Solution Of A Complex Structural Problem By 3D-Seismic

1978 ◽  
Author(s):  
Henk van Deemter
2016 ◽  
Author(s):  
Kevin Christopherson

ABSTRACT East Africa is an integral part of the Tullow business. Tullow has been active for over ten years in the onshore rift basins of East Africa, which began with the opening of the Uganda Lake Albert Rift Basin in 2006 following the drilling of Mputa-1. We developed multiple sub-surface evaluation tools and an understanding on how rift success factors can combine during the drilling of the Lake Albert Basin that we then applied to the Tertiary rifts of Kenya. Extensive Full Tensor Gradiometry (FTG), seismic and drilling has taken place over the last five years in Kenya. This has established the South Lokichar basin as a significant oil basin with significant remaining exploration upside. Up until 2015 exploration drilling in the South Lokichar utilized 2D seismic data. The acquisition of 3D seismic in the north and west of the basin has allowed an improved definition of the structural framework and highlighted additional exploration potential. The Etom-2 well spud in November 2015 highlights the value of this 3D seismic in complex structural settings. Etom-1 was planned and drilled on 2D seismic and encountered 10 m of oil pay. Subsequent re-mapping based upon the 3D seismic revealed that the Etom structure was more complicated than originally interpreted and that Etom-1 had drilled into a collapse graben and not tested the structural crest of the field. Etom-2 targeted the up-thrown northern fault block which was not penetrated by the Etom-1 well and encountered 102 m of oil pay. The northern part of the South Lokichar basin is structurally complex and the 3D seismic provided the required detail to highlight that Etom-1 hadn't properly tested the Etom structure. Further mapping of the 3D seismic in the area around Etom-2 has identified multiple follow-up prospects that could be part of a new play domain in the northern part of the South Lokichar Basin. These targets are the focus for Exploration drilling that is due to commence in Q4 2016.


2005 ◽  
Vol 45 (1) ◽  
pp. 233 ◽  
Author(s):  
J.P. Scibiorski ◽  
M. Micenko ◽  
D. Lockhart

Recent drilling by BHP Billiton Pty Ltd in WA-155-P(1) and WA-12-R, on behalf of its partners Apache Energy Ltd and INPEX ALPHA LTD, has resulted in the discovery of four oil fields in the southern Exmouth Sub-basin, namely Ravensworth, Crosby, Stickle and Harrison. These discoveries, together with the earlier discoveries made by West Muiron–5 and Pyrenees–2, define the Early Cretaceous Pyrenees Member play fairway.The Pyrenees Trend play was first conceived in 1999 following appraisal of the Macedon gas field (Keall, 1999), but the concept remained dormant until the integration of geological information with high quality 3D seismic data led to the recognition of hydrocarbon related seismic attributes in the postulated play fairway.Ravensworth–1 intersected a 37 m gross oil column below a 7 m gas cap in high quality Pyrenees Member sandstones beneath the regionally significant Intra- Hauterivian Unconformity. Ravensworth, located on a northeast–southwest trending fault terrace, is a complex structural-stratigraphic trap that relies on separate top, base and cross-fault seals. High quality 3D seismic data coupled with recent interpretation techniques were integral to its discovery. In particular, the quantitative interpretation of seismic amplitude populations was a key factor in decreasing exploration risk.The Ravensworth discovery was followed by successful exploration wells on the adjacent Crosby, Stickle and Harrison fault terraces. Four appraisal wells have since been drilled at the northern ends of the main discoveries.The oil in the Pyrenees Member discoveries is biodegraded, moderately viscous (8–11 cp) and heavy (18–19° API gravity). Methane-dominated gas caps were intersected in Ravensworth–1, West Muiron–5 and Pyrenees–2.The recent drilling and coring campaigns by BHP Billiton and others in the Exmouth Sub-basin have significantly advanced knowledge of the stratigraphy and depositional environments of the late Tithonian to early Berriasian Macedon, Muiron and Pyrenees Members of the lower Barrow Group. The lower Barrow Group is a third order sequence deposited rapidly in marine to fluviodeltaic environments in response to the breakup of Gondwana and the onset of active rifting along the West Australian margin.BHP Billiton and its joint venture partners are assessing the commercial viability of the Pyrenees Trend discoveries.


2003 ◽  
Vol 82 (2) ◽  
pp. 169-176 ◽  
Author(s):  
H. von Hartmann

AbstractThe article tries to answer the question of the origin and structural development of the deformation of the pre-Permian units southwest of Bremen. An interpretetion of a 3D-seismic survey was made to resolve the structural style of the Upper Carboniferous with the aim to get some clues for the Variscan deformation of the Variscan foreland. The area is suitable for the evaluation because of the existence of a 3D-seismic survey. Moreover, the depth of the Zechstein at. 4500 m is not to deep for imaging deeper reflections and there is not a severe distortion of the reflection pattern by later tectonic developments. Because of the 3D insight into the complex and deep seated structures, other 2D-seismic investigations which image similar parts can be better understood and interpretation errors can be avoided. It is concluded that only 3D-seismic measurements can resolve the complex structural devolopment at this site.


2009 ◽  
Author(s):  
Pablo Andres Borghi ◽  
Erick Raciel Alvarez ◽  
Jaume Hernandez ◽  
Rafael Vela ◽  
Marco Antonio Vasquez ◽  
...  

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