Endpoint Mobility Ratios for Vertical and Horizontal Wells with Incidence of Scale Deposition

One of the most difficult and profit hurting problems found in the oil field is the build-up of scale deposits in the well bore, production string, flow lines and even in storage tanks. These deposits act as a restriction during build-up in the wellbore causing a gradual decrease in production and, in many cases, as a solid barrier for wellbore fluid flow. This paper presents an analytical model based on the existing thermodynamic model showing the endpoint mobility ratios for both vertical and horizontal wells with the incidence of scale precipitation and deposition at the near wellbore region during water flooding. The results revealed that Endpoint mobility ratio for a vertical well with radial flow approaches unity “1” faster than for the horizontal well with elliptical flow. And horizontal wells are good candidates for managing scale precipitation and deposition during waterflooding

Lecturers’ Awareness and Readiness towards the Adoption of Open Educational Resources for Teaching in Tertiary Institutions in Niger State, Nigeria

This study investigated attitudes and self-efficacy towards the utilization of interactive whiteboards (IWB) among university lecturers in North Central, Nigeria. A descriptive survey research design was employed for the study and 315 participants were selected through a multi-stage sampling technique. Four research questions and two null hypotheses guided the study and a 20-item questionnaire was used as an instrument for data collection. The questionnaire was subjected to both validation and reliability checks. Data obtained from the administration of the research instrument were analysed using descriptive statistics of Mean and Standard Deviation for research questions and inferential statistics of z-test for research hypotheses. A decision rule was set, in which a mean score of 2.5 and above was considered agreed, while a mean score below 2.5 was considered disagreed. Findings revealed that lecturers’ attitudes and self-efficacy towards the utilization of interactive whiteboards (IWB) were positive with a mean score of 3.02 and 2.70 out of possible 4.0. Also, gender as a moderating variable had an influence on lecturers’ attitude and self-efficacy towards utilization of interactive whiteboard. Based on these findings, it was recommended among others that lecturers in tertiary institutions should be encouraged to adopt Interactive Whiteboard in order to enhance their teaching. This can be achieved through the provision of enabling work environment that supports the use of information and communication technology in the teaching and learning process

Elemental Sulphur Induced Formation Damage Management in Gas Reservoir

Sulphur compounds are considered as the most hazardous non-hydrocarbons in reservoir fluids, because of their corrosive nature, deleterious effects of petroleum products and tendency to plug porous medium which may impair formation productivity. Precipitation and deposition of elemental sulphur within reservoirs, near well bore region may significantly reduce the inflow performance of sour-gas wells and thus affect economic feasibility negatively. Studies have sought that almost all deep sour reservoirs precipitate elemental sulphur either occurring as a result of decomposition of H2S to give elemental sulphur or occurring as indigenous usually referred to as native sulphur as a dissolved species. Uncontrollable elemental sulphur induced formation damage has been one of the profit hurting syndromes that occurs in deep water sour gas reservoir. Meanwhile many correlations have been formulated thermodynamically to predict the occurrences of elemental sulphur but little information related to effect of its saturation on gas production and its corresponding formation damage. This paper presents an improved model for predicting elemental sulphur saturation and corresponding formation damage around the well bore. Results show that the minimum pore spaces blockage time was over-estimated by previous formulatio

MODELING THE EFFECT OF TEMPERATURE ON ENVIRONMENTALLY SAFE OIL BASED DRILLING MUD USING ARTIFICIAL NEURAL NETWORK ALGORITHM

Due to increase in environmental legislation against the deposition of oil based mud on the environment, drilling companies have come up with an optimum drilling mud such as plant oil based mud with little or no aromatic content, which its waste is biodegradable. Optimum mud carry out the same function as diesel oil based drilling fluid and equally meets up with the HSE (Health, safety and environment) standard. It is expedient to determine the down hole mud properties such density in the laboratory or use of available correlation but most time; the range of data is not either reliable or unavailable. In this study, artificial neural network (ANN) was used to address the unreliable laboratory data and unavailable correlation for environmentally friendly oil based drilling mud such as jatropha and canola oil. The new artificial neural network model was developed for predicting the down hole mud density of diesel, jatropha and canola oil based drilling mud using 30 data sets. 60% of the data were used for training the network, 20% for testing, and another 20% for validation. The test results revealed that the back propagation neural network model (BPNN) showed perfect agreement with the experimental results in term of average absolute relative error returne

Predicting tool for sulphate scale build-up around the wellbore in oilfield

Formation and deposition of scale in porous media due to extensive use of seawater for oil displacement and pressure maintenance is a problem that results in production decline and loss of billions of dollars to the petroleum industry yearly. A variety of models are presently being used in the oil industry for predicting scaling tendency and average scales precipitation inside the reservoir. These models assumed that all the occurring scale precipitation would cause formation damage near the wellbore region however, only a fraction of the precipitated scales escape through the pore spaces to render havoc to flow in the production string. This paper presents a new model based on existing thermodynamic models for predicting barium and strontium sulphate scale build-up rate around an oil production well during water flooding while accounting only for the fraction resulting into formation damage. The key operational and reservoir parameter which influence the magnitude of impairment by scale deposition are identified through the derivation of an analytical expression for the rate of scale build-up, assuming idealised flow conditions. The model is capable of predicting scale build-up rate and fraction of scale deposited in pore spaces at a particular radial distance from a wellbore during water injection

A Modified Model for Predicting Permeability Damage due to Oilfield Scale Deposition

Scaling is a major problem in water flooding caused by the mixing of incompatible injected and formation waters. The phenomenon results in precipitation and accumulation of oilfield scale around the well bore after water breakthrough at reduced reservoir pressure. This results in formation damage, which may influence reservoir well bore performance and success of water flood project. This article presents a modified model for predicting permeability damage due to oilfield scale precipitation at different operational and reservoir/brine parameters. The key operational and reservoir parameters that influence the magnitude of flow impairment by scale deposition are identified through the modification

Investigating the Carrying Capacity and the Effect of Drilling Cutting on Rheological Properties of Jatropha Oil Based Mud

in particular, are among the major concerns of world communities. Studies have shown that diesel oil based mud is highly environmentally unfriendly because of its deleterious effects on the environment and expensive to dispose. For these reasons, it is imperative to promote and propagate the use of environmentally friendly mud for drilling operation. This study investigates the drilling cutting carrying capacity of both jatropha and diesel based drilling muds. It also examines the effect of contaminants on the rheological properties of the muds. The properties measured are Plastic Viscosity, Yield Point, Apparent Viscosity, Mud Weight, Gel strength. The results obtained show that cuttings have detrimental effects on rheological properties of both muds by increase in filter cake thickness, loss circulation, struck pipe and operational cost, hence reduction in drilling efficiency. It also showed that Jatropha oil based mud exhibits better adaptability, higher carrying capacity and less pressure loss in pipe than diesel oil based mud, hence should be encouraged for use during drilling activities. Finally, the results of the study would enable the drilling engineer to determine the hole cleaning capacities, at which percentage of cutting become catastrophic and the extent at which cutting should be allowed in the mud. Key words: Jatropha biodiesel, drilling cutting, environtally friendly based fluid, rhological properties, drilling mud