energy Alliance log interpretation services and Petrel workflow tools. NuTech was used to calibrate, normalize and process 218 log suites. Petrophysical properties were then output into a suitable format for integration into workflow tools.

Working with the tools to build models zone-by-zone, Pioneer quickly determined the horizontal limits of reservoir-quality sands and the object-based stochastic distribution of hydrocarbon pore volume. The firm then drilled 21 wells with a correlation coefficient of 83.1% accuracy in predicting hydrocarbon pore volume. Pioneer was able to pick better infill drilling locations while reducing the risk of non-economic completions. Drilling accuracy improved about 30%. Reservoir characterization of mature fields adds value, because more reserves can be booked. Net property value increases, generating long-term cash flow.

The Petrel/ NuTech workflow enabled Pioneer to model 360,000 acres and map seven structural horizons, while distributing facies, Ø_eff, horizontal perm, vertical perm, SW_irr and net-to-gross properties. The resultant layer of hydrocarbon pore volume captured additional reserves and helped the company rejuvenate economic output in a field that had declined rapidly. This improvement arrested field decline, as modeling results were implemented quickly and cost-effectively.

Overall, time spent modeling was less than two weeks for a first-pass completed project. Model updating now takes one to two days, with three to four hours of daily input. Previous attempts to model a field this size would have taken months to years, with questionable results.

Traditional seismic interpretation tools are combined with new hydrocarbon prospecting workflows to help identify new reserves and make well placement decisions that involve less risk.