Browsing by Author "Duru, Ugochukwu"

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    Hydraulic evaluation of drilling fluid performance on hole cleaning for different rheological models
    (Society of Petroleum Engineers, 2005-08-03) Duru, Ugochukwu; Chukwu, Godwin A.; Obah, Boniface
    Bottom hole cleaning is an important function of drilling fluid that needs special attention during a drilling operation. Good hole cleaning results in an increase in penetration rate and, at the same time, reduces the operating drilling cost. One of the effective steps towards reducing operating cost is to have a well designed drilling hydraulics program that will optimize the energy used at the mud pumps. A variety of hydraulic optimization designs are available depending on the cutting structure and the formation to be drilled but a common objective is to maximize the available hydraulics to provide optimum hole cleaning. Many authors have discussed various ways of effecting proper hole cleaning using different approaches and methods. Fluid velocity, pump rate, fluid rheology, drill pipe eccentricity, pipe rotation and particle settling velocity, among others were used at various times to evaluate effective hole cleaning. The economic appraisal of hole cleaning using hydraulic horsepower and jet impact force by Wright et al (2003) have proved that both can be used for the design of optimum hydraulic programs on the basis of minimum drilling cost. In this study, basic hydraulic models for vertical oil wells were used to determine the pressure drop in a drill string circulating system and hence, the equivalent circulating density (ECD) using both the Bingham plastic and Power law fluids’ rheological models. From the slip velocity relationships, the transport efficiency of the cuttings for both models was determined. An economic evaluation of the hydraulics from the energy and horsepower requirements for both models showed that the power law fluid model provided a better transport efficiency, and hence more economical in terms of minimum drilling cost.
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    Optimizing liquid recovery from a gas condensate reservoir operating below dew poin
    (U. P., 2019) Ariche, Princewill O; Onwukwe, S. I.; Duru, Ugochukwu; Chikwe, Anthony
    Fluid flow in gas condensate reservoir is very complex and involves phase changes, multiphase flow of the fluid, phase redistribution in and around the wellbore and retrograde condensation. This study seeks to evaluate the effect of hydraulic fracturing on gas and liquid production of gas condensate reservoir with pressure below dewpoint. This research utilised a compositional simulator (Eclipse 300) with a single vertical well model, relative permeability model,fluid and PVT parameters to model a gas condensate reservoir operating below dewpoint. Two cases were investigated. Case 1 is a control scenario where the reservoir was unfractured and allowed pressure to deplete using the reservoir energy. Case 2 represents a hydraulic fractured reservoir to ascertain the effect of fracturing on liquid and gas production. The hydraulic fracturing job was done using dual porosity dual permeability condensation model in Eclipse 300 with a conductive fracture attached closer to the wellbore with various fracture parameters. After ten years of production, the cumulative liquid production was 957803STB for the unfractured case. Fracturing the reservoir at fracture half length of 1000ft, fracture width of 0.03ft, fracture permeability of 1000md gave a cumulative liquid production of 1055936STB after ten years of production. Increasing the fracture half length to 2000ft, fracture width to 0.06ft, fracture permeability to 2000md gave a total liquid production of 1056137STB. Further increase of fracture half length to 3000ft, fracture width to 0.1ft and fracture permeability to 3000md gave a total liquid production of 1057139STB. The result obtained showed that continuous increase in fracture parameters may not result to an economic liquid recovery. Based on cumulative liquid production and economic feasibility of the project, a fracture half length of 1000ft, fracture width of 0.03ft and fractured permeability of 1000md proved optimal for the reservoir considered.
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    ItemOpen Access
    Performance of water injection in oil rim reservoir recovery factor
    (STM Journals, 2014) Onwukwe, Stanley; Duru, Ugochukwu; Obah, Boniface
    This study examines the potential improvements in recovery factors in optimizing oil production from oil rim reservoirs through water injection and without water injection (i.e. primary production) scenarios in the development strategies of the oil rim reservoirs.A generic simulation model developed from ECLIPSE dynamic simulator was used as core representative of oil rim reservoirs to experiment production optimization with and without water injection. Reservoir data of permeability, oil rim thickness, fluid properties, m-factor, aquifer strength and process parameters sampled from the Niger Delta oil field were used and a lacket-Burman Design of experiment (DOE) was used to give a central sensitivity results from the simulation runs. Recovery factors were obtained for the two different production scenarios: primary production and production under water injection. Regression analyses were carried out on the experimental results to generate proxyequations for recovery factor for the two production scenarios. It was observed that the use of water injection is irrelevant for oil rims with active water aquifer. However, waterinjection will increase the ultimate recovery of oil rim reservoirs under weak aquifer.