scholarly journals Stratigraphic Study for the Cretaceous-Tertiary period in Qasab-Jawan area in north weastern Iraq by using 2D seismic survey

2021 ◽  
pp. 4779-4790
Author(s):  
Marwa H. Shehab ◽  
Kamal K. Ali

     A seismic study was conducted to re-interpret the Qasab and Jawan Oil fields in northwestern Iraq, south of the city of Mosul, by reprocessing many seismic sections of a number of field surveys by using the Petrel software. Two reflectors, represented by the Hartha formation, deposited during the Cretan age, and the Euphrates formation, formed during the Tertiary age, were delineated to stabilize the structural picture of these fields. The stratigraphic study showed that the Qasab and Jawan fields represent areas of hydrocarbon accumulation. Seismic attribute analysis showed low values of instantaneous frequency in the areas of hydrocarbon accumulation. Instantaneous phase was used to determine the limits of the sequence, the nature of sedimentation, and the type of vanishing, i.e. onlap vs. toplap. Low instantaneous amplitude values were recorded, indicating hydrocarbon reservoirs in the studied area. Various other seismic stratigraphic features were studied , including the distribution mound, flat spot, and channels in the two formations, but they were discontinuous because of the tectonic effects. These activities explain reasonably the distribution of hydrocarbons in the studied area.

2021 ◽  
pp. 2983-2994
Author(s):  
Marwa H. Shehab ◽  
Kamal K. Ali

      A seismic study was conducted to re-interpret the Qasab and Jawan oil field in northern Iraq, south of the city of Mosul, by reprocessing and interpreting many seismic sections of a number of field surveys that included the field area. Two reflectors are detected, represented by Hartha Formations which were deposited during the Cretaceous age and Euphrates Formation which was deposited during the Tertiary age in order to stabilize the structural image of this field. The study was achieved by reinterpreting seismic sections using the Petrel program, where time, velocity  and depth maps were prepared for the two formations. The study showed that the Qasab and Jawan fields generally consist of a structural closure located at the wells of the northern dome. This closure extends to the south east and deviates towards the east in the form of a structural rift. The study concluded the existence of a transverse fault that cuts Qasab and Jawan structures, forming a structural trap that represents the southern part of Qasab structure.


2017 ◽  
Vol 20 (K4) ◽  
pp. 48-56
Author(s):  
Chuc Dinh Nguyen ◽  
Tu Van Nguyen ◽  
Hung Quang Nguyen ◽  
Cuong Van Bui ◽  
Thanh Quoc Truong ◽  
...  

As oil and gas production has been going on over a few decades, conventional plays such as pre-Tertiary fractured basement highs and Cenozoic structural traps become more and more exhausted, and the remaining targets of the same type do not have sufficient reserves for development and production. Exploration activities in Cuu Long basin, therefore, are shifting towards more complicating types of plays which are stratigraphic traps and combination traps. Several researches were conducted in southeastern marginal slope and indicated the possibility of stratigraphic pinch-out traps with insufficient petroleum system and low hydrocarbon potential. In spite of many researches, there are still difficulties in defining the distribution and in evaluating hydrocarbon potential of these traps, so seismic stratigraphy analysis in accompanied with interpretation of seismic attribute and well logs is very necessary to support this problem. Seismic stratigraphic analysis on seismic sections, in agreement with seismic attributes’ and log analysis’ findings, show that the stratigraphic/combination traps in Oligocene C and D were formed during lowstand system tract as sigmoid-oblique clinoforms downlapping onto underlying strata in distributary mouths/delta settings. The integration of seismic attribute analysis and well log interpretation has further defined the fan-shaped distribution of these traps. Thus, using various methods, the stratigraphic traps can be better revealed. Further studies, however, need to be carried out to fully evaluate hydrocarbon potential of these stratigraphic/ combination traps, and minimize risks in exploration drilling.


2020 ◽  
Vol 39 (10) ◽  
pp. 727-733
Author(s):  
Haibin Di ◽  
Leigh Truelove ◽  
Cen Li ◽  
Aria Abubakar

Accurate mapping of structural faults and stratigraphic sequences is essential to the success of subsurface interpretation, geologic modeling, reservoir characterization, stress history analysis, and resource recovery estimation. In the past decades, manual interpretation assisted by computational tools — i.e., seismic attribute analysis — has been commonly used to deliver the most reliable seismic interpretation. Because of the dramatic increase in seismic data size, the efficiency of this process is challenged. The process has also become overly time-intensive and subject to bias from seismic interpreters. In this study, we implement deep convolutional neural networks (CNNs) for automating the interpretation of faults and stratigraphies on the Opunake-3D seismic data set over the Taranaki Basin of New Zealand. In general, both the fault and stratigraphy interpretation are formulated as problems of image segmentation, and each workflow integrates two deep CNNs. Their specific implementation varies in the following three aspects. First, the fault detection is binary, whereas the stratigraphy interpretation targets multiple classes depending on the sequences of interest to seismic interpreters. Second, while the fault CNN utilizes only the seismic amplitude for its learning, the stratigraphy CNN additionally utilizes the fault probability to serve as a structural constraint on the near-fault zones. Third and more innovatively, for enhancing the lateral consistency and reducing artifacts of machine prediction, the fault workflow incorporates a component of horizontal fault grouping, while the stratigraphy workflow incorporates a component of feature self-learning of a seismic data set. With seven of 765 inlines and 23 of 2233 crosslines manually annotated, which is only about 1% of the available seismic data, the fault and four sequences are well interpreted throughout the entire seismic survey. The results not only match the seismic images, but more importantly they support the graben structure as documented in the Taranaki Basin.


1995 ◽  
Vol 35 (1) ◽  
pp. 65
Author(s):  
S.I. Mackie ◽  
C.M. Gumley

The Dirkala Field is located in the southern Murta Block of PEL's 5 and 6 in the southern Cooper and Eromanga Basins. Excellent oil produc­tion from a single reservoir sandstone in the Juras­sic Birkhead Formation in Dirkala-1 had indicated a potentially larger resource than could be mapped volumetrically. The hypothesis that the resource was stratigraphically trapped led to the need to define the fluvial sand reservoir seismically and thereby prepare for future development.A small (16 km2) 3D seismic survey was acquired over the area in December 1992. The project was designed not only to evaluate the limits of the Birkhead sand but also to evaluate the cost effi­ciency of recording such small 3D surveys in the basin.Interpretation of the data set integrated with seismic modelling and seismic attribute analysis delineated a thin Birkhead fluvial channel sand reservoir. Geological pay mapping matched volu­metric estimates from production performance data. Structural mapping showed Dirkala-1 to be opti­mally placed and that no further development drill­ing was justifiable.Seismic characteristics comparable with those of the Dirkala-1 Birkhead reservoir were noted in another area of the survey beyond field limits. This led to the proposal to drill an exploration well, Dirkala South-1, which discovered a new oil pool in the Birkhead Formation. A post-well audit of the pre-drill modelling confirmed that the seismic response could be used to determine the presence of the Birkhead channel sand reservoir.The acquisition of the Dirkala-3D seismic survey demonstrated the feasibility of conducting small 3D seismic surveys to identify subtle stratigraphically trapped Eromanga Basin accumulations at lower cost and risk than appraisal/development drilling based on 2D seismic data.


TERRITORIO ◽  
2020 ◽  
pp. 148-163
Author(s):  
Luca Fondacci

In the 1970s, the fragile historical centre of the city of Perugia was a key area where the binomial of sustainable mobility and urban regeneration was developed and applied. At the turn of the xxi century, the low carbon automatic people-mover Minimetrò broadened that application from the city's historical centre to the outskirts, promoting the enhancement of several urban environments. This paper is the outcome of an investigation of original sources, field surveys and direct interviews, which addresses the Minimetrò as the backbone of a wide regeneration process which has had a considerable impact on the economic development of a peripheral area of the city which was previously devoid of any clear urban sense. The conclusion proposes some solutions to improve the nature of the Minimetrò as an experimental alternative means of transport.


KURVATEK ◽  
2017 ◽  
Vol 1 (2) ◽  
pp. 21-31
Author(s):  
Fatimah Miharno

ABSTRACT*Zefara* Field formation Baturaja on South Sumatra Basin is a reservoir carbonate and prospective gas. Data used in this research were 3D seismik data, well logs, and geological information. According to geological report known that hidrocarbon traps in research area were limestone lithological layer as stratigraphical trap and faulted anticline as structural trap. The study restricted in effort to make a hydrocarbon accumulation and a potential carbonate reservoir area maps with seismic attribute. All of the data used in this study are 3D seismic data set, well-log data and check-shot data. The result of the analysis are compared to the result derived from log data calculation as a control analysis. Hydrocarbon prospect area generated from seismic attribute and are divided into three compartments. The seismic attribute analysis using RMS amplitude method and instantaneous frequency is very effective to determine hydrocarbon accumulation in *Zefara* field, because low amplitude from Baturaja reservoir. Low amplitude hints low AI, determined high porosity and high hydrocarbon contact (HC).  Keyword: Baturaja Formation, RMS amplitude seismic attribute, instantaneous frequency seismic attribute


2007 ◽  
Author(s):  
Srinivasa Rao Narhari ◽  
Nikhil Banik ◽  
Sunil Kumar Singh ◽  
Talal Fahad Al-Adwani

2015 ◽  
Vol 3 (1) ◽  
pp. SB5-SB15 ◽  
Author(s):  
Kurt J. Marfurt ◽  
Tiago M. Alves

Seismic attributes are routinely used to accelerate and quantify the interpretation of tectonic features in 3D seismic data. Coherence (or variance) cubes delineate the edges of megablocks and faulted strata, curvature delineates folds and flexures, while spectral components delineate lateral changes in thickness and lithology. Seismic attributes are at their best in extracting subtle and easy to overlook features on high-quality seismic data. However, seismic attributes can also exacerbate otherwise subtle effects such as acquisition footprint and velocity pull-up/push-down, as well as small processing and velocity errors in seismic imaging. As a result, the chance that an interpreter will suffer a pitfall is inversely proportional to his or her experience. Interpreters with a history of making conventional maps from vertical seismic sections will have previously encountered problems associated with acquisition, processing, and imaging. Because they know that attributes are a direct measure of the seismic amplitude data, they are not surprised that such attributes “accurately” represent these familiar errors. Less experienced interpreters may encounter these errors for the first time. Regardless of their level of experience, all interpreters are faced with increasingly larger seismic data volumes in which seismic attributes become valuable tools that aid in mapping and communicating geologic features of interest to their colleagues. In terms of attributes, structural pitfalls fall into two general categories: false structures due to seismic noise and processing errors including velocity pull-up/push-down due to lateral variations in the overburden and errors made in attribute computation by not accounting for structural dip. We evaluate these errors using 3D data volumes and find areas where present-day attributes do not provide the images we want.


2013 ◽  
Vol 734-737 ◽  
pp. 404-407 ◽  
Author(s):  
Yu Shuang Hu ◽  
Si Miao Zhu

A big tendency in oil industry is underestimating the heterogeneity of the reservoir and overestimating the connectivity, which results in overly optimistic estimates of the capacity. With the development of seismic attributes, we could pick up hidden reservoir lithology and physical property information from the actual seismic data, strengthen seismic data application in actual work, to ensure the objectivity of the results. In this paper, the channel sand body distribution in south eighth district of oilfield Saertu is predicted through seismic data root-mean-square amplitude and frequency division to identify sand body boundaries, predict the distribution area channel sand body characteristics successfully, which consistent with the sedimentary facies distribution. The result proves that seismic attribute analysis has good practicability in channel sand body prediction and sedimentary facies description.


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