This research was carried out to model cumulative Biogas produced from sawdust cow dung and water hyacinth as an alternative means of sawdust disposa. The model was done using statistical tools via determination of coefficients of regression for the following digester setups which were made up A, B, C, D, E, F, and G with varying sawdust concentrations but with a constant concentration of cow dung and water hyacinth. The linear, exponential and polynomial models were tested with the obtained data, and the results obtained for each of the digesters showed that polynomial model best fitted the cumulative biogas production at any given day with R 2 values of 0.

No abstract

Effect of Temperature on the Thickening TimeProperty of Cement Slurry IntroductionCementing techniques involve the deployment of cement slurry on the Oilwell annulus and casing to provide proper zonal isolation. The target is to completely hinder fluids in the well from Interacting from one part to another, provide an anchor for the casing, prevent corrosion of the Casing, prevent shock loads during drilling, prevent blowouts, plug off vugular zones and for Abandonment. A key and essential part of the wellbore construction process is cementing (Lootens, 2004) The integrity of the oil well construction depends, to a large extent on the quality of cement formulation and slurry (Ridha et al., 2010) and this is to ensure the safety of the well and durability (Pourafshary et al., 2009; Ershadi et al., 2011). The incomplete isolation of the zone has been linked to the alteration of the production capacity and efficiency of the oil well operation. If it is inefficient cementing, production below optimum is bound to occur (Calvert, 2006). Poor cement slurry design and poor cementing operations are key factors that can affect the performance of the well efficiency and could result in a reduction in oil production. Environmental damage from oil spillage is the side effect of poor cementing and poor slurry design (Lootens, 2004) that causes death to aquatic lives and land pollution causing low production of agricultural produce, making the environment inhabitable to human and animal life as it causes some respiratory diseases. The spills also result in the loss of oil that is a part of the useful global oil reserve. Temperatures are a key factor of cement slurry formulation. Well cement experience different pressure ranges downhole from pressures within atmospheric pressure to higher pressures of about 1360 kPa in wells over 10000 ft (Joel, 2009). Apart from high temperature and pressure encountered in wells, the slurries are formulated to take care of the weak or vugular formations and reactive fluids. Successes achieved in the formulation of slurry have been linked to researches, discoveries and finding from additives applies for various conditions experienced during cementation operations. Additives add in the adjustment of the slurry system, making it more efficient for obtaining the objective of successfully separating the formation from the casing to ensure that proper zonal separation is obtained during production. To achieve high-quality slurry for a good cementation operation an additive known as retarder is usually added in the slurry system to delay the time the cement sets to allow adequate time for the operation to come to an end.Cementing operations are carried out at high-temperatures and high pressures (HTHP) in wells and this can be quite challenging and this requires cement formulations that are good technically. This study is therefore focused on the effect of temperature on the thickening time. Materials and MethodologyA series of tests were performed at different concentrations and temperatures to e...

This study was carried out using API recommended practice 13B-2 in a cement laboratory, and the essence was to establish the effect of sodium lignosulphonate-based retarder on the free fluid of cement slurry.The test was carried out at different temperatures of 80 o F and 100 o F and retarder concentrations of 0.01 gal/sk, 0.03gal/sk, 0.05 gal/sk, 0.07 gal/sk, 0.09 gal/skand 0.10 gal/sk. The test results obtained showed thefree fluid of sodium lignosulphonate-based retarder at concentrations of 0.01gal/sk, 0.03gal/sk, 0.05gal/sk, 0.07gal/sk, 0.09gal/sk and 0.10gal/skwere 0.8%, 1.2%, 1.46%, 1.75%, 1.92% and 2.12% at 80 o F respectively; similarly at 100 o F the free fluid were 0.79%, 1.21%, 1.56%, 1.72% 1.91% and 2.22%.The results it meant that concentration play a major role in adjusting the free fluid property of cement slurry while temperature has no significant effect on it.

Drilling fluid is an essential element to the drilling process as most drilling challenges can be traced to the condition of the drilling mud used. Density and rheology are among the basic properties of drilling fluid usually defined by a well program and closely monitored during drilling operation. The sustainability of the density of drilling fluid is a key factor that needs deliberate monitoring to ensure that its density is higher than the formation density, so as to avert unexpected complications. Hence this research was aimed at investigating the effect of barite concentration on oil base drilling fluid density and rheology. Formulations and testing procedures were conducted in accordance with American Petroleum Institute (API) specifications. Experimental results showed that the increase of drilling mud is a direct function of increase in concentration of barite. It was also observed that when the barite concentration was 0%, the plastic viscosity decreased as the temperature increased meaning that the drilling mud sagged whereas an increase in barite concentration to 10% revealed an opposite relationship, the plastic viscosity increased as the temperature increased. The yield point at 0% barite concentration gave the least yield point; this signifies that the barite concentration aids in the carrying capacity of the drilling mud. It was also observed that the barite concentration can be used to make the fluid more pseudo-plastic in nature. The consistency index (K) increases as the barite concentration is increased, which indicated that the fluid becomes more viscous when barite concentration is increased. Therefore, results have showed that concentration of barite affect the density of drilling mud as well as rheological properties.