Michelle Tham

3D Coil Shooting on Tulip field: Data processing review and final imaging results

The Tulip 3D survey is a single-vessel full-azimuth Coil Shooting project in Indonesia. The circular geometry is very different to the conventional race-track towed streamer approach. While it results in many acquisition and imaging benefits, it also introduces a number of new challenges in the survey design, modeling, acquisition and processing workflows. This paper presents an overview of the data processing / imaging experience made during the coil shooting project. A processing workflow was tailored to address the challenges, and at the same time taking advantage of the opportunities provided by the circular geometry. The resulting images are demonstrably far superior to the vintage seismic data in the area, and provide a more suitable dataset for AVO inversion to seismic attributes and reservoir property characterization.

Full Azimuth Circular Survey in Indonesia: Survey Design, Onboard Illumination QC and Preliminary Processing Results

Conventional offshore 3D acquisition is still being performed mainly with narrow azimuth streamer configurations, even in structurally complex areas. Attempt at breaking this paradigm have been recently made by the industry through the successful acquisition of some unconventional “Multi-Azimuth” (MAZ), “Wide-Azimith” (WAZ) and “Rich Azimuth” (RAZ) marine surveys. Eni Indonesia and WestenGeco conducted “the first of its kind” full 3D Circular Shooting survey (Coil) over the Tulip Discovery in Indonesia between August and September 2008. This paper presents design, onboard illumination QC and preliminary processing results of this new “Full Azimuth” (FAZ) seismic effort.

Uncovering the Missing Data in the Gas Cloud with P-P Wave Imaging – a Deep Water OBN Survey from Southeast Asia Region

Summary The framework of reservoir modelling is the information and understanding derived from the 3D seismic data covering the area of interest. Uncertainties associated with the underlying seismic data potentially lead to the inability to draw clear conclusions as to the size and productivity of the reservoir. In the presence of low saturation gas bodies in the overburden sediments, the loss of signal strength, frequency bandwidth and the complex wave kinematics compound the challenge. We present a case study from a challenging deep-water oil field in southeast Asia. The project comprised of acquisition, processing, interpretation and QI groups working as an integrated team to meet the objectives of the project. The project utilized a multifaceted approach of combining ocean bottom node seismic data, optimizing preprocessing, building a high-resolution earth model, and using high-end imaging techniques, to significantly improve the overall quality of the seismic data beneath the large bodies of gas hydrates, clouds and free gas. The new data allows improved structural and stratigraphic interpretation providing a better understanding of the reservoir model and reducing the uncertainty related to the reservoir volume, connectivity and compartmentalization, thereby contributing significantly to the geological understanding of the field and influencing the future development decisions.

Marine seismic acquisition: efficiency and environment, new technologies applied in Australia

The design of successful marine seismic surveys is driven by many factors, two prime issues being efficiency and environmental impact. Efficiency is primarily driven by reduction of non-productive time and creating the largest sub-surface illumination area possible in the shortest time. In addition, public opinion and governmental regulations are requiring the industry to minimise their environmental impact. One aspect is reducing the overall sound exposure level (SEL) of the source into the marine environment. Using recent Australian examples, we will discuss and demonstrate the use of two new technology groups that address these concerns. The first is the use of a new type of seismic air-gun with optimal output over the range of frequencies commonly used in seismic exploration, while limiting potential environmental effects from unnecessary high-frequency emissions. The second is continuous data acquisition along the entire boat traverse, including the turns, thereby reducing non-productive vessel time. Both are described with examples from a recent survey acquired offshore north-west Australia.

Depth Imaging Coil Data: Multi Azimuthal Tomography Earth Model Building And Depth Imaging the Full Azimuth Tulip Coil Project

Summary The Tulip 3D is a full azimuth single vessel Coil shooting survey in Indonesia. Coil geometry acquisition records a dataset with a wide range of source to detector azimuths. Amongst the numerous benefits of extended azimuth sampling methods is the advantage of illumination diversity. This has a desirable impact with tomographic velocity model building for depth imaging. The broad range of source to detector azimuth information allows an additional constraint on the travel time tomography by providing a network of intersecting rays not available with narrow azimuth geometries.