ISSN:0141-6421    

DOI:10.1111/j.1747-5457.1993.tb00347.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Sedimentary basins in Argentina cover about 1.4 MM sq. km on land, and 400,000 sq. km offshore as far as the 200‐m isobath. Oil and gas has been produced from six mostly onshore pericratonic basins, all of which belong to the Sub‐Andean domain. Their current daily production amounts to 553,800 brls of oil (of which only 26,500 b/d comes from the offshore) and 2,392 million cu. ft of gas. Currently, proved reserves are around 1,354 million brls of oil and 20.3 trillion cu. ft of gas. Cumulative production to end‐1990 was 5.0 billion brls of oil and 13.7 trillion cu. ft of gas, 93% of which was associated gas.The most important basins from the viewpoint of current oil production are: Neuquén (yielding 44.5% of Argentina's total output); San Jorge (33.2%); Cuyo (9.9%); Magallanes (or Austral) (9.4%) and Tarija/Orán (3%). Yacimientos Petrolíferos Fiscales (the former Argentine State oil agency. YPF) is the largest operator in the country, with about 48% of daily oil and 64% of daily gas production, and the remaining output comes from private companies. However, this balance is expected to change in the near future as a result of deregulation and privatisation policies being implemented by the Go

ISSN:0141-6421    

DOI:10.1111/j.1747-5457.1993.tb00348.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

The Neuquén Basin in western Argentina offers a variety of attractive hydrocarbon plays in both the Jurassic and Cretaceous sequences. Exploration to date has proved hydrocarbon reserves of 800 million cu.m oil‐equivalent 60% of which are gas. These reserves have been found mainly in relatively small structures along the stable platform area, where good reservoir‐quality sandstones and carbonates are present. In the western thrust‐belt, large structures remain untested; however, reservoir quality in this area is a problem. The exploration dilemma is therefore. whether to search for “elephants”, with a high risk of finding adequate reservoirs, or be satisfied with the less risky but smaller rewards associated with fore

ISSN:0141-6421    

DOI:10.1111/j.1747-5457.1993.tb00349.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

The Triassic‐Cretaceous Neuquén Basin of west‐central Argentina covers an area of nearly 200,000 sq. km, encompassing the edge of the Andean Cordillera and the adjacent South American foreland. A seven‐km thick sedimentary succession has been developed after three main geotectonic stages: (1) Basin onset and fault‐induced subsidence after Triassic—Early Jurassic extensional collapse of a Late Paleozoic marginal orogenic belt; (2) Middle Jurassic—Paleogene regional subsidence behind a retreating subduction system; (3) Neogene contractional deformation and local load subsidence forced by advancing subduction conditions.Throughout the Jurassic and Cretaceous periods, depositional patterns were related to waxing and waning of a narrow seaway that was connected to the Pacific realm through gaps in the magmatic arc. Widespread anoxia and Type II organic matter preservation occurred in the context of peak transgressions during the Toarcian, Oxfordian, Tithonian, late Valanginian and Hauterivian. A protracted history of regular subsidence and moderate heat flow at a back‐arc position, together with the presence of widespread evaporite seals, has resulted in regional zonation of the hydrocarbon occurrences. The inverted Cordilleran province became largely overmature; an intermediate gas‐condensate to light‐oil belt developed after local drainage from mature source rocks; and a basin fringe belt, that includes mixed and partially‐degraded oil, was charged after lateral migration 20–50 km updip from effective source units.Reservoirs are provided by Jurassic‐Cretaceous marine‐to‐deltaic and fluvial‐to‐aeolian deposits, and ooidal or skeletal limestones and dolostones. A diverse trapping style includes drapes over basement blocks, variably inverted half‐graben features, detached and wrench‐related anticlines, and closures linked to the intrusion of Tertiary magmatic rocks. Perhaps as much as 50% of the discovered reserves lie in fields with a significant‐to‐dominant stratigraphic component. Exploration activity since the beginning of the century established the presence of recoverable reserves of abou

ISSN:0141-6421    

DOI:10.1111/j.1747-5457.1993.tb00350.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

The Quintuco — Loma Montosa Formation is the largest and most diversified oil‐producing carbonate depositional system in the Neuquén Basin. It was mainly deposited during the Early Cretaceous, in an intracratonic embayment of the Andean orogenic belt which extended eastwards over the South American Plate.Microfacies techniques have revealed that this formation consists of a number of juxtaposed, well‐developed depositional environments, which were from west to east: carbonates (basin, slope, and oolitic build‐up, which developed into an oolitic‐bioclastic platform); then evaporites (lagoonal and sabkha, both with frequent meteoric dolomitization).These environments shifted in time through several transgressive‐regressive cycles controlled by eustatism and synsedimentary differential subsidence, which originated in reactivated cratonic structures. At all times, the carbonate‐evaporitic environments were surrounded by fringing fan‐deltas. During regressive episodes, these extended basinwards as fluvial, and fan‐delta plain and front facies, terminating with unusual mixed carbonate — fan‐delta slope deposits.This extremely diversified association of carbonate, evaporite and siliciclastic sediments in the Quintuco‐Loma Montosa Formation overlies the mature, black shales of the Vaca Muerta Formation, which acted as source beds. Each depositional sub‐environment has the possibility of producing oil as a result of various types of secondary burial porosity (preceded in places by intercrystalline porosity produced by meteoric dolomitization), when combined with appropriate tectonic conditions.In this respect, the Quintuco‐Loma Montosa Formation is the largest and most attractive target for oil expl

ISSN:0141-6421    

DOI:10.1111/j.1747-5457.1993.tb00351.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Nine Mesozoic‐Tertiary basins of different orientations lie along the Argentine continental margin, over a distance exceeding 2,000 km: these are the Salado, Colorado, Valdes, Rawson, San Jorge offshore, North Malvinas (San Julian), West Malvinas and Magallanes (Austral) Basins on the Continental Shelf, together with the Continental Slope. These basins formed following the latest Jurassic — Early Cretaceous extension that accompanied the onset of South Atlantic rifting. Strain was modified by earlier basement fabrics, with consequent transtension. The Cape Fold Belt (Permo‐Triassic) provided a NW‐SE grain to pre‐Mesozoic cover off NE Argentina. In the central‐southern sector, several phases of oblique NEwards Pacific subduction and terrane accretion during the Permo‐Triassic formed back‐arc basins and volcanic belts, producing a more variable fabric orientated close to NNW‐SSE. Atlantic basin fill, of Lower Cretaceous‐Tertiary clastics, was deposited as a result of rift‐shoulder erosion and Atlantic flooding, following eastward tilting. Basin fill thickness is typically 2–4 km, but locally exceeds 6km. The hydrocarbon potential of these basins hinges as much upon the preservation of source rocks within the pre‐rift succession as it does on that of those within the base‐rift succession, and subseq

ISSN:0141-6421    

DOI:10.1111/j.1747-5457.1993.tb00352.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

The history of terrane accretion along the Pacific margin, that formed the Palaeozoic basement to Patagonia, is discussed. This pre‐existing NW‐trending basement fabric was periodically reactivated by shear stress, resulting from near‐continuous oblique Pacific subduction processes, producing pull‐apart and extensional grabens. During the Permo‐Triassic, an asymmetric passive rift developed east of an eastwardly‐dipping simple shear, following the axis of the proto‐South Atlantic, and was invaded by a shallow sea. The Falkland (Malvinas) Microplate is shown to have docked with Patagonia in the Early/Mid Jurassic. Clockwise symmetrical rotation and crustal deformation of the Falklands (Malvinas) and other microplates between east‐west trending, dextral strike‐slip faults controlled the development of the southern transverse Atlantic margin basins. Early restricted deposition in these basins (Early Jurassic‐Neocomian) led to the deposition of proved continental source‐reservoir associations. Rifting and transverse dextral strike‐slip shearing propagated northwards, up the axis of the Atlantic. As terrane collision progressed, the rift zone widened SWwards to the Pacific and NEwards to the Colorado Basin. Atlantic sea‐floor spreading in the Neocomian, and subsequent thermal sag of the Atlantic margin, is shown to have culminated in a major transgression in the Maastrichtian, which formed a regio

ISSN:0141-6421    

DOI:10.1111/j.1747-5457.1993.tb00353.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

ISSN:0141-6421    

DOI:10.1111/j.1747-5457.1993.tb00354.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

ISSN:0141-6421    

DOI:10.1111/j.1747-5457.1993.tb00355.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Book reviewed in this article:Organic geochemistry“Applied petroleum geochemistry”, edited by M. L. Bordenave.“Introduction to organic geochemistry” by S. D and V. J. Killops.Geochemical fossils“Biomarkers for geologists: A practical guide to the application of steranes and triterpanes in petroleum geology”, by D. W. Waples and T. Machihara.“The biomarker guide: interpreting molecular fossils in petroleum and ancient sediments”, by K. E. Peters and

ISSN:0141-6421    

DOI:10.1111/j.1747-5457.1993.tb00356.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY