Microphytoplankton biozonation of late Albian - Turonian succession in Famo-1 well, Gongola Sub Basin, Upper Benue Trough, Nigeria

A comprehensive palynological (Dinoflagellate Cyst) study of 35 ditch cutting samples recovered from Late Albian to Turonian succession penetrated by Famo-1 well in the Gongola sub Basin, Upper Benue Trough, North East, Nigeria, generated biostratigraphically important dinoflagellate cyst species. Intervals (8300 ft. – 8330 ft.) in the lower part of the studied section were barren of dinoflagellate cysts. Interpretation of the first and last (FAD and LAD) appearance datum of the recovered dinoflagellate cyst assemblages allowed the erection of four informal dinoflagellate cyst assemblage biozones. The biozones in stratigraphically ascending order and their ages are as follows: Late Albian-Cenomanian (Biozone I & II), Turonian (Biozone III) and undiagnostic (Biozone IV). The ages of these zones based on stratigraphic positions and series of first occurrences of key species are from Late Albian-Turonian. An inner neritic palaeoenvironment was delineated based on the dominance of Peridinacean cysts over Gonyaulacacean cysts.Keywords: Turonian, Cenomanian, Biozone, palaeoenvironmen

Paleo-environmental reconstruction of oligocene to early miocene sediments of Greater UghelliDepobelt, Niger Delta Basin

Paleoenvironmental study of Oligocene to Early Miocene sediments of Greater UghelliDepobelt Niger Delta Basin were carried outusing foraminiferal micropaleontology as geologic tools.Fifty (50) ditch cutting samples ranging from 20ft.-11,820ft (6.09m-3603.7m) was used with the aim of establishing thepaleo-environment of the well. A total of twenty six (26) foraminiferal species were recorded, most of the species recorded are calcareous and arenaceous benthic foraminiferal species while planktonic foraminiferal species are generally scarce in the well. The non-recovery of planktonic and the general poor recovery of foraminiferal species might be due to environmental factor. The foraminiferal abundances revealed two varying depositional environment which are Continental to Marginal Marine and Proximal to distal Inner Neritic environment. These deductions were based primarily on benthic foraminiferal assemblage, their abundance and diversity. The presence or absence of planktonic foraminifera also helped in deciphering open ocean environments.The Continental to Marginal Marine setting range from 1640ft to 11,100ft due to non-recovery to rare foraminiferal species recorded within this interval while the Proximal to Distal Inner Neritic ranges from 11,160ft to 11,760ft with the presence of few foraminiferal species consisting of rare benthic foraminiferal species and scarcity of planktonics foraminiferal species indicating deposition in a shallow water, suggesting sediments deposition is fluctuating between proximal to distal Inner Neritic.Keywords: foraminiferal; Proximal to Distal Inner Neritic;Paleoenvironment; Niger Delta Basin; Depobel

Palynological zonation of oligocene to early miocene sediments of greater Ughelli Depobelt, Niger Delta Basin

Palynological zonation of Oligocene to Early Miocene sediments of Greater Ughelli Depobelt Niger Delta Basin was carried out using One hundred and ninety (190) ditch cutting samples ranging from 20ft.-11,820ft. (6.09m- 3603.7m), by identifying the different species of palynomorphs present as well as using stratigraphic significant diagnostic palynomorphs to age date and zone the well section, Nine hundred and sixty four (964) species of palynomorps were recovered.Nine hundred and fifty four (954) were miospores(pollen and spore) and ten(10) were Dinocysts.The presence of diagnostic palynomorphs such as Praedapollis africanus, Peregrinipollis nigericus, Retibrevitricolporites obodoensis aided in the establishment of the age and three P-zones in the well. The age of the well section range from Oligocene to Early Miocene.The P-zones established are P560, P580 and P620 zones. P620 and P580 Zones were lumped together and was established based on the occurrence of Top Pradapollis africanus at 4500ft and quantitative base of Peregrinipollis nigericus at 7620ft.This zone were lumped together because Top/FDO Cicatricosisporites dorogenesis (30)/Gemmatriporites sp (573) which represents the base of P620 zone and top of P580 zone were undefined. P560 Zone was defined by the appearance of quantitative base Peregrinipollis nigericus at 7620ft and increase Retibrevitricolporites obodoensis at 11580ft.Keywords: Lithozones; Niger delta Basin; Palynomorphs; Oligocene to Early Miocene; Depobel

Geochemical Maturity and Paleo-Weathering Indices of Sedimentary Succession in JVField Greater Ughelli Depo-Belt Niger Delta Basin

This study evaluates the geochemical maturity and paleo weathering indices of X well JV-Field, Greater UghelliDepo belt Niger Delta Basin, using reflected light microscope and geochemical proxies. The data obtained identified three lithofacies units as Sand, Shale, and Shaly sand facies .The application of source area weathering using Chemical index of alteration (CIA) and Chemical index of weathering (CIW) values for the sampled intervals ranges from (48.6-94.9%) and (60.6-96.7%), and have median values of (83.2 and 90.3) % respectively which is an indication of high weathering at the source. The values are variable and it may be as a result of multiple provenances of the sediments which have variable proportions of source area weathering and related processes or may be due to low concentrations of the alkalis and alkaline earth elements. However, all the samples excluding one with depth (12430ft) show CIA and CIW values greater than 70% indicating high (intensive) weathering either at the source or during transportation before deposition .From the high alteration indices value recorded from the sampled intervals, it can be inferred that the sediments are geochemically and texturally mature

Geochemical characterization of FE-1 well, Onshore Western Niger Delta Basin, Nigeria

Major oxides and trace elements analysis was carried out on ditch cutting samples of FE-1 well, Onshore, Niger Delta Basin, to define their oxygen condition, paleo-climatic conditions, provenance, tectonic setting, sandstone classification and maturity of the sediments. Sedimentological analysis revealed five main lithofacies comprising of sandstone, shaly sand, mudstone, sandy clay and sandy shale. Geochemical results indicates that the average value of silica (87.1 wt. %) is far higher than the average values of the rest oxides which shows the duration and intensity of weathering and destruction of other minerals during transportation. Bivariate plot of La/Sc versus Th/Co, Zr versus TiO2, and trace elemental ratios of Th/Sc, Th/Co, Th/Cr, Cr/Th, La/Sc establishes that the source of the sediment are from felsic rock. Different chemical classification schemes characterized the sediments as quartzarenite, lithic arenites and Fe-rich sand. The plot of Log (K2O/Na2O) versus Log (SiO2/Al2O3) and K2O/Na2O versus SiO2 all plotted mainly in the passive margin zone. The low average value of uranium content, trace elemental ratios of U/Th, Ni/Co, Cu/Zn, V/Cr and binary plot of Ni/Co versus V/Cr indicated an oxic environment of deposition. However, the binary plot of Ni/Co versus V/ (V+Ni) indicates oxic to anoxic condition during deposition of the mixed marine and terrigenous source input sediment. Binary plot of SiO2 versus (Al2O3+Na2O+K2O) designates deposition mainly in humid/semi-humid climatic condition. The samples studied have a much higher SiO2/Al2O3 ratio with low Fe2O3/K2O ratio, thus, they are mineralogically mature. The Al2O3/(CaO+MgO+Na2O+K2O) ratio inferred that there are stable mobile oxides in the samples. Keywords: Major oxides, lithic arenites, provenance, tectonic setting. &nbsp

Recognition of Evamy Et Al P-Zones in the Tertiary Sediments of F- Well, Niger Delta

Palynological evaluation of Tertiary sediments in F- Well, Niger Delta Basin was carried out using Fifty (50) Ditch Cutting samples from a well at different intervals between 2,010ft and 10,170ft. The samples were prepared using standard palynological sample processing technique and analyzed under the microscope. They were about twenty three (23) diagnostic palynomorphs recognized. The evaluation of these  palynomorphs species enabled us to recognize the zones. The presence of diagnostic palynomorphs such as Praedapollis africanus, Peregrinipollis nigericus, Retibrevitricolporites obodoensis and Cicatrisosporites  dorogenesis aided in the establishment of the age and P-zones. The recognized P-zones are P560, P580 and P620 zones. P 560 zone was defined at depth 9,585ft to 9,960ft with increase Retibrevitricolporites oboendensis and the Quantitative Base of Peregrinipollis nigericus P 580 zone was defined at depth 9,585ft to 7,830ft with Quantitative Base of Peregrinipollis nigericus and Top of Cicatrisosporites dorogenesis and P620zone was defined at depth 7,830ft to 6,690ft with Top Praedapolis africanus and Top Cicatrisosporites dorogenesis. Palynological events and zones gotten from the studied sedimentary succession suggest Oligocene – Early Miocene Age, with numerical value of 32.7 – 22.3 Ma when aligned with the Niger Delta Chronostratigraphic Chart.Keywords: Palynology, First Downhole Occurrence, Last Downhole Occurrence, P-zone

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

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

Miospore biozonation of cenomanian - santonian succession in Famo-1 well, Gongola Sub Basin, Upper Benue Trough, Nigeria

The Early Cretaceous succession penetrated by Famo-1 well in Gongola sub Basin, Upper Benue Trough, Nigeria were analyzed for its palynological content. This investigation produced significant Pollen and Spore and the assemblage reveals the dominance of angiosperm Pollen grain and pteridophytes spore. Gymnosperm pollen was scarce and less varied. The studied interval penetrated a sequence of sandstone, sandy shale and mudstone occurring at different intervals in the studied section of the well. Established on the stratigraphic distribution of the palynomorphs recovered from Famo-1 well, three informal assemblage palynozones covering the Early Cretaceous were identified. The zones are: Assemblage Zones I & II (Cenomanian); Assemblage Zone III (Turonian - Santonian). The different zones signifies a time stratigraphic unit comparable to the identified lithostratigraphic units penetrated by the well. The age (Cenomanian - Santonian) determinations are based on the known stratigraphic ranges of pollen and spores and their relative stratigraphic positions. Data from the studied well revealed that there is relatively higher frequency of the land derived pollen and spores compared to marine palynomorph abundance, which suggests a paralic condition of continental to shallow marine environment. The shallow marginal marine environment is further sustained by the presence of foraminifera test linings at some depths which are indicative of marine palaeoenvironment (inner neritic environment). Interpretations from the spore and pollen assemblages reveal sediment deposition took place in a wet to arid climate condition in marginal marine to nearshore environment.Keywords: Palynology, Gongola sub Basin, Cretaceous, Famo-1 Wel

Depositional facies analysis using core samples from greater Ughelli Depobelt, Niger Delta Basin Nigeria

Sedimentological analysis of core samples from Well XY-62 located within the greater Ughelli depobelt of the Niger Delta basin was carried out. Some physical deterioration had set in and some gaps had reduced the total core length available to 316 .90ft. The cores contain three sandstone and one mudrock lithofacies: Fine-grained mmscale laminated sandstone (Sl.f) 40.83%, medium to coarse-grained cm-scale cross-bedded sandstone (Sx.m) 35.34%, pebbly Sandstone (PS) 4.39%, bedded Mudstone (Mb) 19.44%. The sandstone lithofacies differ from one another mainly in grain size, as appears obvious, otherwise they are largely texturally, compositionally, diagenetically and structurally broadly similar. They are generally clean (zero to 20% clay content), moderately well to well sorted, pebbly, and texturally mature. Quartz appears to be the sole framework component, making the sandstones mineralogically mature i.e. quartz arenites and quartz wackes. Being generally weakly consolidated and scantily cemented, the sandstones are all in the early stages of diagenesis, an attribute that has had a desirable effect on their reservoir quality. The bedded mudstone lithofacies contains laminated claystones and fissile shales which are all thought to have compartmentalized the sand reservoirs rather than sealed them. Depositional environments have been inferred to be the foreshore setting, with lagoon subenvironments that favoured mudrock accumulation landward of a barrier bar complex. The overall motif read from both the strip log and the wireline logs indicate neither clear progradation nor unequivocal retrogradation of the lithofacies. It is therefore concluded that the XY- 62 cores were cut from an aggradational depositional setting.Keywords: Cores, Sediment analysis, Depositional environments, Niger Delt

Instrumental Approach and Diagnosis of Total Inorganics in a Typical Carbonaceous Matter

Typical Carbonaceous matter are often widespread and reveal relatively wide range of dominant organic types. The instrumental diagnosis to subject them to oxidation, combustion and/or incineration serve till date mandatory fundamental requirement in the further pursuance of their mineralogical and wet Chemical Analysis. The results of the Ash content from three (3) carbonaceous coal-and shaly coal samples from Northeastern England and Scottish fife show that the variation and/or the volatilization of the inherent sensitive elements are related to both the techniques and the sample composition. From the two techniques adopted, the high-and low-temperature methods the Ash values observed/obtained for Westfied shaly and Beaumont coal types are dependent on their derived material source-argillaceous and pure coal components. However, of the inorganic components (Ash) values that can be recovered from any carbonaceous matter, Radio-frequency method appears to suggest the accurate and reliable alternative for their subsequent geochemical appraisal