bluuebunny/crossref_metadata_2025 huggingface dataset:
Positive Displacement Motor Modeling: Skyrocketing the Way We Design, Select, and Operate Mud Motors
Authors: BA Samba , Pushkarev Maxim , Kolyshkin Anton , Song Lijun , Yin Ling Ling
Published: November 2016

We present in this paper a comprehensive and universal tool/model for the mud motor power section. The model includes performance, fatigue, and hysteresis heating simulation capability. It can be used for improved and optimized power section design, motor selection prior to jobs, drilling parameters optimization, failures analysis, and training. Model predictions are compared with real field cases with good accuracy.

There are many challenges to build a proper model of the power section: a geometry that involves complex kinematics with progressive cavities moving in a spiral motion, unusual contact mechanism with high deformation from the elastomer, the elastomer itself being a highly nonlinear material that experiences hysteresis heating, the fluid aspect with complex 3D path, the interaction between the fluid and the elastomer, the sliding and rotating operating modes, and the load fluctuation in typical downhole instable conditions. To build an adequate model we have developed a set of modules with a unique apparatus helping to make cross-interacting links between them.

The present simulation capability allows us to predict the performance and the fatigue life of the power sections with good precision. We have already run many different power section simulations under different conditions showing good correlation with field data. We provide here direct field operation applications with comparative results between some field failures and model predictions. In addition, we expose how combining accurate profile measurements of the rotor and the stator with the modeling capability can prevent failures due to wrong interference fit or incompatibility between rotors and stators. Besides that, a comparative study with different elastomers in the same power section is also considered. We show also how we can use the model for well planning by selecting the right motor for the right application. Moreover, during the well execution, by combining its prediction and the monitoring system to derive optimized drilling parameters for performance and reliability, one can achieve higher shoe-to- shoe rate of penetration (ROP).
Successful Massive Hydraulic Fracturing of Deviated Wells in Fushan Complex Fault-Block Reservoir, Hainan Island
Authors: Suzhen Li , Xuemei Yan , Yun Xu , Liao Wang , Rui Gao , Daoping Zhu , Siyun Zeng , Xiaoguo Deng , Wuqiong Jiang , Yuzhong Wang
Published: November 2016

Fushan complex fault-block condensate gas reservoir consists of more than 170 low-permeability fault blocks with multilayers of depth from 3300.0m to 4000.0m and temperature from 140.0°C to 174.0°C. Almost half of the new wells cannot achieve the economic production by unsuccessful fracturing and low proppant volume due to high temperature, deviated well with high angle-multilayers in long interval and close to the faults, etc. Based on reservoir and well features analysis, we put forward massive hydraulic fracturing (MHF) for wells with long interval multilayers, which cannot be Layered fracturing. Meanwhile, multistage sand slug and a large volume of proppant in pad stage are executed to decrease the risk of screen out and increase opportunities to break multilayers. Moreover, the low damage fracturing fluid was developed to improve the proppant carrying capacity in high temperature and reduce formation damage. Six deviated wells have been fractured in recent five years with quite good production and long yield period. In one well, over 84.0m3 proppant was pumped in and more than three years of stable production was achieved, which shows the success of MHF in complex fault-block reservoir.

The introduction about MHF in this paper provides some guidelines for fracturing design in complex fault-block reservoirs, and offers an important reference to develop similar fault-block reservoirs as well.
Improving Electrical System Efficiency in Oil & Gas Facilities
Authors: Dennis Peter
Published: November 2016

Practical experience shows that electrical equipment in oil and gas facilities is generally designed above specification and does not operate at or near its most efficient point. Overrated electrical equipment increases both CAPEX and OPEX and can potentially increase global warming. This paper presents different scenarios and solutions for the rating and sizing of electrical equipment from a design perspective to achieve an efficient and cost effective operational electrical system. Standard equipment de-rating factors is discussed and evaluated against actual system requirements.
Multi-Dimension Decision Tool for Assessing Organization Fitness for Change
Authors: ELHabbal Mohamed
Published: November 2016

Organizational change management is the key of success for any organization that needs to survive, compete and excel. Two main business strategies are usually considered when the organization decides to change; Business Process Reengineering (BPR) and Business Process Improvement (BPI). The failure phenomenon of most of change projects has raised two important questions: Is the Organization fit for change? And the other question is How to measure its fitness for change?

The objective of this research work is to introduce to the strategic management field a proposed novel tool designed to measure organization fitness for change projects; this tool is termed "Multi-dimensional Decision Matrix" (MDM©). The MDM© tool main idea is to assess organizations from the three perspectives that construct the whole change process: organization state, change management activities and expected goals and targets using objective technique based on validated measures deciding whether organization is fit to go for BPR project or BPI or even do nothing which in certain cases could be the optimum solution.

The research objective was achieved by performing a wide literature review to study the whole process of change projects in order to ensure that the MDM© tool is well constructed and covers the most important elements that allow decision makers to assess their organization fitness for change. The tool was tested through a validated questionnaire that tests validity and psychometrical usability of the MDM© tool. The questionnaire was directed to strategic managers & top management members in different fields of business including oil & gas companies in order to ensure generalization and applicability of the proposed MDM© tool.

The introduced paper presents a detailed description of the MDM© idea, set up and method of application. It also presents the questionnaire results including charts and graphs that measure six aspects to accept the MDM© tool; logic approach, practicality, has friendly interface, adoptable, can reduce risk of failure and finally overall usage satisfaction for generalization purposes.

The research work concluded that the MDM© tool is conceptually accepted and is fit for the purpose it is designed for. The research output indicated that the MDM© tool is ready for experimental application for different business cases in order to validate and verify its usage. One of the added values of the MDM© is it allows decision makers and change management teams to perform gap analyses for their organization spotting out main strengths and deficiencies within their organizations as part of the tool output.

Multi-dimensional decision matrix (MDM©) tool is novel in its idea, approach and application. It has the potential to be an added value for the body of strategic management and tools of decision making.
Takreer's Approach to Minimize Environmental Emissions by Vapor Recovery During Gasoline and Naphtha Ship Loading
Authors: Dambala Poornan Prasanna , Ali Abdulla Al Hindi Ali Hasan
Published: November 2016

TAKREER, as part of its prestigious Ruwais Refinery Expansion project, has installed a world-class, state-of-the-art Marine Terminal and Jetty Facilities to export various products (Naphtha, Jet Fuel, Gas Oil, Propylene, Gasoline, Bunker Oil) through jetty facilities through a dedicated jetty 4.6 km long with three (3) berths and 39 loading arms. Volatile fuels mainly gasoline and naphtha have significant vapour pressure and amount of vapour lost during ship loading can be significant. Objective of this paper is to showcase how TAKREER approached this challenge and the adopted a solution which not only minimizes environmental pollution but also minimizes loss of profitable products.

The policy of TAKREER is to manage and operate its facilities in a manner that protects the environment, provide a safe, healthy and rewarding workplace for its employees, contractors and communities in which they do business. TAKREER carefully evaluated various technologies on Vapor recovery with the objective of not only reducing the emission of VOCs to atmosphere during ship loading but also efficiently recover them. The key criterion was to adopt a technology which is best-in-class and operates with highest level of vapor recovery efficiency with relative ease of operability and maintainability.
Experimental and Modelling Study on Application of New Class of Asphaltene Inhibitors for Enhanced Oil Recovery Purposes: Adsorption and Wettability Alteration
Authors: Joonaki Edris , Burgass Rod , Tohidi Bahman
Published: November 2016

In this communication, a novel approach for combined Enhanced Oil Recovery (EOR) and asphaltene inhibition is proposed employing a New Class of Asphaltene Inhibitor (NCAI).

Following primary and secondary oil production, appropriate EOR techniques can increase oil recovery. Gas injection is commonly used, however there are risks associated with asphaltene precipitation and deposition which could result in flow assurance concerns in addition to changes in wettability.

This work investigates the effect of a newly developed AI on the wettability of synthesized substrates. An Environmental Scanning Electron Microscopy (ESEM) technique is utilized for monitoring the wettability alterations of the substrates caused by NCAI. This research also presents adsorption equilibrium and kinetics data for the NCAI on sandstone rocks. Batch experiments are conducted at various temperatures (from 25 °C to 75 °C) to illustrate the adsorption behaviour of this new chemical compound on reservoir rock surfaces. Conductivity measurements are utilized to determine the amount of the chemical compound adsorbed on crushed sandstone rock surfaces. The adsorption results are examined by employing various adsorption isotherms of Langmuir, Freundlich, Temkin, and Linear. The obtained experimental adsorption kinetic results are described and evaluated by pseudo-first-order, pseudo-second-order and intra-particle diffusion models. It can be inferred from the results that higher NCAI concentrations results in higher adsorption of NCAI onto rock surfaces. These experimental and modelling investigations provide a new tool for understanding the usefulness of this NCAI as a surface active agent in chemical based EOR techniques, especially for integrated processes with asphaltene precipitation and deposition inhibition.
Sulphur Condenser Effective Modification/Refurbishment
Authors: Ravi Arumugam
Published: November 2016

The Sulphur Recovery Units (SRU's), at Dolphin Energy's Gas Processing Plant were installed to process the conversion of unwanted H2S present in feed gas to the plant into Sulphur. Sulphur condensers are operated in each of these SRU's, and used to condense gaseous Sulphur formed within the unit through the Claus process.

Following several years' reliable operation of these SRU's, a series of tube failures occurred in some of the Sulphur condensers. This resulted in unplanned outages of the SRU's and costly interventions to make necessary repairs as well as to identify the root cause of the failures.

Failure analysis of condenser tube leaks was carried out by a third party consultant and a process licenser. The study included a review of the design, operation and failure mode of the rupture tube. Root cause analysis revealed that the most probable damage mechanism was Film boiling and Flow Induced Corrosion (FIC) on tube and tube sheet.

Management of Change (MOC) was approved to carry out In-Situ refurbishment of all four condensers to restore the mechanical integrity based on constructability study and root cause analysis.

This paper presents the details of the root cause analysis, a brief on the refurbishment / modifications implemented and discusses outcome of these efforts. Cited information may permit other operators with SRUs incorporating Sulphur Condensers to take active steps to avoid such incidents from occurring within their facilities.
Design of Concrete Gravity Quay Walls - British Standards vs. Eurocode
Authors: Sarhan Hazem , Riazi Fatemeh
Published: November 2016

Concrete blockwork quay walls are a common type of retaining structures used in marine and port facilities. Such gravity type retaining walls comprise of precast concrete blocks that are durable and well-suited for harsh marine environments. They have been widely used in the Gulf region in ports and more recently as part of the oil and gas offshore artificial islands infrastructure utilized during construction and operations stages. The main design reference of marine structures, including block work quay walls, is BS6349 which is based on Allowable Strength Design (ASD) method. In 2010, this code was updated based on Ultimate Limit State (ULS) or Load and Resistance Factor Design (LRFD) method in accordance with Eurocode. The updated code has not been applied in many marine projects (yet) and there are uncertainties about the effect of its application on the design.

To investigate this effect, three designed gravity quay wall sections with heights ranging from 10.5 to 23.6 m were checked based on both ASD and ULS methods under static and seismic conditions. The stability analysis checks showed that the results are close for static condition but show significant differences under seismic conditions. A parametric study was conducted to investigate the effect of using Eurocode 8 on the design of gravity quay wall sections under different seismic conditions.

The analysis indicated that Eurocode 8 (ULS) resulted in conservative sections compared to ASD methods of BS6349 for cases with surface Peak Ground Acceleration (amax) higher than 0.1g – 0.15g. Results based on the Eurocode 8 design have been compared with USA codes and guidelines (AASHTO [2012], Caltrans [2014] and NCHRP 12-70 [2008]) which indicated that gravity structures designed using Eurocode 8 resulted in conservative sections in medium to high seismic areas.

This study presents an assessment of the effect of using different codes on the design of gravity quay walls. Considering that the latest code versions are stipulated in the design, it is important for both Owners and Designers to appreciate the resulting effects on design and cost implications.
Testing the Untestable… Delivering Flowrate Measurements with High Accuracy on a Remote ESP Well
Authors: Camilleri L. , El-Gindy M. , Rusakov A. , Bosia F. , Salvatore P. , Rizza G.
Published: November 2016

Flow-rate testing is the most fundamental form of reservoir surveillance and is typically performed on a monthly basis using a test separator. Unfortunately, in some remote locations, the logistical challenges are so onerous that testing cannot be conducted with sufficient frequency and, in some cases, testing is only performed once per year. This case study demonstrates the novel use of ESP gauge data for obtaining accurate liquid rate and water cut trends in an unmanned desert location without the need for mobilizing surface well testing hardware.

The liquid flow rate calculation was based on the principle that the power absorbed by the pump is equal to that generated by the motor, which provides a linear equation which can be resolved for rate. Water cut was calculated by measuring the production tubing differential pressure, which provides the average fluid density, which is subsequently converted to a water cut. Analytical equations are used throughout the process ensuring that the physics are respected at all times, which yields greater repeatability and confidence than analogous methods, which are based on correlations and artificial intelligence.

The algorithms used real-time data from existing permanent downhole gauges and ESP surface controllers, which provided the necessary measurement metrology to capture well performance transients and provide a full production history. This method also has the advantage that there is no need to mobilise testing equipment to the well site thereby minimizing cost as well as eliminating flaring and HSE risks associated with remote location operations. This case study demonstrated a new technique for providing continuous calibration of the flowrate models without any physical measurement of flowrate or fluid specific gravity, while taking into consideration changing well and ESP performance over time. This novel calibration method is also based on analytical equations and derived from first principles. After one year of production, a test separator was specially mobilized to the well-site to validate the liquid rate and water cut calculations and associated calibration technique to consider the method for field wide application.

This case study demonstrates that the proposed real-time algorithm provides the necessary metrology and data frequency to determine the production index as well as a trend of drainage area reservoir pressure over time. It enables a reduction in physical testing frequency while providing liquid rate and water cut with high frequency, repeatability and resolution thereby delivering both cost savings and improvements in information quality.
Development and Validation of Methodologies for Sour Gas Related Corrosion and Scale Studies at xHTHP Conditions
Authors: Yan Chao , Guraieb Paula , Ghorbani Nasser , Tomson Ross C.
Published: November 2016

Hydrogen sulfide (H2S) produced from oil and gas wells can lead to significant flow assurance and HSE issues due to uniform and localized pitting corrosion. Ferrous iron released from corroded metal or the formation will lead to the precipitation and possible deposition of various scales such as iron carbonate (FeCO3) and iron sulfide (FeS). Deposition or fouling of these scale types can lead to equipment malfunctions. Corrosion and scale issues become more complicated and severe as production wells are under extreme temperature and pressure (xHTHP). However, one of the major challenges for sour gas related corrosion and scale research is to develop reliable methodologies to simulate the production conditions.

Reliable methodologies have been developed to perform corrosion and scale research under xHPHT conditions (up to 250 °C and 25,000 psig) in strictly anoxic (<< 1 ppb dissolved O2) realistic brines. For corrosion studies, an xHTHP flow-through apparatus with multiple tubular coupons has been built. Coupons were characterized by XRD, SEM, and VSI. A modified flow-through apparatus with a troilite (FeS) packed column was customized to study solubility of FeS, allowing for accurate precipitation and inhibition prediction. All wetted parts were made of titanium and tubing sections were lined with Teflon to prevent iron contamination.

In corrosion studies, magnetite was found as protection layer in a simple NaCl brine at 250 °C on C 1010 coupon. However, when strictly anoxic (<< 1 ppb O2) realistic brine was used, ankerite with formula CaMg0.27Fe0.73(CO3)2 (Figure 15) formed instead of magnetite as passive layer. Solubility study of troilite were performed at 100, 175 and 250 °C with 1M and 3M ionic strength brines. Under those conditions, iron sulfide tends to form pyrrhotite (Fe1-xS) and troilite (FeSt) phase instead of mackinawite, the metastable phase (FeSm), which is common at low temperature. Phase transition between troilite and pyrrhotite at elevated temperature was observed during the solubility experiments. Solubility of iron sulfide decreases with increasing temperature and increases with increasing pressure. Experimental details and major findings from this research will be discussed.

Reliable methodologies have been developed and validated to perform corrosion and scale research under xHPHT conditions with strictly anoxic realistic brines. Both methods are customized to perform sour gas related research and testing. Various experimental parameters including temperature, pressure, salinity, dissolved oxygen concentration, H2S concentration, H2S to CO2 ratio, pH, metal coupon type and crystal phase of FeS can be controlled or selected for corrosion and scale studies. Furthermore, a semi-empirical model is being developed based on experimental data for prediction of FeS precipitation and inhibition (or dispersion) as well as material selection for xHTHP wells.
Successful Flood-Front and Breakthrough Prediction of Miscible WAG in a Complex Carbonate Reservoir - A Case Study
Authors: Qureshi Z. U. , Ashqar Ayham , Banyopadhyay Indrajit , Al Hammadi Khaled
Published: November 2016

Water alternating gas (WAG) is employed to improve flood mobility, and sweep efficiency during gas injection by squeezing more oil out of the reservoir. Injected water sweeps the lower part of the reservoir, while gas tends to sweep the upper part due to gravitational forces. Accurate mapping of fluids and their distribution across the reservoir is an important aspect of characterizing reservoir properties. Understanding the performance of the injected fluids, and their flow pattern is critical to understand reservoir behavior, the interaction between the fluids at reservoir level, and quality check the reservoir dynamic model.

Techniques such as tracer injection and time lapse logging are utilized as a method to monitor, and confirm flood front arrival. Pulse neutron decay time log (PNL) is a common method used to monitor reservoir fluid movement behind casing. Multi detector pulse neutron decay improves the tool capabilities and enhances its potential in detecting gas flood front and its miscibility.

Interpreting reservoir monitoring logs requires combining the innovative knowledge on the tool physics and understanding reservoir properties. Integrating all available data is an important step towards the correct interpretation.

Multi detector neutron pulse decay was run in time lapse logging using same tool provider to allow consistency. The tool has successfully mapped the approach of injected gas, it clearly showed the change in fluid properties over time, and most importantly has shown the type of fluid approaching. Few months later gas tracer was found in the close-by producer.

This paper shows a case study of successful integration of the results of six years’ time lapse logging with the dynamic simulation model, in a field located onshore Abu Dhabi UAE, and subject to rich gas EOR recovery through WAG cycling system. Gas tracer and PNL were used to monitor the flood front and break through. The flood movement mapped from neutron pulse decay with time lapse, was successfully history matched in the dynamic simulation model. The calibrated simulation model is used to monitor the further advancement of flood front.
GASCO ASAB-0 Turnaround 2016; Systems Dynamics for Extra-Ordinary Results
Authors: Al Hamed Omar , Nair Girish Kumar
Published: November 2016

Oil and Gas world is going through difficult times, with crude prices breaching some of the all-time low values. GASCO believes that, such situations call for extra ordinary efforts to control and extract best results out of every opportunity. Shutdowns/Turnarounds are such cost centric opportunities where careful and controlled actions can have significant effects on company bottom lines. This paper intends to portray the caution, controls and practices during Execution during Asab-0 Turnaround-February 2016, which enabled in producing extra ordinary results for GASCO.

GASCO operates its Turnarounds (TA) based on a well-documented ‘Shutdown Manual’, which has strong background in Maintenance Excellence practices on a well-defined process approach.

In order to control the TA effectively, Key Result Areas (KRA) were identified and actions were put in place for lean management of the various elements involved. Principles of Systems Dynamics were used to integrate various functions, people and hierarchies to break down silos in communication. Each of the KRA’s had elements of this approach in order to achieve performance up-scaling.

The KRA’s identified were: Cost optimization - achieved through resource optimization (pooling; Seamless integration for optimal use of all available resources (human/equipment)), iterative/dynamic planning, adequate contracting strategy (Performance-based), integrative thinking approach (Minimal Compartmentalization) with stakeholders and early start up.Scope Control - managed through strict control over scope creep and exercising continuous, dynamic scope optimizations.Schedule Control – optimization by implementing Critical Chain Method instead of Critical path, thus buffering floats towards end of TA activities enabling early completion. Also, "Daily Look Ahead" and "Look Back" prevented schedule slips.Quality – ensured by implementing GASCO TA vision of "Faultless Turnarounds", achieved through micro level planning. Many tools like IPF Functional test control sheet, Start up Readiness Certificates etc. were put in place to ensure ownership of quality to avoid errors, rather than rectify them.Efficiency, Effectiveness – Maximization achieved by establishing a transparent communication environment where cross functional interactions were ensured to be seamless and through careful resource/process management.

In line with GASCO’s established objective of ‘Delivering Exceptional Results’ and Turnaround Excellence goals, ASAB-0 Turnaround delivered a saving of approximately 6 MUSD by achieving plant start-up 3 days in advance, without compromising on HSE or Quality. Combined effect of all the above practices helped GASCO ASAB team deliver these extra ordinary results.
Free Rotating Eccentric Guide Shoe Reached TD in High Angle Well Saves ±60 Hours of Rig Time
Authors: Shabbir Huzefa , Al-Marzooqi Abdulmohsen , Khamis Mostafa , Marwan Kadri
Published: November 2016

In the pursuit to access reserves at ever increasing departures the ability to successfully run very long casing strings in highly deviated wells is essential. Running 6200 ft. (1890 m.) long 7″ liner in a highly deviated ‘S’ shape well (80 Deg.) with high dogleg severity 15 Deg. /100 ft. across whipstock window) is considered a big challenge. The severity of this challenge increases multifold while passing the string through challenging interbedded formations.

The case presented here had unique achievement that last seven days while performing extensive open-hole logging after drilling 8-½″ section and prior running the liner hanger system. Aligned with the pre-determined challenges; the normal drilling practice is performing two wiper trips. First wiper trip after drilling the 8-½″ section, pulling out till the 9–5/8″ window at 8740 ft. and RIH again till 8-½″ TD at 14442 ft., the first wiper trip would have consumed +/- 24 hours rig time. Then follow with another wiper trip through running 8-½″ drilling BHA from surface till TD at 14442 ft. after pulling out of hole with the logging tools, the second wiper trip would have consumed +/- 36 hours. Accordingly, a total of +/- 60 hours rig time would have been consumed in both wiper trips. Wiper trips would have increase the gap between finalizing drilling 8-½″ hole and running liner hanger system. Increasing the gap would thereby increased the possibility of open-hole pack-off while running the liner hanger system. Accordingly, an optimum solution is to run Free Rotating Eccentric Guide Shoe (FREG) with two Sure Seal valves each provided a 3.14 square inch (20.3 CM2) minimum flow area to allow large cuttings and debris to pass through. In addition, any resulting side force during running would rotates the guide shoe away from the obstruction, thus allowing continued running of the pipe to the predetermined depth without rotation of the entire casing or liner string and reducing the risk of string stuck. Accordingly, the risk of pulling out of hole twice and performing two wiper trips was eliminated.
Frost Heave in Cryogenic LPG Storage Facilities – Impact and Mitigation
Authors: Thirugnanam N , Adel Khalid , Awadhi Ibrahim Al
Published: November 2016

LPG storage facility in a GASCO plant is 35 years old and contains two propane tanks and two pentane tanks each of 60m diameter and 24m height surrounded by massive conical earth embankments. Cryogenic storage temperature (-45°C) of the products freeze the soil below tanks causing frost heave, a phenomenon of soil expansion due to capillary intake of ground water in freezing zone to form ice. To avoid potential risk of frost heave causing additional loads on tank bottom slab, original design provides heating systems at bottom and sides. Its partial failure and inaccessibility through embankments led to serious concerns on tanks safety/ integrity.

This paper discusses several investigative studies performed on progressive heating element failures, subsoil frost heave prospects and mitigation measures to assure the integrity of tanks during its residual service life.

Tank heating system consists of heating tapes in 1" GI conduits concealed in embankment/concrete base. In each tank, 64 Nos. of conduits exist at 900mm c/c; about 17% of them failed and 45% are in blocked conduits, but functioning. Aged inoperative tapes could not be replaced due to corroded conduits, snapping and access problems.

Based on the status of heaters failure/ performance & their current duty-cycle, soil/ ground water temperature below tanks, thermal analysis was conducted and appropriate "duty-cycle" implemented - to avoid the failure risk of 300mm thick tank bottom slab which was not designed for frost heave load.

Frost heave is caused by Frost susceptible soil, Water presence and Freezing temperature; role of each forms the basis for studies. Soil samples collected from 5 Nos. 30m deep boreholes were tested and confirmed for frost-vulnerability. Permanent piezometers installed in boreholes upto 4m below tank base continuously monitor ground water level and temperature. Borescope/videoprobe investigation provided heating tapes and conduits condition.

Based on gathered information, comprehensive simulation for different heater failure scenarios were performed using ground-freezing analysis models. Results of the study showed that by adjusting the heater duty-cycles to maintain cut in/out temperatures at +5/+10°C (41% duty-cycle), soil shall not freeze until 6 adjacent heater fail; while in reality there are only 2 adjacent heaters failures. It was also inferred that with 100% duty-cycle, upto 10 adjacent heaters can fail before freezing begins.

Continuous maintenance activities namely de-choking/ nitrogen purging of conduits, monitoring soil conditions and implementation of recommendations from sound engineering analyses resulted in maintaining safety and integrity of ageing storage tanks.

The multi-perspective studies about frost heave effect on cryogenic tanks in the wake of progressive failure of heating elements are exclusive in nature. The findings and mitigation measures will provide ample guidance and knowledge to the industry in managing and operating similar ageing storage facilities in a safe manner.
Deriving 3D Model of Reservoir Geomechanical Properties Through an Integrated Geostatistical and Basin Modeling Approach - An Example from a Mature Field in Saskatchewan, Western Canada
Authors: Saikia Kalyan , Ikuku Clara E. , Zawar Pankaj
Published: November 2016

Measurement of geomechanical properties using seismic and laboratory methods have been used in oil and gas industry for several years. Laboratory methods, in most cases, take only small samples from consolidated rocks, which may not be representative of the elastic regime existing in the reservoir owing to sample size. In general, geomechanical studies are performed on a well-by-well basis. Measurements calculated at the wellsite are then used as calibration points to convert the 3-D seismic data to geomechanical cube. However, elastic properties measured this way are restricted to the well location and cannot be interpolated across the reservoir. To overcome these challenges, this paper describes an approach for deriving and discretizing geomechanical and other elastic properties in the reservoir by integrating results of 3D geo-cellular and basin models.

The workflow presented in this paper is utilized to calculate cell-by-cell elastic properties of the reservoir by integrating parameters from both basin model and 3D geo-cellular grid. The basin model reconstructs the geologic history (i.e. burial history) by back-stripping the reservoir to its original depositional thickness. Through this reconstruction, the mechanical compaction, pore pressures, effective stress, and porosity-vs-depth relationships are established for the reservoirs. In the final stage, dicretized calculations of geomechanical properties are assigned to each lithotype (facies) in the geomodel. The discretization of elastic properties into 3D grids resulted in better understanding of the prevailing rock elastic properties and stress regimes helping hydraulic fracturing operators in the effective design of their depletion strategies with minimal drilling risks and costs. This approach provides an innovative way of determining effective minimum horizontal stress for the entire reservoir through distribution of elastic properties in a 3D grid. The conventional approach of using small sample plugs is not sufficient to describe elastic properties for an entire reservoir and can be replaced by current approach.
Remnant Life Study of Rotating Machinery at Zakum Field, Umm Shaif Field and Das Island
Authors: Almemari S. , Duncan A.
Published: November 2016

Regular life cycle of any equipment undergoes various stages starting with R&D phase, concept design, procurement, construction, initial operation, beneficial operation, mature operation, and at last, remnant life stage. Cost involvement accordingly varies per stage, which can be demonstrated with reference to fig. 1. Anticipated cost for an equipment at the remnant life stage is at highest compared to other costs during equipment life, which shall be assessed thoroughly to sustain optimum operation in line with maintaining reasonable expenditure. The scope of RLA was to assess life expectancy, performance, technical integrity, CAPEX, and emission across ADMA OPCO's existing critical list of rotating machineries. Approach taken to conduct the study and compile the results was through various interviews, site visits, data reviews / analysis, and collecting team experiences. As a result from RLA, ADMA OPCO highlighted major areas of concerns and were given a better position to develop a well-established CAPEX estimate and replacement scope for existing rotating machinery fleet.
Structured Analysis of Pump Systems Unleashing Novel Horizons of Energy Savings
Authors: Sajjad S. , Dias B. , Al Jenaibi E.
Published: November 2016

Pumps are large consumers of energy and play a vital role in daily operations at the Oil & Gas processing facilities. General tendency to oversize pumps during design phase in order to tackle all possible scenarios or conditions leads to inefficient pump operation thus resulting in higher energy costs. Changes in feed characteristics and throughput for a given facility due to numerous reasons also supplements higher energy costs and inefficient pump operations. Energy performance study has been conducted for selected pumps at an Oil & Gas processing facility. In this study, most of the pumps indicated higher head than actual requirements for the given flow conditions, highlighting potential of energy savings. Generally, multiple solutions are applicable for optimization of any pump operation. Potential solutions include changing running / standby configuration, installing Variable Frequency Drive (VFD), replacing pump motor, trimming impeller, replacing pump and modifying the system resistance by adding, removing or changing the components like valves and orifices etc. Each solution exhibits different magnitude of energy savings and CAPEX requirements. This paper introduces a systematic methodology for a structured analysis of pump systems, to explore and evaluate potential solutions for energy efficiency improvement. Targeting pumping system improvement thru this structured approach would help to evaluate all pertinent solutions, in conjunction with techno commercial analysis, and identify the best solution. Proposed methodology has been applied on four different cases of pump operation optimization and the results are discussed in this paper.
Implementation of Cross OPCO ADMA-ZADCO Marine Technical Compliance Assurance Model
Authors: Al-Shehhi Mohamed , Al-Hosani Khaled
Published: November 2016

Implementation of Marine Cross OPCO (ADMA-ZADCO) Technical Compliance Assurance Model
ADMA Integrity Assurance in Major Projects
Authors: Al Marzooqi Mahdi Mohamed , Al-Hameli Mohamed Saif , Al-Sayed Talal A , Khade Sanjay Harishchandra , Yella Srikanth
Published: November 2016

Through this paper, the author intends to share the valuable experience of benefits in introducing the Integrity assurance program in a structured manner at early projects stage starting from Assess, Select Define through to the commissioning stages.

ADMA is pioneer in major Oil & Gas producers worldwide where critical Integrity Deliverables are embedded through customsied locally designed Code of Practice (CoP-036 "Integrity Assurance in Projects) in Value Assurance Process (VAP) stages, enabling robust control on Integrity Measures upfront. Early identification of Integrity risks with proactive mitigations based on experience from previous Projects. This initiative prevents operating critical facilities with unknown HSE and business risks. The process is embedded within project activities implemented through PMT having full knowledge of design and complete as-built data. This essentially ensures best outcome with significant cost savings.

Early interventions result in timely risk reduction. Saving significantly in CAPEX / OPEX and enabling smooth commissioning handover. Preventing failures, unplanned shutdowns thereby providing adequate confidence to stake-holders during entire life-cycle of the facilities.

Being unique in MENA; ADMA is the first and only company in ADNOC group where there is direct involvement/integration from Integrity Division in the major full field development projects, thus decades of operational experience and lessons learnt are directly fed into the projects.
Proactive Learning from Process Safety Events to Prevent Process Safety Events in an Oilfield Services Provider
Authors: Peresypkin Sergey , Fei Leong Weng
Published: November 2016

Since the introduction of upstream process safety programs to manage various critical activities of an oilfield services provider, much has been learned in this pioneering field which allowed us to further fine- tune the program in preventing process safety events during well services operations. This paper examines in detail, using several past upstream process safety incident case studies within the Middle East and Asia Pacific region, and demonstrates how effectively investigated and understood UPS barrier failures contribute to improved implementation of the upstream process safety program and effectively prevent recurrence of such events. Key failure modes and root causes involved in these upstream process safety incidents and near misses will be analyzed in detail. Using barrier check tools employed as part of the upstream process safety program for the various well services activities, an analysis will be done to evaluate if the barrier check tools would have helped prevent these incidents. Some leading performance indicators will also be discussed and use of learnings from process safety events serve as a validation point for understanding effectiveness of the operationalization effort for upstream process safety. The barrier check tools will be briefly introduced early on to give context to this endeavor. Where there are inadequacies in the program, these will be identified from this review and will be fed back into review of the upstream process safety program. Highlighting the impact of the program in potentially preventing these incidents helps reinforce the appreciation for effective implementation and execution of the upstream process safety requirements. The proactive learning process from operationalization of upstream process safety goes toward improving the execution of the program as well as driving towards consistency within the industry in operationalizing upstream process safety.
Well Productivity Analysis Integrating Ultra-High Resolution LWD Images and PLT: A Data Integration Case Study
Authors: Shehhi H. M. , Shehab S. S , Celma R. I. , Girinathan S. , Sadaoui B.
Published: November 2016

The Production estimated from standard porosity logs in carbonate reservoirs has often been greater than expected. This study looks for the correlation between well productivity and high resolution porosity information derived from borehole electrical images. Good production contribution has been obtained from intervals where logs show low porosity (verified by PLT analysis) whereas zones having higher porosity could have major or minor contribution to the well production. Carbonates, in general, have complex porosity systems with widely varying proportions of primary and secondary porosities. The term "secondary porosity" includes vugs, moulds, bioturbation features and open fractures that are often missed on conventional porosity logs. These diagenetic phenomena are not captured on coarser resolution conventional logs (density, neutron and sonic), thus porosity is usually under-estimated or overlooked.

Resistivity images have been known to provide both high resolution and azimuthal borehole coverage to characterize reservoir heterogeneity from a qualitative perspective. New generation LWD borehole imagers record wireline-par resolution data while rotating at full borehole coverage (unlike wireline imagers). This case study sets sight on two horizontals wells – one injector and one producer – targeting Lower Cretaceous carbonates. Production / Injection logging (PLT) data are integrated with high resolution image-derived geological information to explain the nature of flow profile and dominant textural parameters at play at various levels along the borehole-section. Part of this exercise seeks to derive a more quantitative high resolution image-based secondary porosity by solving the porosity from the Archie equation in the flushed zone.

The workflow arrived at, allows one to understand correlations between various carbonate porosity components and well productivity data. In the present case study, it is concluded that not all productivity is derived from primary porosity. This is important in terms of well completion, carrying out optimized completion, design of hydraulic fracturing stages and placement of packers and inflow control devices.
Integrated Reservoir Characterization to Approach the Carbonate Permeability Distribution Challenges: Case Study from Offshore Abu Dhabi
Authors: Elarouci F. , Maalouf C. B , Espinoza I. Baca , Al-jaberi S. M. , Amer M. , Smith S. S. , Jalalh A. A.
Published: November 2016

Heterogeneous carbonates formations have unique challenge to obtain representative permeability values. During the exploration phase and due to the limited number of wells and technologies, the initial formation evaluation might be misleading. The permeability results from conventional core analysis (CCA) might be significantly under evaluated because vertical interference tests from a wireline formation tester and production tests show different results. This paper describes a case study in offshore Abu Dhabi and solutions that should be assessed to overcome this challenge.

An integrated approach was performed to determine the possible causes of permeability mismatch between cores, logs, wireline formation testers and production tests in this field. Based on logs and core data, the reservoir was subdivided into different layers and further refined using permeability indices from NMR logs. Formation testers with advance measurements were used to evaluate effective vertical and horizontal permeability of a single layer. The production testing covering several layers was used to fine-tune subzone permeability and subsequent flow units.

The results from this study show that permeability given by CCA was somewhat misleading due to physical limitations from core plugging. The detailed core description and well-test data indicate that a significant portion of flow passes through high-permeability (vuggy) sections of the formation that cannot be measured by plugs. A formation tester was applied to check vertical and horizontal permeability in one productive zone.

Various methods were integrated in the study to reconcile the unexpected high productivity of the sub-layer and explain permeability distribution from different tools. This case study provides a useful example in identifying and explaining data from reservoirs where the dynamic well productivity data differs from static data prediction.
Experimental and Numerical Studies on EOR Using a Biosurfactant
Authors: Saito Minoru , Sugai Yuichi , Sasaki Kyuro , Okamoto Yoshifumi , Ouyang Chencan
Published: November 2016

The EOR potential of a biosurfactant was evaluated through core flooding experiments and numerical simulation in this study. The biosurfactant which was called surfactin was generated by a microorganism belonging to Bacillus species. The EOR potential of surfactins has been already reported by previous papers, however, that of surfactins can be different depending on their making process such as the conditions of incubation, extraction, purification, etc. This study used a surfactin which was made by Kaneka corporation's original techniques.

Core flooding experiments were carried out under ambient temperature and pressure to evaluate the EOR potential of the surfactin. Berea sandstone cores whose permeability was 50 md were used in this study. The surfactin solution was injected into cores after water flooding. 3 experiments were carried out by injecting surfactin solution whose surfactin concentration was 0.3 %, 0.03 % and 0.003 % respectively. An experiments were carried out by injecting the culture solution which had been diluted so that the surfactin concentration was 0.3 %. 4 experiments were carried out by injecting sodium dodecyl sulfate (SDS) solution which had been supplemented with a slight amount of surfactin or the culture solution. An injection was continued until oil was not produced completely.

Higher oil recovery was obtained by injecting higher concentration of surfactin. 13.6 % of original oil in place (OOIP) was recovered by injecting 0.3 % of pure surfactin solution, whereas 6.3 % of OOIP was recovered by injecting 0.3 % of pure SDS solution. 0.27 % of SDS solution which was supplemented with surfactin whose concentration was 0.03 % could recover 14.7 % of OOIP. 23.9 % of OOIP could be recovered by injecting the culture solution which was diluted by 16 times so that the surfactin concentration was 0.3 %. Enhancement of oil recovery which was obtained by injecting SDS solution supplemented with the culture solution was a little lower than that with pure surfactin.

The EOR potential of surfactin is quite higher than that of SDS. It was shown that the surfactin can be useful as a cosurfactant for SDS. Culture solution of the microorganism demonstrated much higher EOR potential than pure surfactin, therefore, it may include effective components other than the surfactin. Utilization of the culture solution is economically advantageous.

Numerical simulation was also carried out using UTCHEM, a reservoir simulator for chemical EOR. The simulation model accurately history matched the core flooding experiments and allowed us to scale from the lab scale to the pilot scale.