Numerische Simulation der Kohlenwasserstoffgenese an der Subduktionszone vor Costa Rica
type: CreativeWork
description: In this study sediment samples drilled during ODP Leg 170 at Sites 1039 and 1040 were analyzed with organic geochemical and organic petrological methods. These methods included determination of organic carbon, sulfur and iron contents, Rock-Eval pyrolysis on sediments and kerogen concentrates as well as gas chromatographic studies of the soluble organic matter n-alkane and fatty acid distributions. With these studies information about type, origin and preservation of the organic matter was obtained. Some results were used as input parameters for the numerical modeling of temperature and subsidence history as well as hydrocarbon generation. The seismic profile SO81-200 was used together with organic geochemical data for the numerical modeling of hydrocarbon generation and migration of different models with different heat flow histories. In an area off Costa Rica which was studied by 3D-seismic investigations (3D box) bottom simulating reflectors (BSRs) were found. These BSRs are an indicator for gas hydrates but they show a small-scale patchy distribution in the 3D box. Pressure and temperature was calculated to test the assumption that variations in pressure/temperature ratios are the cause for the patchy BSR distribution. Studies on the organic matter revealed that most of the organic matter incorporated in the sediments overlying the Cocos plate is of marine origin and has a suitable potential for generating hydrocarbons. For the generation of methane and oil kinetics for Type II kerogen were used. The subducting sediments were treated as one sedimentary unit with a mean organic carbon content (TOC) of 0.5% and a hydrogen index (HI) value of 270 mg HC/g TOC. Except for the wells drilled during ODP Leg 170 there are no other wells available which could contribute suitable calibration parameters. Therefore several models with changing input parameters were calculated to determine the influence of single parameters on the result and to give a range for the amount of …
abstract: In this study sediment samples drilled during ODP Leg 170 at Sites 1039 and 1040 were analyzed with organic geochemical and organic petrological methods. These methods included determination of organic carbon, sulfur and iron contents, Rock-Eval pyrolysis on sediments and kerogen concentrates as well as gas chromatographic studies of the soluble organic matter n-alkane and fatty acid distributions. With these studies information about type, origin and preservation of the organic matter was obtained. Some results were used as input parameters for the numerical modeling of temperature and subsidence history as well as hydrocarbon generation. The seismic profile SO81-200 was used together with organic geochemical data for the numerical modeling of hydrocarbon generation and migration of different models with different heat flow histories. In an area off Costa Rica which was studied by 3D-seismic investigations (3D box) bottom simulating reflectors (BSRs) were found. These BSRs are an indicator for gas hydrates but they show a small-scale patchy distribution in the 3D box. Pressure and temperature was calculated to test the assumption that variations in pressure/temperature ratios are the cause for the patchy BSR distribution. Studies on the organic matter revealed that most of the organic matter incorporated in the sediments overlying the Cocos plate is of marine origin and has a suitable potential for generating hydrocarbons. For the generation of methane and oil kinetics for Type II kerogen were used. The subducting sediments were treated as one sedimentary unit with a mean organic carbon content (TOC) of 0.5% and a hydrogen index (HI) value of 270 mg HC/g TOC. Except for the wells drilled during ODP Leg 170 there are no other wells available which could contribute suitable calibration parameters. Therefore several models with changing input parameters were calculated to determine the influence of single parameters on the result and to give a range for the amount of …
author: Lutz, Rüdiger
language: ger
keywords: info:eu-repo/classification/ddc/550, Geowissenschaften, Costa Rica, Subduktion, Sediment, Kohlenwasserstoffe, Entstehung
date published: 2001
date modified: 2026-07-30T19:42:39Z
provider: RWTH Aachen University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Publikationsserver der RWTH Aachen University