bluuebunny/crossref_metadata_2025_split huggingface dataset:
Asphaltene Precipitation Behavior during Gas Injection in a UAE Carbonate Reservoir and a Faster Experimental Strategy to Predict Asphaltene Onset Pressure
Authors: Zhou Yu , Sarma Hemanta K. 
Published: November 2012

Abstract
Asphaltene deposition is a major production constraint in several carbonate reservoirs in United Arab Emirates (UAE). The negative effects of asphaltene include plugging of reservoir formation, wellbore, tubing and surface production facilities and causing shutdown of certain wells. Many of these carbonate reservoirs are likely to be parts of a strategic EOR program through gas injection in the near term. However, as gas injection may further exacerbate the asphaltene problem, it is essential to investigate, as a priori, the effects of gas injection on asphaltene precipitation and deposition and this is the motivation for this study.
A critical analysis of the asphaltene problems to be faced in this particular field was carried out with both HC and CO2 gases as likely injectants under reservoir conditions. In doing so, different gas injection scenarios were studied. The results from experimental studies have been interpreted. The effects of gas injection ratio and depressurization speed on asphaltene onset pressure (AOP) have also been carefully studied. The strategy to adopt an equal-time-stepwise depressurization approach in this study yielded a more reliable result than conventional AOP detection method and also helped reduce the experimental time. In addition, asphaltene precipitation growth history and its nature as solids were studied with the aid of a high pressure microscope (HPM).
The asphaltene onset pressure is found to be affected by the way of system depressurization (frequency and time step magnitude) since it has a direct bearing on the stabilization time. Based on this study, a faster and more reliable method of AOP determination by using light scattering technique with near infrared range (NIR) light was proposed. The AOP of oil depends on the volume of injection for both HC and CO2 gases. It is noted that asphaltene deposition envelope enlargs with the increasing volume of injected gas.
Challenging Rig-less Intervention Succeeds in Severance of Heavy-Walled Tubular
Authors: Qutob A. H , Forsyth G. R , Hassan I. K 
Published: November 2012

Abstract
The objective was to conduct a rig-less tubular cutting operation in an onshore well in Bu Hasa field, operated by Abu Dhabi Company for Onshore Oil Operations (ADCO), for the purpose of retrieving the completion and ultimately re-completing the well.
The 382ft section of blast joints combined with scale build up in the 2-7/8″ completion tubing above the production packer made it difficult to jar and unset the packer and retrieve the completion. The decision was made to cut the blast joint as close to the packer as possible. Several challenges prevented the use of a conventional electric-line deployed chemical cutter service, which include the 85 degree deviation at cutting depth, scale build up preventing accessibility to the target cut zone, the Dual Completion design removed the ability for tubular tension and annular pressure which reduces the chances of noting the telltale indications of a successful cut.
A coiled tubing deployed motor-assisted tubing cutter assembly, preceded by a scale cleanout tool string, were mobilized and successfully completed the objective despite the challenges most notably the wall thickness of the blast joint and deviation at cutting depth. This allowed ADCO to proceed with their workover program.
Proper planning, effective application design and pre-job testing were paramount to the success of the operation. No previous history of any blast joint cuts, therefore this successful cut, coupled with the highly challenging well conditions, demonstrates the ability to conduct future rig-less thru-tubing cutting operations in a similar fashion, reducing operators rig time and associated costs. The technical contribution of this successful test and subsequent job application has potential to save operators a substantial amount of rig time as cost savings by conducting the pipe recover operations as described.
Solving Stick-Slip Dilemma: Dynamic Modeling System Significantly Reduces Vibration, Increases ROP by 54%
Authors: Rahman Norain Abd , Mohaideen Azlan , Bakar Farah Hanim , Tang Kien Hoe , Maury Radha , Cox Paul , Le Phi , Donald Hugh , Brahmanto Edwin , Subroto Bramanta 
Published: November 2012

Abstract
In mid 2010, Petronas Carigali (PCSB) initiated a drilling campaign of a green field development at the Malay Basin, offshore Peninsular Malaysia. The operator is required to drill a borehole through a challenging interbedded formation with hard streaks calcareous to access natural gas reserves in one of the fields. In two development wells, stick-slip reached an unacceptable level increasing the risk of tool failure while driving up field development costs. The operator required an analysis methodology to ascertain the root cause of drilling dysfunction to optimize the bottom hole assembly (BHA) design and drilling parameters to mitigate vibration and improve drilling performance. To solve the problem, a finite element analysis (FEA) based modeling system was employed to analyze application details from the previous two wells and derive an improvement scheme.
Drilling dynamics data and logging information was collected along with operating parameters, mud logs and PDC bit dull grades. Additional problems were identified included hole washout, insufficient WBM lubricity and issues with a reaming stabilizer. An advanced rock-strength analysis system was used to determine unconfined compressive strength (UCS) of the interbedded formation.
Once all issues had been identified, the model was calibrated and readied for dynamic simulation. A variety of BHA configurations and PDC bits were run under different drilling conditions and operating parameters. The results of the simulations provided sufficient insight to the cause of the high levels of lateral and torsional vibration.
Using the knowledge gains, engineers selected the most appropriate PDC bit and BHA configuration. An optimum range of operating parameters with different weight on bit/revolutions per minute combinations were provided to field personnel to ensure the highest possible rate of penetration (ROP) and still remain in the established low vibration window.
The modeling effort proved successful and the third well was drilled with significantly lower torsional vibration compared to the first two wells. This paper will detail the collaboration and integrated approach of the service company in determining vibration issues and solving the problem, hence enhancing the drilling performance of upcoming wells.
Digital Rock Physics and Challenge in Formation Evaluation of Carbonate Reservoir, Case Study
Authors: Gibrata Muhammad A , Ayoub Mohammed R , Kalam M Zubair , Ali Basioni Mahmoud , Al-Amrie Omar Y. , Hendrawan Irfan , Lopez Oliver 
Published: November 2012

Abstract
A project study has been performed in order to evaluate a number of reservoir characterization and petrophysical parameters using Digital Rock Physics (DRP) technology in complex carbonate reservoir, on-shore Abu Dhabi. High-resolution images (X-ray micro-tomographic) of the rock's pores and mineral grains were obtained, processed and the rock properties were evaluated by numerical simulation of the physical processes of interest at the pore scale.
The selection of core samples in carbonate reservoir was performed with considering reservoir rock type, logs and routine core analysis data for validation and application phase. A set of special core analysis (SCAL) data were acquired earlier on the core samples in different carbonate reservoir rock types of varying levels of heterogeneity, lithology, porosity, and absolute permeability. This set of measurements formed the baseline for our validation study, then similar DRP approach and improvement is applied for non-SCAL cores. This process is used in DRP study to evaluate cementation exponents ‘m’, saturation exponents ‘n’, water-oil relative permeabilities, capillary pressures and elastic parameters such as compressional/shear wave velocities.
An integration of core and logs data in particular carbonate reservoir has been used to provide accurate and reliable results in the validation phase of DRP. It has been observed in DRP that connected micrite phase conductivity contribution has been determined for improvement approach by assigning a finite conductivity σmic to the micrite phase to get reliable formation factor, cementation and saturation exponent. DRP and core J-capillary were integrated to provide reliable saturation-heights in this carbonate reservoir. The integration of formation evaluation in this case study has provided improvement, reliability in DRP results for formation evaluation and the potential to improve the quality and timeliness of carbonate reservoir characterization.
Integrated Reservoir Characterization of an Upper Kharaib Carbonate Reservoir from Onshore Abu Dhabi (UAE)
Authors: Rebelle Michel , Duval Christine , Munoz Véronique , Lescoeur Maurice , Rousseau Mathieu 
Published: November 2012

Abstract
More than 30 years of experience in Middle-East carbonate reservoirs has allowed TOTAL to propose an original integrated workflow to characterize sedimentary and petrophysical properties from core and log data in order to populate, propagate and consequently predict the reservoir behavior within a geomodel.
An onshore field from Abu Dhabi has been recently studied with focus on the Upper Kharaib formation. Based on a detailed sedimentology and diagenesis investigation on cores, Petro-Geological Groups (PGG) are defined from both sedimentology, petrophysics, and associated logs responses. Comparison of PGG with Petrophysical Groups (PG), built from discriminant CCA and Pc data through objective statistical contingency and non-linear loops, strengthens the geological significance of the PG which can be considered as static rock-types.
Saturation laws defined from Pc plugs are thenafter compared with Sw resulting from preliminary quantitative interpretation as additional control of consistency between coresand log data.
Supervised facies modelling allows for the vertical distribution of these PGG throughout the non-cored intervals.
Permeability modelling is also an important step in order to deliver a permeability field within the geomodel. This small scale permeability (issued from the cores and logs) is compared with large scale permeability (from well tests) to insure reconciliation between the two scales.
PGG maps are delivered for each reservoir layer, associated petrophysical properties can be consequently propagated in 3D.
This powerful integrated workflow, relying on a comprehensive integration of all available data at different scales, has been successfully applied for geomodelling issue, allowing for both the understanding and the prediction of petrophysical properties distribution, with a strong relationship between Petrophysics and Geology at core and log scales. This approach gives significant support for the defining and capturing of key flow units heterogeneity and distribution.
Managing the Corrosion Impact of Dense Phase Co2 Injection for an EOR Purpose
Authors: Bonis Michel 
Published: November 2012

Abstract
A review of the main corrosion issues and of the associated corrosion control methods is made in a situation where CO2 is injected as a dense phase at high pressure for an EOR purpose on oil fields. Two distinct sources of CO2 are considered, either from produced gas or from flue gas, i.e. with more detrimental impurities being present.
The use of CO2 from flue gas requires that the so-called NOx and SOx are removed as soon as possible to prevent very serious corrosion problems or very stringent dehydration requirements. Even more constraining can be the necessity to remove the oxygen: although the presence of oxygen is not critical on the injection side, its eventual breakthrough to production facilities will pose dramatic corrosion problems on both C Steel and CRA facilities. As a consequence, until it can be demonstrated with a high level of confidence that this oxygen is totally consumed in the reservoir before reaching producing wells, a prudent approach consists in removing it from the injected CO2 down to about 100 ppm mol.
Apart from these particular aspects related to the use of flue gases, no serious and unconventional corrosion and mitigation difficulty is foreseen on the CO2 injection side when only CO2 is injected. In particular, the dense phase network can be designed in C Steel as long as no free water may separate from the dense CO2. This condition is quite easy to assure in most cases, thanks to the high water solubility in CO2 at high pressures. On the other hand the injection of a mixture of produced water and CO2 at high pressure obviously poses more serious corrosion issues requiring a CRA network along the whole injection network subjected to the mixture.
The proper evaluation of all these corrosion aspects finally requires having in hands the most relevant prediction models, not only in the corrosion area but also in the thermodynamics of dense CO2 mixtures with impurities and in the reservoir modeling area: it is indeed essential accurately predicting how the injected products will move back to production facilities and possibly impact the production side.
A New Fracture Gradient Prediction Technique That Shows Good Results in Gulf of Guinea
Authors: Oriji A. Boniface , Ogbonna Joel 
Published: November 2012

Abstract
One of the major challenges of drilling and completion of oil and gas wells is the uncertainty in the formation fracture gradient and the fracture pressure. It is not uncommon that many drilling companies have spent money, resources and time in drilling and completing wells that should have been simply and optimally done. Fracture gradient evaluation constitutes one of the essential parameters in the pre-design stage of drilling operations, reservoir exploitations and stimulations. Several calculation methods and computer models have been presented in the literature for different regions of the world. Most of these techniques were based on either parametric or empirical correlations, which required a prior knowledge of the functional forms or the use of empirical charts which were not very accurate.
This paper presents an innovative method of predicting formation fracture gradient for Gulf of Guinea region. A combination of "Mathew and Kelly" correlation, "Hubbert and Willis" correlation and Ben Eaton mathematical models were used in developing the simplified technique based on field data from the Gulf of Guinea. The model compared favorably with the existing fracture gradient results in the Gulf of Guinea with less than 1 % deviation from other correlations thereby saving the rigors and time in using tables, charts and other long techniques. Although the method was developed specifically for the Gulf of Guinea, it should be reliable for other similar areas provided that the variables reflect the conditions in the specific area being considered.
Innovative Scheme for Crude Oil Stabilization Using Condensate
Authors: Agrawal Dinesh , Huda Badrul 
Published: November 2012

Abstract
For a new sour field development, the scheme for crude oil stabilization is designed using condensate as stripping agent in the crude oil stabilizer in place of conventional scheme using sweet fuel gas. The article discusses the scheme and its advantages compared to other industry practice of ‘Reboiled Stripper’ for Crude Oil Stabilization.
The design is based on splitting of gas condensate produced during gas compression in to heavy cut and lights in a condensate splitter operating as a distillation column. The lights are recycled back in to the gas compression for gas injection while heavy condensate is vaporized and used as stripping agent in crude oil stabilizer.
The benefits are higher oil volumes with some improvement in oil API achieved through ability to mix higher fraction of the condensate produced in to oil, while maintaining Reid Vapor Pressure (RVP) and Hydrogen Sulphide (H2S) Specifications for oil export.
The scheme eliminates light condensates drying and pumping for injection in to reservoir as it mixes it with gas for injection and a common gas drying and compression system can be used for injection in to reservoirs. Also instead of boiling crude at higher temperatures in the reboiler of crude oil stabilizer which is the case for the ‘Reboiled Stripper Scheme’, clean condensate vapors are used for stripping H2S and light hydrocarbons in crude stabilizer with operations at near 100°C.
This will reduce the system fouling while providing higher plant availability by eliminating reboiler from the Crude oil Stabilizer. The estimated Capital Cost is lower in comparison to other schemes.
Thus the design gives a simplified scheme for simultaneous processing of condensate with crude oil stabilization, producing oil in quantity and specification similar to the ‘Reboiler Option’ while providing additional bebefit of lower CAPEX with higher plant availability.
Evolution of the Smart Production Testing Strategy in ADMA-OPCO
Authors: Al-Hosani M. A. , Khan M. N. 
Published: November 2012

Abstract
With time increasing maturity of hydrocarbon reservoirs is adding more challenges to reservoir management strategies. To enhance the understanding of complex hydrocarbon recovery mechanisms, frequent production testing programs have become a crucial part of the reservoir management cycle.
Abu Dhabi Marine Operating Company (ADMA-OPCO) has been continuously working on improving its offshore production testing capabilities to bridge the gap between the current practice and the increasing demand for production testing.
In this regard, a multidisciplinary taskforce evaluated three different options: Refurbishment of the existing production testing facilities, addition of a Test Vessel in the mobile testing fleet and the installation of permanent Multi Phase Flow Meters (MPFM) on different wellhead towers.
Based on the operational flexibility, better measurement accuracy and the low operating cost, the installation of the permanent MPFM on different wellhead towers was qualified as the most viable option. This strategic decision brought a significant gain of 36% in the production testing performance in the first year of implementation (2011).
The aim of this paper is to highlight the key milestones from a real implementation case during the process of adopting the smart production testing approach by ADMA-OPCO, which can be used as the reference guide for different oil operating companies that would be willing to take up the similar practices.
Robust Maximum Reservoir Contact Pilot Well Design, Optimization and Implementation for Development of a Giant Oilfield
Authors: Khedr Osama , Al Marzouqi M. , Jackson Alfred , Ibrahim Muhammad , Nadeem Muhammad 
Published: November 2012

Abstract
The first Maximum Reservoir Contact (MRC) wells for a major operating company offshore Abu Dhabi have been successfully designed and implemented. In this paper, the design, optimisation, piloting, field implementation, and post-job field data evaluation for the most critical well are discussed.
The re-development strategy for the company hinges on the move to an islands-based development concept. This concept dictates that a significant number of wells be extended reach, long horizontals to maximize reservoir contact and exposure.
The increased reservoir exposure will translate proportionally to accrued production (or injection) benefits and value, balanced reservoir sweep, and maximizing recoveries.
Hundreds of these MRC wells will be ultimately needed, to maximize recovery and drive the field daily production output from the current level to an increase of at least fifty per cent. However the challenges of designing, drilling and completing these complex wells are new to the operating company.
The operator embarked on a program of drilling pilot wells with a view to establishing new learning and understanding, which translates into efficiently designing, deploying and operating these wells for the field re-development.
The paper shows the methodologies employed for one of these pilot wells, right from the concept stage through to the modelling, design and optimisation. It also shows how operational considerations were fed into the optimisation workflow, and how the resulting design was implemented in the field.
The obtained field measurements such as resistivity, fluid mobility, production logging, production rates were compared to the initial design and performance forecasts, and excellent conformance is demonstrated, further validating the robustness of the implemented designs.
The paper highlights the lessons learnt from this exercise, and also proposes a recommended methodology for approaching and adopting the design and implementation of advanced wells, within oil and gas producing assets.
Interfacial Tension (IFT) and Surface Alteration Interplay
Authors: Stukan Mikhail , Abdallah Wael 
Published: November 2012

Abstract
The two main parameters required to assess an enhanced oil recovery (EOR) technique in terms of its efficiency are interfacial tension and surface (wettability) alteration. The impact of these parameters on recovering what is left in the reservoir is crucial. With the current interest in brine injection as a potential-EOR method, the role of IFT and wettability alteration needs better understanding. In this study, a theoretical model is developed to evaluate the impact of both parameters. The results of this study indicate that salinity injection affects more surface wettability rather than interfacial tension.
Conventional techniques of contact angle measurements on reservoir rocks at downhole conditions are very complicated. They are highly sensitive and require good core preservation and preparation. We propose a protocol to measure contact angle dependence on brine salinity, which includes a single contact measurement in rock/brine/oil system using fresh water and a set of less complicated measurements in brine/oil and rock/brine/air systems. The results of our predictive protocol for contact angle measurements are in very good agreement with conventional experimental measurements using glass/brine/dodecane system. The fact that simple contact angle measurements on the surface in air are required to calculate contact angles at different salinities makes the utilization of this protocol very attractive and less sensitive to surface preparation and its complexity.