scholarly journals Sequence Stratigraphic Interpretation of FX-1 and FX-2 wells, Onshore Western Niger Delta, Nigeria

2020 ◽  
Vol 24 (2) ◽  
pp. 303-311
Author(s):  
F.O. Amiewalan ◽  
F.A. Lucas
Keyword(s):  
Sequence Stratigraphy ◽  
Niger Delta ◽  
Gamma Ray ◽  
Computer Software ◽  
Well Logs ◽  
Data Simulation ◽  
Candidate Sequence ◽  
Depositional Sequences ◽  
Sequence Stratigraphic ◽  
Sequence Boundaries

The area of study is a portion of the Greater Ughelli Depobelt in Niger Delta Basin. The main aim of the paper is to interpret the sequence  stratigraphy of FX-1 and FX-2 wells by employing data sets from biostratigraphic data and well logs. Standard laboratory techniques were used for  data treatment while computer software such as Petrel and StrataBugs were used for data simulation, processing, integration and interpretation. Sedimentology, interpreted gamma ray and resistivity well logs integrated with biostratigraphic data were utilized to define the candidate maximum flooding surfaces and sequence boundaries. The wells have the following distributions of sequences: FX-1 well have five depositional sequences with eight candidate maximum flooding surfaces at depths 10011 ft., 9509 ft., 9437 ft., 6362 ft., 5752 ft., 5507 ft., 5161 ft. and 4816 ft. dated 34.0 Ma, 33.0 Ma, 31.3 Ma, 28.1 Ma, 26.2 Ma, 24.3 Ma, 23.2 Ma and 22.0 Ma and seven candidate sequence boundaries at 9616 ft., 6656 ft., 6116 ft., 5639 ft., 5424 ft., 4859 ft. and 4581 ft. dated 33.3 Ma, 29.3 Ma, 27.3 Ma, 24.9 Ma, 23.7 Ma, 22.2 Ma and 21.8 Ma, respectively. FX-2 well have four depositional sequences, five candidate MFSs were identified at 7764 ft., 7196 ft., 6721 ft., 5862 ft. and 5571 ft. dated 34.0 Ma, 33.0 Ma, 31.3 Ma, 28.1 Ma and 24.3  Ma and five candidate SBs at 6941 ft., 6029 ft., 5688 ft., 5653 ft. and 5542 ft. dated 32.4 Ma, 29.3 Ma, 27.3 Ma, 24.9 Ma and 23.7 Ma respectively. The correlation of the two wells and sequence stratigraphic interpretation is a supplementary understanding of the subsurface geology of the Onshore, western Niger Delta area of Nigeria. Keywords: Bio-stratigraphic data, Well logs, Sequence stratigraphy, Well correlation.

Sequence Boundaries Identification of Putaohua Oil Layer in Qijia-Gulong Area

2013 ◽  
Vol 734-737 ◽  
pp. 166-169
Author(s):  
Hong Qi Yuan ◽  
Ying Hua Yu ◽  
Dong Li Sun
Keyword(s):  
Sequence Stratigraphy ◽  
Well Logs ◽  
Geochemical Data ◽  
Correct Identification ◽  
Seismic Profiles ◽  
Main Research ◽  
Sequence Stratigraphic ◽  
Genetic Interpretation ◽  
Sedimentary Succession ◽  
Sequence Boundaries

Sequence is a relatively conformable succession of genetically related strata bounded by unconformities or their correlative conformities. The correct identification of sequence boundaries is the key to the success of the sequence stratigraphic approach. Stratigraphic boundaries provide the fundamental framework for the genetic interpretation of any sedimentary succession, irrespective of how one may choose to name the packages of strata between them. Sequence stratigraphy of main research content is mainly chronohorizon (unconformity or conformity) identification, and to determine its causes and characteristics. Then, the key to sequence stratigraphy is identification unconformity and their correlative conformities. Unconformity and their correlative conformities on the seismic profiles, well logs, lithology, paleontology, and geochemical data have distinctive sequence boundaries mark characteristics.

scholarly journals Sequence Stratigraphy of Well DX, Gongola Sub-Basin, Upper Benue Trough, Nigeria

2019 ◽  
Vol 23 (10) ◽  
pp. 1855-1860
Author(s):  
F.O. Amiewalan ◽  
E.O. Bamigboye
Keyword(s):  
Gamma Ray ◽  
Third Order ◽  
Depositional Sequence ◽  
Benue Trough ◽  
Sequence Stratigraphic ◽  
Surface System ◽  
Sequence Boundaries ◽  
System Tracts ◽  
Maximum Flooding Surface ◽  
Gamma Ray Log

: Biostratigraphic study of Well DX has yielded Cretaceous miospores and dinoflagellates cysts which heightened the recognition of sequence boundaries (SB), Maximum Flooding Surfaces (MFS) and associated Systems Tracts. Five maximum flooding surfaces between 95.6 Ma and 89.0 Ma, four sequence boundaries between 96.4 Ma and 93.0 Ma and threedepositional sequences were identified with varying average thicknesses of sediments interpreted from the gamma ray log and biostratigraphic data. The threedepositional sequences interpreted are -depositional sequence I (96.4 Ma - 95.4 Ma) (8240 ft. - 8120 ft.), depositional sequence II (95.4 Ma - 94.0 Ma) (8120 ft. - 7850 ft.) and depositionalsequence III (94.0 Ma - 93.0 Ma) (7850 ft. - 7550 ft.). All the depositional sequences fall within the third order cycle. The age of the well was attempted based on the presence of some selected marker fossils - Ephedripites spp., Classopollis spp., Spiniferites spp., Cyclonephelium distinctum, Cyclonephelium vannophorum, Subtilisphaera spp., Eucomiidites spp., Triorites africaensis, Odontochitina costata and Droseridites senonicus recovered from the studied intervals and was dated Albian - Santonian. The Sequence stratigraphic interpretations are useful in further deepening the knowledge of thesubsurface geology of the studiedwell in Gongola Sub Basin, Upper Benue Trough of Nigeria.Keywords: Sequence Boundary, Maximum Flooding Surface, System tracts, Depositional sequence

High Resolution Sequence Stratigraphy of Silurian Strata in Tazhong Area

2013 ◽  
Vol 734-737 ◽  
pp. 111-116
Author(s):  
Lei Zhang ◽  
Lun Wei Zhu ◽  
Xue Juan Zhang
Keyword(s):  
High Resolution ◽  
Sequence Stratigraphy ◽  
Third Order ◽  
Sequence Stratigraphic ◽  
Stratigraphic Framework ◽  
Tazhong Area ◽  
Sequence Boundaries ◽  
High Resolution Sequence Stratigraphy ◽  
Comprehensive Study

According to the fundamental principles of high resolution sequence stratigraphy, this paper focused on the application of high resolution sequence stratigraphy to Silurian strata in Tazhong area. Based on the comprehensive study of logging, drilling and seismic information, the high resolution sequence boundaries of Silurian strata and two scales of datum level cycles (long-term and intermediate-term) can be recognized in Tazhong area. Seven chronstratigraphic boundaries can be recognized in Silurian strata, including four sequence boundaries, which were the transformation from datum level falling to datum level rising, and three flooding surfaces, which the transformation from datum level rising to datum level falling. The Silurian strata in Tazhong area can be divided into three third-order sequences which correspond to three long-term datum level cycles, and 11 fourth-order sequences (parasequence sets) relating to 11 intermediate-term datum level cycles. The classification aforementioned can much better solved the corresponding problem between the six lithological sections of Silurian strata and sequence formations, finally establishes the high resolution sequence stratigraphic framework of Silurian strata in Tazhong area.

Surface to subsurface correlation of the Middle-Upper Triassic Shublik Formation within a revised sequence stratigraphic framework

2020 ◽  
Vol 8 (2) ◽  
pp. SJ1-SJ16
Author(s):  
William A. Rouse ◽  
Katherine J. Whidden ◽  
Julie A. Dumoulin ◽  
David W. Houseknecht
Keyword(s):  
Large Scale ◽  
Gamma Ray ◽  
Upper Triassic ◽  
North Slope ◽  
Depositional Sequences ◽  
Sequence Stratigraphic ◽  
The North ◽  
Depositional Patterns ◽  
Resource Exploration ◽  
Unconventional Resource

Recent work on cores and outcrops of the Middle-Upper Triassic Shublik Formation has facilitated surface to subsurface correlation of depositional sequences across the Alaska North Slope. Five transgressive-regressive depositional sequences have been defined within three large-scale stratigraphic units. Outcrop spectral gamma-ray (GR) profiles were used to correlate observed stacking patterns with nearby exploration wells, and GR logs from 161 exploration wells were used to correlate the three large-scale stratigraphic units across the North Slope and nearby offshore. Interpretations of depositional facies and sequence stratigraphy in cores from 26 wells were used to corroborate regional correlations. Isochore maps constructed for each of the three stratigraphic units illustrate the influence of accommodation on depositional patterns and suggest reactivation of several older tectonic elements during Shublik deposition. An isochore map of the richest, oil-prone interval of the Shublik Formation reveals a thick pod south of Harrison Bay, the eastern part of which lies beneath a recent giant Shublik-sourced oil discovery in the Cretaceous Nanushuk Formation. In addition, when integrated with thermal maturity, this isochore map may provide leads for areas that are optimal for unconventional resource exploration.

scholarly journals Facies, sequence stratigraphy and reservoir/seal potential of a Jilh Formation outcrop equivalent (Wadi Sahtan, Triassic, Upper Mahil Member, Sultanate of Oman)

GeoArabia ◽  
2012 ◽  
Vol 17 (3) ◽  
pp. 85-128 ◽  
Author(s):  
Michael Obermaier ◽  
Thomas Aigner ◽  
Holger C. Forke
Keyword(s):  
Gamma Ray ◽  
High Energy ◽  
Second Order ◽  
Late Triassic ◽  
Small Scale ◽  
Third Order ◽  
Sequence Stratigraphic ◽  
Oman Mountains ◽  
Sequence Boundaries ◽  
Reservoir Potential

ABSTRACT The investigated Middle to Upper Triassic Upper Mahil Member, representing a Jilh outcrop equivalent in the Northern Oman Mountains, illustrates the proximal portion of a flat epeiric carbonate ramp. A sedimentological study of well-exposed outcrops in Wadi Sahtan may serve as a reference section for a sequence-stratigraphic framework and detailed facies description of the Upper Mahil Member. It also provides an insight into the seal and reservoir potential of carbonates in a low-accommodation inner ramp setting. Outcrop observations and thin section analyses yielded 14 different lithofacies types ranging from a supratidal marsh to high-energy subtidal shoal environment. Vertical facies stacking patterns show three basic small-scale cycle motifs (fifth-order). While mud-rich backshoal cycles with claystone intercalations and rooted/bioturbated mud-/wackestones illustrate potential baffles and seal units around the center of the Upper Mahil, potential reservoir units occur stratigraphically in the upper part of the formation. There, a few meter-thick trough cross-bedded oolitic-/peloidal-rich grainstone depicts maximum accommodation within backshoal to shoal cycle types below the erosional base-Jurassic unconformity. The investigated outcrop section in Wadi Sahtan was subdivided into nine almost complete third-order sequences. Two to four of these sequences are further stacked into three second-order super-sequences which are well reflected in the gamma-ray pattern. The highest reservoir potential occurs around second-order maximum floodings. Internal seals can be observed at third-order sequence boundaries where shales and muddy carbonates are up to 20 m thick. A regional correlation with subsurface data from Yibal and Lekhwair in Oman shows that the apparent thickness changes in the Upper Mahil (Jilh) are mainly determined by the Late Triassic/Early Jurassic erosional truncation. The occurrence of thick anhydrite units in the subsurface indicates a more proximal setting towards the southwest.

scholarly journals Geological Evaluation of Hydrocarbon Prospect of FOB-field, Coastal Swamp Depobelt, Onshore, Niger Delta Basin, Nigeria

2019 ◽  
pp. 1-12
Author(s):  
Frankie O. Balogun ◽  
Franklin A. Lucas ◽  
Osarodion Ebomwonyi
Keyword(s):  
Late Miocene ◽  
Niger Delta ◽  
Seismic Facies ◽  
Well Logs ◽  
Environment Model ◽  
Multidisciplinary Data ◽  
Sedimentary Succession ◽  
Sequence Boundaries ◽  
Niger Delta Basin ◽  
Geological Position

Well logs, biostratigraphic data, seismic data and semblance map which together form a multidisciplinary data approach, were utilized in the geological evaluation of hydrocarbon prospect FOB-Field, onshore Coastal Swamp Depobelt in the Niger Delta Basin. Structural interpretation of faults, correlation of wells and 3D seismic interpretation were carried out using Schlumberger’s window based petrel software integrated with various lines of evidence such as sequence boundaries and maximum flooding surfaces. The penetrated sedimentary succession was established to constrain the alternation of sand packages from proximal to distal. The studied wells were dated mid to late Miocene based on the geological position of the sequence boundary (10.35Ma) and geological ages of the Mfs (9.5MaMfs) and (10.4MaMfs) respectively corresponding to the Coastal Swamp Depobelt of the Niger Delta Basin. Integration of well logs, seismic, semblance, paleobathymetric and biostratigraphic data indicated mid to late Miocene and neritic to bathyal paleoenvironment of deposition. Integration of fault integrity, seismic, well logs and key stratigraphic markers were utilized to build a seismic facies model and a gross depositional environment model for the FOB-Field.

scholarly journals Delineation of Stratigraphic Units in Xyz Field of Niger Delta Using Geophysical Logs

2019 ◽  
Vol 3 (1) ◽  
pp. 38-49
Author(s):  
Charles C. Ekeh ◽  
Etim D. Uko ◽  
Ejiro F. Eleluwor ◽  
Friday B. Sigalo
Keyword(s):  
Niger Delta ◽  
Well Logs ◽  
Surface Porosity ◽  
Depositional Sequences ◽  
Petrophysical Parameters ◽  
Geophysical Logs ◽  
Net To Gross ◽  
Geophysical Well Logs ◽  
System Tracts ◽  
Optimum Recovery

AbstractGeophysical well logs were used to delineate the stratigraphic units and system tracks in the XYZ Field of the Niger Delta. The gross percentages for sand levels range from 93-96% in the shallow levels to 60-66% in the deeper levels. Porosity values ranged between 27% at shallower sections and 9% at deeper depths. Six depositional sequences were identified and categorized into their associated system tracts. Porosity decreases with depth in normal compacted formation for both sandstone and shale units. Surface porosity for sandstone is 42%, and for shale it is 38.7% from extrapolation of sub-surface porosity values to the surface. The depth to the base of Benin Formation is highly variable ranging between 1300 and 2600m. This study reveals the possibility to correlate sand levels over long distances which enables inferring porosity values laterally. The knowledge of the existent stratigraphic units, the Benin, Agbada and Akata Formations and their petrophysical parameters such as porosity, lateral continuity of the sands and shales, the variation of the net-to-gross of sands with depth, enables the reservoir engineer to develop a plan for the number and location of the wells to be drilled into the reservoir, the rates of production that can be sustained for optimum recovery. The reservoir engineer can also estimate the productivity and ultimate recovery (reserves) using the results on this work.

Detailed quantitative sequence stratigraphic interpretation for the characterization of Amangi field using seismic data and well logs

2021 ◽  
Vol 19 (3) ◽  
pp. 63-82
Author(s):  
S. Inichinbia ◽  
Halidu Hamza
Keyword(s):  
Seismic Data ◽  
Gamma Ray ◽  
Hydrocarbon Exploration ◽  
Well Logs ◽  
Rock Properties ◽  
Sequence Stratigraphic ◽  
Resistivity Logs ◽  
Hydrocarbon Saturation ◽  
Shaly Sand ◽  
Net To Gross

The sequence stratigraphy of Amangi field of the Niger Delta was studied using seismic data and well logs. The field is a structurally  complex one and presents serious challenges to hydrocarbon exploration and production. The main objective of these analyses is to  identify sand intervals using the available data. Well log data were used as additional tools to constrain the seismic correlations in order to solve the correlation problem. The well logs were evaluated for the field’s petrophysical properties by combining the gamma ray and resistivity logs to determine reservoir zones with considerable hydrocarbon saturation. Also, the relationship between some basic rock properties/attributes and litho-types were determined for the study area. Next, well-to-seismic ties were produced and two horizons were picked. Acoustic impedance inversion was also performed which revealed “hard sands” due to mixed lithologies (heterolithics). This made it difficult to discriminate the sands from shales in the P-impedance domain alone. So, progress was made to determine the net-to-gross of the field. The analysis revealed that these reservoirs have shaly sand with shale content of 10%, porosity averaging 21%, and hydrocarbon saturation of 90%. The result established a vertical stack of a series of reservoirs in an anticlinal structure of which the H1000 and H4000 stand out for their huge volumes of rich gas condensate accumulation. This discovery provoked the drive for the first phase of development of this field. Keywords: stratigraphy, facies, net-to-gross, horizon, lithology, well-to-seismic tie, impedance

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