Deciphering the Impact of Subsurface Geology on Reservoir Quality Indicators: Petrophysical Evaluation from Niger Delta

Abstract The Thamama group of reservoirs consist of porous carbonates laminated with tight carbonates, with pronounced lateral heterogeneities in porosity, permeability, and reservoir thickness. The main objective of our study was mapping variations and reservoir quality prediction away from well control. As the reservoirs were thin and beyond seismic resolution, it was vital that the facies and porosity be mapped in high resolution, with a high predictability, for successful placement of horizontal wells for future development of the field. We established a unified workflow of geostatistical inversion and rock physics to characterize the reservoirs. Geostatistical inversion was run in static models that were converted from depth to time domain. A robust two-way velocity model was built to map the depth grid and its zones on the time seismic data. This ensured correct placement of the predicted high-resolution elastic attributes in the depth static model. Rock physics modeling and Bayesian classification were used to convert the elastic properties into porosity and lithology (static rock-type (SRT)), which were validated in blind wells and used to rank the multiple realizations. In the geostatistical pre-stack inversion, the elastic property prediction was constrained by the seismic data and controlled by variograms, probability distributions and a guide model. The deterministic inversion was used as a guide or prior model and served as a laterally varying mean. Initially, unconstrained inversion was tested by keeping all wells as blind and the predictions were optimized by updating the input parameters. The stochastic inversion results were also frequency filtered in several frequency bands, to understand the impact of seismic data and variograms on the prediction. Finally, 30 wells were used as input, to generate 80 realizations of P-impedance, S-impedance, Vp/Vs, and density. After converting back to depth, 30 additional blind wells were used to validate the predicted porosity, with a high correlation of more than 0.8. The realizations were ranked based on the porosity predictability in blind wells combined with the pore volume histograms. Realizations with high predictability and close to the P10, P50 and P90 cases (of pore volume) were selected for further use. Based on the rock physics analysis, the predicted lithology classes were associated with the geological rock-types (SRT) for incorporation in the static model. The study presents an innovative approach to successfully integrate geostatistical inversion and rock physics with static modeling. This workflow will generate seismically constrained high-resolution reservoir properties for thin reservoirs, such as porosity and lithology, which are seamlessly mapped in the depth domain for optimized development of the field. It will also account for the uncertainties in the reservoir model through the generation of multiple equiprobable realizations or scenarios.

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Lithofacies Analysis and Qualitative Minerology of the Sediments of #3 Well in the Greater Ughelli Depobelt, Niger Delta Basin

Journal of Scientific Research ◽

10.3329/jsr.v13i2.49948 ◽

2021 ◽

Vol 13 (2) ◽

pp. 601-610

Author(s):

K. Itiowe ◽

R. Oghonyon ◽

B. K. Kurah

Keyword(s):

Physical Properties ◽

Clay Minerals ◽

Niger Delta ◽

Reservoir Quality ◽

X Ray Diffraction ◽

X Ray ◽

Sandy Shale ◽

Heterogeneous Nature ◽

Niger Delta Basin ◽

Shaly Sandstone

The sediment of #3 Well of the Greater Ughelli Depobelt are represented by sand and shale intercalation. In this study, lithofacies analysis and X-ray diffraction technique were used to characterize the sediments from the well. The lithofacies analysis was based on the physical properties of the sediments encountered from the ditch cuttings. Five lithofacies types of mainly sandstone, clayey sandstone, shaly sandstone, sandy shale and shale and 53 lithofacies zones were identified from 15 ft to 11295 ft. The result of the X-ray diffraction analysis identified that the following clay minerals – kaolinite, illite/muscovite, sepiolite, chlorite, calcite, dolomite; with kaolinite in greater percentage. The non-clay minerals include quartz, pyrite, anatase, gypsum, plagioclase, microcline, jarosite, barite and fluorite; with quartz having the highest percentage. Therefore, due to the high percentage of kaolinite in #3 well, the pore filing kaolinite may have more effect on the reservoir quality than illite/muscovite, chlorite and sepiolite. By considering the physical properties, homogenous and heterogeneous nature of the #3 Well, it would be concluded that #3 Well has some prospect for petroleum and gas exploration.

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Sedimentary facies and petrographic analyses of Miocene nearshore deposits, Central Swamp Depobelt, onshore Niger Delta Basin: implications for reservoir quality

Journal of Sedimentary Environments ◽

10.1007/s43217-021-00076-1 ◽

2021 ◽

Author(s):

Joseph Nanaoweikule Eradiri ◽

Ehimare Erhire Odafen ◽

Ikenna Christopher Okwara ◽

Ayonma Wilfred Mode ◽

Okwudiri Aloysius Anyiam ◽

...

Keyword(s):

Niger Delta ◽

Sedimentary Facies ◽

Reservoir Quality ◽

Petrographic Analyses ◽

Niger Delta Basin

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Time-Lapse Seismic for Reservoir Management: Case Studies From Offshore Niger Delta, Nigeria

SPE Reservoir Evaluation & Engineering ◽

10.2118/170808-pa ◽

2016 ◽

Vol 19 (03) ◽

pp. 391-402

Author(s):

Sunday Amoyedo ◽

Emmanuel Ekut ◽

Rasaki Salami ◽

Liliana Goncalves-Ferreira ◽

Pascal Desegaulx

Keyword(s):

Case Studies ◽

Niger Delta ◽

Reservoir Management ◽

Time Lapse ◽

Seismic Survey ◽

Elastic Model ◽

Field Development ◽

4D Seismic ◽

The Impact

Summary This paper presents case studies focused on the interpretation and integration of seismic reservoir monitoring from several fields in conventional offshore and deepwater Niger Delta. The fields are characterized by different geological settings and development-maturity stages. We show different applications varying from qualitative to quantitative use of time-lapse (4D) seismic information. In the first case study, which is in shallow water, the field has specific reservoir-development challenges, simple geology, and is in phased development. On this field, 4D seismic, which was acquired several years ago, is characterized by poor seismic repeatability. Nevertheless, we show that because of improvements from seismic reprocessing, 4D seismic makes qualitative contributions to the ongoing field development. In the second case study, the field is characterized by complex geological settings. The 4D seismic is affected by overburden with strong lateral variations in velocity and steeply dipping structure (up to 40°). Prestack-depth-imaging (PSDM) 4D seismic is used in a more-qualitative manner to monitor gas injection, validate the geologic/reservoir models, optimize infill injector placement, and consequently, enhance field-development economics. The third case study presents a deep offshore field characterized by a complex depositional system for some reservoirs. In this example, good 4D-seismic repeatability (sum of source- and receiver-placement differences between surveys, dS+dR) is achieved, leading to an increased quantitative use of 4D monitoring for the assessment of sand/sand communication, mapping of oil/water (OWC) front, pressure evolution, and dynamic calibration of petro-elastic model (PEM), and also as a seismic-based production-logging tool. In addition, 4D seismic is used to update seismic interpretation, provide a better understanding of internal architecture of the reservoirs units, and, thereby, yield a more-robust reservoir model. The 4D seismic in this field is a key tool for field-development optimization and reservoir management. The last case study illustrates the need for seismic-feasibility studies to detect 4D responses related to production. In addition to assessing the impact of the field environment on the 4D- seismic signal, these studies also help in choosing the optimum seismic-survey type, design, and acquisition parameters. These studies would possibly lead to the adoption of new technologies such as broad-band streamer or nodes acquisition in the near future.

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Liverpool Merchants in 19th-Century Niger Delta

Social Sciences and Missions ◽

10.1163/18748945-03103001 ◽

2018 ◽

Vol 31 (3-4) ◽

pp. 310-340

Author(s):

Nimi Wariboko

Keyword(s):

Nineteenth Century ◽

Business Ethics ◽

Niger Delta ◽

Max Weber ◽

Economic Conditions ◽

The Political ◽

Religious Ethics ◽

Business Practices ◽

Christian Missions ◽

The Impact

Abstract How does religion or worldview affect business practices and ethics? This tradition of inquiry goes back, at least, to Max Weber who, in the Protestant Ethic and the Spirit of Capitalism, explored the impact of theological suppositions on capitalist economic development. But the connection can also go the other way. So the focus of inquiry can become: How does business ethics or practices affect ethics in a given nation or corporation? This paper inquires into how the political and economic conditions created and sustained by nineteenth-century trading community in the Niger Delta influenced religious practices or ethics of Christian missionaries. This approach to mission study is necessary not only because we want to further understand the work of Christian missions and also to tease out the effect of business ethics on religious ethics, but also because Christian missionaries came to the Niger Delta in the nineteenth century behind foreign merchants.

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Study of a Context Quality Model for UbiPri Middleware

KnE Engineering ◽

10.18502/keg.v5i6.7075 ◽

2020 ◽

Author(s):

Diandre de Paula ◽

Daniel Saraiva ◽

Romeiro Natália ◽

Nuno Garcia ◽

Valderi Leithardt

Keyword(s):

Quality Indicators ◽

Data Privacy ◽

Context Information ◽

Adaptation Process ◽

Context Aware ◽

Quality Model ◽

Context Aware Computing ◽

Quality Of Context ◽

The Impact

With the growth of ubiquitous computing, context-aware computing-based applications are increasingly emerging, and these applications demonstrate the impact that context has on the adaptation process. From the context, it will be possible to adapt the application according to the requirements and needs of its users. Therefore, the quality of the context information must be guaranteed so that the application does not have an incorrect or unexpected adaptation process. But like any given data, there is the possibility of inaccuracy and/or uncertainty and so Quality of Context (QoC) plays a key role in ensuring the quality of context information and optimizing the adaptation process. To guarantee the Quality of Context it is necessary to study a quality model to be created, which will have the important function of evaluating the context information. Thus, it is necessary to ensure that the parameters and quality indicators to be used and evaluated are the most appropriate for a given type of application. This paper aims to study a context quality model for the UbiPri middleware, defining its quality indicators to ensure its proper functioning in the process of adaptation in granting access to ubiquitous environments. Keywords: QoC, Model, Context-Aware, Data, Privacy

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