Wide-azimuth TTI imaging at Tahiti: Reducing structural uncertainty of a major deepwater subsalt field

Abstract

The Tahiti field is a recent major development in the deepwater Gulf of Mexico. The field’s prolific Miocene reservoir section lies below a thick salt canopy with structural dips as high as 80 degrees, adjacent to a near-vertical salt root. Successful appraisal and initial development was enabled by interpretation of proprietary depth imaging products generated from narrow-azimuth seismic data. However, reservoir-scale mapping and fault definition remained problematic due to seismic imaging and illumination challenges. In 2009–2010, the Tahiti partnership initiated a reimaging project using multiclient wide-azimuth seismic data. The project employed current technologies for multiple attenuation, tilted transverse isotropy velocity modeling, and migration. Increased azimuthal coverage and inherent multiple suppression provided by wide azimuth acquisition delivered significant imaging enhancements. Advanced noise and multiple attenuation techniques provided cleaner data with improved signal-to-noise. Earth models representing multiazimuth subsurface velocities and anisotropy parameters calibrated to well control with detailed salt interpretation resulted in higher confidence structural imaging. Comparison of Gaussian beam, one-way wave equation, and reverse time migration algorithms shows that reverse time migration generally provides superior subsalt and salt-body data quality, with improved event positioning, higher resolution, and enhanced steep dip imaging. The resulting seismic volumes enable accurate mapping of reservoir horizons and faulting. This will improve resource determination and future well placement in the next phase of field development.

Adequate velocity model as a basis for effective seismic imaging when mapping hydrocarbon traps associated with salt domes

“…Èñ-ïîëüçîâàíèå àíèçîòðîïíûõ ìîäåëåé ñ âåðòèêàëü-íîé îñüþ ñèììåòðèè ïðè ñóùåñòâåííî íàêëîí-íîì çàëåãàíèè ñëîåâ ìîaeåò çíà÷èòåëüíî ïîíè-çèòü ýôôåêòèâíîñòü ïðîöåäóð ïîñòðîåíèÿ ñåéñ-ìè÷åñêèõ èçîáðàaeåíèé Bowling et al, 2010;Epili et al, 2011;Swanston et al, 2011;. Ýòî äåìîíñòðèðó-åòñÿ íà ðèñ.…”

Cable-free Seismic Acquisition System

“…최근 다중방위 (Mahmoudian et al, 2015;Swanston et al, 2011), 다성분 (Grechka et al, 2005;Sanchis and Elboth, 2014), 3D 탐사 (Gharibi et al, 2012;Jeong and Suh, 2006;Naghizadeh, 2015), 탄성파 모니 터링 (Kim et al, 2011;Stammeijer and Hatchell, 2014;Yin et al, 2015) 등 다양한 자료취득 기술요구와 산악지형, 삼각주 지역, 육상과 해상 경계지대 등 다양한 지형조건에서 적용할 수 있는 탄성파 탐사기술 수요가 증가하고 있다 (Lansley, 2013). 수진기와 수진기가 케이블로 연결되지 않는 독립된 수 진기를 사용하는 무선(Cable-free) 탄성파 탐사기술은 다양한 탐사기술과 다양한 지형조건에서 탐사측선 설계가 가능하고 또한 수진기 설치와 수거가 편리한 장점이 있다 (Freed, 2008).…”

Interpretation, Modelling and Halokinetic Evolution of Salt Diapirs in the Nordkapp Basin

“…Risking a prospect in these areas of uncertainty can be a tedious job. The risk of missing the structural trap increases dramatically and the well can drill unexpectedly through salt resulting in saltrelated drilling problems (Swanston et al, 2011) (Fig.2B). Additionally, this phase is followed by the development of side-tracks which will increase considerably the project budget.…”