No. Registros Solicitud 1 5614 colombia
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DE - DESCRIPTORS: Amazon-Basin; Apaporis-River; basement-tectonics; Brazil-; Caguan-Subbasin; Chiribiquete-Subbasin; Colombia-; Florencia-High; geometry-; geophysical-methods; geophysical-surveys; gravity-methods; Guaviare-River; Guyana-Platform; lineaments-; Llanos-; magnetic-methods; magnetotelluric-methods; orientation-; petroleum-; Putumayo-Basin; Solimoes-Basin; South-America; surveys-; tectonics-; Yari-High CC - CATEGORY CODES: 29A-Economic-geology,-geology-of-energy-sources; 16-Structural-geology DT - DOCUMENT TYPE: Abstract; Serial; Conference-Document BL - BIB LEVEL: Analytic RF - REFERENCE SOURCE: GeoRef, Copyright 2002, American Geological Institute. Reference includes data supplied by American Association of Petroleum Geologists, Tulsa, OK, United States IS - ISSN: 0149-1423 CO - CODEN: AABUD2 AN - ACCESSION NUMBER: 1998-064657 UD - UPDATE CODE: 199824 Registro 5437 de 5614 - GeoRef 1997-2001 TI - TITLE: Contrasting submarine fans off the Amazon and Magdalena rivers. AU - AUTHORS: Pirmez-Carlos; Flood-R-D; Ercilla-G AF - AUTHOR AFFILIATION: Lamont-Doherty Earth Observatory, Palisades, NY, United States BK - BOOK TITLE: In: AAPG international conference and exhibition; abstracts. BA - BOOK AUTHORS: Anonymous SO - SOURCE: AAPG Bulletin. 82; 10, Pages 1952. 1998. PB - PUBLISHER: American Association of Petroleum Geologists. Tulsa, OK, United States. 1998. CP - COUNTRY OF PUBLICATION: United-States PY - PUBLICATION YEAR: 1998 CN - CONFERENCE INFORMATION: AAPG international conference and exhibition. Rio de Janeiro, Brazil. Nov. 8-11, 1998. LA - LANGUAGE: English AB - ABSTRACT: The Amazon and Magdalena submarine fans are the two largest modem turbidite systems of the South American continent. Both river systems drain the Andes Mountains and major fan development occurred after the Miocene. Despite the contrasting margin setting--a passive margin for the Amazon and an oblique convergent margin for the Magdalena--both fans show overall similar morphologic characteristics, with the development of large channel-levee complexes and meandering channel systems. During the Pleistocene, fan construction in both systems resulted from the lateral switching of fan depocenters, but while a relatively long-lived canyon on the Amazon led to autocyclic channel avulsion to occur within the fan; margin tectonics affected the position of the Magdalena River with consequent formation of several smaller canyon-channel systems along the margin. During the Late Pleistocene and Holocene these fans were the locus of large scale mass-wasting, triggered by mud diapirism and instability of rapidly deposited channel-levee systems. Partial reactivation of older channel systems occurred on the Magdalena Fan, while mass-wasting was coeval with the final stages of channel-levee development on the Amazon Fan. The last sea level rise shut down turbidity current activity on the meandering channels of both fan systems, but recent tectonic activity on the lower Magdalena Basin led to switching of the river and the onset of large scale slumping and turbidity current activity off the present river mouth. The Holocene Magdalena system negotiates the irregular basin and ridge topography of the accretionary prism, outpouring large scale mass flows on the abyssal plain. DE - DESCRIPTORS: abyssal-plains; accretion-; Amazon-River; Andes-; Atlantic-Ocean; Cenozoic-; clastic-rocks; Colombia-; diapirism-; drainage-basins; Equatorial-Atlantic; fluvial-features; Holocene-; Magdalena-River; mass-movements; meanders-; ocean-floors; passive-margins; plate-convergence; plate-tectonics; Pleistocene-; Quaternary-; sea-level-changes; sedimentary-rocks; slumping-; South-America; submarine-canyons; submarine-fans; topography-; transgression-; turbidite-; upper-Pleistocene CC - CATEGORY CODES: 07-Oceanography DT - DOCUMENT TYPE: Abstract; Serial; Conference-Document BL - BIB LEVEL: Analytic RF - REFERENCE SOURCE: GeoRef, Copyright 2002, American Geological Institute. Reference includes data supplied by American Association of Petroleum Geologists, Tulsa, OK, United States IS - ISSN: 0149-1423 CO - CODEN: AABUD2 AN - ACCESSION NUMBER: 1998-064640 UD - UPDATE CODE: 199824 Registro 5438 de 5614 - GeoRef 1997-2001 TI - TITLE: Stress determination along the Andes Cordillera. AU - AUTHORS: Last-Nigel-C; Markley-Marvin-E AF - AUTHOR AFFILIATION: BP Exploration (Colombia), COL, Colombia BK - BOOK TITLE: In: AAPG international conference and exhibition; abstracts. BA - BOOK AUTHORS: Anonymous SO - SOURCE: AAPG Bulletin. 82; 10, Pages 1932. 1998. PB - PUBLISHER: American Association of Petroleum Geologists. Tulsa, OK, United States. 1998. CP - COUNTRY OF PUBLICATION: United-States PY - PUBLICATION YEAR: 1998 CN - CONFERENCE INFORMATION: AAPG international conference and exhibition. Rio de Janeiro, Brazil. Nov. 8-11, 1998. LA - LANGUAGE: English AB - ABSTRACT: This study concentrated on the impact of rock mechanical and hole stability considerations on the planning of the first horizontal well in the foreland area of the Andes foothills in Colombia. The key challenge which would impact well design was the assessment of the stress state in a setting which was thought to be neither representative of the active tectonics in the nearby foothills, nor of a classical passive margin. A methodology was developed to estimate the actual stress state in the reservoir and its overlaying sediments. Stress orientations were determined from borehole breakouts in offset vertical wells. An initial estimate of stress magnitudes was made by imposing the assumed constraint (based on structural interpretation) of a limiting strike-slip regime on the region. A sensitivity analysis was used to refine and confirm the stress state based on comparing the predicted critical mud weights from a range of other plausible stress models to the drilling performance and logging data from offset wells. The stresses associated with the model most consistent with the existing field data provided the basis for well trajectory planning and borehole stability evaluation in both the pi lot and horizontal well. In addition: 1. Drilling performance and wellbore stability studies from the nearby foothills gave valuable information and insight. 2. Offset vertical wells in the field provided clear warning signs (cavings, high torque, high overpulls and stuck pipe) of potential difficulties in directional wells. 3. Careful selection of casing setting depths could alleviate some of the instability. 4. Mud weight ranges for stable hole were calculated from the deduced stresses. 5. Natural directional "drift" tendencies of non-steered off -set vertical wells indicated strong correlation with structural dip and therefore the least problematic drilling direction. The planning process lead to the following important pre-drill recommendations for implementation of the proposed horizontal well: 1. The well should be drilled from North to South (close to S10W) to capitalize on the anticipated natural drift tendency (up-dip), reduce directional work and minimize hole instability problems (parallel to the minimum horizontal stress). 2. The calculated mud weight ranges should be used to guide mud weight selection to mitigate against hole instability and associated drilling problems. 3. All reasonable measures should be taken to monitor open hole condition (for example, excessive cavings), particularly in the build section. Be prepared to react. 4. A pilot hole should be drilled to confirm the planning and design assumptions, and additional selective data acquisition (for example logging to obtain formation tops and dips) used to optimize the drilling of the subsequent build section. The well was drilled successfully to plan, demonstrating the value of understanding the stress state and implied design issues when planning the first well of this type in a new and somewhat unusual geological setting. Indeed there had been initial conjecture that the well could not be drilled. The multidisciplinary, integrated approach was a key factor in determining the successful outcome. DE - DESCRIPTORS: Andes-; boreholes-; dip-; drilling-; horizontal-drilling; models-; oil-wells; optimization-; petroleum-; petroleum-engineering; planning-; reservoir-rocks; sensitivity-analysis; simulation-; South-America; stress- CC - CATEGORY CODES: 29A-Economic-geology,-geology-of-energy-sources DT - DOCUMENT TYPE: Abstract; Serial; Conference-Document BL - BIB LEVEL: Analytic RF - REFERENCE SOURCE: GeoRef, Copyright 2002, American Geological Institute. Reference includes data supplied by American Association of Petroleum Geologists, Tulsa, OK, United States IS - ISSN: 0149-1423 CO - CODEN: AABUD2 AN - ACCESSION NUMBER: 1998-064563 UD - UPDATE CODE: 199824 Registro 5439 de 5614 - GeoRef 1997-2001 TI - TITLE: Calibration of marine and non-marine Cretaceous biostratigraphic frameworks on the African margin of the South Atlantic Ocean and their correlation to the South American margins. AU - AUTHORS: Chen-Yow-yuh; Huang-Ting-chang; McLaughlin-Peter-P AF - AUTHOR AFFILIATION: Exxon Exploration Company, Houston, TX, United States BK - BOOK TITLE: In: AAPG international conference and exhibition; abstracts. BA - BOOK AUTHORS: Anonymous SO - SOURCE: AAPG Bulletin. 82; 10, Pages 1901. 1998. PB - PUBLISHER: American Association of Petroleum Geologists. Tulsa, OK, United States. 1998. CP - COUNTRY OF PUBLICATION: United-States PY - PUBLICATION YEAR: 1998 CN - CONFERENCE INFORMATION: AAPG international conference and exhibition. Rio de Janeiro, Brazil. Nov. 8-11, 1998. LA - LANGUAGE: English AB - ABSTRACT: Synthesis of multi-fossil-group biostratigraphic studies of the Cretaceous of central and West Africa permit us to establish a preliminary, integrated biostratigraphy for marine and non-marine sediments on the African margin of the south Atlantic Ocean. This zonation is based on studies in Chad, Niger, Central Africa Republic, Angola, Ivory Coast, and Senegal and is tied to a global chronostratigraphic standard. The findings were compared with coeval zonations from South America (Brazil, Venezuela, Colombia, Ecuador, and Peru) to establish preliminary correlations across the Cretaceous south Atlantic Ocean. Spores and pollen are a valuable tool for regional correlation. They occur relatively continuously through the period and are well represented in various sedimentary environments, both non-marine and marine. We identified over forty morphologically distinctive and stratigraphically restricted palynomorphs that divide the period into twenty-three zones. For the Albian and younger section, the non-marine zonation is calibrated to the chronostratigraphic standard based on coeval dinoflagellate, foraminifera, and nannoplankton data. Comparison between the palynomorph biostratigraphy of West and central Africa with the published literature for Brazil suggests that the biostratigraphic frameworks of these areas are generally compatible. Most variations are due to endemic species that constitute less than 20% of the total assemblage or due to minor regional variations of the ranges of a few forms. DE - DESCRIPTORS: Africa-; Angola-; assemblages-; Atlantic-Ocean; biostratigraphy-; biozones-; Brazil-; calibration-; Central-Africa; Central-African-Republic; Chad-; chronostratigraphy-; Colombia-; correlation-; Cretaceous-; depositional-environment; Ecuador-; Ivory-Coast; marine-environment; Mesozoic-; miospores-; Niger-; palynomorphs-; Peru-; pollen-; Senegal-; South-America; South-Atlantic; spores-; variations-; Venezuela-; West-Africa CC - CATEGORY CODES: 12-Stratigraphy DT - DOCUMENT TYPE: Abstract; Serial; Conference-Document BL - BIB LEVEL: Analytic RF - REFERENCE SOURCE: GeoRef, Copyright 2002, American Geological Institute. Reference includes data supplied by American Association of Petroleum Geologists, Tulsa, OK, United States IS - ISSN: 0149-1423 CO - CODEN: AABUD2 AN - ACCESSION NUMBER: 1998-064546 UD - UPDATE CODE: 199824 Registro 5440 de 5614 - GeoRef 1997-2001 TI - TITLE: A different seismic interpretation approach to define stratigraphic sequences and predict facies distributions in continental strata; an example from the middle Magdalena Basin, Colombia. AU - AUTHORS: Olaya-Ivan-D AF - AUTHOR AFFILIATION: Ecopetrol, Instituto Colombiano del Petroleo, COL, Colombia BK - BOOK TITLE: In: AAPG international conference and exhibition; abstracts. BA - BOOK AUTHORS: Anonymous SO - SOURCE: AAPG Bulletin. 82; 10, Pages 1948. 1998. PB - PUBLISHER: American Association of Petroleum Geologists. Tulsa, OK, United States. 1998. CP - COUNTRY OF PUBLICATION: United-States PY - PUBLICATION YEAR: 1998 CN - CONFERENCE INFORMATION: AAPG international conference and exhibition. Rio de Janeiro, Brazil. Nov. 8-11, 1998. LA - LANGUAGE: English AB - ABSTRACT: Conventional methods of seismic stratigraphic analysis, which depend on angular discordance and terminations of seismic reflections, are not very dependable or accurate in continental strata due to the dominance of nearly horizontal and parallel and/or discontinuous and incoherent seismic rejections. We have developed a philosophically different, robust approach to analysis of seismic reflections from continental strata. This approach relies on prediction of seismic reflection and wave-form attributes from stratigraphic analysis of well-log data; comparison of the predicted with the observed reflection attributes; adjustment, if necessary; and prediction of well-log attributes from observed seismic reflection attributes at other locations. This method acquires robustness for the following reasons. (1) Our stratigraphic analysis of well logs identifies chronostratigraphic units which are correlated across facies tracts. Since seismic reflections are generated from chronostratigraphic units, observations from the two data sets are comparable. (2) Stratigraphic cycles and their facies components (which are laterally variable within cycles) are identified at high vertical resolution in well logs. This high-resolution information is transferred to the seismic domain in the form of a prediction, using the relation that the magnitude of the impedance contrast multiplied by the continuity of the stratigraphic unit under consideration generates reflections. Well-log predictions of continuity, amplitude and wave-form character of the seismic response are compared with the observed, and the observed seismic character acquires geologic meaning. (3) Since the two data types generate the same types of stratigraphic information, but at different vertical and lateral resolution, the approach of hypothesis formulation and hypothesis testing using alternating data types is a powerful means to evaluate the accuracy of stratigraphic predictions. DE - DESCRIPTORS: accuracy-; amplitude-; chronostratigraphy-; Colombia-; cycles-; elastic-waves; geophysical-methods; geophysical-surveys; high-resolution-methods; impedance-; interpretation-; lithofacies-; Magdalena-Basin; reflection-methods; seismic-methods; seismic-response; sequence-stratigraphy; South-America; surveys-; waveforms-; well-logs CC - CATEGORY CODES: 12-Stratigraphy; 20-Applied-geophysics DT - DOCUMENT TYPE: Abstract; Serial; Conference-Document BL - BIB LEVEL: Analytic RF - REFERENCE SOURCE: GeoRef, Copyright 2002, American Geological Institute. Reference includes data supplied by American Association of Petroleum Geologists, Tulsa, OK, United States IS - ISSN: 0149-1423 CO - CODEN: AABUD2 AN - ACCESSION NUMBER: 1998-064519 UD - UPDATE CODE: 199824 Registro 5441 de 5614 - GeoRef 1997-2001 TI - TITLE: Fold and thrust belt along the western flank of the Eastern Cordillera of Colombia; style, kinematics and timing constraints derived from seismic data and detailed surface mapping. AU - AUTHORS: Restrepo-Pace-Pedro-A; Colmenares-Fabio; Higuera-Camilo; Mayorga-Marcela; Leal-Jairo AF - AUTHOR AFFILIATION: Conoco Colombia, Houston, TX, United States BK - BOOK TITLE: In: AAPG international conference and exhibition; abstracts. BA - BOOK AUTHORS: Anonymous SO - SOURCE: AAPG Bulletin. 82; 10, Pages 1956. 1998. PB - PUBLISHER: American Association of Petroleum Geologists. Tulsa, OK, United States. 1998. CP - COUNTRY OF PUBLICATION: United-States PY - PUBLICATION YEAR: 1998 CN - CONFERENCE INFORMATION: AAPG international conference and exhibition. Rio de Janeiro, Brazil. Nov. 8-11, 1998. LA - LANGUAGE: English AB - ABSTRACT: Direct evidence for polyphase deformation along the western flank of the Eastern Cordillera of Colombia along the Middle Magdalena Valley has been obtained from detailed surface mapping and seismic data. The sequence of events and related evidence is summarized as follows: Latest Campanian to Maastrichtian uplift of the Central Cordillera signaled by the presence of extensive alluvial fans, i.e., Cimarrona and Puerto Romero Formations. These consist largely of coarse clastic conglomerates and sandstones containing milky quartz pebbles most likely to be derived from basement rocks to the west. The Late Maastrichtian unconformity that strips-out the Cimarrona deposits locally, may indicate incipient structuration along the western flank of the Eastern Cordillera. A well developed east dipping Late Paleocene-E. Eocene unconformity recognized seismically throughout the Middle Magdalena Valley, is represented along the Eastern Cordillera mountain front by a deeply scouring unconformity beveling a westerly vergent thin-skinned belt of tightly spaced folds and thrusts. Synkinematic deposits containing large clastic fragments mainly of Cretaceous cherts are preserved as piggybacks of the main thrust sheets (Pocara and the base of La Paz Formations). The relief generated by this foldbelt constrained the axis of late Eocene sediments to run along the present crestal zone of the Eastern Cordillera (Villamil and Restrepo-Pace, 1997) and caused east tilting of the Middle Magdalena Valley basement by flexural loading. At the thrust front, a series of intra-cutaneous wedges were developed at some point in Late Miocene time as evidenced by onlapping relationships within the Miocene Real deposits at the top of its fluvial section. Late Miocene reactivation of some of the west vergent structures, in a break-back sequence, exhumed and refolded the Late Paleocene-E. Eocene foldbelt. In the field, tilted synkinematic deposits and the refolded Late Paleocene-E. Eocene unconformity may be observed. In the hinterland, major inversion of the Mesozoic extensional faults occurred, with concomitant deposition of molassic sediments in the Middle Magdalena Valley (seismically transparent section at the top of the Real Group. DE - DESCRIPTORS: Andes-; clastic-rocks; Colombia-; contraction-; deformation-; Eastern-Cordillera; faults-; fluvial-environment; fold-and-thrust-belts; geophysical-methods; geophysical-surveys; imbricate-tectonics; kinematics-; mapping-; maturity-; migration-; molasse-; petroleum-; polyphase-processes; reactivation-; sedimentary-rocks; seismic-methods; source-rocks; South-America; surveys-; tectonics-; thin-skinned-tectonics; thrust-faults; unconformities- CC - CATEGORY CODES: 29A-Economic-geology,-geology-of-energy-sources; 16-Structural-geology DT - DOCUMENT TYPE: Abstract; Serial; Conference-Document BL - BIB LEVEL: Analytic RF - REFERENCE SOURCE: GeoRef, Copyright 2002, American Geological Institute. Reference includes data supplied by American Association of Petroleum Geologists, Tulsa, OK, United States IS - ISSN: 0149-1423 CO - CODEN: AABUD2 AN - ACCESSION NUMBER: 1998-064504 UD - UPDATE CODE: 199824 Registro 5442 de 5614 - GeoRef 1997-2001 TI - TITLE: Stratigraphic and structural constraints on Campanian-Oligocene tectonostratigraphic development of northwestern South America. AU - AUTHORS: Villamil-Tomas; Restrepo-Pace-Pedro-A AF - AUTHOR AFFILIATION: Conoco, Advance Exploration Organization, Houston, TX, United States BK - BOOK TITLE: In: AAPG international conference and exhibition; abstracts. BA - BOOK AUTHORS: Anonymous SO - SOURCE: AAPG Bulletin. 82; 10, Pages 1979. 1998. PB - PUBLISHER: American Association of Petroleum Geologists. Tulsa, OK, United States. 1998. CP - COUNTRY OF PUBLICATION: United-States PY - PUBLICATION YEAR: 1998 CN - CONFERENCE INFORMATION: AAPG international conference and exhibition. Rio de Janeiro, Brazil. Nov. 8-11, 1998. LA - LANGUAGE: English AB - ABSTRACT: The position of the central axis of deposition over Colombian and Venezuelan continental crust has varied markedly though time. The axis of the depocenter migrated from west to east from Late Cretaceous to Oligocene, but at times, secondary drainage divides were established by local uplift events. In late Oligocene times with initial inversion of the Eastern Cordillera, the central axis of deposition divided into two permanent main axes, the proto Magdalena and the proto Orinoco systems. The west to east migration of the central axis of deposition had a tectonic origin and it happened in combination with tectonically driven changes in accommodation space. The evolution of depocenters can be divided into the following phases: A, ACAD: The Albian-Campanian basin was open to the west and the central axis of deposition was not confined to a position between mountains. This basin can be considered as a retro-arc post-extensional sag that behaved like a passive margin. B, CCAD: The axis of Campanian and early Maastrichtian depocenter was located along or west of the present Central Cordillera but migrated to the east pushed by the uplift of the mountain chain. C, MCAD: The central axis of late Maastrichtian deposition runs approximately over the present day western foothills of the Eastern Cordillera, possibly crosses over the Santander massif and continues into the Maracaibo Lake. Accommodation space decreased from Campanian to Maastrichtian times, as reflected in a regional facies change from distal marine shales to shallow marine sandstones and carbonate buildups. In K-T boundary times parts of the eastern margin of the Eastern Cordillera were uplifted by initial inversion of deeply-rooted Jurassic and early Cretaceous normal faults leading to a secondary axis of deposition located east of the uplifted region (PSAD). This K-T boundary uplift caused the erosion of the upper portions of the Cretaceous in the eastern foothills of the Eastern Cordillera. D, EPCAD: In Paleocene times the central axis of deposition was located along the spine of the Eastern Cordillera and extended into the Maracaibo Lake. Accommodation space decreased from Maastrichtian to Paleocene times, this is expressed as a regional facies change from shallow marine sandstones and isolated carbonates to coastal depositional systems. In many regions of Colombia, the base of coastal deposits is an unconformity or a paraconformity. E, LPCAD: In latest Paleocene times, the central axis of deposition shifted to eastern regions of the Eastern Cordillera and accommodation space decreased leading to deposition of a sand-prone unit. F, EECAD: The Early Eocene central axis of deposition was located along the present-day Llanos foothills; accommodation space decreased and the regional and well-recognized Middle Eocene unconformity began to develop. In mid Eocene times the axis of deposition probably continued to shift eastwards but accommodation space decreased dramatically, this unconformity marks the climax of the pre-Andean Orogeny in northern South America. Deposition during middle Eocene was dominant in the Maracaibo Lake area where large amounts of sediment derived from vast exposed areas accumulated in a large deltaic system. G, LECAD: The Late Eocene central axis of deposition was confined to the present position of the Llanos foothills. Late Eocene deposition reflects a regional increase in accommodation space and deposition of the principal reservoirs of rich petroleum basins (i.e., the Mirador, La Paz, upper Misoa formations). In Oligocene times inversion of the Eastern Cordillera divided the main depocenter into two central axes. Accommodation space diminished in uplifted regions and continued to increase in the depocenters allowing sporadic marine ingressions to the present position of the Llanos foothills. As uplift of the Eastern Cordillera continued, the eastern depocenter axis (proto Orinoco) migrated east and the western depocenter axis (proto Magdalena) migrated west. This process continued through the rest of the Cenozoic. DE - DESCRIPTORS: accommodation-zones; Andes-; Campanian-; carbonate-rocks; Cenozoic-; clastic-rocks; Colombia-; continental-margin; Cretaceous-; depositional-environment; Eastern-Cordillera; lithofacies-; marine-environment; Mesozoic-; northwestern-South-America; Oligocene-; Paleogene-; sandstone-; Santander-Colombia; sea-level-changes; sedimentary-rocks; Senonian-; shale-; shallow-water-environment; South-America; structural-controls; tectonics-; tectonostratigraphic-units; Tertiary-; transgression-; unconformities-; Upper-Cretaceous; Venezuela- Yüklə 20,82 Mb. Dostları ilə paylaş:
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