Browsing by Author "Isehunwa, S."

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Filtration losses in oilwell cement contaminated by pseudo oil base muds
(2010) Isehunwa, S.; Mumuni, T. O.
Contamination of oilfield cement slurries by drilling fluids is one of the causes of cement job failures and it results in expensive remedial actions. While the general adverse effects of Pseudo Oil Base Mud (POBM) contamination of cement slurries are known, little has been published on the actual effects of POBM on specific slurry properties. The effect of POBM on the filtration losses in oil well cement slurries was investigated. POBM contaminated slurries at varying contamination volumes up to 40% at intervals of 5% were prepared. The filtration losses were determined using standard American Petroleum Institute (API) procedures. The results show that while API fluid losses increased with time, it decreased with increasing POBM contamination in cement slurries.
Improved reservoir description using surface oil viscosity data
(Society of Petroleum Engineers, 2003) Umeh, N.; Isehunwa, S.; Okorafo, C.; Owolabi, S.; Agu, I.; Olare, J.; Biambo, T.
Subsurface oil viscosity data are usually not readily available for most reservoirs, as they are expensive to acquire. On the other hand, surface oil viscosity is routinely measured and therefore readily available for all producing wells. A method has been developed for converting the surface viscosity to reservoir viscosity data, using SPDC's "Field A" as a case study. Surface oil viscosity data from all producing wells in "Field A" where collected from SPDC-West Production Chemistry laboratory and converted to reservoir viscosity using a simple method that utilizes relevant PVT data. The method allows a better and more detailed subsurface description of reservoir viscosity in line with facies variations. The study also shows that reservoir oil viscosity could be lower in some sands than previously estimated. This gave a significant impact on reserves in one of the reservoirs where scope to increase the booked reserves by about 60 MMstb was observed. Opportunity to also –increase constrained off take from 2300 b/d to 3000 b/d in some planned new wells was also observed.
Modelling the effects of modified local starches on the rheological and filtration properties of a water – based drilling fluid
(2021-07) Akintola, S. A.; Isehunwa, S.
This study is designed for the comparative analysis of chemically modified local starches used as additive in improving the rheological and fluid loss properties of a water- based drilling fluid. Additives are added to a drilling fluid in order to enhance the various functions of the drilling mud. Different drilling fluid samples were formulated without additive and with various concentrations modified starches. A laboratory investigation on the drilling fluid rheological and filtration properties using the API recommended standard procedures, pressure were studied at 1000 psi with a temperature range of 40.0 to 180.0 ° C, using a High Pressure High Temperature, (HTHP) rheometer and Fann Model 35A respectively From the analyses of the experimental results, it was observed that effective viscosity, plastic viscosity and yield point decrease steadily with increase in temperature. The experimental results, water based drilling fluid treated with chemically modified local starches improves the filtration and rheological properties of the drilling mud. Finally, this paper also presents a predictive model equation good enough to analyse trends and predict future values for effective and plastic viscositie