S-Cube XWI has generated a 3D velocity model from seismic data which is the digital model at the heart of seismic derisking to evaluate the earth’s internal structures from probing prior to drilling.
S-Cube delivers its models through its XWI toolbox, which contains a patented technique called Adaptive Waveform Inversion AWI (AWI™). The company claims that it is arguably the most accurate and efficient algorithm in the world to determine the final velocity model from a highly inaccurate starting model.
XWI has now been run on the Chevron-operated Jansz field, a gas-filled structure 250 km off the coast of North West Australia that is part of the offshore Gorgon project – one of the largest and costliest energy projects in the world, costing over AUS$69 billion.
Final Investment Decision (FID) for Phase 2 of the project was announced earlier this year. Phase two will expand the subsea gathering network in both fields, and this will also involve a new drilling campaign, as well as the installation of new subsea manifolds to accommodate new wells, and flowlines to tie into the existing subsea equipment.
The S-Cube XWI computation ran on the Amazon Web Services (AWS) cloud iteratively churning through 100Gb of data taken over a subset of the structure for a week. Out of the process emerged the Base Cretaceous Unconformity (BCU) interface and the high porosity interval immediately below with the model showing continued convergence with iteration.
The XWI model achieved layer of layer downhole validation with the Jansz-3 and Io-1 wells. Both wells were held blind to the XWI computation giving extra confidence in extrapolating away from existing well-bores. The model can then be used to determine optimal location for subsequent new well-bores.
S-CUBE XWI model evolution employs RWI and AWI™ for the long to intermediate length scale updates before switching to industry-leading conventional FWI for final refinements to the detail. FWI alone applied from the same starting model and same lowest frequency range leads to waveform inversion misconvergence.
With the use of the XWI model, the well placement decisions in the second stage of the Gorgon oil and gas project off Australia's northwest coast can be optimised for highest yield production thereby gaining the highest possible return on the capital investment made.
The expansion is estimated to cost several billion dollars and will include drilling new wells in the Gorgon and Jansz-lo fields. It is expected to commence next year.
The Jansz-lo field is being developed as part of the larger Gorgon Project, which also involves the development of the Gorgon fields offshore, as well as onshore elements including a three-train LNG plant for producing 15.6 million t of LNG a year, a domestic gas plant for supplying 300 TJ of gas a day to Western Australia, CO2 removal and compression facilities, a 4km-long loading jetty and export pipelines.
Jansz-Io field is located within production licences WA-36-L, WA-39-L and WA-40-L, approximately 70 km north-west of the Gorgon gas field and 220 km off the north-west coast of Western Australia. Water depths at the field range from 1200 m to 1400 m.
The project is a joint venture between the Australian subsidiaries of Chevron (47.3%), ExxonMobil (25%), Shell (25%), Osaka Gas (1.25%), Tokyo Gas (1%) and JERA (0.4%).
Read the article online at: https://www.oilfieldtechnology.com/digital-oilfield/13062018/s-cube-xwi-generates-3d-velocity-model/