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

MODELING OF WAX DEPOSITION DURING OIL PRODUCTION USING A TWO-PHASE FLASH CALCULATION

Wax deposition is a serious problem in the Petroleum Industry that results in the plugging of flow strings, formation damage, loss of hydrocarbons, increased production cost. The existing models used jn the oil industry for predicting wax phase equilibrium parameters over-estimate the amount of wax that is formed in terms of the wax weight fraction and the number of moles of solid. The Coutinho correlation is the latest of these models and is used to calculate the melting temperature and the enthalpy of fusion of the crude oil components. It did not consider the effect of branching of carbon atoms in the hydrocarbon structure/compound. But branching of carbon atoms in the hydrocarbon compounds affects its melting point. In this work, the correlation for calculating the melting temperature in crude oil developed by Coutinho has been modified to take into account the effect of branching of carbon-carbon chains in isoparaffins and the model has been used to calculate a new set of equilibrium parameter. The modified regular solution theory was used to calculate the activity coefficient ratio that was used as an input to the new model. Wax phase equilibrium flash calculations were carried out with the new set of equilibrium parameters. The wax mixture was then characterized using the weight fraction of component in the solid phase and weight fraction of component in the solid phase in the mixture. In order to check the reliability of the model, the data presented by Hanquan was used as input into the models developed by Won, Chung, Countinho and the new one. The new model predicted a more conservative value for the number of moles of solid formed, weight fraction of component in the solid phase and weight fraction of component in the solid phase in the mixture for C1s-C4o.This is an improvement over the existing models which overestimate the values of the parameters

EFFECT OF OILFIELD SULPHATE SCALES ON PRODUCTIVITY INDEX

The precipitation and deposition of scale pose serious injectivity and productivity problems. Several models have been developed for predicting oilfield scales formation and their effect on deliverability of the reservoir to aid in planning appropriate injection water programme. In this study an analytical model has been developed for predicting productivity index of reservoir with incidence of scale deposition in the vicinity of the well bore

A SHETTLE’S METHOD MODEL FOR AUTOMATING PRECONCEPTION SEX SELECTION

The world over, and especially in Africa and Asia, couples show a preference for particular sex of children; eithermale or female. This preference may arise due to economic reasons, customs of the people, or simply for a “genderbalanced family”. Whatever the reasons, the fact still remains that couples would like to be able to choose the sex oftheir children. While there are various options to achieve sex selection, all of them are either too expensive or tooinvasive. This paper presents how Shettles’ method being the least expensive and the most reliable method ofpreconception sex selection was modeled to enable automation. The results show that it is a more consistent andreliable method for gender selection. In addition, the result also shows that the Shettles’ method lends itselffavourably to computer programming and would be very useful in the lives of couples that desire a particular genderof offspring.Keywords: Computer assisted, Preconception, Sex selection, Model, Programming

Attitude of crop farmers towards e-wallet platform of the Growth Enhancement Support Scheme for input delivery in Oke-Ogun area of Oyo state

E-wallet-powered Growth Enhancement Support Scheme was designed by the Nigerian Government to facilitate and improve farmers’ prompt access to agricultural information and input services. An assessment of the pilot phase of the scheme becomes necessary for an effective implementation. The study therefore assessed the attitude of crop farmers towards the e-wallet platform of the Growth Enhancement Support Scheme. A total of 120 crop farmers across the study area were sampled through a simple random sampling method. Data were collected through a well-structured interview schedule, and analysed using percentages, PPMC and Chi-square. Farmers’ mean age was 47 years. Majority were males, married and have an average of 15 years farming experience. Maize and cassava were the most grown crops. Majority indicated non commitment of the ADP and long distance to redemption centre as major constraints to use of e-wallet. More than half had favourable attitude towards the e-wallet platform of the Scheme. There is significant relationship between the years of farming and educational level with farmers’ attitude towards the e-wallet. Constraints faced also had negative influence on attitude to the scheme. Establishment of more redemption centres to stop the rigor of long queues and reduce long distance covered before accessing the centres will make prompt access to information targeted by e-wallet achieve desired end.</jats:p

A New Model for Predicting Elemental Sulphur Deposition in a Sour Gas Reservoir

This research work is concerned with developing a more accurate correlation for the prediction of elemental sulphur deposition in a sour gas reservoir by exploring the relationship between compaction and elemental sulphur deposition over time and also incorporating porosity damage caused by reservoir compaction into the previous models in order to obtain a more robust representation of what actually occurs in the reservoir. The models considered indicates that the established new model gives the most accurate, reliable and practical result in predicting sulphur deposition which suggests that the rate of sulphur precipitation is seemed to have been underestimated by previous models. This may have not been unconnected with the fact that the new model based on non-Darcy flow, incorporated the porosity reduction caused by reservoir compaction which has been hitherto neglected by previous works. Therefore, reservoir compaction is a common phenomenon, which should be considered in sulphur deposition prediction since it leads to a faster rate of sulphur deposition

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