Browsing by Author "Daniel, A."

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Estimation of developed reserves in gas lifted wells.
(Society of Petroleum Engineers, 2009) Daniel, A.; Isehunwa, S. O.
Reliable estimates of petroleum reserves are invaluable in reservoir management decisions and economic evaluation. Classical decline curve analysis techniques have been routinely used and are generally accepted in the industry to reliably estimate developed reserves up to a predetermined economic limit qec in oil wells. However Decline curve analysis techniques are based on the assumption that past production trends and their controlling factors will continue in the future and therefore can be extrapolated for predictions. During gas lifting, production trends could be distorted hence there is need to modify the classical decline curve analysis equation. In this study, the principle of superposition has been applied to the entire duration of production (t) of wells producing under gas lift. This resulted in the so called Double Semi log equation for well decline analysis. Model validation with two fields in the Niger Delta area show excellent results and the economic advantage of gas lifting. The Models showed excellent correlation coefficients with available field data. It is concluded that gas lift could increase the reserves in some wells. Furthermore the Double Semi log technique provides a better and more reliable theoretical foundation, easier and more reliable technique for decline analysis in gas lifted wells.
Nasopharyngeal carcinoma in Ibadan, Nigeria: a clinicopathologic study
(Pan African Medical Journal, 2020-06-20) Ogun, G. O.; Olusanya, A. A.; Akinmoladun, V. I.; Adeyemo, A. A.; Ogunkeyede, S. A.; Daniel, A.; Awosusi, B. L.; Fatunla, E. O.; Fasunla, A. J.; Onakoya, P. A.; Adeosun, A. A.; Nwaorgu, O. G.
Introduction: nasopharyngeal carcinoma is relatively common in our environment. It is one of the most difficult malignancies to diagnose at an early stage. The aim of the study was to determine the clinical features, clinical disease stage of nasopharyngeal carcinoma at presentation and at diagnosis as well as the histologic types at the University College Hospital, Ibadan, Nigeria. Methods: this was a ten year retrospective study of all histologically confirmed nasopharyngeal carcinoma between January 2007 to December 2016 using clinical and pathology records and files. Results: there were 73 cases. The male: female ratio was 1.7. The age of patients ranged from 12 to 80 years with a mean age of 39 ± 16 years. The median age at diagnosis was 40 years. The peak age group of occurrence was 40-49 years. The most common symptoms were namely epistaxis in 67.1% of patients at presentation, neck mass/swelling (64.4%) and nasal mass/obstruction (63.0%). Majority (54.8%) of the patients presented late with stage 3 or 4 disease. Most (94.5%) of the tumours were of the non-keratinizing squamous cell carcinoma subtype. The keratinizing and basaloid variants accounted for 4.1% and 1.4% of the tumours respectively. Conclusion: vague, non-specific symptoms make patients present at late stages of the disease, making it almost impossible to attempt cure. The dominant histopathological type is non-keratinizing squamous cell carcinoma and resembles that seen in most parts of Nigeria and endemic areas of the world
Pharyngo-cutaneous fistula post total-laryngectomy: a local experience
(2020-03) Ogunkeyede, S. A.; Adeyemo, A. A.; Daniel, A.; Yaro, P. J.; Ogundoyin, O. A
Background: Pharyngo-cutaneous fistula is a major complication of total laryngectomy. Despite its significant impact on the patients' nutrition and management outcome, there is lack of consensus for recognising high-risk patients and factors associated with fistula formation. Hence, this study was aimed at determining the incidence of pharyngo-cutaneous fistula and factors associated with fistula formation. Methods: A retrospective collection of data on all cases of laryngeal cancer diagnosed histologically and had total laryngectomy, in the Otorhinolaryngology Department of a tertiary centre in Southwestern, Nigeria, from 2007 – 2016. The data collected include age, gender, tumour stage, tracheostomy, adjuvant therapy extent of laryngectomy procedure and factors for pharyngocutaneous fistula. Results: Forty-two patients had total laryngectomy, male to female ratio was 7.4:1 and mean age was 52.3 ± 2.1 years. All patients had pathological diagnosis of stage 3 (83.3%) and stage 4 (16.7%) laryngeal cancer, respectively. The incidence of pharyngo-cutaneous fistula was11.9% and the factors related to fistula formation were prior radiotherapy treatment and diabetes. Age, gender, neck dissection procedures, site of primary tumor and emergency tracheostomy did not contribute to fistula formation. Spontaneous fistula closure was achieved in all cases except one patient who had surgical closure. Conclusion: Pharyngo-cutaneous fistula formation post-surgery is related to the presence of co-morbidities. The high percentage of spontaneous closure underscores the need for a conservative management approach