TOWARDS AN EFFICIENT EXPLORATION FRONTIER: CONSTRUCTING A PORTFOLIO OF STRATIGRAPHIC TRAPS IN FLUVIAL-LACUSTRINE SUCCESSIONS, COOPER-EROMANGA BASIN

2002 ◽  
Vol 42 (1) ◽  
pp. 131
Author(s):  
T. Nakanishi ◽  
S.C. Lang
Keyword(s):  
Net Present Value ◽  
Spatial Arrangement ◽  
Mean Value ◽  
Seismic Survey ◽  
3D Seismic ◽  
Sequence Stratigraphic ◽  
Depositional Systems ◽  
Efficient Exploration ◽  
3D Seismic Data ◽  
Eromanga Basin

In the Cooper-Eromanga Basin, the future of exploration lies in identifying an appropriate exploration portfolio consisting of stratigraphic traps in structurally low or flank areas. A variety of stratigraphic trap prospects in the Moorari and Pondrinie 3D seismic survey areas are identified in the Patchawarra, Epsilon, Toolachee and Poolowanna formations. To identify the stratigraphic traps, an integration of sequence stratigraphic concepts applied to non-marine basins and advanced 3D seismic data visualisation was employed. This paper focusses on estimating the chance of geologic success and the probabilistic reserves size for each prospect within its sequence stratigraphic context (lowstand, transgressive or highstand systems tracts). The geologic chance factors for an effective stratigraphic trap include reservoir, top seal, lateral seal and bottom seal within each depositional systems tract, the seal effectiveness of the adjacent depositional systems tracts and the appropriate spatial arrangement of these factors. The confidence values for the existence of geologic chance factors were estimated according to the distributions of the possible reservoir and seal rocks within each genetic-stratigraphic interval and the chance of geologic success of each prospect was calculated. For probabilistic reserves estimation, geologically reasonable ranges were estimated for each parameter employing Monte Carlo simulation to calculate the reserves distribution. When a series of possible exploration portfolios, including single or multiple prospects from the prospect inventory are plotted in terms of the chance of geologic success vs. the mean value of the reserves estimate, an efficient exploration frontier emerges. The portfolio candidates on the efficient exploration frontier were assessed with regard to chance of economic success and expected net present value (ENPV) using a simple cash flow model. The results indicate that appropriate portfolios include multiple prospect exploration especially with lowstand systems tract plays using single or multiple exploration wells. The portfolio construction approach for stratigraphic trap exploration should ultimately be made consistent with conventional play types, to enable an assessment of all exploration opportunities.

VISUALISATION OF A FLUVIAL CHANNEL RESERVOIR ANALOGUE FROM THE BIRKHEAD FORMATION, MERRIMELIA, MERANJI AND PELICAN FIELDS, EROMANGA BASIN

2003 ◽  
Vol 43 (1) ◽  
pp. 453 ◽  
Author(s):  
T. Nakanishi ◽  
S.C. Lang ◽  
A.B. Mitchell
Keyword(s):  
Seismic Data ◽  
Sedimentary Facies ◽  
Mean Value ◽  
3D Seismic ◽  
Point Bar ◽  
Channel Belt ◽  
Point Bars ◽  
Seismic Amplitudes ◽  
3D Seismic Data ◽  
Eromanga Basin

The effective production of hydrocarbons from the Birkhead Formation, Eromanga Basin, relies heavily on understanding the complex distribution of reservoir and seal rocks deposited in a fluvial environment. To visualise this complexity, sequence stratigraphic concepts applied to non-marine basins were combined with 3D seismic data visualisation in a study of the Birkhead interval over the Merrimelia, Meranji and Pelican fields.Fluvial channel, crevasse splay channel, floodplaincrevasse splay complex and floodplain facies were recognised from the well log motifs in the Birkhead Formation. The interval is interpreted as an alluvial transgressive systems tract bounded by flooding surfaces consisting of shaly or coaly intervals. Lateral discontinuity of the fluvial system can be demonstrated between these surfaces. Seismic amplitude distributions in the 3D seismic data in the upper part of this transgressive systems tract illustrate well developed meandering fluvial channels. Combining the spatial distributions of sedimentary facies from the well logs and the seismic amplitudes results in the interpretation of a fluvial meandering channel belt that includes point bars and abandoned channels.The point bar sandstones in the channel belt should make good reservoirs and the juxtaposition of the point bar and abandoned channel facies can result in a stratigraphic trap component to the reservoir rocks within the channel belt. Although the point bars are known to be wet in the study area, it is still useful to consider their capacity as oil reservoirs, since they may serve as analogues for similar untested point bars elsewhere. Multiple realisations of the distribution of sandstone thickness of the point bars were generated by conditional simulation, using seismic amplitudes to control extrapolation of the well data. This gave a potential reserves distribution with a mean value of 18.8 million bbl in place. The complexity of the fluvial channel systems in the Birkhead Formation described in this paper should aid understanding of the reservoir and seal distribution and help optimise production from this interval in other fields.

Creation of Geological 3D-Model of Komyshnianske Field Based on the Sequence Stratigraphy Principles

2021 ◽  
Author(s):  
Oleksii Viktorovych Noskov ◽  
Serhii Mykhailovych Levoniuk ◽  
Mykyta Leonidovych Myrontsov
Keyword(s):  
Sequence Stratigraphy ◽  
3D Model ◽  
Gas Condensate ◽  
Seismic Survey ◽  
3D Seismic ◽  
Reservoir Properties ◽  
New Approach ◽  
Sequence Stratigraphic ◽  
Seismic Resolution ◽  
Sedimentation Conditions

Abstract Currently, the sequence-stratigraphic section dismemberment is only being implemented in Ukraine, so this article is highly relevant. The authors created geological 3D model of Komyshnianske gas condensate field based on sequence-stratigraphic section dismemberment for the first time at this area. This approach is effective for the following conditions:-insufficient field geological study;-thickness of productive horizons does not reach the seismic resolution boundaries;-no significant difference in impedance values on reflection horizons. The selected technique includes the following stages:-field geological study, facies analysis (integration of well geophysical complexes, cores);-deduction and correlation of sequence boundaries;-construction of discrete log, which corresponds to specific sequences distribution;-conducting seismic interpretation of the 3D seismic survey study of research area;-construction of a structural framework with the involvement of correlated sequences boundaries;-comparison of volume seismic attributes with selected sequences distribution. A geological 3D model of Komyshnianske gas condensate field was created based on sequence-stratigraphic principles. During the research, a geological structure of field was analyzed, the separated conditions of sedimentation (sequences) were deducted and interpreted. During the seismic interpretation of 3D seismic survey of study area, local features of wave field were identified, their reflection in the core material was found and linked to the concept of changing sedimentation conditions. With a general understanding of the material transportation and accommodation direction, used method allows to qualitatively outline the distribution boundaries of sedimentation certain conditions and predict their development outside the study area. Construction of facies discrete log and their distribution in the seismic field allows grouping thin bed layers of collectors to reach the seismic resolution and use them to predict the distribution of facies associated with changes in the rocks reservoir properties (tracking beach facies of deltas/avandeltas, sloping sediments, etc.). The constructed model could be used as a trend for reservoir distribution at the stage of construction of static geological model. Involvement of sequence-stratigraphy technique is new approach to sedimentation conditions study within Dnipro-Donetsk depression (DDD) areas. The paper shows that provided methodology gives:-improved geological understanding of field through sedimentation analysis and facies logging;-trends for reservoir properties distribution with the involvement of construction facies volumes;-proposals for further field E&D. The general provisions under conditions of geological materials sufficient base can be applied to other DDD areas, especially in pre-border zones. Involvement of sequence-stratigraphy technique is new approach for sedimentation conditions study within Dnipro-Donetsk depression (DDD) area. On the example of Komyshnianske gas condensate field, the article shows that provided methodology gives:-improved geological understanding of field through sedimentation analysis and facies logging;-trends for reservoir properties propagation with the involvement of seismic volume studies;-propositions for further field Exploration & Development.

Why 3D seismic data are an asset for exploration and mine planning? Velocity tomography of weakness zones in the Kevitsa Ni-Cu-PGE mine, northern Finland

Geophysics ◽  
2018 ◽  
Vol 83 (2) ◽  
pp. B33-B46 ◽  
Author(s):  
Alireza Malehmir ◽  
Ari Tryggvason ◽  
Chris Wijns ◽  
Emilia Koivisto ◽  
Teemu Lindqvist ◽  
...  
Keyword(s):  
Seismic Data ◽  
Mine Planning ◽  
Seismic Survey ◽  
Open Pit ◽  
3D Seismic ◽  
Reflection Data ◽  
Northern Side ◽  
Weakness Zone ◽  
Weakness Zones ◽  
3D Seismic Data

Kevitsa is a disseminated Ni-Cu-PGE (platinum group elements) ore body in northern Finland, hosted by an extremely high-velocity ([Formula: see text]) ultramafic intrusion. It is currently being mined at a depth of approximately 100 m with open-pit mining. The estimated mine life is 20 years, with the final pit reaching a depth of 500–600 m. Based on a series of 2D seismic surveys and given the expected mine life, a high-resolution 3D seismic survey was justified and conducted in the winter of 2010. We evaluate earlier 3D reflection data processing results and complement that by the results of 3D first-arrival traveltime tomography. The combined results provide insights on the nature of some of the reflectors within the intrusion. In particular, a major discontinuity, a weakness zone, is delineated in the tomography results on the northern side of the planned pit. Supported by the reflection data, we estimate the discontinuity, likely a thrust sheet, to extend down approximately 600 m and laterally 1000 m. The weakness zone terminates prominent internal reflectivity of the Kevitsa intrusion, and it is associated with the extent of the economic mineralization. Together with other weakness zones, a couple of which are also revealed by the tomography study, the discontinuity forms a major wedge block that influences the mine bench stability on the northern side of the open pit and likely will cause more issues during the extraction of the ore in this part of the mine. We argue that 3D seismic data should routinely be acquired prior to commencement of mining activities to maximize exploration efficiency at depth and also to optimize mining as it continues toward depth. Three-dimensional seismic data over mineral exploration areas are valuable and can be revisited for different purposes but are difficult to impossible to acquire after mining has commenced.

Preconditioning point-source/point-receiver high-density 3D seismic data for lacustrine shale characterization in a loess mountain area

2017 ◽  
Vol 5 (2) ◽  
pp. SF177-SF188 ◽  
Author(s):  
Wei Wang ◽  
Xiangzeng Wang ◽  
Hongliu Zeng ◽  
Quansheng Liang
Keyword(s):  
Data Quality ◽  
Seismic Data ◽  
Ordos Basin ◽  
Seismic Inversion ◽  
High Density ◽  
Seismic Survey ◽  
3D Seismic ◽  
Noise Characteristics ◽  
Lacustrine Shale ◽  
3D Seismic Data

In the study area, southeast of Ordos Basin in China, thick lacustrine shale/mudstone strata have been developed in the Triassic Yanchang Formation. Aiming to study these source/reservoir rocks, a 3D full-azimuth, high-density seismic survey was acquired. However, the surface in this region is covered by a thick loess layer, leading to seismic challenges such as complicated interferences and serious absorption of high frequencies. Despite a specially targeted seismic processing workflow, the prestack Kirchhoff time-migrated seismic data were still contaminated by severe noise, hindering seismic inversion and geologic interpretation. By taking account of the particular data quality and noise characteristics, we have developed a cascade workflow including three major methods to condition the poststack 3D seismic data. First, we removed the sticky coherent noise by a local pseudo [Formula: see text]-[Formula: see text]-[Formula: see text] Cadzow filtering. Then, we diminished the random noise by a structure-oriented filtering. Finally, we extended the frequency bandwidth with a spectral-balancing method based on the continuous wavelet transform. The data quality was improved after each of these steps through the proposed workflow. Compared with the original data, the conditioned final data show improved interpretability of the shale targets through geometric attribute analysis and depositional interpretation.

Reservoir characterization using microseismic facies analysis integrated with surface seismic attributes

2016 ◽  
Vol 4 (2) ◽  
pp. T167-T181 ◽  
Author(s):  
Aamir Rafiq ◽  
David W. Eaton ◽  
Adrienne McDougall ◽  
Per Kent Pedersen
Keyword(s):  
Seismic Data ◽  
Principal Curvature ◽  
Facies Analysis ◽  
Shape Index ◽  
Seismic Attributes ◽  
Seismic Survey ◽  
3D Seismic ◽  
Frequency Distributions ◽  
Scaling Properties ◽  
3D Seismic Data

We have developed the concept of microseismic facies analysis, a method that facilitates partitioning of an unconventional reservoir into distinct facies units on the basis of their microseismic response along with integrated interpretation of microseismic observations with 3D seismic data. It is based upon proposed links between magnitude-frequency distributions and scaling properties of reservoirs, including the effects of mechanical bed thickness and stress heterogeneity. We evaluated the method using data from hydraulic fracture monitoring of a Late Cretaceous tight sand reservoir in central Alberta, in which microseismic facies can be correlated with surface seismic attributes (primarily principal curvature, coherence, and shape index) from a coincident 3D seismic survey. Facies zones are evident on the basis of attribute crossplots, such as maximum moment release rate versus cluster azimuth. The microseismically defined facies correlate well with principal curvature anomalies from 3D seismic data. By combining microseismic facies analysis with regional trends derived from log and core data, we delineate reservoir partitions that appear to reflect structural and depositional trends.

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