The operational condition that dominates the survey planning and implementation is the presence of major shipping transit fairway to and from the Suez Canal. This shipping thoroughfare covers about 70% of the survey area. Operational considerations necessitate a shooting orientation that closely parallels the shipping lanes, which approximates the strike direction of the subsurface target. Shooting in the dip direction, across the shipping lanes, was not considered to be operationally feasible for a 3D spread or operation. Wave equation simulation was used in preparation of the acquisition program specifications. The technique was utilized to produce synthetic seismogram shot records that were in turn examined, interpreted and processed to assess the impact of various parameter combinations on meeting technical, operational and economic requirements set by the exploration staff.
Survival analysis is the analysis of time-to-event data. Two important functions in the analysis of survival data are the survival function and the hazard function. The Kaplan-Meier method is widely used to estimate the survival function. One of the objectives of the analysis of survival data might be to examine whether survival times are related to other features. A popular regression model for the analysis of survival data is the Cox proportional hazard regression model. The most commonly used approaches, for the baseline survival function, are the Breslow and Kalbfleisch-Prentice methods. These methods provide a step function estimate of the survivor function and in many instances a continuous estimate would be preferable. For these reason, in this paper we proposed a kernel smoothing technique for baseline estimator, based on Kalbfleisch-Prentice method. We start with kernel smoothing of baseline hazard function, based on Kalbfleisch-Prentice estimator and epanechnikov kernel, than we use it to calculate the baseline survival function. To evaluate the usefulness of the kernel estimator of the baseline function, in the case of right censoring, based on Kalbfleisch-Prentice estimator we conduct simulation studies across a range of conditions, by varying the sample size and censoring rate. We compare it with the smoothing of the Breslow estimator regarding bias.
The Tempest 3D model and dataset were generated to test industry's ability to correctly image deep water Gulf of Mexico subsalt structures. The project included four steps: (a) design of a 3-dimensional model based on real Gulf of Mexico geology; (b) acquisition design that included narrow azimuth, mid (range) azimuth and wide azimuth geometries; (c) numerical simulation using twoway wave equation algorithm and construction of three synthetic datasets; (d) application of various prestack depth migration algorithms for testing of subsalt imaging quality. The project parameters acquisition design and prestack depth migration algorithm parameters were all selected based on a single guideline: to be done as close as possible to field data acquisition and imaging. By following this guideline we obtained a dataset which realistically represents our ability to resolve subsalt imaging challenges. In this paper we present the project steps and demonstrate its main results.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.