bluuebunny/crossref_metadata_2025 huggingface dataset:
Bio-Derived Porous Graphitic Carbon as Highly Efficient Mercury Scavenger from Natural Gas Streams
Authors: Edathil Anjali Achazhiyath , Kumar Reddy K. Suresh , Pal Priyabrata , Srinivasakannan C. , Banat Fawzi
Published: November 2017

Remediation of toxic mercury emissions in the form of elemental mercury (Hg°) from the well head has become a dire necessity in the fast paced natural gas processing industries, as even low levels of mercury can damage the cryogenic aluminum heat exchangers and other plant equipment. Also, enforcing stringent measures to reduce the effect of elemental mercury is of great environmental concern owing to its high toxicity, volatility, chemical inertness and neurological health impact. Thus, synthesis of efficient and cost-effective porous carbon based sorbents having high selectivity and sorption capacity has attracted considerable interest, and is a widely used and industrially preferred technique. The present work focuses on the development of low cost and biomass derived graphitic carbon as a potential candidate for scavenging mercury from natural gas processing as well as refining operations. The bio-derived porous graphitic carbon (PGC) material was fabricated through a facile and sustainable method, from the natural biopolymer (calcium alginate) by pyrolyzing at 900°C under an inert atmosphere. The performance was examined by testing the graphitic carbon in a bench scale setup and using simulated environment mimicking the plant conditions. The adsorption results show evidence that accessible high pore volume, hierarchical pore structure, coupled with long range ordering enables the proposed PGC as an efficient low cost adsorbent for removing elemental mercury from natural gas. The high adsorption capacity of 626 μg/g exhibited by the graphitic carbon at an adsorption temperature of 50°C, outperformed the leading porous carbon currently used for gas phase mercury removal. Also, the increasing cost of conventional sorbents make these poly saccharide based biomaterials an attractive candidate. All these findings demonstrate the promising solutions offered by PGC for scavenging elemental mercury from natural gas.
Building Variable Saturation Height Functions with an Improved Rock Typing Scheme
Authors: Kundu Ashish , Voleti Deepak Kumar , Rebelle Michel , Al Housani Habeeba Ali
Published: November 2017

The studied lower Cretaceous carbonate ramp deposits are heterogeneous with pervasive diagenetic processes leading to complex pore network and rock texture. Before this study, field development was based on log based water saturation modeling. This saturation modeling was dependent on the hydraulic flow units and porosity classes, which was meant to be, but was not explicitly representative of the defined geologic facies. The assignment of the relative permeability data is also very challenging in the absence of proper Rock Type model. Often in carbonate reservoirs, there is no direct or linear relationship between Reservoir Rock Types (RRT), sedimentological facies assemblages and water saturation distribution across the field. Hence, accurate integration of the sedimentological, diagenetic, depositional environment information and petrophysical properties is essential in building a robust RRT model. This RRT model can then explain the rock-fluid interaction through a reliable saturation height model.

In the first part, the paper illustrates the workflow which involves integrating lithofacies, depositional packages, degree of cementation, pore-type from sedimentology and relating resultant pore-typing to core porosity–permeability data. This workflow resulted in a strong reservoir rock typing scheme, which was key in building a robust saturation height model. Precisely, this was achieved by assigning "most-of lithofacies and diagenetic indicators" to each rock type defined. In the second part, a Variable Saturation Height Function (VSHF) was developed using mercury injection capillary pressure (MICP) data. The function was made variable with depth by bringing one or both of the reservoir parameters (Phi and K) into the equation. Most importantly, VSHF explicitly scans the lower and upper Sw boundary of a particular rock type and helps in removing the skewness in the Sw difference histogram between model and log Sw. One of the important steps in the workflow was to normalize the MICP data to log derived Sw values, provided the confidence on the Sw calculation from logs is high. After stress and closure correction, the normalization of the reservoir Pc data was achieved through an independent correction factor.

Both of the workflows (rock typing and saturation height modeling) were built based on data from 30 cored wells. The workflows were tested on 15 cored wells and more than 600 non-cored wells. Rock type maps were found to be more correlatable with reservoir quality maps than lithofacies maps alone. This is a result of the diagenetic processes undergone by the rock during and after deposition modifying the original depositional controlled pore architecture. With this approach the water saturation distribution was more consistent with logs and core derived Sw data.

The workflows shown in this paper are reliable and can be extended to other carbonate fields’reservoir characterization.
A Case Study on the Development and Implementation of a Software Assisted Pipeline Integrity Management System
Authors: Qasim Muhammad , Spencer Kevin , Rao Girish
Published: November 2017

This paper is a case study relating to the development and implementation of a pipeline integrity management system (PIMS) for a major pipeline operator in the Middle East. This paper provides an overview of the project and underlines the practical steps and systems adopted by the operator in order to maintain the integrity of their pipeline network.

A successful and effective integrity management requires a comprehensive support system. As a minimum, that system must address people (organized teams of various disciplines contributing to the overall objective i.e. pipeline integrity management), process (standards and policies on how to achieve the objective) and tools (resources to achieve the objective such as software) to manage the pipeline integrity. This paper describes the development and implementation of a geospatial pipeline data model, supported by a software system which fulfils the PIMS support requirements and is aligned with pipeline integrity management industry best practices and international codes and standards.

The paper explains the importance of gathering accurate data in the development and implementation of PIMS. The paper highlights the challenges faced during the PIMS implementation stage and how these were resolved through collaboration with the various stakeholders. For example, the paper discusses data completeness difficulties commonly faced for older pipelines and provide practical solutions for data maintenance and information reliability (e.g. interviews of personnel, documentation of methodologies and engineering judgments agreed by stakeholders, etc.) which provides consistent application of integrity procedures.

The paper further details how the PIMS assisted the operator in maintaining the safe operation of their pipeline network in compliance with international codes (i.e. ASME B31.8S and API 1160) and industry best practices.

The paper explains the practical steps adopted and could be used as a road map for development and implementation of PIMS by other operating companies.
Gas Injection Optimization in a Giant Offshore Carbonate Field and Impact on Field Development Plan. Case Study
Authors: Ahmad Fazeel , Sarsekov Arlen , Iwama Hiroki , Saif Omar Yousaf , Abed Abdalla , Al-Naeimi Ahmed Khalifa
Published: November 2017

Gas injection is a part of secondary recovery factor to improve reservoir sweep efficiency and recovery factor. However defining optimum gas injection rate in a multi layered heterogeneous carbonate reservoirs is a big challenge and any deviation from optimum gas injection rate can cause fast Gas Cap expansion or fast reservoir depletion.

Proper dynamic synthesis of the multi layered reservoir was performed. Openhole logs and available cased hole logs were QCed and reinterpreted for better undestanding of fluid movement. Efficient gas injection rate for each string and balance between water injection and gas injection were evaluated.

Gas tracers study was carried out by injecting gas tracers into gas injection wells. The results of the study were used for optimizing the gas injection strategy.

As a result of overall gas injection optimization, a positive impact is observed on the total field gas production rate or total field GOR which has been reduced and many oil wells became active resulted in additional oil production gain.
A Smarter and Cost Saving Approach for Inhibited Hydrotest Water for Large Storage Tanks Commissioning
Authors: Sabry Houssam
Published: November 2017

This paper describes how demineralized water was substituted using inhibited sea water for hydro testing large capacity storage tanks and the huge cost savings achieved in the process.

ADGAS built two new Paraffinic Naphtha Tanks in 2014-2016. The tanks are of double walled doubled deck floating roof construction. The holding capacity of the tanks was approx. 50000m3.The tanks were to be hydro tested before commissioning. The volume of the Hydrotest water used was 50000 m3 for inner tank and 10000 m3for the annular space between the walls hence totaling 60000 m3for one tank.

Demineralized water was the primary choice for Hydrotesting. Minimum cost of desalinated water for testing one tank would be USD 222000 (USD 3.7x60000). Utilizing a conventional multifunction inhibitor would cost approximately USD 1.2 Million for both tanks. ADGAS used a newly developed floating corrosion inhibitor that would only wet the surfaces to be protected. Cost of this innovative chemical is only USD 11000/tank.

The corrosion inhibitors used was a float coat mixed with oxygen scavenger. Float Coat inhibitor is a biodegradable, nitrite and amine free, and environmentally acceptable for use. This was spray/brush applied on the tank walls for surface protection. Sea water was deoxygenated using an oxygen scavenger and gradually filled in to the tank. The floating properties of the inhibitor ensured uniform reach of the inhibitor.

Total cost savings achieved:

Cost of demineralized water: 222000×2= USD 444000. (Both tanks)

Cost of chemicals: Float coat USD 11000/tankOxygen scavenger USD 49800/tankTotal: USD 60800/tank

Total cost of chemicals for two tanks: 60800× 2= USD 121600.

Savings: 444000+ 1200000-121600 = USD 1321600
Effective Insertable Progressive Cavity Pump Anchor Optimizes Workover Costs
Authors: Sultan A. , Khalil M. , Attar I. , Gazi N. , Al-Sabea S.
Published: November 2017

As oil and gas fields are depleted, artificial lift (AL) systems are often required to maintain delivery volumes and to maximize recovery. To handle adverse conditions, such as high viscosity oil, high water cut, sand, low reservoir pressures, high temperatures, low productivity wells, and high angle wells, special AL systems may be required.

In highly productive Burgan reservoirs, high water production is a major issue in both vertical and horizontal wells thus requiring AL systems to maximize the oil recovery. Unfortunately, there are pump failures or getting stuck due to changes in the well condition or uncertainties. Replacing the failed pump needs more cost and availability of rigs.

Conventional PCPs are installed by running the stator assembly on the bottom of the tubing and the rotor on the bottom of the rod. In case of malfunction in the system due to change in the well condition may lead to pump failure and its replacement.

Besides production losses during the pump failure, the availability of the workover rig is a major issue. This led to go for new innovation and technology to restore the production and minimize the cost especially at current low oil price environment.

A new Anchoring device for insert-able PCP can be run in the well without using any rig. The use of the anchors eliminates the need for the pump seating nipple, thus removing the need of pulling tubing to install or change the setting depth.

Moreover, by having retrievable seating mechanism, changing the setting depth of the pump can be done by un-seating the anchors and re-seating those at the new desired setting depth. This is beneficial in wells with dynamic and changing fluid levels.

The insert-able pump anchor also can be used where tubing has a hole near the pump seating nipple, or have a problem with the completion like damaged AL system. The insert-able pump anchor allows the user to select the best pump seating depth after the well is completed and tubing has been run.

In this particular well, PCP was stuck, rod was broken, production was stopped, and loses were increasing. To restore the production, reduce the cost and time, insert-able PCP anchor was run at certain depth after punching the tubing in order to allow for a new pump intake zone and landed the anchored pump above the punched area. This system eliminated costly and time consuming tubing pulls with workover rig to change damaged pump and thus saved money. The well went back to production in short period of time after this procedure and showed good performance.

This new and innovative system and procedure can be used in similar well conditions in other fields to save time and money to create additional value.
Thirsty Reservoirs - Challenges in Drilling Through Severe Lost Circulation Zones
Authors: Gooneratne Chinthaka P. , Gomez Gonzalez Ernesto S. , Al-Musa Abdulaziz S. , Osorio Hugo F.
Published: November 2017

In this paper, we present a thorough analysis of drilling methods and fluid and mechanical solutions to mitigate lost circulation (LC), as well as risk control measures undertaken, while drilling 5 wells on two platforms with severe LC zones in the reservoir. The drilling rate of penetration (ROP) was significantly reduced compared to the ROP utilized in the sections above the reservoir, along with the pump rate, to minimize enhancing fractures in a highly permeable zone. A combination of bridging, cement and resin based materials were also used in the 5 wells to mitigate and partially/fully cure losses. Risk control measures included only having a maximum of two rigs drilling in the reservoir section at the same time, rig capacities to sustain bad weather without support from boats, each rig in the vicinity having barite, lost circulation materials (LCM), and other resin based LCM materials available and having cement retainers (CRs) on standby and using them not only when curing losses but also to secure the well in the event mud/barite/chemicals on the rig could not sustain hole filling during bad weather.

Even though the losses were not completely cured in wells B and E, which led to the cessation of drilling operations before reaching the planned total depth, the LC mitigation methods used ensured access to 20 % of the net payzone in well B and 30 % in well E, a significant achievement in such severe LC zones. Evaluation of three fluid solutions used to mitigate losses showed that spotting cement through a cement retainer (CR), set close to the previous casing shoe, gave a higher possibility of curing losses compared to conventional LCM resin based LCM and directly spotting cement on loss zone with open ended drillpipe (OEDP).
Diagnosis and Treatment of Sinking Ground
Authors: Perumal K. , Adel K. , Al Awadhi I.
Published: November 2017

Ground settlement in PLANT areas are major concern as it might affect integrity of structures and safe operations. In a recent incident at GASCO Sulphur Handling Terminal (Ruwais), substantial ground settlements were observed at sulphur granulator unit area which affected nearby foundations/structures. Various reasons can contribute to settlement issue and this paper presents the methods employed to determine the root causes, assessing the impact on existing structures/foundations and identifying corrective actions required to ensure safe operation.

A detailed study was carried out to ascertain the extent of settlement and to identify the reasons. In order to assess the severity of settlement and its pattern, topographical survey was performed. Geotechnical investigations including boreholes, trail pits with associated field & laboratory tests were executed to study the ground conditions, soil chemistry, collapse potential and strength characteristics of ground. Equipment vendor were also consulted during various stages of study to discuss allowable operational limits. Study results revealed the root cause of ground settlement and appropriate remedial methods were finalized considering techno-economic factors.

Topography results determined the affected foundations/structures and settlement extent. Geotechnical investigation findings indicated that the settled area is a reclaimed land consists of dredged hydraulic fill. The fill material was poorly compacted calcareous soil, contains high proportion of carbonates & gypsum. Carbonate sand is susceptible to dissolve in presence of acidic water & has collapse potential properties. Leaky chemical drain channels were noticed at affected locations.

Many possible causes of settlement were analyzed and evaluated based on investigation results. It is concluded that principal root cause of the settlement is leakage of acidic/non-acidic water from drain channels into ground which had weakened and consolidated the calcareous soil.

Static and dynamic analysis were performed for settled foundations/structures to ensure its stability under various potential loading conditions. Necessary modifications and repair work details are finalized based on analysis results. To avoid further settlement, various options for ground improvement are studied including compaction grouting, underpinning of foundations, jacking/relevelling of super structure, compensation grouting & replacement of foundations.

Study outcome showed that ‘compaction grouting’ is most suitable & economic long term solution. This method involves drilling and injection of vertical and inclined holes in the ground at affected areas with high pressure grouting and thus displace & compact the soil to prevent settlement.
Soft-SAFT Equation of State as a Valuable Tool for the Design of new CO2 Capture Technologies.
Authors: Crespo Emanuel A. , Amaral Mónique , Dariva Claudio , Carvalho Pedro J. , Coutinho João A. , Llovell Fèlix , Pereira Luis M. , Vega Lourdes F.
Published: November 2017

The design, simulation and/or optimization of new processes rely on the availability of robust and accurate models or equations of state (EoS). However, traditional cubic equations of state (EoS’s), traditionally used in many process simulators, fail on describing complex polar and associating behavior of some molecules, leading to unreliable results and hence, poor design and optimization. This problem can be overcome with the use of robust, reliable equations of state. This work belongs to a long term project assessing the performance and usefulness of an advanced EoS (soft-SAFT), as a valuable tool for the description of highly non-ideal systems and thus, for the reliable simulation/design of new technologies.

We focus here on assessing the validity of soft-SAFT, a molecular-based EoS, for the development of novel technologies for CO2 capture using polyether blends as solvent. Within soft-SAFT polyether molecules are modeled as chains with end-groups having an association site, explicitly mimicking the hydroxyl end-groups. The study comprises polyethers, including glymes, and their mixtures with CO2 at different conditions. It is shown that soft-SAFT is able to successfully describe the thermodynamic behavior (e.g. vapor pressures and liquid densities) of these solvents in wide temperature and pressure ranges. Moreover, by explicitly considering the quadrupolar moment of CO2, and using one, temperature and pressure independent binary interaction parameter, an accurate description of the gas solubilities in several polyethers was achieved. For glymes, which among polyethers exhibit the highest CO2 solubilities, such parameter was found to correlate with the molecular weight of the solvent. Finally the equation was used to predict the thermal and pressure cycle capacities of the different solvents. Results presented here reinforce the use of soft-SAFT as a reliable tool for solvent screening, offering reliable predictions of phase equilibria and solubility behavior in a wider number of systems.
Youth Development Through Competence Assurance Management Systems
Authors: Al-Harbi Abdulla Ahmed , Shokry Karim S. , Al-Marzooqi Abdulla Juma , Ali Adeib
Published: November 2017

YOUTH DEVELOPMENT PROGRAM (YDP) Objective/ Scope

The Youth Development program is an unprecedented approach in the region for fresh graduate and non-graduate employees who join the ADNOC group that takes them through a natural career progression. The YDP is suite range of comprehensive well-structured competence development programs that guides and enables YDP Entry Point Employees to develop their competencies while performing their roles and responsibilities safely, effectively and efficiently.

The YDP covers two sub Competence development programs for Graduate and non-Graduate employees. Competence Assurance Management System (CAMS++) introduced as an improved and single unified Competence Development Program for Graduate employees.

It enables consistency and fully supports performance-driven culture where all Graduates are accountable for delivering clear and measurable results that add value to the organization.

CAMS++ is for fresh university Graduates (Bachelor and Master Degrees), who enter at Grade 11 in ADNOC. Graduates following a technical program will be progressed to a target position at Grade 13 after completing the program, while for some support functions the target position will be at Grade 12. This procedure applies to all Graduates entering ADNOC Group in both Technical & Non - Technical Disciplines.

In order for a business to be successful, attention needs to be given to the performance of its people. More specifically, for management to have reasonable assurance of meeting their business objectives, they need to be assured that the workforce is competent. For the individual, tools are required to assist him/her to attain skills, to enhance personal development and career progression, and to take personal responsibility to drive his/her own career in order to compete for job opportunities across the ADNOC Group.

Primarily CAMS++ has been designed to support the overall objectives and Values of the ADNOC over and above the numerous benefits it offers to the young graduate for his / her personal development In alignment with ADNOC vision, the CAMS++ will enable consistency and fully support performance- driven culture where all Graduates are accountable for delivering clear and measurable results that add value to the organization.

Below is a quick demonstration of how CAMS++ is contributing towards each of the ADNOC Values. This is an essential part of the business need both in short and long term for both the organisation and the graduate. CAMS++ helps to fill the gap between the actual and the expected, it creates a bridge between the graduate and the organization under the supervision and guidance of the veteran performers and seasoned domain experts to ensure a smooth transition from a fresh graduate to independent employees in the least amount of time
Innovative Approach of Reviving Water Injectors with Minimum Cost Investment and Maximize Production Offtake. Case Study
Authors: Sarsekov Arlen , McNeilly Kevin
Published: November 2017

Water injection is a part of secondary recovery factor and it helps to sustain reservoir pressure and maximize production offtake. In the offshore environment, water injectors are injecting sea water. This paper will show how to revive water injectors without utilizing the conventional stimulation and minimize the cost if investment.

Back flow of water injectors is one of the methodologies to increase injectivity index for water injectors as the main source of injection degradation is poor water injection quality, not chemical reaction inside the formation.

This paper will show the source of the water injection degradation along with "Back Flow" methodology and improvements after it.
Optimizing Cost and Restoring Integrity with the First Saudi Aramco Mechanical Descaling Using a Wireline Torque Action Debris Breaker Tool
Authors: Al-Ghamdi Abdullah A. , Zefzafy Ibrahim M. , Al-Malki Mohammad H. , Turner Russell
Published: November 2017

This paper aims to address the great success of utilizing the torque action debris breaker (TADB) tool as a wireline mean to restore wellbore accessibility. The tool was trial tested to remove hard scale accumulation consisting of 95% Iron compounds. Iron compound scale are generally among the most difficult types of scale to be removed by chemical means as historical data showed high failure rate in terms of succeeding to eliminate wellbore blockage. Subsequently, wells have to be treated mechanically using an extensive and costly solutions such as coiled tubing (CT) milling operation to allow for accessing the wells for routine surveillance. Instead, a simple, innovative, and cost effective TADB tool was deployed using a slickline unit. This tool can be conveyed with different sizes of cutters to allow for optimum scale removal and is activated via downward jarring action. Throughout the entire length of tubing, hard Iron compound scale bridges were removed from one oil producing well and well accessibility was restored. The tool contains a unique helical sub which applies a rotational torque with each downward jarring action with cutters designed for maximum cutting capabilities that is safe to internal completion sections. During the trial test, TADB tool was deployed with 1.875" wireline string with two cutting sub sizes and removed accumulated scale inside the 4 ½" tubing in just 12 hours operation. The rotational movement of the tool maximizes the removal and cutting rate which was in the range between 230 to 1,600 ft. /hour depending on size of the cutting sub. Field trial has shown that increasing the size of wireline string increase the TADB tool weight and operational functionality which should translates into higher cutting rate and operational efficiency. The implementation of this technology has generally optimized operational cost compared to lengthy and costly CT operation by minimizing foot print, equipment, manpower, job duration, and provide a more environmentally friendly solution.
Coupling Geostatistics and Rock Physics in Reservoir Modeling and Characterization
Authors: Azevedo Leonardo , Amaro Catarina , Grana Dario , Soares Amílcar , Guerreiro Luís
Published: November 2017

Data integration is a key step in reservoir modeling and characterization. If done properly, the integration of different sources of information about the subsurface petro-elastic properties of interest allow a better description of the reservoir while accounting for existing uncertainties. Under this scope, geostatistical seismic inversion techniques have been successfully applied to integrate seismic reflection and well data for seismic reservoir characterization. Depending on the available seismic reflection data, these geostatistical modeling techniques allow inferring acoustic and/or elastic spatial distributions of the the subsurface. The resulting elastic models are then used as secondary variables to infer the petrophysical properties (e.g. facies, porosity) of the reservoir. Consequently, these petrophysical models are not directly constrained by the existing seismic reflection data and the uncertainties related with the seismic inversion problem are not properly propagate during the entire geo-modeling procedure. This work introduces a framework to incorporate rock physics modeling within conventional pre-stack iterative geostatistical seismic inversion methodologies. The proposed technique allow inverting from pre-stack seismic reflection data directly for facies, porosity and pore fluid. This technique is based on three main concepts: i) the model parameter space is perturbed using stochastic sequential simulation and co-simulation; ii) a statistical rock physics modeling technique is used to link the elastic and petrophysical domain within the inversion procedure; and iii) the use of a global optimizer based on cross-over genetic algorithms driven by the mismatch between real and synthetic seismic reflection from iteration to iteration. This work illustrates the successful application of the proposed iterative geostatistical seismic inversion technique to a real dataset. The retrieved petro-elastic models are simultaneously, and consistently, conditioned by the well-log data, seismic reflection data and the reservoir geology (i.e. pore geometry) as expressed by a rock physics model.
Experimental Data Acquisition and Modeling for the Study of Miscible CO2 WAG in Carbonate Reservoirs Under Oil-Wet Conditions
Authors: Joubert T. , Duchenne S. , Bourgeois M. , de Loubens R. , Petitfrere M.
Published: November 2017

Prediction of miscible WAG performance relies on proper calibration of thermodynamical and petrophysical models. Swelling, miscibility and stripping phenomena must be captured in the equation of state (EOS) and the oscillations of gas and water saturations require using history-dependent relative permeabilities. This paper presents data synthesis and numerical interpretation of a complete experimental program including bulk PVT measurements, horizontal coreflood experiments at reservoir conditions and a spontaneous imbibition test.

Prior to flooding experiments, CO2-oil phase behavior was characterized through swelling test, slim tube, multiple contact test (MCT) and supercritical fluid extraction (SFE) to provide a reliable equation of state. Coreflood experiments were conducted using carbonate outcrop cores, carbonated water, undersaturated live oil from a Middle East field, and multiple contact miscible CO2. Produced gas and oil were experimentally separated at reservoir conditions. X-ray monitoring was carried out. The experimental data were matched using our in-house research reservoir simulator (IHRRS) and an optimization module.

We used the classical and an extended version of Larsen & Skauge relative permeabilities model, coupled to our calibrated equation of state (EOS) slightly corrected with alpha-factors to impose the residual oil saturation. Spatial variations of remaining oil were observed, with a minimum achievable oil saturation of 7 %. The condensate produced by stripping and the oil produced by mechanical sweep were matched separately. Two-dimensional simulations were performed to take into account gravity segregation, evidenced by in-situ saturations measurements. We found an acceptable history-match for each three-phase experiment individually. Significant relative permeability hysteresis was observed for both gas and water phases. Some of the three-phase parameters were found dependent on saturations path and not compatible for simultaneous history-match of multiple experiments.

This paper provides a robust methodology for miscible CO2 WAG experimental data acquisition and history match. The hypotheses and limitations of the relative permeability model were stated: for instance, trapped water saturation may be introduced. A new hysteresis model was developed allowing for water trapping, which improved the quality of the history match of the experimental observations.
Evaluation of Viscously Unstable Water Flooding with Gravity Effects and Permeability Heterogeneities Through High-Resolution Simulations
Authors: Vaillant G. , de Loubens R.
Published: November 2017

This paper aims at evaluating the interactions between gravity segregation and viscous fingering during water injection into viscous oils, in order to estimate the recovery factor accurately, e.g. before assessment of tertiary EOR mechanisms. Based on simulations of homogeneous and heterogeneous reservoir sector models with horizontal wells, we wish to identify the dimensionless groups affecting the water breakthrough time and the oil recovery, and to quantify the impact of viscous instabilities in 3D domains versus 2D vertical cross-sections.

High-resolution numerical simulations, based on very fine grids and a high-order spatial discretization scheme implemented in our parallel in-house research reservoir simulator, were required to properly capture the complex flow patterns of these two-phase immiscible displacements. We analyze the competition between viscous and gravity effects using different values of injection flow rate, oil viscosity, density difference between oil and water and domain aspect ratio. This analysis is carried out in 2D and 3D, for simple permeability distributions with different correlation lengths, by inspection of production data and saturation maps.

For the investigated range of parameters, capillary effects are negligible and we identify three flow regimes before water breakthrough. When gravity dominates, viscous fingering is strongly attenuated by the rapid formation of a gravity tongue but a ‘ridge instability’ phenomenon may occur. In contrast, when viscous forces are preponderant, the gravity tongue is very weak or non-existent, and the flow pattern in vertical cross-sections is often characterized by one dominant viscous finger. In the transition regime, the gravity tongue and the viscous fingers coexist and may reach the producer quasi-simultaneously, leading to an optimum injection velocity in terms of breakthrough sweep efficiency. We then examine the dependency of water breakthrough and oil recovery upon the end-point mobility ratio and the viscous-to-gravity ratio Rv/g=(μoUkvΔρg)HL. We also compare the early-time and late-time impacts of permeability heterogeneity and transverse viscous fingering.

In the context of viscous oil recovery by water injection, high-resolution simulations are required to represent the interplay between gravity segregation, viscous fingering and permeability heterogeneity. In the present study, under low capillary effects, it is quite remarkable that the post-breakthrough recovery is well predicted by 2D simulations and is mostly controlled by two dimensionless groups. This may be useful to create screening models for quick-look estimation of oil recovery on different sector models representative of an oil field.
Preserving and Securing Legacy Well Log Data
Authors: Pankaj Purohit , Fatema Al Nuaimi , Pranav Kumar , Amit Kumar
Published: November 2017

Well logging is the process of recording various petrophysical, properties of rock/formations penetrated by drilling tools. Log responses are functions of lithology, porosity, fluid–content and textural variation of formation. This information coupled with characteristics of sedimentary structures derived from high resolution dipmeter surveys provide detailed insight into the sedimentary environment and allows estimation of the reservoir geometry & orientations.
The Ideal approach for casing leak repairs in Old wells
Authors: Al-Dossary Abdulla Faleh , Al-warthan Abdulasalm , Al-Badran Mohammed , Al-Ghamdi Ibrahim S. , Mutawaa Wessam
Published: November 2017

Casing leak is one of the major reasons for wells to be worked over in oil fields. It has a negative impact on well production and might damage the productive zone depending on the leak severity, well completion configuration and well integrity. It is also detrimental to well hardware and safety. In the worst case scenario hydrocarbon reaches the surface causing an environmental spill and the well has to be plugged and abandoned. Most of the reported casing leaks occurred due to corrosion are the result of poor cement and long exposure to corrosive gases. Other reasons for casing leaks could be drill pipe wear, damaged casings owing to improper torque up practices, or wrong casing grade selection. The production wells are to be drilled and completed with the intent to pump hydrocarbons for the longest possible period of time before any work over (WO) is due. Casing leaks could occur in the course of drilling operations or after completion time. There are two types of casing leaks encountered during work over operations: two-way and one-way leaks (dumping or taking) depending on direction of flow, cement integrity and formation characteristics behind the casing. The first example is seen mostly across shallow aquifers that have sour gas and are difficult to cement due to incurable losses. The second example occurs across highly over pressurized corrosive water bearing zones that are tight and underlying, or overlying high permeable zones, making cementing the annulus difficult and causing potential leaks. The WO team has come up with an effective approach for each type of leak that is time saving and cost-effective, and provides a long lasting solution. Also, drilling and cementing practices in fields where casing leaks occur have been revisited to prolong the life of wells. This paper explains all types of leaks and their consequences. In addition, it highlights the circumstances that accompany casing leaks and provides an analysis tool for best casing leak repair approach based on a thorough in depth statistical study.
A New Thermally Stable Synthetic Polymer for Harsh Conditions of Middle East Reservoirs. Part I. Thermal Stability and Injection in Carbonate Cores.
Authors: Dupuis Guillaume , Antignard Sebastien , Giovannetti Bruno , Gaillard Nicolas , Jouenne Stephane , Bourdarot Gilles , Morel Danielle , Zaitoun Alain
Published: November 2017

A great number of Middle East fields have too harsh reservoir conditions (high temperature, high salinity) for conventional EOR polymers used as mobility control agents. Traditional synthetic polymers such as partially hydrolyzed polyacrylamide (HPAM) are not thermally stable.

At temperatures above 70°C, acrylamide moieties hydrolyze to acrylate groups which ultimately may lead to precipitation and total loss of viscosifying power. Thermal stability can be improved by incorporating specific monomers such as ATBS or NVP. However, their polymerization reactivity can cause some compositional drift and limit their molecular weight / viscosifying power. Compared to HPAM, they will require a higher dosage and higher cost.

In this study, we present thermal stability and propagation behavior of a new class of synthetic polymers with high thermal stability. In harsh conditions of Middle East brines, with salinity ranging from sea water to 220 g/L TDS, they present excellent thermal stability until temperature as high as 140°C. Adsorption and mobility reduction were evaluated through coreflood experiments using carbonate cores and Clashach sandstone cores, with permeability ranging between 100mD and 700mD. Mobility and permeability reductions indicate a good propagation in both types of rocks.

The development of this new polymer is a major breakthrough to overcome the current limits of polymer EOR applications in harsh reservoir conditions. Moreover, molecular weights can be tailored from low to high molecular weights depending on reservoir permeability. Further work is needed to evaluate resistance to mechanical degradation, salt tolerance and adsorption in carbonates and sandstones.
Real Gas Lift Optimization: An Alternative to Timer Based Intermittent Gas Lift
Authors: Moffett R. E. , Seale S. R.
Published: November 2017

A simple electronic control method for automatically determining the "on-time" parameter for intermittent gas lifted wells using existing continuous gas lift valves is presented. Lift gas consumption and production during intermittent operation is compared to previous continuous gas lift results of the same wells in an unconventional reservoir. Performance during abnormal field conditions is analyzed. Interpretation of pressure/flow curves is explained.

Algorithms in electronic controllers normally used for plunger lift optimization are adapted to intermittent gas lift. Several pressure and flow phenomenon indicate the stage of the intermittent gas lift cycle. The most important indicator is a sudden increase in tubing pressure and gas production rate which signifies the arrival of fluid at the surface of the well. A setpoint is used to determine that the fluid slug has arrived and the gas injection is then brought to a halt until a timer or other parameter determines the beginning of the next injection cycle.

Nearly all wells which were tested with the new control algorithm showed a large drop in consumption of lift gas, which was the only target of the test. The wells which showed the greatest lift efficiency improvements produced on average less than 150 barrels of total fluid per day. Many wells may have been producing less fluid under continuous gas lift due to higher average bottomhole pressure under continuous injection conditions. Nearly all wells maintained or increased production after the change. The use of an automatic on-time adjustment maintained production under scenarios where strict timer-based systems would have failed to produce fluid. The amount of time needed to restart a well after an automatic shut-in was reduced by closing the gas lift injection valve when a flow obstruction was indicated by rising tubing pressure and automatically restarting the well when conditions improved.

This method is a simplified control strategy which can be implemented and maintained with little user intervention. Practicing engineers responsible for optimizing large groups of wells may find value in this novel strategy. The shale operator received a ROI of 7 days using this new approach.
High-Density Surveillance in a Supergiant Field: Integrating Clastic Sedimentology With Dynamic Data in a Mature Asset
Authors: Jude E. , Wells M. , Brown R. , Camplin D.
Published: November 2017

The Main Pay reservoir of the supergiant Rumaila oil field in southeast Iraq has been on production since 1953, and is now in a mature production phase. An onshore field of this scale and longevity is in a rare position to benefit from large volumes of high density dynamic data, including repeat cased hole saturation logs, formation pressure data and production logging tool runs. In mature field life these data are beginning to highlight complex reservoir behaviour, not fully captured in previous subsurface descriptions.
Water Shut - Off Treatments in Oilfield by Micro and Nano Technology: A Good Way to get More Oil and Less Water.
Authors: Casalini A. , Lima R.
Published: November 2017

It has been developed a novel chemical based water shut-off technology for reducing water cut and increase crude oil production in mature fields.

This technology employs polymeric gel beads (micron size range) suspendend in an organic solvent, hereinafter referred to as SMART W, which can swell selectively in contact with formation water and remain stable in contact with crude oil. Then an interconnected network of swollen particle can be generated in situ exclusively inside the water rich pattern. A proper amount of this gel can be able to plug water inflow pattern, even fracture or high permeability paths originated, while the crude oil filled fractures or paths continue to produce as before treatment. Gels beads dimensions can be properly chosen to act on water coming from fractures or high permeability paths and can be applied by means of common bullheading procedures and equipment.

This is of outmost importance if wells are not able to produce in natural flow, like those that are producing by Sucker Rod Pump or other similar crude oil lifting system, then reducing water will increase crude oil production by same extent. In this way is then possible to increase estimated recoverable reserves or reduce investment cost to access to such reserves, infact water production is a major problem that affects all wells and, in some context, can cause the premature shut-in of the well itself. Finally reduction of produced water is anyway important with consequential advantages in terms of i) corrosion, ii) bacterial growth, iii) scale deposition, iv) sand production and more in general has a positive impact on oil center facilities overall treatment capacity.

SMART W had been succesfully evaluated first at laboratory scale and then with several field trials in order to demonstrate the effectiveness and the significant benefits in terms of water/oil ratio. In addition, this technology has also been proven satisfactory in terms of duration of treatments effectiveness and selectivity. No any adverse effect has been expected or detected on oil center facilities. Versalis S.p.A. succeeded in scaling up the formulation of a microgel polymer to industrial level in order to have it available in industrial quantities.
Skill Development Tool to Build Future Petro-Technical Professionals
Authors: Al Hadhrami Ayesha , Kumar Pranav , Saleh Nawal Eisa , Alnaqbi Manahel Mohamed , Jaradat Amin , Bamatraf Majdi Mohamed
Published: November 2017

Success of any company depends on the ways its employees are developed. The ability and performance of the professionals play an important role. Emiratization department of ADCO has been working on developing the Fresh Graduates to a Professional Petro-technical expert over the years. This paper will focus on explaining the methodology and techniques used in the Graduate Development Program (GDP). Results of the GDP shown in the paper will prove the success of the GDP. Measurement of GDP success is achieved with set of metrics involving standard procedures, progress, communication, reporting, assessment & development. The performance of a GDP is measured with level as Awareness, Knowledge and Skills. The competencies on which GDP is assessed are based on Core, support, general and behavioral elements. Line Manager, Supervisor, Coach, Mentor, assessors and Verifier are roles played by senior employees in developing a GDP. There are other parameters which help a GDP to move from Entry point level to a core position after finishing 100% from the core elements. Implementation and validation of the GDP is calculated from the assessment process. Assignments are given to GDP employees on the basis of Awareness, Knowledge, and Skill, which the Entry Point employees have to complete during their development period. These levels have different elements which can be a Question, Observation and Product from the business. All the levels of the element are approved by supervisor, who also assesses the real work activities performed by GDP. Progress of GDP is done from entry level to an independent position.

The methodology and calculation devised in the GDP can be useful for other Oil and Gas companies to develop the Graduate employees to experience level. This is in line with the nationalization policies that various companies are following. This paper has explained the methods and processes used to develop a fresh graduate to a next generation Petro-technical professional.