bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of Rice Husk as Fluid Loss Control Additive in Water-Based Drilling Mud
Authors: Okon Anietie N. , Udoh Francis D. , Bassey Perpetua G. 
Published: July 2014

Abstract
Organic polymers are commonly used to control filtrate loss in water-based drilling fluids both in circulating and non-circulating periods during drilling operations. In Nigeria, the over dependence on these polymers to achieve this function of drilling fluid is worrisome on the overall well drilling cost. Therefore, a substitute for these polymers with locally available materials is indispensable. In lieu of this fact, an agro by-product, rice husk was evaluated as a possible filtration loss control additive in water-based drilling mud and the results compared with sodium carboxymethyl cellulose (CMC) and polyanionic cellulose (PAC) using static fluid loss measurement approach. The results obtained depict that with a concentration of 20g content of rice husk to 350mL mud (about 20lb/bbl) there was a decrease of 64.89% in fluid loss compared to 62.77% and 59.57% for CMC and PAC respectively at a content of 10g per 350mL mud. Additionally, filter cake thickness measurement from the husk showed a decrease of 3.03% and 8.57% respectively when compared to CMC and PAC. Thus, exploitation of rice husk as fluid loss control additive in water-based mud would be a welcome development in the oil and gas industry since its characteristics of high resistance to water penetration and thermal stability would be applicable to deep wells where high temperature is anticipated since CMC and PAC temperatures degrade at this condition.
Nanocompletions Versus Intelligent Well Completions, Investigating the Future of Nanotechnology in Well Completions - A Case Study
Authors: Opeoluwa Olawale 
Published: July 2014

Abstract
The oil and gas industry continues to face different challenges in the field of exploration and production. From field exploration to exploitation, including survey methods, drilling techniques, completion systems, production to reservoir monitoring, operations and processes are not only cost intensive but also technologically demanding. Hence, the potential for applications of nanotechnology in the Oil and Gas Industry is huge. However, despite several research efforts, few “nano-breakthroughs” have been achieved in the industry due, in part, to its high cost of application. This paper investigates the application of a specific nanotechnology- polymer supported nano-particles (PSNPs) in production tubing/completions of stacked reservoirs and compares this to Intelligent Well Completions (IWC) using a Niger Delta Case Study- Well X. It also employs the novel idea: nanocompletions- the integration or, better still, the adaptation of known applications of potentially viable nanostructures to the development of the major components and functionality of well completion systems/options. The lower costs, high sensitivity and fast response speeds achievable with PSNPs make them viable alternatives to IWCs, and most recently developed completions systems in the independent monitoring of flow properties and downhole data gathering for future field development plans and precise reservoir modelling. Cost benefit analysis of the proposed nanocompletions in solving challenges of downhole measurements and Intelligent Well Completions is presented. This paper shows that the application of nanotechnology in monitoring Well X and by inference any other well, in similar geological zones, can provide higher efficiencies and cost- savings.
Statistical Characterization of Performance of Biopolymer Drill-In Fluid for Different Rheological Models
Authors: Owusu M. , Enty G. S. , Osei-Twum A. 
Published: July 2014

Abstract
Appropriate selection of rheological models is important for hydraulic calculations of pressure loss prediction and hole cleaning efficiency of drilling fluids. Power law, Bingham-Plastic Herschel-Bulkley models are the conventional fluid models used in the oilfield. However, there are other models that have been proposed in literature which are under / or not utilized in the petroleum industry. The primary objective of this study is to recommend a rheological model that best-fits the rheological behaviour of xanthan gum based biopolymer drill-in fluids for hydraulic evaluations. Ten rheological models were evaluated in this study. These rheological models have been posed deterministically and due to the unrealistic nature these were replaced by statistical models, by adding an error (disturbance) term and making suitable assumptions about them. Rheological model parameters were estimated by least-square regression method. Models like Sisko and modified Sisko which are not conventional models in oil industry gave a good fit. Modified Sisko model which is a four parameter rheological model was selected as the best-fit model since it produced the least residual mean square. There is 95% certainty that the true best-fit curve lies within the confidence band of this function of interest.
Effects of Both Wellbore and Reservoir Properties on Dimensionless Pressure and Dimensionless Pressure Derivative Distribution of a Horizontal Well in a Reservoir Subject to Bottom Water, Gas Cap and Single Edge Water Drive Mechanisms
Authors: Edobhiye O. , Adewole E. S 
Published: July 2014

Abstract
This paper investigates the effects of both wellbore and reservoir properties on dimensionless pressure and dimensionless pressure derivatives of a horizontal well in a reservoir subject to bottom water, gas cap and single edge water drive mechanisms. Properties considered in this paper include dimensionless reservoir thickness, dimensionless well stand-off, dimensionless wellbore radius, dimensionless well length, infinite conductivity and uniform flux completions. The effects of rectangular and square reservoir geometries were also considered. New procedures were developed for prolonging the period of clean oil production. In order to achieve these objectives, Source and Green's function together with the Newman product rule were utilized.
Results show that dimensionless pressure increases with reservoir thickness. Dimensionless well stand-off did not show any effect on dimensionless pressure and its derivative. Dimensionless wellbore radius and dimensionless well length were found to be inversely related to dimensionless pressure. Infinite conductivity and uniform flux completions did not affect dimensionless pressure.
The information presented in this paper will help in the correct design and completion of wells in the reservoir and points of perforation locations for prolonged clean oil production.
Field Case Histories: Countering Lost Circulation with Monofilament Polypropylene Fiber
Authors: Mofunlewi Samuel S. , Okeke Chinyere , Bankole Abidemi , Ighodaro Osaze 
Published: July 2014

Abstract
One of the most time consuming and cost inflating events in drilling operations is loss of circulation. It has been globally estimated to cost the drilling industry more than $1billion annually in rig time, materials and other financial resources. Lost circulation is the total or partial loss of drilling fluids or cement slurries into highly permeable zones, cavernous formations, or natural/induced fractures during drilling or cementing operations. Lost circulation usually occurs when the hydrostatic head pressure of the column of drilling fluid exceeds the formation pressure.
This expensive problem is typically minimized or prevented by blending additives into the mud or cement system. One such additive is a monofilament polypropylene fiber. The fiber is an inert fibrous material that forms a network across the loss zone bridging and sealing the zones effectively.
The monofilament polypropylene fiber was proposed as an additive to a cementing system designed to counteract lost circulation issues that were expected while cementing two wells in the Niger Delta Basin in Nigeria. The loss in circulation was believed to be caused by natural fracture systems and high permeability within the zones to be cemented. The additive was first tested in the laboratory and determined to be efficient at countering the type of losses expected, and then was used in the field.
This paper will focus on the laboratory testing and the field application of the monofilament polypropylene fiber in two Niger Delta wells. The paper will include a thorough description of prior attempts to solve the lost circulation problem and results of using the new material.
Inclusion of Well Schedule and Project Life in Well Placement Optimization
Authors: Awotunde Abeeb A. 
Published: July 2014

Abstract
Well placement optimization plays an essential role in reservoir management. When wells are placed in optimum positions in the reservoir and operated at optimum rates or bottomhole pressures, the financial return on investment is expected to be high. In a highly heterogeneous reservoir, placing the wells in appropriate positions, although very challenging, can improve the profitability of investment significantly. Also, operating the wells under appropriate controls can enhance the viability of the project. One challenge with well placement, however, is how to simultaneously optimize well locations, well controls, well types, well schedules and project life cycle. Many works addressing the issue of well placement optimization often fix the project life and also assume that the wells were drilled at the beginning of the project. It is well known that all wells cannot be drilled all at the beginning of the project due to manpower and facility constraints, even if that scenario is the optimal choice for high net present value of the project.
In this work, we present an optimization framework that simultaneously finds the optimal number of wells, their types, locations, controls, well schedules and the optimal project life cycle. The method is an extension of our previous work in which all the above except well schedules and project life cycle have been determined using global optimization strategy. We included an additional variable that represents the project life in the list of optimization parameters and one variable per well to represent the fractional time at which the well is to be drilled, completed and put on production or injection. This fractional time is a fraction of the total project life and each well has its own fractional time. This means that wells will not be drilled all at the same time during the project life. To ensure that too many wells are not scheduled for drilling/commissioning during the same year, we adopted the penalty approach to enforce a set of inequality constraints that ensure that the number of wells drilled and put on operation in any particular year is not more than a predetermined number. Differential Evolution was used as the global optimizer to solve the problem. Results show that the method is able to yield high net present value corresponding to the estimated set of parameters including well schedules and project life cycle.
Integrated Model-Based Approach to Drilling Project Management
Authors: Omosebi O. , Osisanya S. O. , Ahmed R. 
Published: July 2014

Abstract
Drilling operations account for over 80% of the total cost of a well and this cost will continue to increase rapidly as the petroleum industry moves deeper offshore to explore additional reserves. In many regions around the world especially the Gulf of Mexico, Gulf of Guinea and North Sea (i.e. The Golden Triangle), daily operational cost of an offshore rig range from $1 million to $1.5 million. This high cost, as well as increasing concern to exceed stakeholders expectation, has underlined the necessity for sound project management to ensure that wells are drilled at lowest possible costs since the major objective in all drilling operations is to safely drill useable holes at minimized cost. Most often, only technical aspects of rig operations are thought to influence the number of days spent on location. In a more practical sense, however, both technical and non-technical issues control the success of rig operations; hence the need for a holistic approach for effective project delivery.
In this paper, a comprehensive and integrated model-based approach is proposed for managing drilling projects. This technique is based on project management body of knowledge and it emphasizes both technical and non-technical factors that influence successful drilling operations. Using this method, a dynamic well plan can be developed which can always be updated with current information obtained as drilling progresses. This scheme facilitates real-time documentation of lessons learnt which will aid planning and implementation of future drilling programs. Furthermore, project performance can easily be tracked on the basis of triple constraints of time; scope and approved budget since high-quality drilling management practice involve effective monitoring and control of these constraints. Collaborative engagement of drilling contractor, operating and service company representatives throughout the project phases is indispensable for full implementation of the proposed system. This scheme ensures development of detailed and dynamic authorization for expenditure (AFE) that accounts for non-technical project constraints. This paper is most applicable in management and systems technical category.
Impact of Radioactive Sources on the Environment: A Case Study of an Abandoned Oil Well in the Niger Delta
Authors: Dosunmu Adewale , Odagme B. S , Kamal K. 
Published: July 2014

Abstract
Crude oil exploration involves various operational processes and practices such as remote sensing methods of mapping. Moreover, radioactive detectors and explosives associated with seismic exploration, drilling and production equipment, LWD, MWD, uncontrollable wellbore instability, stuck pipe and loss of logging tools in hole issues leading to sidetracking, abandonment activities which leaves an impact on the environment. In this work, the radiological hazard indices in an abandoned oil well of Niger Delta was evaluated in the soil/sediment and water samples of the area to ascertain the impacts on the area and possible solutions were recommended. For soil samples, the mean value of Annual Gonadal Equivalent Dose (AGED) of the five locations was 665.25±65.07mSvy−1 and that for Annual Effective Dose Equivalent (AEDE) (Outdoor and Indoor) were 115.75±11.86μSvy−1 and 463.02±44.44μSvy−1 respectively. The Excess Lifetime Cancer Risk mean value was (0.41±0.04) × 103. The mean values for Representative gamma index, Iγ, the External Hazard index, Hex, and the Internal Hazard Index, Hin, were 0.62±0.01, 0.53±0.06 and 0.66±0.02 respectively. The radiation indices for the water at the abandoned well site, and many locations in the village were also calculated. For soil/sediment samples, the mean value for these indices were above the permissible value which showed radiological elevation in the areas. The radiological elevation from the percentage risk analysis signifies a radiological burden on the people and the environment of these areas and there is the possibility of developing cancer due to exposure to radiation before the age of 70 years for the people living in the areas.
Developing a Robust Emergency Pipeline Repair System in Nigeria
Authors: Iyede Efemena , Akinola Mobolaji 
Published: July 2014

Abstract
Pipelines form the backbone of oil and gas production, and are no doubt, one of the safest and most economical means of oil and gas transportation today. Consequently, increased oil and gas production means significant increase in the application of long distance pipelines for onshore and offshore oil and gas transportation.
In sub-saharan Africa, the pipeline industry is gaining momentum as more investment is planned for the oil and gas sector over the next few years. Statistics have shown that more investments by indigenous and foreign companies including government partnerships have been put in place towards developing pipeline infrastructures in Nigeria. With reports of approximately 12,000km of total pipeline length currently installed in Nigeria, forecasts predict a construction of up to 2,000km more in the next 5 years to boost domestic gas supply and other petrochemical infrastructures. [Pipeline and Gas Journal, Vol 239 No.1, 2012]
From an economic standpoint, pipeline assets can be categorized into critical and non-critical pipelines, based on the level of impact they have on the Operators' production figures. Critical Pipelines are those that generate important loss of production, and financial risk to the Operator, should operation be interrupted for a significantly long time. The failure of such pipelines can also be a disaster in terms of environmental contamination resulting from leakages or oil spillage. This therefore means, pipeline Operators need to adequately prepare in advance for emergency failures as they can be very dramatic with associated high production losses and environmental damage.
The onus lies on pipeline operators to put in place a robust strategy ensuring preparedness for "unexpected" failures. Therefore, an Emergency Pipeline Repairs System (EPRS) becomes imperative in the Operational Management System.
This paper focuses on good EPRS practice, key components of a robust EPRS strategy; some pipeline defects and emergency repair options, and concludes with a case study of EPRS mobilization in Nigeria showing major lessons learnt.
Application of Time Series Analysis to Predict Reservoir Production Performance
Authors: Olominu Oluwafemi , Sulaimon Aliyu A. 
Published: July 2014

Abstract
Decline curve analysis (DCA), material balance (MB) and numerical simulation are used to predict reservoir performance. However, these methods have peculiar strengths and limitations. While some are based on analytical observations and theories others are purely stochastic. The objective of this study was to investigate the applicability of Time Series analysis to predict oil cumulative production as a measure of reservoir performance. The Box Jenkins method of Time Series analysis utilizing the Autoregressive Integrated Moving Average (ARIMA) models was used to predict and analyse oil cumulative production of wells and reservoirs. The process involves a robust transformation of production datasets into time series. A best fitting model was chosen using maximum absolute deviations as a measure of fit. Predictions of the ARIMA model were validated with historical data and its performance was compared with Decline Curve analysis (DCA).The coefficient of each model was optimized using the simplex optimization technique.
The results show that ARIMA (1,1,0) model gives the best match with actual cumulative oil production data. The model had the least maximum deviation of 4.24% compared to 178.95%, 182.32% and 24.45% for ARIMA (1,0,0), ARIMA (2,0,0) AND ARIMA (1,2,0) respectively after predicting for 900 days. Analysis of results after 1097 days of production also shows that the ARIMA (1,1,0) predicts better than the DCA method. The maximum deviation for both ARIMA and DCA were 1.81% and 12.79% respectively. The best model coefficients fall between 1.99 and 1.9999999. A model coefficient too high or too low will definitely lead to erroneous predictions. This study has shown that ARIMA (1,1,0) can be used to model and predict reservoir/well cumulative oil production accurately for short to mid-long term periods. Furthermore, the model performs better than the DCA for medium to mid-long term predictions. The accuracy of the model can be improved as more data become available for history matching to further refine the model coefficients. A model coefficient of 1.995 is recommended when few data are available.
A Laboratory Study of ASP Flooding on Mixed Wettability for Heavy oil Recovery Using Gum Arabic as a Polymer
Authors: Avwioroko Jerome , Taiwo Oluwaseun , Mohammed Ismail , Dala Joshua , Olafuyi Olalekan 
Published: July 2014

Abstract
A Laboratory Study of ASP Flooding on Mixed Wettability for Heavy Oil Recovery Using Gum Arabic Polymer Alkaline-Surfactant-Polymer (ASP) flooding process offers a promising approach to recover the residual oil which often times is more than 50% of original oil in place.
This paper presents the summary of the laboratory studies on the effect of wettability on oil recovery of Alkaline/Surfactant/Polymer flooding using a Local Polymer – Gum Arabic which is vastly available in Nigeria. Engineering grade class IV glass beads were treated with chemicals to water-wet (WW) and oil-wet (OW) conditions. Different degrees of wettability were obtained by mixing the WW and OW glass beads in different ratio before each flooding experiment. The mixing ratio used were 100%WW and 0%OW; 75%WW and 25%OW; 50%WW and 50%OW; 25%WW and 75%OW; 0%WW and 100%OW. The displacement efficiency of Alkaline/Surfactant/Polymer flooding and Polymer flooding at the different wetting conditions was evaluated by laboratory coreflood experiments.
From the experimental result, it was also observed that oil recovery increases as formation becomes more strongly water wet. The experiment results indicate that the displacement efficiency of water floods and ASP flooding is markedly affected by the wettability of the core. The wettability is one of the important factors to determine the oil recovery of water and ASP flooding. Water-wet and oil-wet conditions are favourable to obtain high enhanced oil recovery for ASP flooding using locally available Gum Arabic.
Application of Mechanical Cleaning Device: Hole Cleaning Tubulars, to Improve Hole Cleaning
Authors: Nwagu Chike , Awobadejo Toyin , Gaskin Keith 
Published: July 2014

Abstract
Efficient removal of drilled cuttings from a wellbore during the drilling process is critical to the success of any drilling operation. The negative consequences of inefficient hole cleaning can range from the occurrence of significant Non Productive Time due to time and resource consuming remedial operations, to the potential sticking of the drilling BHA and potential loss of the entire wellbore. These can carry very significant financial consequences ranging from tens of thousands to millions of dollars (USD).
While hydraulic hole cleaning during the drilling of vertical wells is a relatively straight-forward matter, the cleaning of deviated wellbores presents entirely different challenges which have been well documented. The Illah field, located offshore the Niger Delta region of Nigeria, presents specific challenges which result in the requirement for significantly deviated wells, which present numerous hole cleaning difficulties. Some of these challenges include but are not limited to: Vertically stacked and laterally offset objective reservoirs.Multiple completion objectives and strategies per wellbore requiring complex well designs.
It is a well-documented fact that cuttings removal in inclined wellbores becomes more difficult as the hole inclination increases. In the medium to horizontal deviation scenarios the tendency for cuttings to accumulate into "beds" comes into play and these cuttings beds will increase in severity in the critical angle range depending on other factors such as particle/cutting size. Some other factors which could contribute to the accumulation of cuttings in inclined boreholes include; drilling fluid rheology and density, flow rates, drill string RPM and mechanical wellbore instability.
This paper which is a case study of drilled wells in the Illah field, concentrates on the effects of the application of a mechanical cleaning device; Hole Cleaning Tubulars, to the problem of down hole accumulated drilled cuttings whilst drilling deviated wells.