Modified reservoir quality indicator methodology for improved hydraulic flow unit characterization using the normalized pore throat methodology (Niger Delta field as case study)

The detailed characterization of complex reservoir units, typical of the thin-bedded canyon turbidites system within the clastic environment is essential for accurate reservoir modelling. The sedimentary architecture usually overprinted by late diagenesis results in the intrinsic complexities which poses major problems in modelling these systems. Although the average permeabilities exhibited by most clastic reservoirs is relatively high, the low permeabilities of the component shale strata results in low sweep efficiency and transmissibilities, and may form effective flow baffles. Recent advances in petrophysical modelling and formation evaluation studies demonstrate the applicability of normalized pore throat radius Rtot methodology for improved reservoir characterization and production optimization in challenging systems.This paper presents a modification of the reservoir quality indicator (RQI) methodology for hydraulic flow unit characterization using the normalized pore throat concept. Result of the analysis for the various genetic reservoir units demonstrates an improvement with a correlation coefficient of 78% for the proposed modified RQI over 31% for the existing RQI method in defining the unit slope line for the Channel Storey Axis unit. In addition, regression analysis between the irreducible water saturation from mercury injection capillary pressures and FZI depicts a higher correlation coefficient of 76% for the modified RQI over 64% for the existing method. The higher correlation coefficient indicates an improved efficacy of the proposed model for hydraulic flow zone characterization. The efficacy of the proposed methodology was also validated with a numerical flow simulation model. This demonstrates improved efficient for reservoir characterization studies

Pore Pressure and Fracture Gradientassessment from Well Log Petrophysical Data of Agbada Formation, South-East Niger-Delta

Changing down-hole conditions observed during hydrocarbon exploration can be divers. Some desired ones concern oil/gas shows while others may vary from borehole/drilling fluid association and pressure situations. Managing pressure variations and geopressure zones while drilling has been an issue of concern which has yield generic positive results over the years. However pre-pressure zones (i.e. zones above pressure zones), can display characteristics that are worthy of note in view of the underlying rock potential. Pore pressure and fracture pressure has been evaluated using Eaton’s equations amongst others on data for some reservoir of Agbada formation in the petroliferous Niger Delta. This is in view of knowing the potential of this pre-pressured zone with effective porosity and water saturation necessitated by production operations and well re-entry processes. These computations adopted various pressure models and have yielded good result presented as plots. It was observed that depth of rock units is the main indicator of rock shrinkage leading to increase in fracture due to increase in production and hydraulic fracturing. Adequate attention must be paid to the integrity (density) of the explored formation as they become sandwiched with under-compacted argillaceous sediments

A Simple Model to Predicting Pore Pressure from Shear Wave Sensitivity Analysis

A successful seismicity alongside core analysis provides data for subsurface structural mapping, definition of lithology, identification of the productive zones, description of their depths and thickness. Inadequate understanding of Pore pressure of a formation is regarded as one of the major problems drillers face in the exploration area. This may be amongst others, the pressure acting on the fluids in the pore spaces of the rock. Pore pressure can be normal, abnormal or subnormal. Shear waves are slow and thus, get to the surface after primary wave. It is with this intrinsic property that this project was initiated and researched. Data was obtained from a major operator in the Niger Delta. Methods of this study are as follows: Log description, interpretation and analysis and evaluation of pore pressure using the petro-physical parameters, model development using Domenico's equation as foundation and the shear wave velocity estimation. The result from this study, shows the importance of well logs and shear wave velocity in the evaluation of pore pressure, it also indicates where pressure can be encountered during drilling activities

Modelling the Effect of Composition Change during Condensate Dropout in a Horizontal Gas Well.

This paper presents a mathematical model describing the behavior analysis for a two-phased gas-condensate system narrowing down on the three zone method. The three zone method accounts for the composition change in the reservoir and is based on modeling the depletion by three main flow regions: • A near wellbore region (Region 1) where the oil saturation is important allowing both phase, vapor and liquid to be mobile. • Region 2 where condensate and gas are present but only the gas is mobile. • An outer Region 3 exists when the reservoir pressure is greater than the initial gas dew point and contains only gas. This research proposed a fourth region (Region I) which is the immediate vicinity of the well where accumulation of liquid buildup at high rates which yielded from an increase of liquid saturation and a probable decrease in gas relative permeability. The existence of the fourth region or flushed zone is particularly important as it represent the total skin effect: mechanical skin, rate dependent two-phase skin and skin due to gas condensate blockage. The calculated well deliverability rate using the modeled equation for gas condensate reservoir showed a relatively high difference when compared to other known equations. This significant difference is as a result of the effects of the proposed Region I. The developed correlation confirms that as the pressure drops below dew point there occurs condensate banking which when the critical saturation is reached becomes mobile and leads to a reduction in gas flow rate in the reservoir

Well Placement Optimization Using a Basic Genetic Search Heuristics Algorithm and a Black Oil Simulator

In petroleum reservoir management, the essence of well placement is to develop and maintain reservoir pressure in order to achieve maximum production for economic benefits. Large production can be achieved with the placement of multiple wells but this approach is capital intensive and inefficient for the development of a reservoir. A preferable option is the optimal placement of production and injection wells so as to fully capitalize on the imbedded hydrocarbons at a relatively decreased capital investment. The aim of this study is to use developed algorithm and a black oil simulator to place wells in the zones for optimal recovery in the reservoir. Optimal production was determined out of eight scenarios created from well placement in a hypothetical reservoir (finch reservoir) using a black oil simulator, alongside an algorithm developed with java for determining the best possible locations for well placement, taking into consideration the reservoir permeability, fluid saturation, and pay zone thickness. The results of this study reveal that well placement using the engineering judgment coupled with the application of the algorithm using a black oil simulator results in better production compared to other scenarios which consider the combined effect of algorithm and black oil simulator alone

Sustainable Development of Nigeria\u27s Solid Minerals Through Metal Recycling: a Review

Metal recycling as a path way to sustainable development of Nigeria solid minerals deposits has been reviewed. This paper brings to bear the United Nations Sustainable Development Goals (2015-2030), classification of solid mineral deposits in Nigeria, potential contribution of the solid mineral sector to the nation\u27s gross domestic product (GDP), lifetime (lifecycle) management of a mineral resource, sustaining mineral resource through metal recycling (use of secondary materials) with some of its accompanying benefits, economics of metal recycling and the need for environmental impact assessment when sitting a recycling plant. The review has revealed the following; Metal recycling could oil the nation\u27s wheel of realising some of the objectives of the United Nations Sustainable Development Goals (SDGs), every state in Nigeria has at least one solid mineral deposit, one tonne of steel made from recycled steel translates to saving 1,115kg of iron ore, 625kg of coal and 53kg of limestone, recycling results in reduction of about 200 million tonnes yearly of CO2 emissions, recycling also results in 76%, 40% and 86% reduction in water pollution, water USAge and air pollution respectively and energy savings derivable from recycling 39% aluminum, 31% copper, 74% lead, 42% steel and 20% zinc are 95%, 85%, 60%, 62-74% and 60% respectively. Therefore, metal recycling provides one of the viable tools for sustaining the nation\u27s solid mineral deposits especially the metallic ores for the benefit of generations yet to be born

Evaluation of the Fluid Loss Property of Annona muricata and Carica papaya

This technical paper evaluates the fluid loss property of Annona muricata and Carica papaya , prepared and measured as per API standard. This is a laboratory measurements carried out using low temperature and low pressure filter press. The prepared fluids were supplemented with 2 ppb XCD polymer product to enhance their carrying capacity. Their characteristics and commercial availabilities were also investigated. The 30 minutes filtrate volumes at 5 ppb, 10 ppb, 15 ppb and 20 ppb were obtained. The graph of concentrations versus the volume of the filtrate obtained was plotted. It was discovered that the concentration increases with decrease in volume of fluid loss and impermeable filtered mud cake was also obtained. Though, both gave good results, but the results of Annona muricata under the same conditions and concentrations were better than that of Carica papaya