Electricity generators of varying capacities are popularly utilized in Nigeria as alternative source of power owing to the unreliability of electricity supply through the national grid. This study evaluated the impact of emissions from generating sets on air quality and human health in selected areas of Abeokuta city, Nigeria. The levels of particulates (PM 1 , PM 3), carbon monoxide, carbon dioxide, sulphur oxides, nitrogen oxides, nitrogen dioxide, hydrogen sulphide and methane were monitored using portable samplers. Copies of questionnaire were administered to generator operators and nearby residents so as to collect additional information. The capacities of sampled generators ranged from 1 to 25 kVA. The range of mean concentrations of PM 1 (4.7-219.2 mg/m 3), PM 3 (7.8-251.6 mg/m 3), carbon dioxide (4.5-10.9%), methane (0.0-1.2 ppm), carbon monoxide (141.1-4167.0 ppm), NO x (4.0-85.7 ppm), methane (2.3-31.0 ppm), sulphur oxides (3.5-65.6 ppm) and hydrogen sulphide (0.0-0.7 ppm) was highest at generator sites. The distance of sample sites to generator locations accounted for 14-66% variation of pollutants levels. Ailments frequently suffered by the exposed residents included nasal congestion (66%), cough (33%), headache (24%) and fever (12%). A national policy on appropriate use of electricity generator is urgently needed in Nigeria.
The prohibitive costs & risks associated with performing PLT and potentially the isolation of the water producing zone through WSO in deepwater fields such as Akpo renders these operations economically unattractive. This paper addresses the application of analytical method including the use of 4D monitor results to replace conventional PLT to identify, screen and select viable successful water shut off candidates. Prior to executing water shut-off treatment programs, a combination of 4D seismic interpretation, production history review as well as the collection of completion and reservoir information were thoroughly performed to ensure that the wells are properly selected. Well's diagnostic plot (WOR and WOR′) must be consistent with the type of water coning or channeling problem identified from the 4D time lapse seismic and also the depth of possible mechanical plug must be around or above estimated current oil-water contact (COWC). Two candidate wells having 6-5/8″ SAS Slot 10 in 8.5″ open hole, at approximately 4,000 meter TD, and 82 deg C reservoir temperature were selected. The water cut values were 55% in one well and 60% in the other. This paper presents below the significant upside for WSO attributed to the use of analytical method and integration of 4D seismic data by eliminating the need to run a traditional PLT. The operation was technically & economically successful on one well with a decrease of watercut from 55% to 16% resulting in the well incremental oil production of ~3kbopd. Operation is planned mid 2019 for the second well
Regional studies are known to show major compartmentalization in an oil field, while observations during development and production often highlight local structural connectivity issues that require fault characterization at field-scale to mitigate uncertainty in reserve or stakes. The Akpo field, located in the deep offshore Niger Delta, exemplifies a maturing field where these structural connectivity issues are dominant and play significant roles in field development. Structural discrepancies in the crest and flanks of the anticline result in varying water contacts and overpressure differences, affecting connected volumes and sweep efficiency. Qualitative fault throw analysis, aided by 4-D monitoring results, show that same faults may be sealing and communicating at difference areas, across reservoir fairways in the deep offshore turbiditic channel complexes, delineated as architectural elements. Shale Gouge Ratio (SGR) helps in further constraining the sealing/leaking impact of fault gouge at a log-scale, such that adjacent well data can be used quantitatively to assess preferential flow paths across and within faults zones. This revealed an along-fault, up-fault and across-fault connectivity anisotropy. This work addresses how the fault characterization was used to assess the following: Reservoir compartmentalization, leading to panel separated as fault blocks.Communication across fault, shown by throw map and SGR.The varying water contacts, which tend to result from upwelling of fluid within panel.Sweep across panels, from injectors to producers.The well in real-time operational situation, where well trajectory traverses a fault. The study resulted in an improved infill well planning and placement, targeting unswept hydrocarbon, where well trajectories were determined by knowledge of fault compartmentalization, initial static connectivity shown by virgin pressures and present dynamic communication across injector-producer pairs. Post-mortem analysis of these infill wells was helpful in understanding the dynamic role of the crestal-collapse faults offsetting the reservoirs in the Akpo anticline, leading to optimization and increased productivity.
With increasing complexity of reservoir developments, there is often a marked deviation from the field development plan (FDP), thus, requiring complementary developments with infill wells. This paper addresses this necessity whilst using the Akpo field reservoir B as a case study. Our case is an oil-bearing, highly faulted turbidite channel-levees system. The reservoir comprises three different units (Upper, Middle and Lower) with gross interval of about 140 m and good porosity and permeability values. The hydrocarbon-water contact (HWC) varies across fault blocks with little certainty about reservoir connectivity. It was assumed in the initial FDP that two producers located around the top structure would be supported by two injector wells located on the flanks near the HWC. In 2011, the first producer (Akpo-XP) was completed in the three units and equipped with an inflow control valve (ICV). From fluid samples collected and the selective acquisition of dynamic data from these intervals, results showed that the Upper unit was disconnected from the Middle and Lower units. Consequently, Akpo-XP was forced to produce only from the Middle and Lower units in order to be supported by a northern injector (Akpo-YW) in the same interval. To complete the initial development, another pair of wells (producer-injector) was drilled and completed in the upper unit. All wells were equipped with down-hole pressure gauges for connectivity assessment. In 2015, a seismic monitor was acquired, processed and interpreted whilst integrating production, injection and pressure data. The 4D seismic data confirmed specific fluid movements in the reservoir and a reservoir re-development could be sanctioned with two infill wells (one producer and one injector) with estimated increase in up to 16 Mboe of reserves and incremental production of 13 kbopd. A post-mortem analysis of these two infill wells showed a combined incremental production slightly above expectations.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.