Results
Abstract The Niger Delta Deep Offshore Basin has been the latest frontier within the Niger Delta for hydrocarbon exploration and production activities. Until the onset of drilling activities in the early 1990s, little was known about the biostratigraphy of this frontier setting. Thus, uncertainties existed in the ages ascribed to the various stratigraphic sequences. Presently, several wells have been drilled in the deep offshore Niger Delta and three-pronged biostratigraphic data and some sequence stratigraphic interpretations have become available. We have integrated biostratigraphic data comprising palynological, foraminiferal, and calcareous nannoplankton zonation and biofacies, wireline log information, and regional-3D seismic data, with simple basic sequence stratigraphic analysis for a detailed well correlation, regional mapping of hydrocarbon-bearing intervals, and evaluation of the thicknesses of promising stratigraphic intervals. Results indicate a significant effect on not only the earlier conceptualized age of the deepest prospective reservoirs, but also the ages of possible source rocks in the Paleogene of the Niger Delta offshore sequence. Our findings will help in the realistic assumptions of source rock characterization, charge modeling/prediction, and the stratigraphic thicknesses of the offshore sequences and their reservoirs. We examine the specific derivable age interpretations from the integration of at least six wells, biostratigraphic data with seismic, and the implications of these interpretations for hydrocarbon prospectivity of the Paleogene sequences. Furthermore, we document the biostratigraphy work done in the area, in all the structural belts where drilling has occurred including the deepest well drilled in the deep offshore Niger Delta, Bosi-006. The results of this study have a critical impact on the current regional geologic understanding of the deep offshore Niger Delta.
- Africa > Nigeria > Niger Delta (1.00)
- Africa > Niger (1.00)
- Geology > Geological Subdiscipline > Stratigraphy > Biostratigraphy (1.00)
- Geology > Structural Geology > Tectonics > Compressional Tectonics > Fold and Thrust Belt (0.70)
- Geophysics > Seismic Surveying > Seismic Processing (0.68)
- Geophysics > Seismic Surveying > Surface Seismic Acquisition (0.54)
- Africa > Nigeria > Niger Delta > Niger Delta Basin (0.99)
- Africa > Cameroon > Akata Formation (0.99)
- Africa > Nigeria > Gulf of Guinea > Niger Delta > Niger Delta Basin > OML 95 > Delta Field (0.98)
- (3 more...)
Abstract Hydrocarbons are bypassed in known fields. This is due to reservoir heterogeneities, complex lithology, and limitations of existing technology. This paper seeks to identify the scenarios of bypassed hydrocarbons, and to highlight how advances in reservoir characterization techniques have improved assessment of bypassed hydrocarbons. The present case study is an evaluation well drilled on the continental shelf, off the West African Coastline. The targeted thin-bedded reservoir sands are of Cenomanian age. Some technologies for assessing bypassed hydrocarbon include Gamma Ray Spectralog and Thin Bed Analysis. NMR is important for accurate reservoir characterization of thinly bedded reservoirs. The measured NMR porosity was 15pu, which is 42% of the actual porosity. Using the measured values gave a permeability of 5.3mD as against the actual permeability of 234mD. The novel model presented in this paper increased the porosity by 58% and the permeability by 4315%.
- Geology > Structural Geology > Tectonics (1.00)
- Geology > Geological Subdiscipline (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Sandstone (0.72)
- Africa > Nigeria > Niger Delta > Niger Delta Basin (0.99)
- Africa > Nigeria > Gulf of Guinea > Niger Delta > Niger Delta Basin > OML 95 > Delta Field (0.99)
- Africa > Nigeria > Gulf of Guinea > Niger Delta > Niger Delta Basin > OML 49 > Delta Field (0.99)
- (2 more...)
- Reservoir Description and Dynamics > Reservoir Characterization > Exploration, development, structural geology (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Open hole/cased hole log analysis (1.00)
- Reservoir Description and Dynamics > Reservoir Fluid Dynamics > Flow in porous media (0.92)
Interpretation of 3D Seismic Data for Prospectivity of Underexplored Deep Formations in Pateke Field, Niger Delta Basin, Nigeria
Nwike, I. S. (Department of Geology, Chukwuemeka Odumegwu Ojukwu University, Uli Campus, Nigeria) | Onwuemesi, A. G. (Department of Geological Sciences, Nnamdi Azikiwe University, Awka, Nigeria.) | Nwozor, K. K. (Department of Geology, Chukwuemeka Odumegwu Ojukwu University, Uli Campus, Nigeria) | Onuba, L. N. (Department of Geology, Chukwuemeka Odumegwu Ojukwu University, Uli Campus, Nigeria)
Abstract Overlooked prospects and underexplored fields in the Niger Delta Basin continue to attract the attention of many stakeholders in the industry as the quest to achieve the national 40 billion barrels oil reserve target continues to gain momentum. A key area of interest is that many wells drilled earlier in the basin were limitedlargely by technology from probing deeper formations. With the availability of 3D seismic data, improved subsurface knowledge, more efficient interpretation tools and skills, this study reevaluated the hydrocarbon potentials of the economically strategic ‘Pateke’ field in the Coastal Swamp Depobelt where the deepest well was drilled to a total depth of 8950 feet (2728 meters). Thereevaluation approach involved high precision fault and horizon mapping, seismic attribute extraction and analysis using the Petrel platform. The interpretation shows the structural framework of the field to be constituted by five faults with two major faults trending east – west and northwest – southeast respectively, thus dividing the field into three fault blocks. Integration of Root Mean Square (RMS) Amplitude, Envelope and Sweetness seismic volume attributes suggest probable hydrocarbon accumulations within the fault blocksthat lie far beneath the reach of the present wells in the field. The implication of this result is that the full potentials of ‘Pateke’ field are yet to be achieved considering the positive indications of economically recoverable hydrocarbons in the deeper sections of the field.
- Africa > Nigeria > Niger Delta (1.00)
- Oceania > New Zealand > North Island > Tasman Sea (0.84)
- Phanerozoic > Mesozoic (0.49)
- Phanerozoic > Cenozoic (0.47)
- Geology > Sedimentary Geology > Depositional Environment (1.00)
- Geology > Geological Subdiscipline > Stratigraphy (1.00)
- Geology > Geological Subdiscipline > Economic Geology > Petroleum Geology (0.72)
- (2 more...)
- Geophysics > Seismic Surveying > Surface Seismic Acquisition (1.00)
- Geophysics > Seismic Surveying > Seismic Processing (1.00)
- Geophysics > Seismic Surveying > Seismic Interpretation (1.00)
- Oceania > New Zealand > North Island > Tasman Sea > Taranaki Basin > PMP 38158 > Pateke Field (0.99)
- North America > United States > Texas > Anadarko Basin (0.99)
- North America > United States > Oklahoma > Anadarko Basin (0.99)
- (5 more...)
Experimental Investigation of the Feasibility of Polymer Flooding in a Shallow Niger Delta Oil Reservoir
Ogienagbon, Adijat (Petroleum Engineering Department, University of Benin) | Taiwo, Oluwaseun Ayodele (Petroleum Engineering Department, University of Benin) | Mamudu, Abbas (Petroleum Engineering Department, University of Benin) | Olafuyi, Olalekan (Petroleum Engineering Department, University of Benin)
Abstract The global oil price as well as Nigeria’s current reserve is on a continuous alarming decline. With the increasing finding cost of new wells and demand for energy, improving oil recovery from existing wells becomes highly pertinent. Generally, waterflooding leaves approximately two thirds of the OIIP as un-swept or residual oil resulting to a low recovery factor. The improvement of recovery factor is one of the identified five Research & Development (R&D) grand challenges or upstream business needs highlighted by the SPE R & D committee. Enhanced Oil recovery (EOR) methods provide an avenue to Petroleum engineers to unravel this challenge. In lieu of this, we investigated the feasibility of improving recovery with polymer flooding technique in the Niger Delta region of the Sub-Sahara Africa. A sequence of brine saturation, oil saturation, water flooding and polymer flooding was carried out on four different cores (core A, B, T & R). Core A & B are ROBU cores (specially manufactured synthetic cores), T is Bentheimer core and while R is a reservoir rock core sample from a shallow central Onshore Niger Delta reservoir. The results show comparative responsiveness of oil recovery to polymer flooding by the various core samples. Core samples T & R are good candidates for polymer flooding having produced 21.28% & 13.33% after polymer flooding. Model Bentheimer rock sample (T) which has close petro-physical properties to that of the case studied reservoir has the highest displacement efficiency of 52.63%. The core flood analysis demonstrated that polymer flooding could improve oil recovery within the Central Onshore reservoir of the Niger Delta.
- Geology > Sedimentary Geology > Depositional Environment (1.00)
- Geology > Geological Subdiscipline > Economic Geology > Petroleum Geology (0.65)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Sandstone (0.47)
- Energy > Oil & Gas > Upstream (1.00)
- Materials > Chemicals > Commodity Chemicals > Petrochemicals (0.46)
- Africa > Togo > Dahomey Basin (0.99)
- Africa > Nigeria > Dahomey Basin (0.99)
- Africa > Ghana > Dahomey Basin (0.99)
- (5 more...)
Bright spots, dim spots: Geologic controls of direct hydrocarbon indicator type, magnitude, and detectability, Niger Delta Basin
Wojcik, Krzysztof M. (Shell Nigeria Exploration and Production Company, Shell Exploration and Production Company) | Espejo, Irene S. (Shell International Exploration and Production Company) | Kalejaiye, Adebukonla M. (Shell Petroleum Development Company) | Umahi, Otuka K. (Shell Petroleum Development Company)
Abstract Bright-spot amplitude anomalies have been an attractive exploration target in the Niger Delta since the early 1970s, and the bright-spot play can now be considered mature. There is a need to extend the bright-spot exploration success to include other types of direct hydrocarbon indicators such as dim spots or polarity reversals. Several true dim spots have been identified in the basin, calibrated with well data and characterized in detail to enable a systematic analysis of the geologic factors that produce the dim-spot response. Dim spots in deeper stratigraphic intervals reflect a high degree of compaction and quartz cementation and are characterized by minimal fluid signal and commonly very low detectability. Robust and detectable dim spots have been identified in shallow marine/deltaic systems in the Niger Delta in shallower stratigraphic intervals with a relatively strong fluid signal. The key factor promoting a robust dim-spot response is the presence of acoustically soft, clay-rich shales as the bounding lithology. The variability of the bounding shales in the Niger Delta is stratigraphically constrained and, to some degree, predictable. The change from hard mudstones to soft claystones, which can be recognized in seismic data, may result in a transition from bright to dim spots, possibly taking place within the same stratigraphic interval and over short distances. Many clastic basins globally follow a similar stratigraphic and diagenetic evolution; thus, the Niger Delta example may be a good analog for dim-spot plays elsewhere.
- Africa > Nigeria > Niger Delta (1.00)
- Africa > Niger (1.00)
- Phanerozoic > Mesozoic (0.68)
- Phanerozoic > Cenozoic (0.46)
- Geology > Geological Subdiscipline (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (0.65)
- Oceania > Australia > Western Australia > North West Shelf > Carnarvon Basin > Dampier Basin > Dixon Basin > Rankin Platform > North West Shelf > WA-5-L > Goodwyn Field (0.99)
- Oceania > Australia > Western Australia > North West Shelf > Carnarvon Basin > Dampier Basin > Carnarvon Basin > Rankin Platform > North West Shelf > WA-5-L > Goodwyn Field (0.99)
- Oceania > Australia > Western Australia > North West Shelf > Carnarvon Basin > Carnarvon Basin > Dixon Basin > Rankin Platform > North West Shelf > WA-5-L > Goodwyn Field (0.99)
- (8 more...)
Coblending of seismic attributes for interpretation of channel geometries in Rence Field of Niger Delta, Nigeria
Chinwuko, Augustine Ifeanyi (Nnamdi Azikiwe University) | Onwuemesi, Ajana Godwin (Nnamdi Azikiwe University) | Anakwuba, Emmanuel Kenechukwu (Nnamdi Azikiwe University) | Onyekwelu, Clement Udenna (Sunlink Petroleum Limited) | Okeke, Harold Chinedu (Nnamdi Azikiwe University) | Obiadi, Izuchukwu Ignatius (Nnamdi Azikiwe University)
Abstract Coblending of seismic attributes is used in the interpretation of channel geometries in the Rence Field of Niger Delta, Nigeria. We aimed at seismically defining the geometries of hydrocarbon reservoirs with particular emphasis on channels in the shallow marine (offshore) Niger Delta. The coblending application enhanced the ease of detection and the continuity of the channels, leaving the channel environs unchanged. The result of the seismic facies analysis revealed that the Rence Field can be distinguished into two seismic facies, namely, layered complexes and chaotic complexes. The result of well to seismic ties revealed high- and low-amplitude reflection events for sand and shale units, respectively. Seismic structural interpretation of the Rence Field revealed 4 major regional faults and 12 minor faults. Seven of the faults were antithetic, and the rest were synthetic faults. One mega-channel feature that trends east–west was identified in the attribute maps generated. It was characterized by sinuosity of 1.3, with a length of 22,500 m, and a distance of 17,500 m. The average depth of the channel was approximately 170 m with amplitude of 1670 m and the wavelength as high as 7640 m. A depositional model generated from the attribute maps indicated a prograding fluvial environment of deposition. The attribute map also determined that there was shifting in the location of barrier bars within the area. This shifting could be attributed to the growth fault mechanism. At the stoss side of the sinusoidal channel, there were prominent sand point bar sequences. The petrophysical analysis of the well data revealed 90% net-to-gross, 28% porosity, 27% volume of shale, and 24% water saturation indicating that the reservoir was of pay quality. Based on the petrophysical analysis, results, and identification of channel deposits, the study area proved highly promising for hydrocarbon exploration.
- Africa > Nigeria > Niger Delta (1.00)
- Africa > Niger (1.00)
- Geology > Sedimentary Geology > Depositional Environment > Continental Environment > Fluvial Environment (1.00)
- Geology > Geological Subdiscipline (1.00)
- Geology > Structural Geology > Fault > Dip-Slip Fault > Normal Fault (0.87)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (0.76)
- North America > United States > Gulf of Mexico > East Gulf Coast Tertiary Basin > Orca Basin (0.99)
- Europe > Norway > Norwegian Sea > Åre Formation (0.99)
- Africa > Nigeria > Niger Delta > Niger Delta Basin (0.99)
- (4 more...)
Summary Multiattribute seismic analysis and stratal slicing had proved very useful in the detection of near-surface deep-water channels and depositional facies. The integration of deep-water channel morphology and facies architecture with modern fluvial systems and ancient Tertiary outcrops has improved our understanding of the eastern offshore Niger Delta deep-water sedimentology and reservoir distribution. Subaqueous extension of sediment-ladden fluvial channel arising from sustained flooding events are referred to as hyperpycnal systems. These constitute very efficient mechanisms for transporting large quantity of sands into the Niger Delta basin setting. The movement of land-derived hyperpycnal deposits does not require steep slopes, as the energy of flow is maintained by river discharge during flood. These hyperpycnal deposits are characterized by gentically related facies of bed-load, suspended-load and lofty transport processes respectively. Flood-dominated fluvial-deltaic systems have genetic relationship to hyperpycnal depositional model in the deep-water Niger Delta. These are characterized by channel levee complexes and submarine fan lobes.
- Africa > Nigeria > Niger Delta (1.00)
- Africa > Niger (1.00)
- Geology > Sedimentary Geology > Depositional Environment > Continental Environment > Fluvial Environment (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock (1.00)
- South America > Argentina > Mendoza > Rayoso Formation (0.99)
- Africa > Nigeria > Niger Delta > Niger Delta Basin (0.99)
- Africa > Nigeria > Anambra Basin (0.99)
- (4 more...)
Abstract Sand production in oil wells impairs full reservoir production capability, erodes sand face completions, down-hole tubular and surface equipment. The debilitating effects of sand production on surface production equipment are manifested in the plugging of flow lines, production manifolds and separators, leading to significant deferment in production due to downtime of facilities for sand clean out and component repair and replacement. 2000 oil wells in the Niger Delta area have been reviewed to understand the sanding tendencies of the oil well completions and establish the completion strategy and practices that have successfully reduced sand production and its impact. It is observed that over 100 Mbopd oil is locked in as a result of produced sand. A plethora of sand control mechanisms such as Internal Gravel Packs, External Gravel Packs, Stand-Alone Screens, Premium Screens and Sand Consolidation Chemicals have been installed to reduce sand production in oil wells to acceptable rates but several cases of failures have been observed reviewing the past history of the oil wells. While several operators have developed guidelines to judge when sand control is required and how to operate the oil wells safely, there are still grey areas to be explored to understand the variation of formation consolidation indices from one Depo-Belt to another. The sand production performance of 2000 wells have been reviewed to examine whether the tendency for sanding can be attributed to oil well completion techniques or in-situ formation consolidation or a combination of both. It is also widely believed that formation burial depth can be used as a consolidation parameter to decide whether to include sand control in oil completion design or not. This paper seeks to share the results of the review of a large population of wells located and completed in different Depo-Belts in the Niger Delta with a view to helping operators streamline their decision-making process to include or not to include sand control systems in their oil wells for efficient production performance at less deferment due to sand production and lower completion and operating cost.
- Africa > Niger (1.00)
- Africa > Nigeria > Niger Delta (0.58)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (0.31)
- Africa > Nigeria > Niger Delta > Niger Delta Basin (0.99)
- Europe > Norway > North Sea > Central North Sea > South Viking Graben > PL 046 > Block 15/9 > Volve Field > Smith Bank Formation (0.98)
- Europe > Norway > North Sea > Central North Sea > South Viking Graben > PL 046 > Block 15/9 > Volve Field > Skagerrak Formation (0.98)
- (9 more...)
Abstract The hazard associated with abnormal formation pressures are of great concern to operating companies in the oil industry worldwide. As an effort to alleviate this problem in the Niger Delta, a spread of overpressures as they occur in the basin are shown in a map of the area. The table from which the map was produced contain the values of the top of overpressures obtained from shale resistivity, acoustic and resistivity plots against true vertical depth. The depth to the top of overpressures from the more than 230 wells studied, range from 6,500ft along the shelf, to 15,000ft at the middle belt and 16,000ft at the west-belt of die Niger Delta Basin Complex. Shale resistivity ratios and shale transit time differences obtained from normal and observed (abnormally high pressured.) resistivity's and transit times respectively, have been used in conjunction with the fluid pressure gradient, to generate the prediction curves. Comparison is made between the predicted formation pressures using the predicted curves and actual measured pressures. The standard deviation for the resistivity method is ±0.626% psi/ft. (or about ±63 psi per 10,000ft.) and the acoustic method is ±2.058% psi/ft. (or about ±200 psi/ft. per 10,000ft.) Using data from previously published papers, correlating equations for predicting formation fluid pressure gradient are presented for some other major producing areas. References and illustrations at end of paper. Introduction Operators involved with the exploration, drilling and production operations, are more and more frequently confronted with complications associated, with overpressured (abnormally high fluid pressured) formations. This is found to be true in me Niger Delta Basin area of Nigeria. Figure 1 is a location map of the Niger Delta Basin. Nigeria occupies an area of about 370,000 square miles, with the Niger Delta Basin area being the only major oil and gas productive region. Three main areas of Basin Complex have been mapped in Nigeria. These are the West African Massif (eastern end), the Northern Nigerian Massif and the Eastern Nigeria Massif. These Basins and Troughs taken together with onshore part of the Niger Delta Complex, occupy about 178,000 square miles, about half the total area of Nigeria. The Cenozoic Niger Delta Complex area today occupies around 30,000 square miles of the Southern Nigerian Sedimentary basin onshore. The total complex (onshore-offshore area) must exceed 100,000 square miles. Review Of Geology Of The Niger Delta Details of the geology of the Niger Delta has been discussed in details by several authors. This coastal sedimentary basin originated in the early Cretaceous period as an X-shaped depression oriented NE-SW and NW-SE, and it is defined by a set of older meganestone elements which were stable during the Cenozoic. These acoustic elements include the Benin Flank to the northwest, the Cretaceous Benue Trough to the north, and the Calabar Frank to the east. An extensive alternating sequence of sand/shale deltaic complex covering over 7.50 miles in thickness was deposited within this active depression.
- Africa > Nigeria > Niger Delta (1.00)
- Africa > Nigeria > Cross River State > Calabar (0.24)
- Phanerozoic > Mesozoic > Cretaceous (0.75)
- Phanerozoic > Cenozoic (0.55)
- Africa > Nigeria > Niger Delta > Niger Delta Basin (0.99)
- Africa > Cameroon > Akata Formation (0.99)
- Africa > Nigeria > Gulf of Guinea > Niger Delta > Niger Delta Basin > OML 95 > Delta Field (0.98)
- Africa > Nigeria > Gulf of Guinea > Niger Delta > Niger Delta Basin > OML 49 > Delta Field (0.98)