Browsing by Author "Osundare, Olusegun Samson"
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Item Open Access Estimation of plugging and abandonment costs based on different EU regulations with application to geothermal wells(Stanford University, Stanford, USA, 2018-02-15) Osundare, Olusegun Samson; Teodoriu, Catalin; Falcone, Gioia; Ichim, AdonisThis paper presents the cost of plugging and abandonment (P&A) of the Horstberg Z1 well and shows how the well history is considered in the P&A planning process together with existing European regulations. Three different design plans are presented, based on innovative ideas and best practices in the oil and gas industry. Horstberg Z1, located in Germany, was originally a gas well, converted to a scientific geothermal well to prove the single well concept. After serving as a geothermal well for several years, the well has been proposed for P&A. The three designs presented in this work fulfill the purposes of well P&A, and meet the BVOT requirements, which are standard requirements for wells in Lower Saxony, Germany. Following a financial analysis of the designs, it is noted that rig costs are the largest element of the total expenditure, contributing over 50% in the design plans considered. As the number of cement plugs and round trips increase per design plan, the implementation period also increases, which impacts on the total cost. Based on the investigations made in this project, a minimum of USD 1,275,500 is required for the plug and abandonment cost of the well, excluding the well site re-cultivation. A rigless solution for pulling heavy casing out of the wellbore, to avoid the use of a conventional workover rig, would significantly reduce the plug and abandonment cost of the Horstberg Z1 well.Item Open Access Gas-liquid flow regime maps for horizontal pipelines: predicting flow regimes using dimensionless parameter groups(Begell House, 2022-10-27) Osundare, Olusegun Samson; Elliott, Alexander; Falcone, Gioia; Lao, LiyunFlow regime maps are essential to gas-liquid flow applications in many industrial processes to accurately identify the flow regimes before estimating multiphase features. Flow regime classifications were originally based on visual observations of two-phase flow experiments. The observations were mapped on two-dimensional plots (called “flow regime maps”) and the boundaries between regimes determined. Over the years, different coordinates have been proposed for the maps (e.g., superficial velocities and momentum fluxes), in search for parameters that are independent of the given experimental set-up. This paper reports a study on developing new flow regime maps with a broader range of applications by using dimensionless parameter groups as the map coordinates. Various flow regime maps were developed with the use of different combinations of these parameter groups, then they were examined and assessed using datasets from published experimental research and the MultiFlowMet II project for validation. This initial feasibility study develops proof-of-concept flow regime maps that demonstrate the potential of dimensionless parameter groups to more accurately characterise multiphase flow in horizontal pipes, with the optimisation of these maps being considered in future works. The analysis revealed that combinations of the mixture Froude number (Frm) versus the ratio of gas superficial velocity to liquid superficial velocity (vSG/vSL), with the liquid phase Froude number (FrL) versus the gas phase Froude number (FrG) show potential for unambiguous identification and mapping of flow regimes, even for datasets with a wider range of operating conditions.Item Open Access Liquid-liquid flow pattern prediction using relevant dimensionless parameter groups(MDPI, 2020-08-24) Osundare, Olusegun Samson; Falcone, Gioia; Lao, Liyun; Elliott, AlexanderAccurate predictions of flow patterns in liquid-liquid flow are critical to the successful design and operation of industrial and geo-energy systems where two liquids are jointly transported. Unfortunately, there is no unified flow pattern map, because all published maps are based on limited ranges of dimensional parameters. Dimensional analysis was performed on oil-water horizontal flows, to obtain some relevant dimensionless parameter groups (DPG) for constructing flow pattern maps (FPM). The following combinations of DPG were used: (i) the ratio of mixture Reynolds number to Eötvös number versus water fraction, (ii) the ratio of Weber number to Eötvös number versus water fraction, (iii) the mixture Froude number versus water fraction, (iv) the water Froude number versus oil Froude number, (v) the ratio of gravity force to viscous force versus water fraction. From twelve published experimental studies, 2696 data points were gathered and analysed covering a variety of flow patterns including stratified, stratified mixed, dispersed oil in water, dispersed water in oil, annular and slug flows. Based on the performed analysis, it was found that flow patterns could occupy more than one isolated region on the DPG-based flow pattern map. None of the combinations of DPG can mark out all the considered flow patterns, however, some combinations of DPG are particularly suitable for marking out the regions associated with some flow patterns