Evaluating the Efficiency of Nigerian Local Bentonite as an Extender in Oil Well Cementation

Nigerian local Bentonite has been in use as an extender in cementing operations since 2003 but has not been widely accepted because of some of its effects and challenges on most of the cement properties. This study is on the experimental and economic evaluation of the effect of Nigerian local bentonite obtained from Awkuzu in Anambra state and the imported bentonite on fresh and salt water cement slurry. The experimental test were basically on the thickening time and the ultrasonic compressive strength.  Both local and foreign  bentonites proved effective in fresh  water  cement slurries and can  be used interchangeably except in cases where higher Plastic Viscosity (PV) and Yield Point (YP) are required .The foreign bentonite proved more effective under this high rheological properties for the same concentration with the local bentonite . In the  salt water cement slurries both local and foreign bentonite were not fully effective, but the local bentonite responded better in the case study  design in terms of  rheology and free fluid tests.  For the  economic  evaluation, a case study of a project involving the 13 3/8 inch  casing cementing operation was  simulated  using fresh water cement slurry. The foreign bentonite contributed 21% to the overall cement slurry cost while local bentonite contributed  2%.leading to  a total savings of $7,509.85. Therefore , local bentonite could be a more efficient and cost effective means of cement slurry extender if properly managed and evaluated

Analytical modeling of pipeline failure in multiphase flow due to corrosion in Niger Delta Region

Pipeline could be said to be the safest and the most economical means of transportation of hydrocarbon fluids. Pipelines carrying oil and gas may suffer from internal corrosion when water is present. The corrosivity varies due to several factors such as; temperature, total pressure, CO2 and H2S content in the gas, pH of the water, flow conditions, inhibiting chemicals etc. Corrosion, when not properly dealt with could lead to pipeline integrity issues which will be very uneconomical for the operator company. This research focuses on the development of a model that can predict pipeline failure due to corrosion in multiphase flows. The role that velocity, density, water cut and other parameters play in predicting corrosion is critically analyzed with Norsok Model. The result shows that velocity plays a key role in corrosion prediction.Increasing oil velocity from 0.1 to 1.25 m/s leads to an increase of corrosion rate from 1.67 to 5.58 mm/yr. This is because at the selected pH of 4, the corrosion rate is very sensitive to mass transfer and turbulent mixing which are in turn enhanced at higher flow rates

Analysis of filtration properties of locally sourced base oil for the formulation of oil based drilling fluids

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 70oC 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