scholarly journals Recognition of the pre-salt regional structure of Kwanza basin, offshore in West Africa, derived from the satellite gravity data and seismic profiles

2020 ◽  
Vol 17 (6) ◽  
pp. 956-966
Author(s):  
Longjun Qiu ◽  
Zhaoxi Chen ◽  
Yalei Liu
Keyword(s):  
Oil And Gas ◽  
Gravity Data ◽  
Shielding Effect ◽  
Regional Structure ◽  
Seismic Profiles ◽  
Satellite Gravity ◽  
Oil And Gas Exploration ◽  
Tectonic Model ◽  
Salt Structure ◽  
Seismic Reflection Profiles

Abstract Kwanza basin, located on the west coast of Africa and the east side of the South Atlantic Ocean, has the potential for deep-water oil and gas exploration. Previous studies have shown that the pre-salt system within the area has high potential for oil and gas storage. However, due to the shielding effect of the evaporating salt rock during the Aptian period, the quality of seismic reflection profiles of the pre-salt layers is poor. This means that the pre-salt sequences, the main fault, the scale and distribution pattern of the rift are not clear. To clarify the pre-salt regional structure pattern and further guide pre-salt exploration, we carried out a series of analyses and target processing of seismic and gravity data. Further, combining other available geological and lithology data as well as a tectonic model, we put forward a new understanding of the pre-salt structure of Kwanza basin. The research shows that the Kwanza basin can be divided into three uplift belts below the salt layer, which are distributed in the NW–SE trending direction. The three key profiles illustrate the distribution of uplift and depression in detail. The explained structural highs distributed in the outer Kwanza basin may be related to oil and gas reservoir. This study could provide the geophysical basis for the re-interpretation of the pre-salt seismic sequence, the strategic selection of pre-salt oil and gas and the next exploration deployment.

Transfer Zone Characteristics in No. II Fault Zone and its Control on Petroleum, TaZhong Area

2011 ◽  
Vol 356-360 ◽  
pp. 3009-3015
Author(s):  
Yu Hang Zhang ◽  
Xing Yan Li ◽  
Zhi Feng Yan
Keyword(s):  
Fault Zone ◽  
Oil And Gas ◽  
Structural Evolution ◽  
Strike Slip ◽  
Fault Analysis ◽  
Seismic Profiles ◽  
Oil And Gas Exploration ◽  
Detachment Faults ◽  
Tazhong Area ◽  
Transfer Zone

According to interpreted cautiously with 2D and 3D seismic profiles, the typical transfer zone was identified in No.Ⅱ fault zone of TaZhong area, near the TaZhong 46 well of central uplift belt in Tarim basin. Discussed the transfer zone characteristic on the basis of seismic interpretation, it’s clearly triangle transfer zone and caused by strike-slip affection. Using structural analysis method, it is indicated that the transfer zone composed by thrusting-detachment faults. According to structural evolution analysis, the transfer zone had been affecting constantly by transpression during the caledonian-late hercynian, Analyzing geologic setting and regional geology characteristic, TaZhong No.Ⅱ fault zone are sinistral transpression strike-slip fault. Analysis the control action of transfer zone’s for trap, reservoir, hydrocarbon migration and sedimentary, the Transfer zone have the advantage target for oil and gas exploration.

scholarly journals Initial exploration of Hydrocarbon resources by Gravity Data: A Case Study in the South of Qom Province, Iran

2015 ◽  
Vol 2 (1) ◽  
pp. 52-57
Author(s):  
Payam Salimi
Keyword(s):  
Oil And Gas ◽  
Gravity Data ◽  
Geophysical Methods ◽  
Local Effect ◽  
Oil And Gas Exploration ◽  
Residual Gravity ◽  
3D Geometry ◽  
Residual Gravity Anomaly ◽  
Matlab Programming

Geophysical methods widely used in oil and gas exploration. Modeling of gravity data is used extensively to illustrate the geometry and interface between the sediments and bedrock. Which can help the salt dome, anticline folds, dome-shaped uplift of the continental platform and reef masses to be identified. There are various methods to illustrate the bedrock topography, and we will describe one of these methods in present paper. Using the upward continuation, we extract the residual gravity anomaly which in fact shows the local effect of bedrock gravity on the observed gravity. Then, according to the Oldenburg - Parker method, the residual gravity data are inversed and finally the 3D geometry the bedrock is illustrated. It should be noted that some software's like Surfer and Excel are used in this research but the program main code is written using Matlab programming.

A new method for underwater dynamic gravimetry based on multisensor integrated navigation

Geophysics ◽  
2020 ◽  
Vol 85 (3) ◽  
pp. G69-G80
Author(s):  
Zhiming Xiong ◽  
Juliang Cao ◽  
Kaixun Liao ◽  
Meiping Wu ◽  
Shaokun Cai ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Finite Impulse Response ◽  
Gravity Data ◽  
Satellite System ◽  
New Method ◽  
Integrated Navigation ◽  
Oil And Gas Exploration ◽  
Half Wavelength ◽  
Marine Gravity ◽  
Global Navigation Satellite

Underwater gravity information plays a major role in deepwater oil and gas exploration. To realize underwater dynamic gravimetry, we have developed a strapdown gravimeter mounted in a pressure capsule for adaption to the underwater environment and we adopted a two-stage towed underwater gravimetry scheme. An improved strapdown gravimeter and other underwater sensors were installed in a towed vessel to form an underwater dynamic gravimetry system. Because the global navigation satellite system cannot be used for underwater dynamic gravimetry, we developed a new method based on underwater multisensor integrated navigation, in which a federal Kalman filter was applied for error estimation. This new method allowed us to obtain the accurate attitude, velocity, and position necessary for gravity estimation. In addition, the gravity data can then be extracted from the noisy data through finite impulse response low-pass filtering. We acquired the underwater gravity data at a depth of 300 m to test the validity of the new method and evaluate the accuracy of the underwater gravity system. The results indicated a repeatability from 0.85 to 0.96 mGal at a half wavelength of approximately 0.2 km and also indicated good consistency with the marine gravity data.

Subsalt imaging in northern Germany using multiphysics (magnetotellurics, gravity, and seismic)

2020 ◽  
Vol 8 (4) ◽  
pp. SQ15-SQ24
Author(s):  
Christian H. Henke ◽  
Markus H. Krieger ◽  
Kurt Strack ◽  
Andrea Zerilli
Keyword(s):  
Oil And Gas ◽  
Gravity Data ◽  
Salt Dome ◽  
Gravity Modeling ◽  
Field Source ◽  
Oil And Gas Exploration ◽  
Exploration Drilling ◽  
Seismic Depth Migration ◽  
Improved Model ◽  
Subsalt Imaging

Imaging subsalt is still a challenging task in oil and gas exploration. We have used magnetotellurics (MT) to improve the integration of seismic and gravity data to image the Wedehof salt dome, located in the Northern German Basin. High-density natural field source broadband MT data were acquired and enhanced the definition of the top and overhanging salt structures in addition to imaging the salt dome root. Salt boundaries show strong resistivity contrasts with the surrounding sediments and thus represent a good target for electromagnetic measurements, especially for top salt and salt flanks imaging. With integrated 3D gravity modeling focusing on the salt dome’s flanks at intermediate depths, an improved model was achieved. The new model provided sound input to a follow-up seismic depth migration that led to an improved imaging of the subsalt target proven by subsequent exploration drilling. The integrated interpretation of MT, gravity, and seismic combines the strengths of the different physics, thus increasing imaging reliability and reducing exploration drilling risks. Using a conservative workflow that included a feasibility study with field noise evaluation and careful acquisition parameter testing prior to survey start, a broadband array data acquisition, and advanced processing, the survey area's severe cultural noise issues could be overcome.

Redefined Distribution of the Permian Volcanic Rocks in the Tarim Basin: Based on Logging and Seismic Data

2013 ◽  
Vol 448-453 ◽  
pp. 3723-3727 ◽  
Author(s):  
Yun Pan ◽  
Zong Xiu Wang ◽  
Mao Pan
Keyword(s):  
Tarim Basin ◽  
Seismic Data ◽  
Oil And Gas ◽  
Volcanic Rocks ◽  
Oil Field ◽  
Shielding Effect ◽  
Underlying Structure ◽  
Oil Exploration ◽  
Oil And Gas Exploration ◽  
The North

There are a lot of Permian volcanic rocks which are widely distributed in Tarim Basin. Because of the shielding effect of the volcanic rocks to the underlying structure, the distribution of the volcanic rocks in Tarim Basin is very important to the deep oil and gas exploration. However, with the progress of oil exploration in Tarim oil field in recent years, much more logging and seismic data is available. Based on the model of logging-seismic integrated identification, the distribution of the Permian volcanic rocks is revised by using the drilling, logging and seismic data. It shows that the rhyolite is mainly distributed in the north basin, and the basalt is widely distributed in the basin. Moreover, the basalt has larger area than which delineated by other people.

scholarly journals The Wishbone Ridge at the Chatham Rise Intersection: Structural Characteristics and Tectonic Implications

2021 ◽  
Author(s):  
◽  
Rachel Barrett
Keyword(s):  
New Zealand ◽  
Seismic Reflection ◽  
Structural Characteristics ◽  
Gravity Data ◽  
Large Igneous Province ◽  
Magnetic Data ◽  
The West ◽  
Satellite Gravity ◽  
Gondwana Margin ◽  
Seismic Reflection Profiles

<p>Geophysical data show that the West Wishbone Ridge, offshore of eastern New Zealand, is best described as having previously been a crustal transform fault, which first propagated along the eastern margin of the Hikurangi Plateau as subduction along the New Zealand sector of the Gondwana margin began to slow and reorientate between 105 and 101 Ma. Variation in the strike of the West Wishbone Ridge has resulted in contrasting compressional and extensional zones along the ridge. These regimes reflect the direction of strike offset from the direction of fault propagation, and constrain the sense of motion along the West Wishbone Ridge as having been dextral.  We find evidence that Cretaceous subduction along the Chatham Rise margin extended east of the margin offset at 174°W that marks the edge of Hikurangi Plateau subduction beneath the margin. Rotation of the Chatham Rise margin between 105 and 101 Ma was accommodated by westward broadening of the extensional zone of deformation associated with the West Wishbone Ridge near its intersection with the Chatham Rise. The amount of offset along the ridge indicates that significant transform motion along the West Wishbone Ridge south of ~40.5°S ceased ca. 101 Ma, coeval with the cessation of spreading of the Osbourn Trough, and of subduction of the Hikurangi Plateau.  Additionally, we find anomalously thick oceanic crust adjacent to the WWR and north of the Hikurangi Plateau (>12 km thick). This is attributed to the proximity of this crust to the Hikurangi Plateau Large Igneous Province.  The results of this study are based on seismic reflection and magnetic data recently collected during the 2016 R/V Sonne survey SO-246, as well as previously collected seismic reflection profiles and satellite gravity data.</p>

scholarly journals Usporedba različitih pristupa Bouguer-ove redukcije na temelju satelitskih gravimetrijskih podataka

Geofizika ◽  
2020 ◽  
Vol 37 (2) ◽  
pp. 237-261
Author(s):  
Fan Luo ◽  
Xin Tao ◽  
Guangming Fu ◽  
Chong Zhang ◽  
Kun Zhang ◽  
...  
Keyword(s):  
Gravity Anomaly ◽  
Gravity Data ◽  
Gravity Anomalies ◽  
Gravitational Effect ◽  
Seismic Profile ◽  
Bouguer Gravity ◽  
Seismic Profiles ◽  
Satellite Gravity ◽  
Free Air ◽  
Free Air Gravity

Satellite gravity data are widely used in the field of geophysics to study deep structures at the regional and global scales. These data comprise free-air gravity anomaly data, which usually need to be corrected to a Bouguer gravity anomaly for practical application. Bouguer reduction approaches can be divided into two methods based on the coordinate system: the spherical coordinates method (SBG) and the Cartesian coordinates method; the latter is further divided into the CEBG and CBG methods, which do and do not include the Earth’s curvature correction. In this paper, free-air gravity anomaly data from the eastern Tibetan Plateau and its adjacent areas were used as the basic data to compare the CBG, CEBG, and SBG Bouguer gravity correction methods. The comparison of these three Bouguer gravity correction methods shows that the effect of the Earth’s curvature on the gravitational effect increases with increasing elevation in the study area. We want to understand the inversion accuracy for the data obtained by different Bouguer gravity reduction approaches. The depth distributions of the Moho were obtained by the interface inversion of the Bouguer gravity anomalies obtained by the CBG, CEBG, and SBG, and active seismic profiles were used as references for comparison and evaluation. The results show that the depths of the Moho obtained by the SBG inversion are more consistent with the measured seismic profile depths. Therefore, the SBG method is recommended as the most realistic approach in the process of global or regional research employing gravity data.

scholarly journals Geological Structure Analysis of Satellit Gravity Data in Oil and Gas Prospect Area of West Aceh-Indonesia

2019 ◽  
Vol 8 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Dian Darisma ◽  
Marwan Marwan ◽  
Nazli Ismail
Keyword(s):  
Gravity Anomaly ◽  
Oil And Gas ◽  
Deep Structure ◽  
Gravity Data ◽  
Bouguer Anomaly ◽  
Geological Structure ◽  
Satellite Gravity ◽  
Vertical Derivative ◽  
Free Air Anomaly ◽  
Shallow Structure

Estimation of the subsurface geological structures in oil and gas prospect area of West Aceh has been done by utilizing gravity field anomaly of satellite gravity data. This research aim to analyze satellite gravity data in order to get geological features which is include deep and shallow structure or fault around oil and gas prospect area in West Aceh. The satellite gravity data is originally provided as Free Air Anomaly and should be corrected to get Complete Bouguer Anomaly (CBA). Furthermore, CBA was transformed into a horizontal plane and corrected from regional anomalous effects to obtain residual anomaly, horizontal and vertical derivative. From CBA, the gravity anomaly show good correlation with geological boundaries on different rock formation and the anomaly is decrease from NE-SW. Residual anomaly also gives same information with CBA but this anomaly focus on shallow structure. Furthermore, horizontal derivative and vertical derivative also show good correlation with geological structure or fault but in some areas the anomaly related with deep structure cannot be seen on the surface or geological map. Despite the result cannot correlate directly with oil and gas prospect area, satellite gravity can be used to identify gravity anomaly and also fault that related with hydrocarbon anomaly area

scholarly journals Diagenetic related flat spots within the Paleogene Sotbakken Group in the vicinity of the Senja Ridge, Barents Sea

2019 ◽  
Vol 26 (3) ◽  
pp. 373-385 ◽  
Author(s):  
Manzar Fawad ◽  
Nazmul Haque Mondol ◽  
Irfan Baig ◽  
Jens Jahren
Keyword(s):  
Biogenic Silica ◽  
Oil And Gas ◽  
Barents Sea ◽  
Rock Physics ◽  
Gas Oil ◽  
Seismic Profiles ◽  
Oil And Gas Exploration ◽  
Fine Grained ◽  
Ridge Area

Rock physics analyses of data from a wildcat well 7117/9-1 drilled in the Senja Ridge area, located in the Norwegian Barents Sea, reveal changes in stiffness within the fine-grained Paleogene Sotbakken Group sediments, caused by the transformation of opal-A to opal-CT, and opal-CT to quartz. These changes manifest as flat spots on 2D seismic profiles. These flat spots were mistaken as hydrocarbon–water contacts, which led to the drilling of well 7117/9-1. Rock physics analyses on this well combined with a second well (7117/9-2) drilled further NW and updip on the Senja Ridge indicate overpressure within the opal-CT-rich zones overlying the opal-CT to quartz transformation zones in the two wells. The absence of opal-A–opal-CT and opal-CT–quartz flat spots on seismic in the second well is attributed to differences in the temperature and timing of uplift. Amplitude v. angle (AVA) modelling indicates both the opal-A–opal-CT and opal-CT–quartz interface points plot on the wet trend, whereas modelled gas–brine, oil–brine and gas–oil contacts fall within quadrant-I. These findings will be useful in understanding the nature of compaction of biogenic silica-rich sediments where flat spots could be misinterpreted as hydrocarbon-related contacts in oil and gas exploration.

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