bluuebunny/crossref_metadata_2025 huggingface dataset:
Innovative Method of Getting Multiphase Inflow Profile from Fiber Optic Installations
Authors: Kortukov Dmitry , Shako Valery
Published: November 2019

Fiber Optic provides massive amount of information from downhole of the well. The main challenge, however, is to extract the value out of these measurements, which can be used to further improve efficiency of field development. There were number of various methods/workflows developed to provide such conversion. But all the workflows shared the same problem – high ambiguity of interpretation. This is the main cause, why Fiber optic systems were not accepted as reliable multiphase inflow profile measurement.

To address this challenge, innovative method of distributed temperature interpretation was developed. It is based on the fact, that any short term transient events in the well, such as production rate change, will create dynamic temperature change. Such dynamic temperature change is sensitive to specific flow and phase content of flow, and as such, can be used to convert temperature measurements into multiphase inflow profile.

This paper presents field Application example of this innovative method. It describes workflow of data preparation and interpretation, showing the final result in form of inflow profile along the horizontal producing section, composed of 133 producing intervals.
Unconventional Oil Studies of Shilaif Source Rock in Western UAE
Authors: Tian Wenyuan , Jia Minqiang , Xiao Dengyi , Luo Beiwei , Yang Jianfang , Al Suwaidi Saeed K. , Ji Yu , LV Mingsheng , Shashanka Ashis , Mao Demin , Hu Xinli
Published: November 2019

Unconventional studies of UAE is in the early stage, especially in the western part, where the wells were drilled only for conventional oil & gas, with few unconventional data acquired. Shilaif formation is one of the main source rock of Cretaceous in western UAE. The main lithology of Shilaif are argillaceous limestone, lime mudstone and shale. Source rock geochemical analysis and basin modeling studies of western UAE show good source rock of Shilaif with high TOC, large thickness and high maturity mainly distribute in the south-east part of the study area, which is the high potential area for unconventional oil exploration.

Based on the available 3D seismic data and log data, a series of techniques were used to predict the sweet spots of unconventional oil of Shilaif source rock, which includes the following main techniques: 1. 3D Seismic CRP Gather Conditioning; 2. Petrophysics Modeling; 3. Pre-stack Inversion; 4. Fracture Prediction; 5. Hydrocarbon Prediction; 6. Pore Pressure Prediction; 7. In-Situ Stress Analysis. Based on these techniques, one SW-NE belt of sweet spots were predicted in Lower Shilaif formation of the study area, with thick good source rock, high oil retention, high brittleness, high pressure, medium fracture and medium DHSR.
Mechanistic Optimization of Commercial Gas Dehydration and Natural Gas Liquids Recovery Units
Authors: Dara Satyadileep , AlWahedi Yasser , Berrouk Abdallah , Leyland Simon , El Nasr Adel , Khan Ibrahim , Geuzebroek Frank
Published: November 2019

Objective

This study aims at high-fidelity modeling and mechanistic optimization of gas dehydration and NGL (Natural Gas Liquids) systems of a commercial natural gas plant based in Abu Dhabi, UAE. Scope of the work includes development of models, validation of models with plant data, optimization analysis and real-time validation at the plant site.

Method

In this work, we developed a dynamic model for the gas dehydration system and a steady state model for the natural gas liquids recovery unit. An advanced process simulator that follows equation-oriented approach is employed as the modelling and optimization platform. We first show the comprehensive plant data reconciliation followed by the model validation using the operating data of the years 2016 and 2018, to ensure that the model predictions match the real plant operation. We then present how the mechanistic optimization entity result in the best operating conditions for the natural gas liquids recovery system. We also show the optimization analysis that aims at maximizing the adsorption cycle time for the dehydration unit while minimizing the total heating duty required for the regeneration of the molecular sieve beds.

Results

Optimization analysis reveals a significant increase in the annual net revenue of natural gas liquid recovery unit as a result of modifying various process operating conditions that lead to higher liquid hydrocarbon production and lower operating costs related to steam and refrigeration. Similarly, optimization analysis of the dehydration system indicates that adsorption-step time can be increased to a higher value, which results in significant reduction of regeneration costs.

As a next step, we aim to carry out the validation tests on the plant site to verify and implement the model recommendations in the real plant to verify the model recommendations. We also plan to derive the set of operating guidelines that allow the operators to drive the plant towards optimal operation.

Novelty & Significance
Prevent Cement Strength Retrogression Under Ultra High Temperature
Authors: Zhu Jun
Published: November 2019

The cement strength retrogression is expected for Portland cement when it is exposed to high temperature (>110°C / 230°F) environment. Strength retrogression is defined as a change in the hydration products that can be described as a decline of cement strength at elevated temperatures where decreased strength is observed with increasing time. When strength retrogression occurs, not only is there a reduction in the strength of cement, but also an increase in permeability which compromises zonal isolation and/or pipe support, the operation life span of the wellbore would be seriously influenced. It has been a common practice by adding Silica into the cement to counteract and control cement strength retrogression for many years in oil & gas industry. While as drilling operation becomes more and more challenging and downhole conditions are much more complex than ever before, for example tremendous HPHT and deep-water wells are under exploration which raise the new challenges and technical problems to operators. Facing with such challenges the cement strength is expected to be compromised which may result in failure of zonal isolation and common use of silica to mitigate the retrogression may not be an adequate way to contribute the reliable strength and permeability of cement under such high temperature well conditions (>220°C/430°F) in a long term. For a better zonal isolation and pipe support, it is necessary to come up with a novel solution to address cement strength retrogression in challenging well conditions especially at ultra-high temperatures.

This paper would introduce a unique design additive - CemStal (Cement Strength Stabilizer) to help address the cement strength retrogression problem even under ultra high temperature (320°C/610°F) well conditions. The conventional silica was used to compare with CemStal under different temperature conditions and various density of cement slurries to test their ability to inhibit cement strength retrogression. All tests were using almost same formula except the silica and CemStal which is added to help prevent strength retrogression, the densities of cement slurry varied from 1.35SG (low density slurry),1.88SG,1.90SG (regular density slurry) to 2.65SG (high density slurry) and curing temperatures for the test were 220°C/430°F (high temperature), 320°C/610°F (ultra high temperature), the curing intervals of 2, 7, 28, 49 and 98 days’ results were investigated in this study.
Evaluation of Porosity and Permeability Vertical Distribution of Rudist Carbonate Build Up Platform Identified by X-ray CT and 3D Modeling, Late Cretaceous Cenomanian in Offshore Abu Dhabi
Authors: Yamanaka Motoyoshi , Taniwaki Takashi , Nanjo Takashi
Published: November 2019

We investigated the method of estimating porosity/permeability using X-ray CT, a non-destructive method. Using X-ray CT, a method of estimating the porosity/permeability is particularly developed in sandstone. However, for the carbonate rocks, the internal structure is complicated due to biological origin. This is difficult to recognize the pore space, therefore a method of estimating the porosity/permeability using X-ray CT has not been studied. This study is based on Yamanaka et al. 2018, which clarifies rudist development in side slab core using X-ray CT and 3D modeling. The study uses X-ray CT to observe the internal structure from the view of development of rudist of the 200 feet section of the Well A in offshore Abu Dhabi, and compares the porosity/permeability obtained from CCA (Conventional core analysis) of the same well and same interval.

Based on the 3D modeling of the X-ray CT, two rudist families (Radiolitidae and Ichthyosarcolites) were identified through their morphological characteristics such as inner diameter and shell thickness. A porosity of slab core around 50 feet is about 18% from CCA (Conventional Core Analysis). This slab core is made up of small rudist populations (length and wide size is 15-10mm), inside core confirmed 3D modeling (surface rendering and volume rendering), and calculated porosity is 0.89% from RCM (Reverse Coupling method). It is understood that this difference is dependent on matrix porosity and further investigation in the future is required in order to measure matrix porosity using thin section and micro X-ray CT. With regards to reservoir properties, the porosity is higher in the lower part than the upper part in the core interval. The size of the Radiolitidae could be dependent on the environment and its vertical variation suggests the change of depositional environment. Larger Radiolitidae, which appeared from 80 to 200 feet below the C-T (Cenomanian-Turonian) boundary, suggests a relatively strong wave influence. From a sedimentological point of view, the coarser matrix grain size supports the interpretation of depositional setting. On the other hand, from 30 to 80 feet below C-T boundary, smaller Radiolitidae is dominated. It was assumed that small Radiolitidae could be due to high physical stress under a restricted environment.

This study shows the advantage of X-ray CT image in rudist recognition, based on interpretation of depositional environment and understanding the reservoir property. The result of this study suggests the strong correlation between porosity/permeability and depositional environment (accommodation space) inferred from rudist fossil.
Parametric Study on Wind Fatigue Life of Long Span Flare-Boom Based on Directional Input Parameters to Harris Wind Spectra and Selection of Wind Blocks
Authors: Samant Sachin , Agrawal Rajender , Kamal Faris , Takieddine Oussama
Published: November 2019

Long span Flare Booms are fatigue sensitive. Most of these Flares are also protected by the passive fire insulation and hence inspection of Flare structural joints for signs of fatigue cracking/damage during it's service life can result in high maintenance cost. Fatigue design is governed by selected wind speeds also called as wind blocks. It is also governed by the shape of the wind load spectrum. These two parameters viz wind speeds and wind load spectrum play a vital role influencing fatigue life. Present paper contains methodology for selection of the wind blocks. Selection of the directional dependent input parameters to a wind load spectrum is also discussed. Both these cases are studied independently to get the insight on the fatigue life impact. Ultimate aim is to ensure adequate/sufficient fatigue design life of the Flare with minimum maintenance cost.
Kick Isolation While Drilling - First Field Test of an Innovative Risk Mitigation Technology
Authors: Salomone Andrea , Burrafato Sebastiano , Ricci Maccarini Giorgio , Poloni Roberto , Molaschi Claudio , Huse Arve , Tangen Geir Ivan , Regener Thorsten , Backhaus Oliver , Grymalyuk Sergiy
Published: November 2019

Uncertainty in predicting formation integrity as well as pressure regimes poses significant risks to drilling operations. Several technologies can predict downhole environments in terms of formation strength, kick detection etc., but no solution currently exists for kick isolation. This paper presents an innovative well control and risk mitigation technology that is deployed while drilling and the result of a field test offshore Italy.

The new system is integrated in the bottom hole assembly (BHA), and in case of a kick can shut-in the annulus and the drillstring on demand to confine the influx at the well bottom below the sealing elements. A bypass port that establishes communication with the drillstring and annulus can be opened above the sealing elements to allow adjusting of the mud weight. Downhole pressure above and below the annular seal and inside the string can be monitored in real time. The system is deployed in combination with Wired Drill Pipe to ensure activation and bi-directional communication that is independent of any fluid flow.

The system was run on top of the directional rotary steerable BHA while drilling an 8½-in. hole section. The field test was conducted after drilling more than 500 m of new formation and 90 hours in hole. Prior to the test, the system was pulled to surface for visual inspection. No irregularities were observed. The system was then run back in open hole, activated according to operating procedures and tested by applying pressure into the annulus. The well was monitored and no leakage was observed concluding a successful test. Finally, the bypass was opened, circulation was re-established, and the system was deactivated and then pulled out of hole.

This paper describes the technology features and summarizes the first field test results of a new risk mitigation technology for well control situations. This document also shows how deploying new solutions can help E&P operators improve well control through a cost-effective solution and reduce operational risk in case of formation fluid influx into a wellbore.
Energy Saving Challenges and Opportunities in Upstream Operations using Value Methodology
Authors: Soliman Mohamed Ahmed
Published: November 2019

The objective of this paper is to investigate and analyze energy saving and process optimization opportunities in upstream surface facilities, from downhole all the way to the gas-oil separation plants (GOSPs), using value Methodology. Function analysis was used to identify those functions that can be reduced, eliminated, or synergized, to minimize GOSP operating and maintenance cost.

In this paper, various energy saving and process optimization opportunities in GOSPs were brainstormed, analyzed, shortlisted, simulated, and validated using actual plant data. Process simulation using Hysys was used to model and verify the feasibility of different process optimization opportunities in GOSPs. A 300 MBD production facility was used to benchmark the Hysys simulation model, and to verify the feasibility of these promising energy saving opportunities. All of the successful opportunities were selected, based on their minimum OPEX and CAPEX, using value engineering methodology.
Elastic Property Estimation in Digital Multiporosity/Multipermeability Cores
Authors: Ramsay Travis
Published: November 2019

A rock-physics-based evaluation of elastic properties is examined in a coal core, using a three-dimensional (3D) reservoir simulator with an embedded petro-elastic model (PEM) to facilitate the evaluation of fracture productivity mechanisms. The analysis expedites what-if scenario evaluation at reduced costs compared to laboratory experimentation. The flow rates and capillary pressure are incorporated into a simulated coreflood to assess the effect of production on elastic properties at the core scale. A simulated coreflood is performed using an automated steady-state fractional flow process for mixed rock-type systems, which was developed as part of a process automation controller for a reservoir simulator. The process automation promotes adherence to established laboratory-based coreflooding procedures while optimizing for work process efficiency. Typical steady-state modeling processes are characterized as occurring in the capillary limit (CL) or viscous limit (VL) conditions, which are differentiated by flow velocity and capillary equilibration. The elastic properties are calculated by the reservoir simulator during the simulation, based on two available petro-elastic modeling methods—one semi-empirical and the other explicit, based on simulator parameters. The impact of flow rate, capillary pressure, and production on the elastic properties of a coal core are evaluated by simulated primary imbibition coreflooding with application to coal bed methane (CBM) production. The elastic properties are analyzed directly while also considering a dimensionless elastic property formulation. This dimensionless determination amplifies changes in elastic properties that might not otherwise be observed in the results directly; additionally, it combines spatial and temporal changes into an amalgamated variable. In addition to the spatio-temporal characterization of the dimensionless solution, results also show that it is consistent with the pressure solution over a given interval of simulated time. Differences in simulated coreflooding results are observed, which are driven by disparate flow regimes and applied capillary pressure. The differences are attributed to the CL condition imbibition coreflooding results showing decreased affinity to the wetting phase compared to VL-based simulation results. The flow component of the digital coreflooding results is considered valuable to overall asset productivity management. The evolution of simulated elastic properties in the digital core similarly shows that changes in saturated rock properties develop with specific flow conditions and highlights potential uses for core scale analysis in fracture productivity assessment.
Insitu Investigation of Aging Protocols Effects on Relative Permeability Measurements Using High Throughput Experimentation Methods
Authors: Youssef Souhail , Mascle Matthieu , Vizika-Kavvadias Olga
Published: November 2019

Relative-permeabilities are a first-order parameter to consider when describing multiphase-flows in porous media. Among many other parameters, the core wettability controls the fluids repartition in the porous media at pore-scale, strongly affecting how the fluids can be displaced (i.e. their relative-permeabilities). As the initial core wettability of reservoir sampled cores is rarely preserved, classical SCAL measurements (such as relative permeabilities) may not reflect the rock properties at reservoir conditions. This originate core wettability may be restored in a process referred as ‘core aging’. It is generally done by injecting the reservoir fluids (brine and crude-oil) in the core to equilibrate the rock surface with respect to the oil and brine components. Here, we investigated the effect of two aging protocols (static and dynamic) on wettability restoration, and characterize the aging using oil/water relative permeabilities measured on the core after aging. The two aging protocols were applied on a set of initially strongly water-wet outcrop sandstone samples (Bentheimer). The relative permeabilities were measured using the steady-state method and a state of the art experimental setup (CAL-X) based on X-ray radiographies. The setup is equipped with an X-Ray radiography facility, enabling monitoring of 2D local saturations in real-time and thus giving access to fluid flow paths during the flooding. Aged samples relative permeability curves show clear differences when compared to water-wet relative permeabilities, hence suggesting that the wettability has been effectively altered. However, the two aging protocols were unable to produce the same results. The dynamic aging has led to an inversion of the original relative permeability curves asymmetry, suggesting a strongly oil-wet system, whereas the static aging protocol has altered the wettability to a lesser extent. The differences can be explained by analyzing a 2D saturation maps. In the case of dynamic aging we observed a homogeneous distribution of fluid saturation during fractional flow. On the opposite, the static protocol results in heterogeneous flow paths, confirming that this protocol did not alter uniformly the wettability of the sample and generates a patchier mixed-wettability system.
Mudmat Analysis of Jacket Structure - Case Study
Authors: N Nagaraju , Kumar Chaithanya , Varghese Nitin
Published: November 2019

A jacket structure is designed to support a platform required for drilling and production facilities. The jacket is subjected to complex, multi-directional loading during installation. Overturning moments from wind, current and wave loads are skewed from overturning moments from pile and jacket weight eccentricity. The mudmat geometry can be simple with symmetrical mudmats at the four corners of the jacket base or can be complex due to full rectangular area with an off-center, open, rectangular bay for conductor installation. Mudmat geometry, loads during pile installation and soil conditions combined to produce a challenging overturning stability problem. Equivalent area methods of API RP 2GEO and ISO 19901-4 may not predict the low overturning resistance, and a typical righting moment analysis may not capture the soil-structure interaction. To address the geometry and complex loading, a plasticity analysis of overturning stability was performed and is described herein.

Partial safety factors as recommended by API RP 2GEO, ISO 19901-4 were used to assess stability so that overturning from the jacket dead weight could be treated separately from the wind, current and wave loading. Since the partial safety factors are lower for the stabilizing forces compared to the forces causing overturning moments, the resulting safety factors can be lower. Moment and force equilibrium were imposed, and the minimum overturning safety factor was found. Although the vector sum of the factored loads was oriented away from a principal axis of the mudmat, upper bound plasticity methods were used to investigate kinematically admissible failure mechanisms. The method of analysis easily accounts for irregular foundation geometry and complex, multidirectional loading with varying degrees of uncertainty. The method fills a gap in API RP 2GEO and can be implemented in a simple spreadsheet.

A case study is presented to demonstrate the safety factor variation using API RP 2GEO method and the proposed failure method with varying eccentricity in the gravity loads and overturning moments due to wind, current and wave loads.
Predictive Maintenance of Gas Turbine Air Inlet Systems for Enhanced Profitability as a Function of Environmental Conditions
Authors: Marwaha Gautam , Kohn Joshua
Published: November 2019

Increasing trends in the digitalization of gas turbine plants allow significant opportunity for utilizing predictive maintenance methods to optimize engine performance. Digital twins have been used extensively to detect anomalies, prevent failures and encourage preventive maintenance activities. An active area of research is how to shift from preventative maintenance based on current conditions, to predictive maintenance based on future conditions. Close mapping of historical engine performance against air quality metrics and ambient weather conditions allow significant progress to be made towards true predictive maintenance, by providing a greater understanding of the condition of the turbine air inlet and compressor section. This allows for increasingly accurate predictions of future engine degradation due to air inlet pressure drop and compressor degradation to a fidelity useful for scheduling maintenance needs. An economic optimization can then be performed balancing the costs of the two engine degradation modes and the corrective actions that can be taken, namely air inlet pressure drop against filter replacement interval, and compressor degradation against compressor soak wash interval. This paper describes our experience in monitoring turbine performance to predict and optimize maintenance needs in combined cycle power plants.
Application of Machine Learning to Estimate Sonic Data for Seismic Well Ties, Bongkot Field, Thailand
Authors: Sukkee Nisa , Ketmalee Thanapong , Jalernsuk Nattapon , Lemaire Renaud , Bandyopadhyay Parthasarathi
Published: November 2019

Seismic well tie is a critical process to verify the time-depth relationship of a well. This process requires density and sonic transit time data. However, sonic logs are usually not acquired due to cost saving, unfavorable well path, or other operational issues. Attempts to generate synthetic logs by Gardner equation, porosity correlation, or depth correlation did not provide the required accuracy. Therefore, the goal of our project was to generate synthetic sonic logs using machine learning technique for seismic well ties. This paper will compare the different methods tested, compare the results and lists the advantages of using Machine Learning.

This approach uses machine learning technique to create synthetic sonic logs. The machine learning model is trained to predict sonic log from other relevant logs. The model representativeness is confirmed by blind tests, which consists of two steps. The first step compares the synthetic sonic logs to the actual sonic logs. In the second step, four synthetic seismograms are generated from actual sonic, machine learning synthetic sonic, Gardner predicted sonic, and averaged constant sonic. The seismic well ties are compared between those four synthetic seismograms. Once the machine learning synthetic and actual logs show similar results, the model is deemed good and can be applied on wells that do not have sonic logs. The synthetic seismograms are then generated using synthetic sonic logs for all the wells that do not have actual sonic logs.

The use of synthetic sonic logs gives us the ability to Generate synthetic seismogram to tie wells that do not have sonic dataReduce the number sonic data acquisition, saving time and moneyReduce the risk of long logging string getting stuck in the hole that would requires fishing operations and its associated cost.
First Commercial Use of New Steerable Liner Drilling Technology Delivers Early Returns for North Slope Operator
Authors: Grymalyuk Sergiy , Regener Thorsten , Mensch Robert , Canizares Paul E , Miller Troy , Hobbs Greg , Marushack Andy , Njoku Johnson , Alvord Chip , Robinson Shon
Published: November 2019

This paper presents and discusses the results of the first six field deployments of a newly enhanced 7-in. steerable drilling liner system in Alaska's Greater Mooses Tooth (GMT) project. The system was operated with a managed pressure drilling service and drilled three-dimensional directional objectives while casing an 8¾-in. hole section through a highly unstable overburden section to the top of the reservoir section. The shales of the overburden section were chaotically disturbed by a prehistoric landslide that left large sections in unknown orientations from the original bedding planes. These sections have subsequently proven mechanically unstable when drilled at high angles. Exploration wells in the area determined that conventional drilling and casing methods would not allow successful completion of development wells. To succeed, the GMT project needed systems that would guarantee reservoir access and well mechanical integrity. The operator elected to deploy the newest version of the steerable drilling liner system because its design indicated a higher performance potential with more fail-safe options to manage the risks presented by this interval.

The new system uses a 4¾-in. pilot bottomhole assembly (BHA) and an expandable underreamer capable of opening the pilot hole from 6-in. to 8¾-in. for the 7-in. liner that is run in parallel with the drillpipe. The underreamer blade design was customized for the application to minimize drilling dysfunctions and optimize penetration rates. Special operating procedures were applied to deploy managed pressure drilling, surveying with a measurement while drilling (MWD) tool below a motor, and drilling with up to three cutting structures engaged at the same time. A new liner cementing concept was developed and proven to enhance reliability and provide flexibility for various contingency options.

The high-risk overburden sections were simultaneously directionally drilled and evaluated with logging while drilling (LWD) measurements while they were secured with the liner to the top of the pay section below. In the first two wells, the planned 18-day deployment was completed in nine days. The duration for the drilling part of the operation planned for 10 days was completed, on average, within 2.5 days without any tool failures or high dynamic dysfunctions while averaging a rate of penetration (ROP) of 35 to 45 ft/hr. Acceptable cementation of the liners was achieved on both wells with bond results comparable to conventional cementing in the section.

This paper summarizes and describes the results and system features in detail, and demonstrates how they can help operators reducing operational risks and saving cost.
Performance Evaluation of Novel Polymers for CO2 Foam Enhanced Oil Recovery
Authors: Majeed Talha , Kamal Muhammad Shahzad , Solling Theis , Mahboob Ahmad , Zhou Xianmin
Published: November 2019

The oil recovery from foam flooding mainly depends on the stability of the foam flow in porous media. At severe reservoir conditions, CO2 foam becomes unstable due to water drainage and gas diffusion through the lamella. The petroleum industry is using several foaming agents to produce and stabilize the CO2 foams. These are mainly water-soluble surfactants, CO2 soluble surfactants, nanoparticles, and water-soluble polymers. Addition of a water-soluble polymer in a conventional foam can increase foam stability, viscosity, and oil tolerance. Most of the previous studies utilized partially hydrolyzed polyacrylamide (HPAM) for CO2 foam stabilization. However, the data on CO2 foam stabilization using other polymers is limited.

In this work, CO2 foam stability was assessed using several novel polymers. The foam was generated using alpha olefin sulfonate (AOS) surfactant at a constant concentration. These polymers were mainly acrylamide-based sulfonated polymers that contain thermally stable monomers that increase salt tolerance and thermal stability. The foamability, foam stability, foam diameter and bubble count per unit area of different foaming systems were measured using a dynamic foam analyzer.

The result showed that the addition of polymers enhanced foam stability and reduced liquid drainage. Novel sulfonated polymers showed much better performance compared to the conventional HPAM polymer. Reduction in liquid drainage rate was much higher for sulfonated polymers compared to the conventional HPAM due to viscosity of the foaming solutions. For HPAM, the viscosity of the solution reduced at high temperature in presence of salts whereas sulfonated polymers maintained a high viscosity in the presence of salts that resulted in less liquid drainage and enhanced foam stability. The foam stability was also assessed using foam structure analysis.

This is the first systematic study on the application of sulfonated polymer with varying molecular weight and structure for CO2 foam stabilization. This study helps in understanding the role of polymer molecular structure, molecular weight, and degree of hydrolysis on foam stabilization for CO2 -EOR.
Casing While Drilling Step Changes Performance for Complex Deviated Wells in the Middle East
Authors: Centeno Manuel , Krikor Ara , Herrera Delimar Cristobal , Sanderson Martin , Carasco Anant , Dundin Alexander , Salaheldin Ahmed , Jokhi Ayomarz , Ibrahim Sameh , Wehaidah Talal
Published: November 2019

The complexity of drilling highly deviated wells in Kuwait drives the need for step changing in the well construction mindset, where severe to complete loss of circulation in Shuaiba formation significantly deteriorate the shale layers in Wara and Burgan formations leading to uncontrolled wellbore stability events.

Casing while drilling (CWD) and two-stage cementing with a light density cement slurry were introduced as a technology system to drill the highly deviated complex wells through unstable and highly fractured formations. Fit for purpose engineering processes, advanced software solutions, a tailored bit and a bottom hole assembly dynamically simulated for drilling stability and directional tendency behavior were designed.

A special light density cement slurry with high compressive strength was also designed to tackle the lost circulation issues when cementing the casing string.

The paper will describe how the technologies can work as one system to solve complicated wellbore problems and address the problematic challenges of drilling unstable shales and fractured formations in the same section of the wellbore. This strategy enabled a significant time saving compared to drilling the section conventionally, removing Non-Productive Time (NPT) resulting from additional trips, cement plugs, stuck pipe, and subsequent sidetracks.
Civil Engineering Challenges in Brownfield Projects - A Case Study
Authors: Nuthanapati Sreekanth , Adel Khalid , Al Awadhi Ibrahim
Published: November 2019

Expansion / Debottlenecking of Industrial or Oil & Gas plants is a common phenomenon and many a times such expansion has to be located within limited plot boundaries posing multiple challenges in locating the equipment and design & execution of supporting civil structures. In some cases, finalized supporting civil structures are not feasible to implement due to additional challenges such as additional underground utilities not identified in as-built survey that may arise during execution stage affecting project schedule. Generally, such unique design challenges are not encountered in Greenfield project development.

This paper presents the typical constraints encountered in expansion projects, key parameters required to finalize the innovative solutions and measures / methods adopted to overcome the constraints in most effective and economical way in one of the major brownfield project without affecting safe functioning of existing plant.

Vibration transmissibility to structures / equipment from new equipment or old equipment vice versa, physical constraints in supporting / routing new piping, underground utilities present in the plot are some of the major challenges faced during detail engineering. Enhancing existing supporting structures for new codal requirements (e.g. revised seismic definition) and enhanced design life to support additional loads of new project in addition to existing ones are some of the additional challenge faced during engineering and construction of the brown field projects

Key parameters to be studied / considered while arriving optimal civil engineering solutions to challenges encountered, dynamic properties of new or existing equipment, foot print and founding details of existing foundations, underground utilities present in the plot / boundaries, presence of ground water table, execution feasibility of proposed new civil structures under plant operating conditions thereby avoiding plant or unit shutdowns etc. The solution arrived may have to be revised based on additional challenges that may unfold during execution stage.

Fit for purpose supporting structure configurations, out of box structural designs, usage of unique material etc., are some of the methods adopted in arriving safe and economically sound design to overcome the constraints.

Brownfield expansion in constrained plots of existing plants is a common phenomenon in all industries. Fit-for-purpose solution needs to be arrived considering constraints applicable to that equipment / plot while maintaining Plant safety and integrity. Similar approaches may be adopted to mitigate challenges in brownfield expansion of other plants to arrive at cost-effective & safe solutions.
Applying High Rate Coiled Tubing with Fiber Optic System to Meet the Growing Challenges of Coiled Tubing Interventions in Sour Gas Producer Wells
Authors: Al-Zaid Mustafa , Bulekbay Aslan , Al-Harbi Abdulaziz , Al-Driweesh Saad
Published: November 2019

Dealing with tight high pressure/high temperature (HPHT) sour gas reservoirs encounters many challenges. One challenge associated with these reservoirs is the development of hard and heavy scale mixture in the production tubing, causing flow and accessibility restrictions. To restore full accessibility, a mechanical de-scaling operations using special milling and cleanout assemblies is the best current solution to this problem, due to the fact that chemical dissolving methods do not deliver the desired results. Another challenge is conventional perforation in some tight wells gives limited penetration, which does not establish the required wellbore reservoir communication. In this case, utilizing the abrasive jetting tool will offer the best solution to overcome the casing string, cement, formation damage achieve optimum penetration which will optimize the stimulation design and enhance the well productivity.

In recent years, using coiled tubing (CT) equipped with fiber optics with aforementioned coil tubing intervention operations, have become a common practice in gas wells. Using this system provides the ability to acquire on-job real time data such as pressure, temperature and gamma ray depth correlation. Furthermore, the incorporation of a new rugged fiber optics system into the intervention strategy has enabled increasing operational success rate and results in robust control on the operation parameters, minimizing the risk of gas influx, reducing coil tubing runs and improving decision making process during the operations.

This paper describes the challenges in mechanical de-scaling and slot cuttings operations, overview of different applications using CT with fiber optics system, provides a comparison between the rugged and standard fiber optics systems and lessons learned of recent implementation of the rugged CT fiber optic system.
Comparative Analysis of Intelligent Algorithms to Predict the Minimum Miscibility Pressure for Hydrocarbon Gas Flooding
Authors: Khan Mohammad Rasheed , Kalam Shams , Khan Rizwan Ahmed , Tariq Zeeshan , Abdulraheem Abdulazeez
Published: November 2019

Over the past two decades, enhanced oil recovery (EOR) has become one of the prominent techniques to increase the recovery of reservoir. EOR consist of four different techniques i.e. thermal, chemical, microbial and gas injection. Gas injection/flooding is one of the most robust applied technique for light oil EOR. Gas injection/flooding comprise of two processes called miscible gas flooding and immiscible gas flooding. Miscible gas flooding is the process in which both injection fluid and reservoir fluid are miscible. The minimum pressure at which both injecting, and reservoir fluids are miscible–is commonly known as Minimum Miscibility Pressure (MMP). The estimation of MMP is the challenging and crucial task in the designing of miscible gas flooding. In this study, we used experimental data along with the machine learning algorithms to find out the relation for MMP. Moreover, the comparison between three different algorithms (Support Vector Machine (SVM), Functional Network (FN) and Artificial Neural Networks (ANN)) was performed based on the results of statistical analysis.

A new empirical correlation was established to estimate MMP as a function of reservoir temperature, reservoir oil composition, and injected gas composition. Since the data set contains reservoir composition data, the developed correlation incorporates the condensing/vaporizing mechanism during the miscible gas flooding process.

The data set used to establish the new empirical correlations was based on experimental data obtained from literature. The data set was separated into two parts called development data and testing and validation data. To establish the new correlations, development data comprising of 70% of the data was used. Whereas, the rest 30% was kept solely to perform testing and validation of the developed correlations. Three different machine learning algorithms called Artificial Neural Networks (ANN), Support Vector Machine (SVM), Functional Network (FN) were used to develop the new correlation. The parameters of each algorithm were optimized to find out the best correlation. For ANN, the number of neurons, weights, and bias were optimized. Whereas for SVM, the epsilon and kernel parameters were tweaked to yield an accurate model. Likewise, for FN model a backward elimination method was found to be the best learning algorithm.

To assess the performance of the developed correlations, statistical analysis was performed. Moreover, to avoid the occurrence of local minimum, multiple realizations (total 5000) with different algorithm parameters were run. The results indicated a minimal and acceptable average absolute error. Based on error, ANN was found to give the best correlation for prediction of MMP.
Reliability Management Digitalization in Oman Gas Company, A Best Practice in Midstream
Authors: Al-Noumani Faisal
Published: November 2019

Digitalization in Oil & Gas industry is essential to move straight forward into industry 4.0 revaluation. All data of assets operation interconnect in one digital platform that helps to analysis data, and optimize process in order to improve economically business target and minimize risk by increasing assets reliability. Oman Gas Company (OGC) reliability management journey provides the cornerstone for developing a culture that safety & environment incidents and equipment breakdown are preventable. The OGC journey in reliability digitalization started with one digital platform that consists of all assets field condition data, and then semi-auto analysis to end up with continues improvements recommendations. The collected asset condition data from field, are the core information used for analysis, which include all occurred failures, downtimes, First Line Maintenance (FLM) checks, maintenance inspection data, process data, alarms, offline/online condition monitoring and as well linked to CMMS (SAP), which all are digitalized using connected a cyber-networking and handheld devices. Analyze & use of all these data are the key of asset performance management, that include reliability, availability, MTBF, MTTR, failure rate, failure mode & bad actors identification, ECA, RCA, RCM validation, process optimization, alarms rationalization and risk assessment. The generated recommendations and corrective actions including repair, upgrade, optimization or adjustment, are all supporting assets reliability & performance improvement. In Oil & Gas industry, the value of the asset and its performance are influencing the operational cost (OPEX) positively in short & long term.
Dynamical Analysis of Phase Inversion in Oil-Water Mixtures
Authors: Al-Jindan Jana , Ahmed Yusuf , Noui-Mehidi Mohamed Nabil
Published: November 2019

In the present paper, a dynamical signal analysis of oil-water dispersion is presented. The focus is on phase inversion physics and the associated dynamical features of collected signals from an acoustic receptor placed within a flow setup where phase inversion where triggered when needed. The acoustic fields associated with the mixing system showed clear differences between oil continuous and water continuous media, phase inversion could be clearly identified from the acquired sensor signals. The dynamical analysis of the experimental data showed characteristic frequency transitions as well as specific attractors. The analysis tools could be used in field application to monitor oil-water flows for flow assurance purposes.
Hydrocarbon Exploration Potential in Migration Pathways
Authors: Taher Ahmed
Published: November 2019

Part of the hydrocarbons generated in the mature kitchens migrate into the conventional traps while the other portions remain in the kitchens as unconventional resources. However, significant part of the generated hydrocarbons could be available in the migration pathways.

Hydrocarbons in the migration pathways are either retained in the rocks in migration routes or accumulated in subtle traps due to the presence of heterogeneities along the migration pathways.

The migration pathways traps are envisaged to be developed in response to the presence of an equilibrium state between the buoyancy forces that are trying to move the hydrocarbon through the rocks and the capillary pressures in the low permeable layers that are resisting these movements (figure 1). The only requirement to develop such traps is for the capillary pressure to be greater than the migration buoyancy force. Smaller pore throat sizes will greatly enhance the seal capacity, especially for the larger oil molecules that are expelled during early oil migration and result in longer oil columns.

The Upper Thamama migration pathways, in east and central Abu Dhabi may represent one of the most potential areas for the secondary migration pathways oil accumulations. Some of the well-known conventional fields in these areas in reality were developed in response to the presence of heterogeneities along the migration pathways. Also, the stratigraphic traps of Mishrif and Mauddud formations in west onshore Abu Dhabi are other examples of the migration pathways hydrocarbon exploration potential.

The exploration activities in the migration pathways will rely heavily on technological improvements in seismic imaging, basin modeling, horizontal drilling, frac testing and steam injection. These will result in discovering a commercial volume of hydrocarbons along the migration pathways.
Enhance the Operating Capacity - Maximize the Revenue
Authors: Muthukrishnan Murali , AlRaeesi Fatima
Published: November 2019

To explore the opportunity for maximum utilization for one of gas processing facilities in line with ADNOC strategy to enhance profitability and asset utilization. A Technical study was conducted to increase the processing capacity up to 115% of its design limit. This was to identify the potential bottlenecks in the facility and suggest debottlenecking options with a reasonable investment.

The Technical study covers the following activities: Rigorous process simulation including the licensor units of NGL & AGRU.Line sizing adequacy check and detailed hydraulic evaluation of the major piping.Equipment adequacy check.Relief & blowdown and flare system adequacy check.Proprietary equipment/design evaluation of licensed units.Adequacy check for In-line instruments like control valves, flow elements/transmitters, ThermowellsRotating equipment adequacy checks performed with the concurrence from OEMs.Obtained Endorsement of NGL licenser (Ortloff) for the methodology of 115% adequacy check, with a recommendation to gradually increase the plant rate in 1% at a time and monitor the performance until achieving the required targetRisk assessment was conducted before the capacity testActual plant capacity test run to verify the study findings.

The study has concluded the following observations for processing 115% of the design capacity: High flow alarms set points need to be changed at some locations due to increase gas flow rates.550 oo 1133 of thermowell are not adequate based on new design CODE. These thermowells are to be replaced for the continuous operation.6 Filters to be upgraded with required capacity.

A Successful two days Test-run was conducted in June 2018 and there are no additional limitations identified other than identified in the study. Following are the outcome. Reduction of the C2 recovery by 1.2 % with no significant change in C3 recovery level.Increase in Residue Gas by 30 MMSCFD per trainIncrease in NGL by 235 TPD per trainIncrease in condensate by 2100 BPD per train

Overall Product wise revenue per train was identified at a sum of 62.5 MMUSD/Y.