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ABSTRACTOver the years, the increased use of different types of drilling fluids additives for water based mud has increased environmental quandary, technical enigmas during drilling, post drilling problems such as production cramps and increased cost of well development. These complicated conundrums are so difficult to be solved because they lack a robust literature review of recent additives in water based muds and may be the reason for technical failure of most drilling programs. The aim of this research is to carry out detailed comparative analysis of a minimum of ten literature reviews of local additives used in formulation of water based muds by evaluating their prospects and challenges in line with API standard. The objectives are to carry out detailed literature reviews of ten (10) recently published papers on the use of local additives in water based muds in Nigeria and predicting their prospects and gaps and to carry out a comparative analysis of drilling fluid properties and API standards of existing literatures used. The ten (10) recent articles used are Okon et al (2020), Peretomode (2018), Agwu et al. (2018), Jimoh et al. (2020), Odeh et al. (2022), Ekeinde et al. (2018), Duru et al. (2020), Udoh and Okon (2019), Azinta et al. (2021) and Okon et. (2018). The drilling properties evaluated are shear stress, viscosity dial reading, plastic viscosity, gel strength, yield point, mud pH, mud density, filtration loss and mud cake thickness. Comparative results of mud density gave a minimum of 5.99ppg for Agwu et al. (2018) who used soda ash. The maximum mud density of 8.94ppg was observed by Ekeinde et al. (2018) who used guar gum and offor. These results are in line with API standard of a range of 8.65ppg 9.55ppg. Comparative results of mud filtrate loss gave a minimum of 1.59ml for Duru et al. (2020) who used mucuna solannie. The maximum mud filtrate loss of 16.77ml was observed by Azinta et al. (2021) who used xanthum gum. These values are in line with API specification with a maximum of 15ml. Five (5) out of the nine (9) drilling fluid properties gave results which are in line with API standards which includes the mud pH, mud cake thickness, filtration loss, mud density and plastic viscosity. This is approximately 55.56% success rates in this study while the remaining four (4) properties make up 44.44% failure rate. However, the results of failure rates showed prospects which can be improved upon since some results were close to the API standard. The benefits of this study to petroleum engineering is that a breakthrough will transform the industry in reducing the cost of drilling programs and perhaps save our environment with biodegradable water-based mud additives. The contribution to knowledge is that this study will add spice to the many existing literatures and enhance the choice of selection of additives. It is recommended that more studies are done to discover more additives and maybe blend some the additives used in this research.Key words: Drilling fluid, water based mud, local additive, mud density, filtration loss, mud cake thickness.1.0Background of StudyDrilling mud, also called drilling fluid, in petroleum engineering, is a heavy, viscous fluid mixture that is used in oil and gas drilling operations to carry rock cuttings to the surface and also to lubricate and cool the drill bit. Mud plays an important role in the marine ecosystem. The activities of burrowing animals and fish have a dramatic churning effect on muddy sea beds. This allows the exchange and cycling of oxygen, nutrients, and minerals between water and sediment. There are three main types of drilling mud: water-based, oil-based and synthetic-based the components of drilling fluidsmud water-based drilling mud most commonly consists of bentonite clay (gel) with additives such as barium sulfate (barite), calcium carbonate (chalk) or hematite. Various thickeners are used to influence the viscosity of the fluid, e.g. xanthan gum, guar gum, glycol, or starch.Oil-based muds have become more widely used because of their distinct advantages over water-based muds. They include;Thermal stability in deep, high-temperature wells. Increased lubricity in deviated offshore wells. Hole stability in thick, water-sensitive shales as advantages of oil-based muds.Oil-based muds can be formulated to withstand high temperatures over long periods of time, however, water-based mud can break down and lead to loss of viscosity and fluid loss control.Oil-based mud (OBM) cutting is a hazardous by-product generated during oil-well drilling. Its chemical composition suggests that it might be suitable as a raw material in cement manufacturing. Oil-based mud is endowed with better capability to stabilize the wall than water-based mud. Water-based mud can swell shale formation, a brittle mineral, collapse boreholes and impact drilling outcome in the drilling operations. The initial cost of oil mud is high, especially formulations based on mineral or synthetic fluids. Kick detection is reduced when using oil muds (compared to that of water-based muds) due to high gas solubility in oil muds. Oil based muds are costly when lost circulation occurs. Aqueous drilling fluids, generally referred to as water-based muds, are the most common and the most varied of the three drilling fluid types. They range in composition from simple blends of water and clay to complex inhibitive, or clay stabilizing, drilling fluid systems that include many.In the exploration for hydrocarbons, drilling a successful hole is an integral part of the process and is contingent upon the drilling fluid's performance. Drilling process involves the penetration of the earth's crust to several thousand feet where the hydrocarbons are accumulated in the reservoir using rotary drilling process to create a passage for the discovered hydrocarbon reserves to be produced at the surface. To achieve this cardinal objective of a drilling operation, the formulated drilling fluid used must exert its basic functions. Drilling fluid is also referred to as drilling mud, and generally viewed as the blood of all drilling operations in the petroleum industry. Drilling fluids are complex heterogeneous fluids, consisting of several additives used in the drilling of oil and natural gas wells since the early 1900s. A complete drilling fluid system must be properly designed to efficiently construct a well. Thus, some of the basic drilling fluid functions include removal of drill cuttings to the surface, bottom-hole cleaning, maintaining the wellbore stability, controlling high-pressure zones, etc. Among the enumerated drilling fluid functions, a major one is to seal the walls of the formation being drilled to prevent filtration. Hence, one of the most desired properties of drilling fluid is the minimum fluid loss volume which can be achieved by the development of a low permeability filter cake on the wellbore. Therefore, every drilling fluid is designed to avoid a continuous fluid loss to the open-hole drilled which is highly undesirable. Drilling fluids are designed to reduce filtrate loss, form thin filter cakes that plaster the walls of the borehole to ensure minimal fluid loss and promote stability of the drilled well.Over the years, the increased use of different types of drilling fluids additives used in water based mud has increased environmental issues, technical problems during drilling, post drilling problems such as production challenges and increased cost of well development. These complicated problems are so difficult to be solved by the only oil and gas because they lack a robust literature review of recent additives in water based muds. These problems are the reason for technical failure of most drilling programs. However, the increasing recent challenges of most drilling operations in Nigeria are the cost and availability of existing expensive foreign additives used in water based muds. This problem is increased with numerous literatures of local additives without proper assessment of all these additives to boost their choice for drilling. The aim of this research is to carry out detailed comparative analysis of a minimum of ten literature reviews of local additives used in formulation of water based muds by evaluating their prospects and challenges in line with API standard.The objectives are to carry out detailed literature reviews of local additives used in water based muds and predicting their gaps, to carry out a comparative analysis of drilling fluid properties and API standards of existing literatures used, and to suggest best technical recommendations based on existing literatures of the way forward on local additives used in water based muds in Nigeria. The abundance of literatures exist on local additives used in formulation of water based muds, but no researcher has ever done a comparative study of all existing researches before laboratory analysis starts. The development of this study would go a long way to boost existing literatures available in the oil and gas industry which will enhance the choice of local additives used in drilling programs in the Nigeria.

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