bluuebunny/crossref_metadata_2025_split huggingface dataset:
Real-Time Production Optimization Experience in an Offshore Gaslifted Field
Authors: Ofonmbuk Umanah , Ifechukwu Michaels , Adebowale Oladepo David 
Published: July 2015

Abstract
The conventional approach of calibrating and updating well models is time consuming. Because of the dependency of the field optimization software on updated well models, the conventional approach reduces the frequency of implementing the optimizer's recommendations.
To operate their fields at their maximum deliverability, taking into consideration all the system constrains, a real-time software/workflow, Intelligent Daily Operation (IDO) was proposed and implemented to monitor, automatically calibrate and update well models.
The question is will IDO and other tools be able to address all these?
The objective of this work was to evaluate IDO and other real-time optimization (RTO) tools that are present in the company, and to identify effective ways of optimizing production using these applications. The workflow is as follows:
Identify critical steps in the current workflow that can be improved by switching over to real time mode. Review the tools that are available for real time performance surveillance and optimization. Identify the scope and limitations of IDO. Suggest ways of using field data source to monitor/validate result of IDO. Identify gaps and suggest ways of closing the optimization cycle.
The study reveals; average monthly savings of 380 engineering hours, achievement of daily update of well models as a result of implementation of RTO tools and after full implementation of RTO applications, monthly implementation of optimizer's recommendation will also be attained.
Certain limitations of the RTO were also identified, it includes inability of the models to match field operating conditions, possibility of erroneous readings from the multiphase meters, on which the production allocation function of the RTO applications depend.
The work further makes suggestions on how to use to the RTO applications for early detection of unhealthy wells, which improves efficiency.
Experimental Model for the Determination of Hydration Potential of Niger-Delta Shales for Drilling Mud Design
Authors: Eme C. , Dosunmu A. , Anyanwu C. , Okoro E. E. , Ekaide E. 
Published: July 2015

Abstract
Maintaining stability between shale-mud interaction is a key factor towards improving safety and drilling efficiency while minimizing costs associated with drilling and production operations. The use of conventional Water Base Mud in drilling shale formation results in the adsorption of water associated with the drilling mud by the shale. Depending on the shale type, water adsorption may lead to various reactions such as swelling, cuttings dispersion, and increase in pore pressure creating wellbore instability to varying degrees. This research provides information on shale characterization of two Wells, A and B in Niger/delta region Nigeria and proposes the development of inhibitive Water based drilling fluids for the shale samples. It also provide results of the shale mineralogy, native moisture content, total organic carbon content, cation exchange capacity and the adsorption isotherm of the shale samples. From the analysis, the X-Ray Diffraction (XRD) results indicate that the shales are dominant of kaolinite. The result of the CEC falls within the Kaolinites group of 3 Meq/100g - 10 Meq/100g according to Boulding and Ginn (2003). Polymeric fluids composed of varying Polymer/salt (KCl, NaCl and CaCl2) concentrations was prepared and evaluated for the shales samples using dispersion test. The result of the analysis was used to design a mud selection template for drilling through shales. Recommendations for improving shale stability were described, based on the current understanding of shale stability.
Effect of Grain Size on Porosity Revisited
Authors: Ogolo Naomi A. , Akinboro Olorunmbe G. , Inam Joseph E. , Akpokere Felix E. , Onyekonwu Mike O. 
Published: July 2015

Abstract
The sand grains of unconsolidated hydrocarbon bearing formations have been found to be well sorted. Porosity which is a very important parameter in estimating hydrocarbon reserves partly depends on the pore spaces between sand grains. In this work, the porosity values of well sorted and moderately sorted sands obtained from three different locations in the Niger Delta were determined. The results showed that porosity increases with decreasing grain size. It was generally observed that porosity increased from about 26% to 42% as the sand grain sizes decreased from 1000microns to 45microns. Theoretically, grain size does not affect porosity for well sorted grains but in nature, sand grain size affects porosity probably because sand grain deformation from a spherical shape increases with decrease in particle size. It is therefore suggested that attempts be made to use naturally deposited sand grain sizes to predict porosity based on the premise that particle shape affects porosity and particle sphericity decreases as grain size decreases and this accounts for the increase in porosity with decreasing grain size.
Mud Cap Drilling in a Highly Fractured HPHT Carbonate Formation: A Case Study in an Iranian Offshore Field Persian Gulf
Authors: Zoveidavianpoor Mansoor , Farahani Vahid 
Published: July 2015

Abstract
Significant and dangerous drilling problem is created when suddenly facing massive lost returns. Consequently, conventional means of controlling the well through circulation down the drill pipe and returning up the annulus becomes impossible. Due to their heterogeneous nature, carbonate rocks typically present drilling challenges. In M offshore field it is common to encounter tight formations, highly fractured rocks, and vugular textures. Accordingly, alternate means of controlling the well and safely drilling ahead must be used.
This paper reviews and discusses the application of mud cap drilling (MCD) which was used to drill a well in a highly fractured formation offshore Iran in Persian Gulf. The target formation in 12 ¼″ section of an appraisal well of Iran's M gas field shared with Saudi Arabia was a carbonate reef. This section contains highly fractured rocks and dissolution channels created by large caverns that partially collapsed with later sedimentation. When these dissolution channels were penetrated by the well path, the formation completely yielded to any small amount of pressure overbalance and complete loss of returns was experienced. Seismic analysis was not successful in clearly identifying these areas. All wells drilled into the target reservoir had the potential for this loss. All attempts at curing this lost circulation with conventional techniques failed. The logical way of approaching the problem and achieving total depth was to drill with MCD technique.
PETRPARS has recently implemented a MCD solution on one well offshore Persian Gulf, Iran, which experienced total losses. Once total losses are encountered, a series of procedures are executed that result in converting the well from a conventional drilling operation to a MCD operation. While drilling Well M03, PETROPARS encountered total lost in Surmeh and Neyriz formations from 7904 to 10184 feet. The consequent actions include trying to cure losses with lost-circulation materials, cementing, waiting on mud materials and enduring other drilling problems associated with massive losses encountered in the lower portion of the well. Full penetration of these formations requires the use of a MCD and consequently well cost was minimized due to application of this method. A comparison for the cost of drilling mud in 12 ¼″ section in well M03 shows 43.7% reduction when drilling shifted to MCD technique.
This paper discusses the operational and technical problems encountered including well control, optimizing mud composition and usage, and formation evaluation on an appraisal well which was drilled on this field. The geology, lithology and causes of loss also will be discussed at this paper.
Safeguarding Pressure Integrity of Surface Well Control Equipment: A Review of Fastlock Drilling Adapter and Blow Out Preventer Connection Failure in High Pressure Well
Authors: Awe S.O. , Erinle A. , Akinfolarin A. , Ibrahim T. , Obanya P. , Roes V. 
Published: July 2015

Abstract
Well control is primarily achieved using mud hydrostatic column to overbalance reservoir pressures. The overbalance from mud can be lost in a well due to following reasons; encountering unexpected higher pore pressure, reduction in mud column due to down hole losses, reduction in mud weight due to dilution and loss of hydrostatic head due to poor drilling practices. Emergency situation is created when escalation of any of the scenarios results to the loss of primary well control. In such instance, the secondary well control equipment such as blow out preventers and wellheads are activated to enable restoration of overbalance and return of drilling operation to normalcy. As part of emergency preparedness, it is important to regularly confirm the pressure integrity of the secondary well control equipment in order to guarantee their availability whenever required. As part of the pressure integrity assurance process in Shell operations, pressure test of the critical equipment is mandatorily carried out every 21days whenever the wellbore is exposed to hydrocarbon bearing reservoir.
Drilling operation has been successfully carried on GXH-1 HPHT well across the hydrocarbon bearing hydrostatic interval. Pressure test that was carried out on the well control equipment after installing the 9 7/8″ production casing and prior to drilling into the high pressure interval of the well revealed loss of pressure integrity at the flange connection between the 15,000psi rated BOP and fastlock drilling adapter on the 15,000psi rated wellhead. Upon observation, the loss of pressure integrity was discovered to be due to washout on the flanges of the BOPs and the wellhead as well as the ring gasket. The well was suspended with plug to allow safe repairs of the damaged flanges.
The damages on the flanges were successfully repaired and pressure tested to full rated working pressure before recommencement of drilling operation. This paper reviews the relevant drilling operations that preceded the loss of pressure integrity of the secondary well control equipment and the root cause analysis carried out on the failure. It also enumerates recommendations from lessons learnt from the incident that will ensure prevention of future re-occurrence of the type of failure.
A Review of Drill-Cuttings Treatment and Disposal Methods in Nigeria- The Gaps and Way Forward
Authors: Mkpaoro M. I. , Okpokwasili G. C. , Joel O. F. 
Published: July 2015

Abstract
Drill cuttings generally are bye products of drilling activities and represent pieces of components that are returned to the surface with the drilling fluid. Drill cuttings from Water Based Muds (WBMs) have been shown to pose little threat especially to the deep offshore environment, while those from Oil Based Muds (OBMs) have been widely prohibited by legislations because of their damaging effect on the environment, hence the recent requirement of zero discharge in onshore and swamp (including near offshore locations) in Nigeria. Presently, in Nigeria, there are three approved cuttings handling methods namely, Cuttings Re-injection (CRI), Thermal Desorption (TDU) and Offshore Disposal. Unfortunately, all of these methods have serious challenges. CRI and TDU treatments for instance, require large volumes of drilling waste and high capital for effective implementation as well as result in high level pollutant residues. Besides, many biological processes on the other hand, require longer treatment periods. To address these gaps, a biochemical treatment method involving the use of microbes in addition to chemical enhancers to degrade hydrocarbon-contaminated wastes into nontoxic residues is appears to be a preferred option. Biochemical treatment has been found to be cost-effective, environmental friendly and very efficient in the treatment of soil contaminated with drill cuttings.
Technical Data Tracking And Cataloguing Improves Asset Performance In Shell Nigeria
Authors: Kingsley Iheajemu , Arnold Obomanu , Erasmus Nnanna , Yvonne Jegede 
Published: July 2015

Abstract
In the Oil and Gas Industry, the availability and reliability of technical data is critical to effective decision making. As we often remind ourselves, most of what we know about our assets is only as good as the information available to us. Unfortunately, the reality is that unreasonable time is spent searching, gathering and many times, reworking available data before use. This has made technical data management one of the biggest challenges we face in our industry.
Data/Information Management provides a systematic approach to collecting, processing and distributing data in order to provide the integrated asset team of geoscientists and engineers, ready access to critical information throughout the life cycle of a field. Technical data tracking and cataloguing is to a large extent one of the strategic approaches to effective data management.
Reliable and sustainable data management must be hinged on a number of strategies some of which are: Tracking and cataloguing critical data.Establishing standard procedures and plans for managing dataEmbedding data analysts within Asset teams to manage data-specific activities.
When properly done, Data Management adds value through reduced cycle times and increased productivity and this is evident in several Shell Nigeria assets where Key Performance Indicators (KPIs) related to Data management have shown significant improvements. In addition, a survey of 247 participants across Shell Nigeria indicates that Engineers spent 18% of their time on data search, gathering, validation and re-work today, when compared to 55% five years ago.
This paper therefore highlights the processes and benefits of tracking and cataloguing of critical data to its final provision at the fingertips of Engineers and Geoscientists.
LPG Hydrate Formation and Prevention using Ethanol and Methanol
Authors: Olabisi Odutola Toyin , Sunday Ikiensikimama Sunday , Appah Dulu 
Published: July 2015

Abstract
Liquefied Petroleum Gas (LPG) is one of the alternate sources of energy because of its availability and high heating value. As the interest in LPG production in Nigeria and other developing countries increases, it is imperative to study some of the flow assurance issues associated with LPG. Due to the presence of moisture in commercial LPG, hydrates can form during LPG production, transportation and storage. Hence, it is important to predict hydrate forming conditions of LPG and propose a prevention plan if the LPG production, transportation or storage system falls in the hydrate formation zone. This paper examines the mechanism of hydrate formation in LPG and how LPG hydrates can be inhibited using methanol and ethanol. The inhibitor effectiveness was evaluated by the degree of temperature depression effected by equal amounts of these inhibitors. It was discovered that Methanol performed better than Ethanol when 20wt% of methanol and 20wt% of ethanol respectively were used in inhibiting hydrates formed in LPG. The effect of dehydration on LPG hydrate formation was also examined by varying the water content of the LPG from 7wt% water to 2.5wt% water. This simple approach to hydrate inhibition will enable the Engineer reduce the risk of hydrate formation during LPG production, transportation and storage.
Optimizing the Sourcing of Natural Gas From Intercalated Fields for Accelerated and Sustainable Low-Cost Natural Gas Supply: A Case Study of the Central Niger Delta Gas Cluster
Authors: Ogwo O. U. , Agha G. U. 
Published: July 2015

Abstract
This work investigates the strategies by which natural gas can be harnessed from intercalated and/or marginal fields in a given resource base and made available to end-users at the barest cost, and at the shortest possible time, ensuring equitable resource utilization. The study examines the operation of the area-franchise strategy as it concerns meeting up the accelerating energy sufficiency demand of the economy while ensuring timely extermination of gas flares; and determines the economics of the supply of dry gas to the power sector from Associated Gas (AG) and/or Non-associated Gas (NAG) wells at the regulated gas price. The work establishes the threshold feed gas volume and cost ratios for the Central Processing Facilities (CPF) and the Mini Processing Facilities (MPFs) that will enable the production of sufficient dry gas at good return on investment (ROI) under a given regulated gas price. Sample field data is used to assess the proposed strategy. It is intended that this work would guide the Government in the formulation of policies that would engender sustainable and implementable regulations on gas distribution and pricing.
Nigeria Gas to Power Value Chain Systems Economic Evaluation and Modeling
Authors: Onwuka Emmanuel I. , Iledare Omowumi 
Published: July 2015

Abstract
Presidential report on the Power Sector Reform 2010 as well as Gas Master Plan (GMP, 2008) vested much commitment to the gas sector towards electricity value chain viability. The result so far has been marginal. The primary challenge lays perhaps, in the impractical gas commitment contracts between the power and gas companies. Other challenges include unfavorable domestic gas pricing mechanism relative to export parity pricing; there is also the uncertainty in the security of supply lines by virtue of vandalism.
Guided by the domestic supply obligation enshrined in the GMP, this paper develops an integrated economic model that evaluates both sides of the gas to power contract. The estimated gas volume required per period is determined to facilitate the decision making process in the Nigerian power sector. A total base case data of electricity demand as established by Presidential pronouncement are imposed as reference inputs into a simple gas conversion model to develop annual gas supply equivalent for a base Take or Pay (TOP) contract life of 25 years. The developed supply profile is applied to the gas pricing model, keeping in perspective, the price transition from opportunity cost pricing in terms of netback gas export price or the export parity price (EPP).
The estimated discounted cash flow model results in terms of economic metric measures (NPV & IRR) and systems performance indicator (HGT & DHGT) show fiscal impact on profitability of gas investment. The validated model indicates that a GDP growth of 7% will require at least 3176 MW annual capacity addition and about 100 Bscf annual cumulative gas input in the next 25 years, given base boiler efficiency of about 83%. As expected, taking gas price from the stipulated 1.8 to 3.35 $/MSCF brings about proportionate increase in the NPV. It also reduces the payback period. Assigning triangular and normal distributions to gas price and turbine performance values respectively, gave the stochastic P90 NPV of between 513 and 1,925 Million USD.
An Assessment of the Role of Supplier Prequalification Audit in the Implementation, Enforcement and Stabilization of Business Regulations on Nigerian Oil Services Companies
Authors: Tubosun Fagbe 
Published: July 2015

Abstract
The strategic importance of compliance with National Business Laws, Regulations and standards in managing the ethical and corporate governance standards of Nigerian companies can no longer be ignored in a globalized business environment. Preparation for business, capability and capacity may be adjudged from level of the companies' compliance with National Laws. Regulations and standards were promulgated to be obeyed by suppliers and buyers as law abiding corporate entities. Non-conformity to business legal requirement may attract sanctions, loss of patronage and income, litigation, corporate image and possibly removal from national companies' register if critical. This paper examines the roles of Nigerian Oil and Gas sector's Joint Prequalification scheme on Oil and Gas service companies' adherence on the implementation, enforcement and sustenance of Nigerian Laws. The study covers about three hundred Nigerian companies in three geographical zones of South-West, South-South and North Central comprising of Lagos, Ondo, Ogun, Oyo, Delta, Rivers, Akwa-Ibom, Cross River, Edo and Abuja. Moreover critical review of several Nigerian Laws, businesses legal requirement, entrepreneur legal awareness level, Regulatory agencies' enforcement strategies and capacities, business growth and continuity as well as its consequences. The study was restricted to the compliance of Nigerian companies with National Laws before and after prequalification assessment exercise based on practical field experience between March 2010 and 31st December 2014. The paper wraps up with summaries of findings, strategic solutions recommendation and conclusion on how Nigerian companies and Regulation Agencies may boost the national economy and optimally promote business activities in a legal conscious and friendly environment through third party business evaluation scheme.
Laboratory Investigation of the Effects of Monovalent and Divalent Salts on Gum Arabic Solutions
Authors: Onaiwu D.O. O , Olafuyi O.A. A , Ogbonna J. 
Published: July 2015

Abstract
In field application, many factors result in the degradation and deterioration of polymer solutions during a polymer flooding project. One of these is the presence of salts which reduces the viscosity of polymer solutions. The degradation of a polymer solution by the ionic salts present in the reservoir environment varies from one polymer solution to another. This depends on the chemical and physical properties of the polymer involved and on the type of salt present in the reservoir. Therefore, a good knowledge of how the polymer solution behaves in the presence of different salts will result in a more efficient polymer flooding projects, which will invariably lead to a better oil recovery.
Gum Arabic solutions containing different salts which are commonly found in reservoirs with high salinity were prepared and viscosity tests were carried out to determine how the viscosities of these solutions varied with the concentrations of the salts. The experiments were performed specifically, on mono and divalent cations solutions.
Take or Pay Obligation in Long Term Gas Contract: Risk Mitigation Options for Off-taker
Authors: Green Ovunda , Iledare Omowumi 
Published: July 2015

Abstract
Traditionally, the gas industry is characterised by long-term take or pay (TOP) clause. It is the basis upon which gas is brought out of the ground. However, the absence of an established international gas market and the capital intensive nature of gas infrastructures quite often do discourage investors from committing funds to gas projects. Thus, a well-structured TOP mechanism serves as a guarantor for investors for the recovery of capital investment and favourable return on investment. TOP obligation, therefore, commits the buyer to take or pay for certain minimum volume of gas over the duration of the contract, usually 20 – 25 years.
This paper examines the risk exposure an off-taker can bear under a TOP obligation and how these risks evolve with liberalisation within the contest of the emergence of global spot markets for gas. Empirical evidence tends to suggest that in order to mitigate volume and price risks, sufficient flexibility in the form of renegotiation clause should be introduced into the TOP obligation. This is to enable parties to adjust the long term Gas Sales Agreement in order to accommodate changing market conditions. Further, transition towards shorter term contract has the capacity to reduce the risk faced by the off-taker under a longer term TOP obligation.