Most of the input parameters such as the gross rock volume (GRV), porosity and water saturation are not specific but range in value, thereby creating uncertainty in the volume estimate. Thus, calculation of volumes (GRV, NRV, NPV, OIP and GIP) was done to consider all possible ranges of the input parameters considering the uncertainty in the reservoir structure and petrophysical values. In this research, structural uncertainty was mainly focused on fluid contact. However, other sources of structural uncertainty can arise mainly from fault plane definition, horizon picking, time to depth conversion, etc. The combination of these uncertainties results in ambiguity in the GRV esti- mates which typically provides the largest uncertainty for calculating hydrocarbon volumes (Shepherd 2009 ). Uncertainty exists in fluid contacts because most wells that penetrated the hydrocarbon-bearing intervals saw oil and gas at down-to situations, that is, fluid contacts are not known precisely for most reservoir compartments. GRV calculation was therefore done to cover all possible values considering the uncertainty in the fluid contact. For example, if an oil-down-to is observed the spill point depth is used for the calculation of high-case GRV.
This study has through the analyses of well log data evaluate the hydrocarbon potential of AK field located onshore eastern NigerDelta in southern Nigeria. Lithologic identifying well log data, hydrocarbon identifying and fluid discriminating information derived from well log data were employed to qualitatively access the hydrocarbon prospect of the field. Quantitative interpretation determined parameters useful to compute the volume of identified oil and gas within the reservoir as well as estimate reservoir properties required for ease of developing and producing the field. Four different hydrocarbon bearing reservoirs were identified in the field and the four of them were encountered by the four wells evaluated in this study. With the incorporation of seismic study, especially to determine the reservoir gross rock volume across the field, it will be easy to determine the volume of hydrocarbon originally in place in the field.
The development of geophysical logging tools and techniques in petrophysicalinterpretation has primarily been focused and directed toward assessing a particular target zone. In petroleum applications, this means determining the amount of oil and gas that is contained in the formation. This is further refined by detailed seismicinterpretation to provide a concept of a potential reservoir.
Abstract Aeromagnetic data acquired by the Nigerian Geological Survey Agency and which covers about 3025 square kilometer of some parts of onshore NigerDelta, Nigeria, was processed and interpreted with the purpose of determining the depth to basement of the study area, delineating areas suitable for hydrocarbon and mineral accumulation, establishing the basement topography, highlighting the structural lineaments with their corresponding trend patterns and then inferring the effect of the above findings as it relates to the tectonic history of the area using the qualitative and quantitative approach. Using polynomial fitting of degree two (2), regional-residual separation was carried out on the Composite Total Magnetic Intensity (CTMI) map, lying geographically within longitude 6°30′ E - 7°0′0″ E and latitude 4°30′ N - 5°0′0″ N, and this generated the regional and residual maps. Some enhancement techniques applied upon the residual map gave rise to some directional gradient maps that depicted structural lineaments trending in the E-W, NE-SW, NW-SE and N-S directions. These lineaments influence the tectonics of the area and as such created faulting and fracturing within the area under review. Quantitatively, the sedimentary thickness was determined using the deeping spikes (blue and green colours) and the shallow spikes (violet, yellow and red colours) models. The deeping spikes highlight zones of deeper magnetic bodies while the shallow spikes reveal magnetic bodies of shallow origin. The deeping spikes also indicate areas with thicker sedimentary cover while the shorter or shallow spikes highlight areas affected with magnetic intrusions. These thick sediments range from 5158.8 m to 11040.2 m but with an average depth of 7359.98 m. The short spikes have sediments thickness ranging from 871.2 m to 4617.7 m but with an average depth of about 2864.24 m. On the average, a thickness value of 4939.2 m was obtained and this suggested that the area holds a promise for the exploration of hydrocarbon.
A new phase began in 2009. During that year Nigeria was (temporarily) relieved from the extreme violence and crime in the NigerDelta. This development was mainly attributed to a general agreement between militia leaders, the Nigerian government and multinationals (such as Shell), called the Presidential Amnesty Programme. The Amnesty Programme was later integrated in the Disarmament, Demobilization and Reintegration (DDR) programme which had the same goals and approach, but just had slightly broader definition. As stated above, the Nigerian government, led by President Umaru Musa Yar’adua, was losing a lot of income due to militia attacks on oil productions. On top of that, during the previous years, most of the NigerDelta community supported these militants, who were active in that region, presumably due to poverty and feelings of insecurity. In other words, President Yar’adua was losing his legitimacy in the region and revenue to uphold the rule of law and the ability to deliver public services. These developments resulted in the Amnesty project, in which the administration stimulated the militia and criminal gangs to hand over their guns and stop with the violence and criminal acts in return for compensation and reintegration (Amunwa, 2012, pp. 2-12) (Cline, 2011, pp. 273-289).
Taking into cognizance all these analyses as regards the crisis in the Western NigerDelta Region particularly in Warri, we would be quick to argue that the root of the Warri crisis is the Kaiama Declaration of the Ijaw youths which was essentially a declaration that the entire NigerDelta Region of Nigeria to some extent Belonged to them. This of course is not a truism as it is a common knowledge that several other ancient ethnic groups like the Ibibios, the Itsekiri, the Andonis, the Urhobos, the Efiks, etc. alongside the Ijaws inhabit the area. The Warri crisis was the beginning of the implementation of the Kaiama declaration by the Ijaw youths. The Itsekiris, a tiny minority occupying lands containing some 20% to 40% of the total oil wealth of Nigeria, were a prime target of the Ijaws and they were to be quick and gain as the Ijaws envisaged that they could easily be run over, considering their status as a minority of minorities and the fact that they, unlike the Ijaws were unprepared for war. Simultaneously, in the hope of making quick work of the Itsekiri, Ijaws took their expansionist agenda also to Edo State as well as to Ondo State where they were brutally halted by the majority ethnic groups in those States as claimed by some scholars. The trigger or opportunity for the commencement of the implementation of the Kiama Declaration and thus of the so called Warri crisis was when the then Military administrator of Delta State, Colonel David Dungs, was seen to have unilaterally announced in a broadcast to the state that the Headquarters of the newly created Warri South-West Local Government Area was Ogbe-Ijoh, an Ijaw settlement, contrary to Ogidigben, an Itsekiri town, as was dully gazzetted by the Federal Government of Nigeria. The Colonel Dungs maneuver is believed to have been sponsored by the Ijaws, he being not from the area but from far away Plateau State in North Central Nigeria and therefore aught not to have had any vested interest in the matter and considering that the action was solely to the benefit of the Ijaws. That the Itsekiris put up no resistance initially buttresses this point. That the ijaws commenced a war rather than a protest and even went on to “capture” and retain known traditional Itsekiri territories like Kantu and Okenrengigho (which they said to have re-christened “Okenrenkoko” contrary to what is on every map of the Area) also buttressed this point. The so-called Warri crisis therefore was not a crisis but a war of attrition waged by the Ijaws against their Itsekiri brothers with whom they had co-existed peacefully before advent of Ijaw nationalism. 15
1. Baseline economic survey of the tourism sector: This is to obtain a deeper insight into what it will take to support tourism as a viable business venture in the State. This strategy should be given priority because according to Robinson (1996) without a full study of the attractions the “State’ possesses, and their evaluation in terms of potential future types of tourists, the ‘State’ cannot begin to plan for the future expansion of the tourist trade. It is then of fundamental importance that a very careful assessment be made of all the attractions - physical, historical, cultural- that the State possesses. 2. Improving tourism infrastructure and facilities: The term “infrastructure” according to
Three kinds of studies are important of proposed landfill sites. First, the geohydrolological integrity of a site must be ascertained to ensure that it is stable and ground water friendly. Geotechnical and hydrogeological data required at landfill sites include, bulk density of the soils, discontinuities, hydrogeological characteristics of va- dose and soil and water geochemistry  . Secondly, biological and chemical studies of the vadose zone are important to assess the natural attenuation capacity of the soils in the event of leakages from the facility into surrounding soils. Finally, the transport and fate of contaminants at the site are always modelled to predict the pathways and receptors of the contaminants over a period of time if pollution occurs. This evaluation of the complex site biophysical factors that control the transformation of waste to the final state is critical to the safe construction of sanitary landfill to ensure that soil and groundwater is protected from contamination from lea- chate and surface runoff . The important site parameters that significantly influence the occurrence of natu- ral attenuation can be subdivided into geological (hydrogeological), chemical and biological characteristics. In a previous study,  used only biological characteristics of soils to assess natural attenuation in the landfill site proposed as an integrated waste management facility for use in the disposal of general refuse and pre-treated hazardous material. The present study evaluates the subsurface biophysical conditions of soils and groundwater in the vadose zone as composite factors in the assessment of the parameters favourable to the potential occur- rence and natural attenuation capacity at the site by using geological and chemical characteristics.
Preliminary analysis of the 4-D seismic data shows that the producing reservoir is situated on the crest of a multi-fractured rollover anticlinal structure (Figure 2), bounded by a major growth fault on the North-East of the field. The significant petroleum reservoir sands in the field consist mainly of middle Miocene deltaic sand- stones, which are poorly consolidated, with high effective porosities and permeability’s . This makes the field ideally suited for a time-lapse analysis, as effects due to fluid saturation change could be readily discernible.
One of the critical challenges in hydrocarbon exploration is the assessment of reservoir quality beyond areas covered by wells. One technique that attempts to provide the prediction of reservoir properties from seismic data and solve this problem is seismic inversion. Integration of seismic and well log data can aid the proper understanding of reservoir characterization in order to optimize hydrocarbon production. However, by estimating acoustic impedance from logs and establishing a relationship among various reservoir properties through the analysis of 3D seismic inversion we can determine reservoir properties beyond well locations . Seismic inversion is a process that converts seismic trace information into acoustic impedance. Through the inverted impedance other reservoir properties such as lithology, porosity and fluid content can be quantified away from the well. The inverted impedance model can also be used for building facies and facies based porosity and permeability model .
Abstract Seismic reflection data obtained from 3D survey in part of the Niger-Delta basin, Nigeria was processed using Velocity Computation Software program (VELCOM), an interactive velocity analysis interpretation program. The application uses the principle of Apparent Velocity Picking, Normal Moveout (NMO) Correction and Stacking. Velocity intervals for 8 Common Depth Points (CDPs) were obtained. Interval velocity ranges between 1814 and 5579 ms -1 and Stacking velocity (V
Abstract Statics correction was applied to a 3D seismic data acquired from an onshore Niger- delta field. The objective of the study was to derive a statics solution, which will correct for time shifts caused by topographic undulations, velocity anomalies in the near-surface and delayed travel times of the reflection signal through the weathered layer. In a previous study by authors, a near-surface seismic velocity and depth model, consisting of the weathering layer and three consolidated (sub-weathering) layers were first estimated. The first-arrivals were picked and used as input for this study. Statics correction consisting of elevation statics, long-wavelength refraction statics, and short-wavelength (residual statics) refraction statics was applied to the data. Interpretation of results show like differences such as a stronger alignment and coherence of reflection events, as well as an upward time shift of the reflection signals when compared with the input data (no statics applied) and the output data (statics applied).
The construction of tall building in seismic regions is becoming increasingly common as urbanization is increases world wide. The design of tall structure should be in such a way that it can resist the lateral load like earthquake force. The most important criteria in the response of high rise buildings against lateral loading largely depends on the characteristics of the loading. There have been so many cases in which the structures failed due to instability caused by lateral loads due to which the second order analysis has become significant in tall structure. The forces that are generated because of earthquake are due to displacement of the ground which generates seismic waves which effects the structures. The structures weaken due to lateral forces generated by earthquake loads. Therefore the structure must be designed properly to overcome this problems.
Low SKS birefringence may result from vertical varia- tions of the seismic anisotropy. Indeed, beneath the western Kaapvaal (Kimberley block), the Rayleigh wave azimuthal anisotropy shows a change of fast propagation directions from N–S in the crust to E–W in the mantle (Adam and Lebedev, 2012). A change with depth in the orientation of the fast direction from E–W to N–S was also detected at depths > 160 km beneath the Limpopo belt by a study associating P wave receiver functions and SKS waveforms inversion (Vinnik et al., 2012). The seismic discontinuity imaged by S wave receiver functions at ∼ 150 km depth (Wittlinger and Farra, 2007; Savage and Silver, 2008; Hansen et al., 2009) also points to vertical variations in the deformation structure within the cratonic root, since drastic changes in composition or S wave velocities with depth are not observed in neither our data set nor in that of James et al. (2004). Most cases presented in Fig. 7 show a decrease in anisotropy at 140 km depth, which would be consistent with the observations of Wittlinger and Farra (2007), but the associated gradient in seismic velocities is too weak to produce a strong impedance contrast. Peslier et al. (2010) and Baptiste et al. (2012) did
Post-construction management monitoring, evaluation and reporting is a critical factor for tracking the performance of the project towards achieving the targeted benefits. According to the Nigerian National Housing Policy (NNHP, 2011), monitoring, evaluation and reporting are an integrated process and coordinated action by several actors in the public and private sector of the economy is vital for housing delivery and management. The 2011 NNHP contended that a lack of monitoring, evaluation and reporting of the various coordinated and integrated efforts of housing delivery and post-construction management are the bane of the current housing estate condition. The availability of such reports is still in almost total deficit. However, the UN-HABITAT Agenda 21 requires that this participatory approach involves and includes directly or indirectly all stakeholders in the design, implementation, monitoring, evaluation and reporting on project development and post-management. At the same time, the NNHP report of 2011 suggested that the mechanisms and institutions for implementing, coordinating, monitoring, evaluating and reporting should be strengthened, to ensure progress and tracking of the implementation of the housing policy. Therefore, the issue of ensuring that social housing estate management is: monitored; evaluated; and reported; for the management style; conditions of the housing estate; and the built environment; cannot be overemphasised as it remains the mortar to the attainment of social (public) housing estate benefits.
Wireline logs from three (3) wells, 1, 2 and 3 were used to quantitatively evaluate the ‘J field’ of the NigerDelta area. The wells had been evaluated using a combination of Gamma-ray log, Resistivity logs and Neutron – Density logs. Wireline log analysis was used in the reservoir evaluation of the ‘J field’; the hydrocarbon sands were delineated by the use of gamma ray, resistivity and density/neutron from which the reservoir prospectivity were determined. Well 1 has 4 reservoirs, well 2 has 4 reservoirs and well 3 has 4 reservoirs, the reservoirs are namely (A, B, C, D) .This investigation helps to identify the lithologies and recognize the hydrocarbon bearing intervals as – well as to quantify the amount/type of hydrocarbon in the reservoirs contained in wells 1, 2, 3) for further exploration and exploitation in the ‘J field’ of the NigerDelta. The petrophysical properties of the reservoirs analyzed include: water saturation for wells 1, 2 and 3 ranging from (0.13– 0.26) %, (0.16 – 0.37) % and (0 – 0.41) %, porosity values; (18 –23) %, (14 – 20) % and (18 – 23) %, hydrocarbon saturation for the wells are; (0.74 – 0.86) %, (0.63 – 0.84) % and (0 – 0.59) % respectively. The net pay thickness for well 1 is 39.88 metres, well 2 is 53.4 metres and well 3 is 53.9 metres. The analysis of the wells depict the presence of hydrocarbons in well 1 and well 2, with only one reservoir (D) in well 3 indicating the presence of hydrocarbon.
silty clay sediments belonging to the Pleistocenic Formation. The general geology of the area essentially reflects the influence of movements of rivers, in the Nigerdelta. In broad terms, the area may be considered Dry flat Country. (short and Stauble, 1967). The NigerDelta consists of three distinct Lithological Formation , the Akata formation , Agbada formation and the Benin formation. The Akata Formation consist of Marine shale . The Agbada formation consists of alternate Layers of Sand Stone and Shale. The Benin formation consists of sands, clay , Peat and some Granular materials. The Coastal Plain slopes gradually from an elevation of 240m to 15m above mean sea level and is largely caused by rain forest. The aquifer has a south west gradient towards the Delta and is thickened seawards in the same direction of ground water movement. The Study area is situated in the Coastal Plain region, quaternary in Age. The Zone is made of Coarse to Medium sand, with Silty and Clay Lenses. Within the Project area , groundwater is abstracted from the Benin formation , mainly in its upper section. (<300m).The aquifer at shallow depth(>10m) are unconfined while the deeper aquifers are confined and isolated from the ground surface and the natural recharge comes Northern high Coastal Plain..
The problem of environmental degradation is global and topical as a result of the heightened industrial activities taking place in all countries of the world, occasioning the dangerous global warming and depletion of the ozone layer, threatening mankind. The NigerDelta region of Nigeria has been the hub of oil exploration and exploitation activities in Nigeria carried out by various multi- national oil companies; and have equally been theatre of conflicts and crises, which has drawn the attention of the entire world. Violent conflicts and militant activities undertaken by the youths of the region have caused the deaths of oil workers of many nations and have continually affected global oil market prices. The paper reveals that environment pollution and degradation occasioned by the operational activities of the oil multi-national underlie the conflict situation and crises in the NigerDelta region. This paper therefore examines and confirms the level, nature and impacts of environmental degradation of the region and concludes that effects of the operation of the oil companies on the environment are not only devastating but have triggered off the crises in the region. The study depended on reports and existing studies on the region, as well as, personal observations of the author who hails from one of the oil producing communities of the NigerDelta.
The 3-D distribution of the collapsed paleokarst system in Upper San Andres reservoir was delineated by detail seismic characterization by integrating core, well log and rock physics data. Tight, fine-scale collapsed paleokarst system was discovered in the area of high volume production with higher acoustic impedance compared to reservoir zones, which exhibited low and uniform porosity development. The model-based seismic inversion method is thus a useful tool to characterize the vertical and lateral extent of this paleokarst system. For large-scale collapsed paleokarst systems along the transition from platform into basin, seismic geometric attribute analysis is a good tool to map its 3D spatial distribution. The development of the paleokarst complex system detected in the San Andres Formation was explained by a proposed carbonate platform hydrological model. Two other collapsed paleokarst system were predicted in the structurally high area of the lower San Andres Formation, G3 and G4 HFS. Production data proved the influence of tight paleokarst system on reservoir compartmentalization.