Steve Campbell

Comparative ray‐based illumination analysis

Two streamer design studies are based on a ten-streamer configuration with a dual source. The maximum offset is about 8 kilometers. The streamer spacing is 100 meters with a 50-meter spacing between the source arrays. This produces a natural crossline bin size of 25 meters. Figure 4 shows the vessel configuration. One streamer survey was shot with an East/West orientation and the other in the North/South direction.

Improved 4D seismic processing: foinaven case study

Using a case history from West of Shetlands, we study the combined impact of improved acquisition and improved processing on 4D time-lapse repeatability, as well as on 3D imaging. We show how, following a carefully planned 4D acquisition, new processing technologies improve the repeatability and interpretability of our three seismic vintages. In the first part of this paper we compare the repeatability of two vintages acquired in a non-4D friendly fashion to that of 4D-purpose data. We show how processing these vintages with an improved 4D sequence, i.e. better regularization and 4D binning, with pre-stack time Kirchhoff imaging, increases the repeatability. In the second part of the paper we also show comparisons of data processed with the new Kirchhoff imaging based 4D sequence to the same data analyzed with a 4D DMO sequence from four years ago.

Foinaven: 4D processing comes up trumps

A good 4D image shows the effect on the seismic of production-related changes from within and sur-rounding a reservoir. It is well understood that the quality of 4D images is driven by two main ingredients: the quality of the acquisition and the quality of the processing. While 4D acquisition has been taking the limelight recently, the evolution of 4D processing algorithms has been steadily, and perhaps quietly, enhancing the quality of 4D images, including data acquired before the advent of carefully designed, dedicated 4D surveys. Using data from the Foinaven Field, one of three BP-operated fields in the West of Shetlands area, this paper shows how such improvements in processing technology over the last decade have enhanced the quality of the 3D imaging, the 4D seismic difference image, and improved the 4D repeatability.

Ultra-deepwater 4-C offshore Brazil

This paper is the case history of an ultra-deepwater 4-C seismic program, recently acquired in the Campos and Santos basins, offshore Brazil. All aspects of the program will be discussed, including the feasibility study which first indicated the potential value of multicomponent technology to this region, to the survey objectives, to the illumination analysis used in designing the survey, to the field operations, to the fully processed results. Acquisition was completed on 19 April 2005, and the fully processed data were delivered in early November 2005.

An optimized workflow for coherent noise attenuation in time-lapse processing

In the time-lapse processing paradigm, a method has recently been proposed to simultaneously adapt multiple models in such a way that 4D differences are optimized (Zabihi et al., 2012). We build on this idea in developing a seismic processing workflow which is optimized for 4D signal enhancement in a more generalized manner, at a lower cost and with minimal impact on turnaround. The workflow is tested on real data with significant improvements in the final 4D product.

A Procedure to Analyze Optimum Orientation to Record Seismic Surveys

The question often arises how to arrange a seismic survey to best image particular events. Often much is known about the subsurface structures overlying the events of interest. In the method described here, ray-tracing is computed from prospective horizons for a simple VelocityDepth model. Surface positions of 3D wavefront traced shot-receiver pairs are accumulated and organized according to attributes such as azimuth and offset. Statistics derived from these data are presented in a graphical format which illustrate preferences in the model for the survey orientation needed to illuminate the prospective horizon.

Combined NMO response and stack array analysis of model‐based data in an environment of strong ground roll

Uphole and well log data can be used to calculate 1D reflectivity (time and offset) results which are then used to produce a rich-offset-sampled synthetic supergather that may be used in an offset matching procedure. An uphole survey provides the time and velocity picture of the near surface and a well log provides the data for the deeper target reflectors needed to model the source generated noise train and primary and multiple pressure, shear and converted waves.