scholarly works
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Item Investigation of the effect of some salts on the rheological properties of xanthan gum and gum arabic present in a drilling fluid(2022) Okaome, P.; Akintola, S.The rheological properties of a drilling fluid are important because they allow for extensive examination of the viscosity, fluid flow profile, pressure loss, equivalent circulation density, and hole cleaning capability making it the foundation for all wellbore hydraulics. The viscosity, gel strength, and yield point of Gum Arabic and Xanthan Gum contained in a fresh water-based drilling fluid were investigated in the presence of three distinct salts: calcium chloride (CaCl2), potassium chloride (KCl), and sodium chloride (NaCl). The salts were introduced separately to three distinct fresh water-based drilling fluid samples in increasing weights. The Fann V-G viscometer was used for the required rheology properties measuring the RPM and gel strength. The plastic viscosity, apparent viscosity, and yield point were calculated from the experimental data. With increasing the salt concentration, the plastic viscosity, apparent viscosity, yield point, and gel strength all decreased, which was observed for all three salts used. This research aimed to investigate the effect of three different salts; Calcium chloride (CaCl2), Potassium Chloride (KCl), and Sodium Chloride (NaCl) on the rheological properties of Gum Arabic and Xanthan Gum viscosified water-based drilling fluid.Item Drilling cost optimization for extended reach deep wells using artificial neural networks(Scholars Middle East Publishers, Dubai, United Arab Emirates, 2021) Akintola, S.; Toheeb, T. O.Global Petroleum reserves are currently getting depleted. Most of the newly discovered oil and gas fields are found in unconventional reserves. Hence there has arisen a need to drill deeper wells in offshore locations and in unconventional reservoirs. The depth and difficulty of drilling terrains has led to drilling operations incurring higher cost due to drilling time. Rate of Penetration is dependent on the several parameters such as: rotary speed(N), Weight-On-Bit, bit state, formation strength, formation abrasiveness, bit diameter, mud flowrate, bit tooth wear, bit hydraulics e.t.c. Given this complex non-linear relationship between Rate of Penetration and these variables, it is extremely difficult to develop a complete mathematical model to accurately predict ROP from these parameters. In this study, two types of models were developed; a predictive model built with artificial neural networks for determining the rate of penetration from various drilling parameters and an optimization model based on normalized rate of penetration to provide optimized rate of penetration values. The Normalized Rate of Penetration (NROP) more accurately identifies the formation characteristics by showing what the rate should be if the parameters are held constant. Lithology changes and pressure transition zones are more easily identified using NROP. Efficient use of Normalized Penetration Rate (NROP) reduces drilling expenses by: Reducing the number of logging trips, minimizing trouble time through detection of pressure transition zones, encouraging near balanced drilling to achieve faster penetration rate.Item Flow assurance in kumuje wet-gas pipeline: analysis of pigging solution to liquid accumulation(2018-09) Akintola, S.; Folorunsho, E.; Ogunsakin, O.Liquid condensation in gas-condensate pipelines in a pronounced phenomenon in long transporting lines because of the composition of the gas which is highly sensitive to variations in temperature and pressure along the length of the pipeline. Hence, there is a resultant liquid accumulation in onshore wet-gas pipelines because of the pipeline profile. This accumulation which is a flow assurance problem can result to pressure loss, slugging and accelerated pipeline corrosion if not properly handled. Kumuje wet-gas pipeline is an onshore 19" carbon steel line which is approximately 70 km long in a hilly terrain with an elevation of 700 m above sea level. With the pipeline’s maximum design gas capacity and field operational capacity pegged at 165 and 135 MMSCFD respectively, this study was tasked with proposing an efficient pigging scheme for the removal of liquid inventory from the pipeline using the capacity of the slugcatcher as the basis for the scheme, also, factors which affected liquid accumulation and pigging efficiency was investigated using a dynamic multiphase simulator – OLGA. Using OLGA 2016.2, both steady and dynamic runs were carried out in other to investigate into some critical factors such as pipe profile and inclination, pig velocity, gas velocity, bypass pig leakage etc. that influence liquid condensation and holdup in a wet-gas pipeline. Of the three (3) pigging schemes considered, scheme 2 proved to be the ideal operational scheme because the surge volume (395 m3) generated by the pig is within the handling capacity of the slugcatcher (600 m3). Also, liquid holdup was seen to be strongly influenced by the pipe profile and a high flow-rate was observed to significantly reduce the volume of liquid held-up in the pipeline. Conclusively, OLGA simulator proved to be an excellent tool in simulating dynamic multiphase flow and predicting liquid holdup in wet-gas pipelines in a hilly terrain.Item Field study of drilling bits performance optimization Using a computer model(2015) Oriji, A. B.; Zakka, B.; Akintola, S.One of the major problems facing drilling operations is the performance of the drilling Bits. The ability of the Bit to crush the rock and the removal of the crushed rock from the wellbore effectively. It is necessary to understand the fundamental difference in Bit design for different rock textures because many variables tend to affect Bit optimization, particularly the type of formations, economics and Bit selection. However, the cost of drilling a well has a considerable effect on the selection and the design of a particular Bit, therefore this paper focuses on the development of a model that will predict future Bit performance and optimization for actual well design and construction. The variables to optimize Bit performance provide means of handling cost estimation hence the model becomes more realistic and dynamic in its application. The input variables and control factors for this model are stretched to minimize cost and maximize performance. The cost per foot and the break even calculations were done using data from the reference well X14 and also the evaluation well X35 from a field-X in the Niger Delta region. A Visual Basic dot Net program model was developed, tested and validated with the real field data to know its accuracy. The model interface shows the detailed application of the Bits in validating the data to provide the equivalent results for the five different Bits. Each set of the Bit record was ran separately on the software and the results for each application developed for comparison. In the software, data application were grouped into two distinct methods namely; rentals method and historical method. Under the rentals method, data were uploaded into the software and ran to generate results while the historical method was basically used for model prediction. The breakeven analysis provided a technique for calculating the performance required for an alternative Bit type to match the cost per foot of the current Bit. Based on the model results , Hughes Tungsten Carbide (HTC) Bit and Security Bit(SEC) used to drill well X14 and X35 were well optimized and should be encouraged in drilling wells within the area.Item Analysis of filtration properties of locally sourced base oil for the formulation of oil based drilling mud(2014) Akintola, S.; Oriji, A. B.; Momodu, M.Oil based drilling fluids are mixtures of clays, oil and other chemical additives suspended or dissolved such as solids and polymers. The environmental problems associated with oil-based drilling fluids are among the major concerns in the petroleum industry leading to increasing stringent regulations to ensure its environmental friendliness. This study examines the use of locally sourced oil like, groundnut oil, melon oil, vegetable oil, soya oil and palm oil as substitute for diesel oil in formulating oil base drilling fluids relative to filtration properties. The filtrate volumes of each of the oils were obtained for filtration control analysis. With increasing potash and industrial starch quantities during formulation, all the local oils had their filtration properties (filtrate volume and mud cake thickness) tending towards that of diesel oil at ambient temperature and atmospheric pressure. When temperature was increased to 70˚C and above, the filtration abilities of all the local oil reduced and degraded due to the flocculation of the clay suspension. The drilling fluids formulated with the local oil where restored by the addition of thinner and organic polymer which significantly stabilized the clay suspension. The polymer and the thinner clearly improved the filtration properties of the locally formulated oil based drilling fluids even when subjected at high temperature, The ranking from the results showing the order of better and effective filtration properties for the local oils are as shown; Melon Oil; Vegetable Oil; Groundnut Oil; Soya Bean Oil and Palm oil.