bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE STRUCTURAL EVOLUTION OF THE GOLDEN LANE, TAMPICO EMBAYMENT, MEXICO
Authors: Wilson H. H. 
Published: December 2007

The Golden Lane oilfields of Mexico will always hold a place of prominence in the annals of petroleum geology. The most prolific oil‐well ever drilled, Cerro Azul No. 4, was one of a string of wildcats which defined a Cretaceous carbonate ridge that lay buried below gently‐dipping Neogene clastics on the Tampico coastal plain. Continued drilling showed that the buried ridge had an arcuate shape, and this led to the interpretation that the feature was a Lower Cretaceous reef. When the Poza Rica “giant” was discovered in detrital Cretaceous limestones west of the ridge, these were naturally considered to be forereef talus. Later drilling offshore discovered another string of Cretaceous carbonate traps which joined the onshore fields to complete the circlet that became renowned as the “Golden Lane atoll.”An abundance of rudists in Cretaceous reservoirs of the Golden Lane and Poza Rica gave rise to the concept of the rudist reef build‐up. A presumed analogue for the rudist reef of the Golden Lane was discovered in Lower Cretaceous rudistid limestones exposed at Sierra El Abra, NW of the oilfields. The foregoing interpretation has become entrenched in geological literature, even though an integrated structural‐stratigraphic synthesis of the Golden Lane is lacking.Time‐stratigraphic control of Cretaceous formations in the Tampico embayment is complicated by scarcity of documented marker fossils, and confused by the common occurrence of reworked detritus. It is ussumed herein that Cretaceous volcanicity in the Tampico embayment, as in the Gulf of Mexico generally, commenced in the Late Cenomanian. From this, it is concluded that much of the Golden Lane and Poza Rica reservoir sequences in which bentonite layers occur are of Late Cretaceous age. The El Abra outcrops, on the other hand, are undoubtedly Early Cretaceous. Structural analyses show that the Golden Lane area has an active and complex structural history. Strong faulting along NE‐SW trends was active in Late Cretaceous time, giving rise to syntectonic débris flows. At the same time, a major positive feature developed to the east in the Gulf of Mexico.By Middle Eocene time, the Gurf of Mexico positive was stripped‐down to metaphoric basement and subsequently collapsed as regional extension sundered the basement and allowed the injection of oceanic crust. A salt basin formed during the Oligocene eustatic low‐stand. Cretaceous carbonates of the Golden Lane were incorporated in a westward‐plunging synform in pre‐Oligocene time, but thereafter were rotated by regional downwarping into the Gurf of Mexico. In Holocene time, the synform was inverted, and these latest stresses were accompanied by injection of numerous dykes and plugs that cut the Golden Lane.From, this structural and stratigraphic synthesis, it is concluded that the Golden Lane anomaly is the product of a complex sequence of post‐Lower Cretaceous structural events. It is bounded on the west by a buried Middle Eocene fault, and on the east by a Neogene growth fault, and is not a Lower Cretaceous carbonate build‐up.
ENVIRONMENTAL SETTING AND DIAGENESIS OF LOWER PERMIAN PALAEOAPLYSIND BUILD‐UPS AND ASSOCIATED SEDIMENTS FROM BJØRNØYA: IMPLICTIONS FOR THE EXPLORATION OF THE BARENTS SEA.
Authors: Lønøy A. 
Published: December 2007

Lower Permian palaeoaplysinid build‐ups, inter‐bedded with inter‐build‐up logoonal sediments occur both on Bjornoya † and in the subsurface of the Barents Sea. They formed on a low‐energy, broad and shallow shelf, and show a cyclic development which was probably related to minor eustic sea‐level changes. During periodic lowering of sea level, build‐ups were subaerially exposed, meteoric diagenesis with Karstification took place within the build‐ups, and hypersaline conditions prevailed in the lagoons.Most diagenetic changes took place early and include fresh‐water dissolution, dolomitization, evaporite precipitation, and pseudomorphic replacement of evaporites. Fracturing and associated hydrothermal calcite, barite and galena cementation occured during the Early Tertiary opening of the Norwegain‐Greenland Sea, and affected the entire western part of the Barents Shelf.In the Barents Sea, the palaeoplysinid build‐ups have composite thickness on the order of several hundred metres and are restricted to positive structural elements. They are regarded as potential reservior rocks in this area, partly because of the high porosity of similar build‐ups in Central Spitsbergen. The reservoir quality of the build‐ups on Bjornoya and from the single cored build‐up complex in the Barents Sea is, however, relatively poor. Early Tertiary fracturing increased the permeability of the bulk rock, but also caused leakage of accumulated hydrocarbons.
COMPOSITE CLASSIFICATION OF FRACTURED AND BRECCIATED CARBONATE ROCKSB EXAMPLES FROM THE ORDOVICIAN ELLENBURGER GROUP, WEST TEXAS
Authors: Ijirigho B. T. , Schreiber J. F. 
Published: December 2007

The attention paid to rock fracturing in recent years is a result of the discovery of large volumes of hydrocarbons in fractured rock reservoirs. This regional study was conducted in order to facilitate a better understanding of the performance of fractured reservoirs, and to select the proper procedures and well intervals for artificial fracturing.Five classification schemes are proposed for fracture, breccia, porosity and permeability developments, as revealed by mega‐ and microscopic examination of cores, thin‐sections and outcrop samples. A composite classification combines the attributes of the other schemes in an attempt to predict residual porosity and permeability on a reservoir scale. Various genetic types of breccia were encountered in this study, but those of tectonic origin predominate and control hydrocarbon production.At the initial time of fracturing, porosities range from low in crackle breccia, to very high in random and pheno‐breccias. With moderate cementation, random and pheno‐breccias remain the most porous and permeable structures, However, with a high degree of cementation, porosity and permeability become negligible in crackle breccia, and very low or absent in pheno‐breccia. The degree of cementation which controls residual porosity depends on the availability of mineral‐laden solutions.
THERMAL MATURATION HISTORY OF THE SIRTE BASIN, LIBYA
Authors: Gumati Y. D. , Schamel S. 
Published: December 2007

The high degree of thermal maturity observed in shallow sediments in the western part of the Sirte Basin, Libya, requires higher geothermal gradients and/or thicker overburden in the past than exist today.The degree of thermal maturity of the Upper Cretaceous shales, the regional structure, and the subsidence history of the basin all indicate that over 3,000 m of section was removed from the western flank of the basin by uplift and erosion in the mid‐Tertiary. Vitrinite reflectance values in wells suggest that gradients of 1.6d̀FC/100 ft to 1.8d̀FC/100 ft existed in the western region at the time of peak thermal activity, in contrast with a general basin average of 1.2 d̀F/ l00ft
THE HYDROCARBON POTENTIAL AND TECTONICS OF INDOCHINA*
Authors: Hayashi M. 
Published: December 2007

The region under discussion is that part of Indochina which includes Vietnam, Laos, Kampuchea and eastern Thailand. The Kontum Massif composed of a metamorphosed basement complex, is the core of the Indochina region, and crops out from eastern Vietnam to Laos and Kampuchea. The concept of concentric growth of orogenic belts along the periphery of this massif seems to have been accepted as being within the scope of the classic theory of orogeny. The application of a modem plate‐tectonic hypothesis with the aid of Landsat image analysis, has, however, enabled a new interpretation of the tectonic development of the area to be made.The hydrocarbon potential of Indochina is here investigated, based on this interpretation of the region's tectonic development, and taking account of the morphological and textural characteristics detected from Landsat imagery. Three areas: (1) the Mekong Delta. (2) the Khorat Plateau, and (3) the Hanoi Basin‐gulf of Tonkin, are selected for detailed discussion of their hydrocarbon potential.
SURFACE AND DEEP STRUCTURAL CONTROL OF THE NW CARBONIFEROUS BASIN OF IRELAND: SEISMIC PERSPECTIVES OF AEROMAGNETIC AND SURFACE GEOLOGICAL INTERPRETATION
Authors: Price C. , Max M. D. 
Published: December 2007

A detailed study of the magnetic and seismic data in and adjacent to the NW Carboniferous Basin of Ireland suggests that surface faults, mainly in the Carboniferous and Devonian rocks, are directly related to regional faults on older subjacent basement. These regional faults have controlled the tectonics of the area since the Late PreCambrian.The primary faults are associated with the steeply‐dipping fault zone whose presence is marked by the Fair Head‐Clew Bay magnetic linear (FCL). The FCL can be traced to the east where it becomes concident with the Highland Boundary Fault zone of Scotland. The Highland Boundary Fault maarks the southern limit of the Dalradian rocks. and was a plate margin beignning in Late Combrian‐ Early Ordovician (Grampian)times. In ireland, the FCL also marks this Lower Paleozoic plate boundary. Associated secondary magnetic linears (linears) indicate the presences of other basement fault caused by mkovement on the FCL, which were rejuvencated during the Upper Paleozoic.Large magnitude movement on these fault‐systems commenced druging the Early Paleozoic and continued through the Devonian, with lesser magnitude movement continuing until after the Carboniferous. The abrupt change from the more than 4,500 m of Paleozoic sediments present south of the FCL to approximately 1,500 m of sediments to the north is a result of complex wrench‐faulting, shown by flower structures in seismic profiles, Fold orientations and fold and fault deflections near the major sinistral fault are also consistent with formation within a sinistral strain field.
EVIDENCE FOR NON‐COLLISION GEOLOGY IN THE MIDDLE EAST
Authors: Kashfi M.S. 
Published: December 2007

It is customary to interpret ophiolite belts, including those of the Middle East, as remnants of oceanic crust. However, the mere presence of an ophiolite belt by itself is not proof that it is the site of a former subduction zone.It is argued in this paper that no subduction zone is, or ever was, present in the Middle East. Earthquake‐intensity and earthquake‐epicentre maps show that shocks of magnitude 6.5 and greater (Richter scale) take place in many areas far removed from proposed subduction zones. Even the major proposed subduction zone of the Middle East‐the Zagros “suture” or Zagros “crush zone”‐ has no associated volcanic rocks, and therefore lacks the lithological suit which typifies so‐called subduction zones. Moreover, basement‐rock exposures and basement reached in deep boreholes indicate that at least the major part of the Zagros Fold Belt is underlain by continental, non‐oceanic crust.The fact that identical lithofacies of the same, late PreCambrian through Early Tertiary, are present on both sides of the alleged subduction zone should be enough to give one cause for thought. Well‐known and closely related faunas have been described from Early and Late Paleozoic strata on both sides of the Zagros suture for many decades.Disagreements among plate tectonicists are many. Some advocate the former presence of two or more plates in this region; others have postulated several microplates; other workers support island‐are interpretations; almost all favour the existence of at least one suture zone that marks the locus of a continent‐continent collision. Nearly all of these hypothese are mutually exclusive. Most would cease to exist if the field data were honoured. These data show that there is nothing in the geologic record to support a separation in the past of Arabia‐Africa from the remainder of the Middle East.
GEOHISTORY, THERMAL HISTORY AND HYDROCARBON GENERATION HISTORY OF NAVARIN BASIN COST NO. 1 WELL, BERING SEA, ALASKA
Authors: Cao S. , Lerche I. 
Published: December 2007

Using a one‐dimensional model, we numerically simulate with time the geological processes of sedimentary deposition, compaction, fluid flow, heat flow and hydrocarbon generation. Input well data, in the form of present‐day formation thicknesses, porosity with depth, thermal gradient, vitrinite reflectance with depth, and fluid overpressure with depth constrain the dynamical model. We present model results for the Navarin Basin COST No. 1 well, including reconstructions of burial history, fluid flow history, thermal history and hydrocarbon generation history.We also demonstrate how important geophysical variables (such as permeability, porosity, fluid pressure, fluid‐flow rate, and thermal maturity indicators) vary with depth and time. Comparison of the model results with observed data illustrates and emphasizes the capabilities of the modelling procedure.The significance of the dynamical model is that it permits a quantitative assessment to be made of (i) the timing and depth locations of the generation and migration of hydrocarbon in a basin, relative to the formation of structural and stratigraphic traps: (ii) the timing of the production of overpressuring and fracturing within a basin: and (iii) the effect of cementation and dissolution on the retention of hydrocarbons in a trap. The model also enables an assessment to be made of the most likely prospective areas for hydrocarbon accumulation in a basin.
THE HEZAN UNITS: A FRAGMENT OF THE SOUTH NEO‐TETHYAN PASSIVE CONTINENTAL MARGIN IN SE TURKEY
Authors: Fontaine J. M. , Monod O. , Perincek D. 
Published: December 2007

Recent progress in structural and stratigraphic analysis of the allochthonous units situated north of Hazro in the Border Fold zone of SE turkey has shed light on the nature and signijicance of the Gondwanan margin there. Allochthonous material consists of several superimposed units ranging in age from the Early Trias to the Late Senonian (Hezan units), in which the transition between neritic carbonates and the pelagic and detrital facies is well indicated by an Ammonitico‐rosso facies of mid Jurassic age. Above it, ophiolitic material and radiolarites represent the former Tethyan crust and cover. The Hezan units thus belong to the former Gondwanan margin thrust southwards in Lute Cretaceous times, and a tentative reconstruction of its Mesozoic evolution there is facilitated by the absence of later major tectonic events.This reconstruction shows marked diferences compared with the more complex nearby margins described in the Hellenides or Zagrides, where parallel ridges and troughs reflect crustal extension. By contrast, the simple “staircase”geornetry of the present margin is best interpreted as the result of the fracturing of the Gondwanan continent, separating the Apulian and African Plates as early as the Trias.
THE HYDROCARBON PROSPECTS OF THE RED SEA‐GULF OF ADEN: A REVIEW
Authors: BEYDOUN Z. R. 
Published: December 2007

The area reviewed covers some 825,000sq. kms. Since the early 1960s. 52 exploration wells have been drilled in the Red Sea. leading to four undeveloped (mainly gas‐condensate and dry gas) discoveries; twelve exploration wells have been drilled in the Gulf of Aden since the late 1970s, leading to one undeveloped oil discovery. Numerous surface oil seeps in the Red Sea testify to oil generation, while many of the drilled wells have also had shows.The syn‐and post‐rift Neogene stratigraphy of the Red Sea is very similar to that of the prolific oil‐producing Gulf of Suez graben, with source, reservoir and seal rocks widely present; pre Neogene rocks. however, are only present in patches. and include some marine Paleogene and Late Cretaceous sediments on older continental clastics in the northern half, and marine Jurassic on Basement in the southernmost sector. In the Gulf of Aden, the Neogene is less thickly developed, and lacks the widely‐occurring evaporite sequence of the Red Sea; the marine Paleogene and Creataceous‐Jurassic sequences of the pre‐rift succession are, however, welldeveloped, although the Jurassic is locally removed by block erosion.The tectonic evolution of the two rift basins is here discussed, and evidence for the areal extent of oceanic floor or stretched coninental crust. for episodic or continuous extension and sea‐floor spreading, and for pre‐rift doming and fracturing, is reviewed. It is concluded that episodic extension and spreading have occurred, and may be more advanced in the Gulf of Aden than elsewhere; this has been accompanied by higher paleo‐temperatures and geothermal gradients along the margins in the past, and high present‐day heat‐flow in the axial regions of both rifts. Overmaturation of the pre‐rift sequence in the southern margins of the Red Sea has resulted, aided by deeper burial, but contrary to prevalent views that the regions is too hot and gas‐prone, black‐oil potential in both basins is present at depths ranging from 1,000 m to a maximum of 4,500 m.Hydrocarbon play in the Red Sea is principally Neogene, and traps are provided by rotated Basement fault‐blocks and horsts in the pre‐evaporite sequence, and by salt flowage and piercement, together with stratigraphic pinch‐out, in the post‐evaporite sequence. In the Gulf of Aden, the main play is in the pre‐rift Paleogene sequence, while lower potential also exists in Neogene and Mesozoic successions. The Arabian side of the Red Sea has the widest and most poorly‐explored shelf of the whole region.
THE SUDANESE RED SEA: 1. NEW DEVELOPMENTS IN STRATIGRAPHY AND PETROLEUM‐GEOLOGICAL EVOLUTION.
Authors: Bunter M. A. G. , Magid A. E. M. Abdel 
Published: December 2007

The development of the Red Sea‐Gulf of Suez Rift follows two tectonic phases: pre‐rift and syn‐rift: rifting of the Afro‐Arabian craton was initiated in Eo‐Oligocene times. Generally good reservoir‐quality fluvio‐deltaic and marginal‐to fully‐marine Palaeozoic, Mesozoic and lowermost Cenozoic (Palaeogene) rocks had been deposited and are partly preserved.Marine Upper Cretaceous shales, carbonates and sandstones in the Gulf of Suez change facies to more continental sandstones of the Sudanese Red Sea; similarly, Post‐Cretaceous pre‐rift limestones and shales change facies to shallow‐marine sandstones. Syn‐rift sedimentation on either side of the Red Sea axial trough is essentially identical to that of the Gulf of Suez. As a consequence of this, the Gulf of Suez ingredients of mature oil‐prone source rocks, reservoirs and seals are present in the Sudanese Red Sea. Heat flows are higher in the Red Sea than in the Gulf.During the early pliocene there was a further episode of doming, further Red Sea extension took place, and the Red Sea attained its current shape.Remapping of 5,000 kms of 1970's‐vintage seismic data in the Sudanese Red Sea has resulted in recognition of many new prospects, which include: post‐salt prospects, similar in structural style to the structures tested by the successful Sudanese Red Sea Suakin‐1 and Bashayer‐1A gascondensate and dry gas discoveries; base‐evaporite prospects of a structural style virtually untested in the Sudanese Red Sea, but known to be prospective in the Gulf of Suez; and preevaporite prospects with structural styles indentical to those most prospective in the Gulf of Suez.
THE SUDANESE RED SEA: 2. NEW DEVELOPMENTS IN PETROLEUM GEOCHEMISTRY
Authors: Bunter M. A. G. , Magid A. E. M. Abdel 
Published: December 2007

From the limited analytical data which is available from the study area, it appears that the Mukawar and Hamait Formations, sandy facies of Upper Cretaceous and Cenozoic age, have little or no hydrocarbon source potential. However, of the twelve Sudanese Red Sea wells, only one penetrated the Mukawar Formation. and the Hamamit is only known in four wells.On the other hand, the lower to middle Miocene Rudeis. Kareem and Belayim Formations were penetrated in several wells. and may have actually generated black oil in attaining their current levels of thermal maturity. The middle to upper? Miocene Dungunab Formation, which is equivalent to thesouth Gharib Formation of the Gulf of Suez. contains thin. regionallyextensive, intra‐evaporite shales. These are early‐mature in coastal areas but, if developed in the deeper offshore. are likely to be post‐mature and are likely to have generated hydrocarbons. The zeit Formation is of variable thickness. the maxima coniciding with areas of deltaic influence. Although information is limited, it appears that occasional thin shales units may have significam source potential. The areas of more concentrated deltaic sedimentation with in the Zeit Formation are more likely to provide gas‐prone source rocks. The Plio‐pleistocene Abu Shagara Group has no oil source‐potential in the nearshore areas. Potential may improve further offshore. where it is possible that these marine sediments may be richer in organic matter and have been subject to higher heat flow.Hydrocarbon generation in the Sudanese Red Sea had been influenced by many factors in addition to rift‐controlled subsidence. These include the high thermal conductivity of evaporites, tectonic overpressuring and, in deeper waters, significantly higher levels of heat flow. Lower to middle Miocene source rocks are likely to have generated hydrocarbons at the end of Miocene times, whereas younger source rocks could be generating hydrcarbons at the present.The source of gas in the Suakin‐1 gas‐condenstae and Bashayer‐1 dry gas discoveries is probably in the lower part of the Zeit Formation, an organically‐rich deltaic facies. The condensate at Suakin‐1 is likely to have been sourced from the inter‐evaporitic shales of the underlying Dungunab Formation. Black‐oil shows have been recorded at several Sudanese Red Sea wells and a significant gas‐condensate discovery was made at Barrqan‐1 in the northern part of he Saqdi sector. It has been suggested that reserves of condensate may be as high as half a billion barrels. Oil seeps on the Dahlac and Farasan Islands in the Ethiopin and Saudi sectors provide further grounds for an optimistic view that generation of commercial volumes of oil in the Sudanese Red Sea cannot be ruled our
PROSPECTS FOR PETROLEUM IN LATE PROTEROZOIC/EARLY PALAEOZOIC BASINS OF SOUTHERN‐CENTRAL AFRICA
Authors: Lawrence S. R. 
Published: December 2007

Interest has focused on Late Proterozoic/Early Palaeozoic basins in the light of encouraging indications from the Cuvette Centrale of Zaire and the Etosha Basin of northern Namibia.This paper focuses on the Ncojane‐Nosop (Nama) basin complex, which extends along the southern side of the “Pan‐African” Damara orogenic belt. The basin system is seen as a foredeepforeland development with respect to a Wilson‐cycle ‐ cratonic collision orogenic history.Stratigraphy and facies developments are used to speculate on the occurrence of source and reservoir rocks. Source rocks would appear to be concetrated in the marginal marine‐lagoonal sediments of the Kuibis and Schwartzrand subgoups of the lower Nama. Reservoirs might occur in reefal or shallow‐water limestones the lower Nama, and in upper Nama “red‐beds” of the Fish River subgropu.Subsidence‐uplift models are used to predict burial/maturation for the lower Nama. There is a critical late or post‐Nama metamorphism, which effectively destroys the source rocks in the foredeep and increases the general level of maturity some distance from the orogenic front. The occurrence of prospective source‐rock facies and the maturity histroy are used to extrapolate the prospective part of the basin eastwards into Botswana.