Use of fault-seal analysis in understanding petroleum migration in a complexly faulted anticlinal trap, Columbus Basin, offshore Trinidad
36
Citation
25
Reference
10
Related Paper
Citation Trend
Abstract:
In the Columbus Basin, offshore Trinidad, evaluating the controls on fault seal is a prerequisite for understanding how the petroleum fields were charged. In this paper, we present a case study from Mahogany field, where interbedded Pliocene–Pleistocene shales and reservoir sands occur in a broad four-way-closed anticline cut by numerous normal faults. Fault seals in this stratigraphic sequence can be successfully evaluated using shale gouge ratio (SGR), with a transition between sealing and nonsealing faults occurring in the SGR = 0.15–0.25 range. Because of the high net-to-gross ratio of individual sands, low SGR values typically correspond to areas of reservoir self-juxtaposition, whereas good seals (SGR 0.2) exist where different sands are juxtaposed against one another. The larger structural geometry, which changes significantly from the shallow reservoirs to the deeper ones, closely controls the distribution of stacked, fault-sealed petroleum accumulations in this field. Petroleum column heights in individual fault blocks within the structure are limited either by (1) a cross-fault spill point at a low-SGR window on the west side of a fault block or (2) a synclinal spill point within a fault block from which petroleum leaves the overall four-way closure. The pattern of hydrocarbon-water contacts in the field suggests that petroleum filled and spilled its way from northeast to southwest across the structure with individual sands acting as a separate flow systems. Despite juxtaposition against each other, communication between stratigraphically different sands is minimal. Vertical migration of petroleum along faults is not required to explain the distribution of charged sands, and this is consistent with both petrophysical data and the known sealing character of the faults. This petroleum migration model serves as a tool for evaluating charge risk and column heights in untested fault blocks in the area.Keywords:
Trap (plumbing)
Petroleum reservoir
Salt tectonics
Cite
Citations (8)
Summary The Tu Chinh – Vung May is a frontier basin offshore Vietnam. This study uses 1D and 2D basin modeling across the Vung May trough, a main trough SE of the Basin, to understand the petroleum systems and hydrocarbon potential of the area. The results indicate all the element of petroleum systems are favorable for the accumulation of significant hydrocarbon reserves.
Trough (economics)
Petroleum system
Hydrocarbon exploration
Basin modelling
Cite
Citations (0)
Cite
Citations (35)
Petroleum exploration activity decreased by 40 to 50 percent in Australia during 1973 relative to 1972. The decrease is attributed to several political and economic factors believed to be unfavorable to the oil and gas industry. Sixty-seven exploration wells and 16 development wells were drilled or drilling in Australia during 1973. About half of the exploration wells were drilled offshore. Offshore, the principal active areas remained the Gippsland basin of Victoria and the northwest shelf of Western Australia. Onshore, there was little significant drilling activity with exception of the Cooper basin of northeast South Australia and southwest Queensland. In this basin there were only 3 exploration tests drilled, but all were gas discoveries. In 1973 Australian oil production was 22,443,266 cu m (141,168,140 bbl) and gas production was 4,343,102,000 cu m (153,832,670,000 cu ft). At mid-1973 Australia's reserves were about 4.5 billion bbl of oil and natural gas liquids and 38 Tcf of gas. Three new-field discoveries and 1 deeper pool discovery on the northwest shelf, together with successful delineation wells on 3 new fields in the Gippsland basin should increase the total reserve. In Papua-New Guinea 2 new areas of exploration drilling not tested previously included the Sepik basin of northern New Guinea and southeast of Papua in the offshore part of the Vogel basin. Geophysical exploration was the principal activity in several parts of Oceania during 1973. Fiji appears to have been the site of greatest activity in this region.
Cite
Citations (0)
The petroleum in the Subei basin is famous for poor,small,beraking to pieces,and scattering in the exploration history of Chinese petroleum,and it is a typical case of the most complex and small faultlock in the East of China.But the faultblock of Tianchang halfgrabenlike depression is more breaking and scattering.Formation of complex fault system depends on its special tectogenesis background,and oilgas migration and oil reservoir formation are closely impartibility with it.Analysis of fault system is a basis for futher realizing oil exploration and development.Fault system research mast not only master part,but also master all.This paper emphasizes method study of fault system,which is also to provide a reference for petroleum exploration in similar tectonic background.
Petroleum system
Petroleum exploration
Cite
Citations (1)