bluuebunny/crossref_metadata_2025 huggingface dataset:
A Stochastic Optimization Approach for Profit Maximization Using Alkaline-Surfactant-Polymer Flooding in Complex Reservoirs
Authors: Tariq Zeeshan , Mahmoud Mohamed , Al-Shehri Dhafer , Sibaweihi Najmudeen , Sadeed Ahmed , Hossain M. Enamul
Published: October 2018

In heterogeneous reservoir formations, water tends to have early breakthrough due to the overriding and viscous fingering during secondary recovery. The overall hydrocarbon recovery efficiency remains very low in gas and water flooding projects because of less viscosity and higher mobility of water and gas. Therefore, there is an underlying need for improving recovery through a suitable chemical enhanced oil recovery (EOR) method. After investigating the feasibility of alkaline, polymer, surfactant, surfactant-polymer, alkaline-polymer and alkaline-surfactant-polymer (ASP) flood, ASP was selected as a chemical EOR method in low permeability heterogeneous reservoirs. However, the performance of the ASP flooding was highly dependent on operational parameters. Thus, it was important to select these parameters with extensive care to increase the recovery along with the profitability. The relationship between the ASP flooding operational parameters and profitability (NPV) has not been yet understood fully.

In this research, the new stochastic optimization approach to optimize the ASP flooding operational parameters has been proposed. To gain the objective of this research, a numerical simulation study was carried out and Particle Swarm Optimization (PSO) was implemented as an optimization algorithm. The net present value (NPV) served as the objective function that has to be maximized among the compared flooding processes. The used operational parameters were location of production and injection well, number of injection cycles, oil production rate, ASP injection time, ASP injection rate, alkaline-surfactant and polymer concentrations, surfactant and polymer viscosities. Sensitivity study of these parameters shows significant impact on net present value and ultimate oil recovery. Results also confirm that NPV is increased significantly after the optimization of all flooding parameters by using Particle Swarm Optimizer.

The new optimized model was developed for designing the ASP as a chemical EOR method in low permeability heterogeneous reservoir. It can be served as a handy tool for reservoir engineer to select the best ASP flood parameters to achieve maximum NPV.
The Accelerated Development of Young Professionals in an Integrated Environment
Authors: Alnahas Mohammed , Hamam Hassan , Sudirman Sharizan
Published: October 2018

An integrated environment consists of professionals from various backgrounds of engineering and geosciences that carry out tasks conjointly through advanced integrated technologies. In the oil and gas industry, the aim is toward developing the optimized field development plan as well as solving complex subsurface challenges. Young Professionals are integrated within the experienced professionals’ team to work on challenging tasks to develop their learning curve.

The Young Professionals’ development plan starts in the integrated environment - of engineers and geoscientists - by assigning them to mentors who are subject matter experts. Spanning from core analysis to reservoir modeling, the Young Professionals work on different tasks in parallel to gain a well-rounded knowledge base in an optimized timeframe. The Young Professionals initially start with simple tasks such as data mining and basic log analysis, before integrating into the more challenging tasks of decision making in modeling.

In an integrated environment, the Young Professionals get exposed to various tasks and concepts, accelerating the learning and development that would take much longer in a silo-type environment. As an added value, the Young Professionals develop their soft skills to communicate with the team and share their opinions.

As the Young Professionals excel in the simple tasks, more challenging tasks from different backgrounds are given to them to challenge and expand their critical thinking methods. Over a relatively short period of time, Young Professionals’ critical thinking methods are developed and they start taking the lead in tasks and even come up with out-of-the-box solutions to overcome the many challenges of developing and optimizing an integrated reservoir study.

Integrated environments provide unique opportunities for Young Professionals to unlock their full potential. Experts from various disciplines carry out their tasks through the Young Professionals. The interactive environment is a key factor in exposing Young Professionals to different challenges, scenarios, and solutions, which help in enhancing their development.
Efficiency of Selected Terpene-Based and Conventional Solvents in the Dissolution of Asphaltene Deposits
Authors: AlAamri Jamal , AlDahlan Mohammed , AlDarwesh Sajjad
Published: October 2018

The need for more efficient, cost effective, relatively high flashpoint, and environmental friendly organic solvent is crucial. Due to safety and environmental effects of the conventional aromatic solvents, efforts are being focused to search for more natural based products.

A total of 14 terpene-based and conventional solvents have been examined to identify their dissolving power of asphaltene/organic sludge. The organic solvents vary in their compositions from xylene or conventional based solvents to the more environmental friendly compounds of terpene (green solvents). They also vary in their flash points from as low as 75°F tod as high as 200°F.

The organic scale/sludge samples have been studied by thermogravimetric analysis (TGA), FT-IR, ESI-MS and asphaltene analyses. The analysis showed the contents of asphaltene, functional groups, saturation level and weigh loss of both deposits. Dissolution tests were conducted on both organic deposits using 11 terpene-based solvents and 3 conventional solvents. Dissolution tests were conducted at room temperature and 50°C with soaking times of 3 and 24 hours.

The solubility of deposit A at most of the solvents was found to be lower than the solubility of deposit B due to variation in both deposits’ compositions. Even though the increase of the soaking time was found to be of positive impact, most of the dissolving occurred in the first few hours. This study results also revealed that the efficiency of the terpene-based organic solvents is a function of terpene concentration; however, increasing the terpene concentration would decrease the flash point, which is of a safety concern in warm climate countries, especially during high temperature seasons. The environmentally friendly terpene-based solvents displayed promising results and can be an alternative to conventional solvents.
Wettability Evaluation by Fast Field Cycling NMR Relaxometry
Authors: Gao Jun , Kwak Hyung T , Al Harbi Ahmad M
Published: October 2018

Wettability is an essential concept to understand oil trapping due to adhesion and capillary forces, and it depends on the fluid/rock molecular interactions within the thin liquid layer on the pore surface. The conventional methods for wettability determination exploit its macroscopic averaging effects during various displacement processes. These methods are sufficient for general categorization; however, they are not easy to be used in the wettability alteration study, which is one of the most import oil mobilization mechanisms for carbonate reservoir. The direct characterization of the microdynamics of liquid molecules on the pore surface would provide not only the measurement of wettability but also the understanding of how added materials affect fluid molecular dynamics and alter the wettability for oil mobilization. This study is to extend the application of the newly developed nuclear magnetic resonance technique and Fast Field Cycling (FFC) NMR relaxometry to more fluids and rock samples as the first stage for the above objectives.

NMR dispersion (NMRD) profile by FFC NMR is a low field magnetic resonance technique, which measures the longitudinal spin relaxation over a wide range of Larmor frequencies determined by magnetic field strength. The dependency of spin-lattice relaxation rate on Larmor frequency allows to identify the liquid molecular dynamic patterns on the pore surface and determine the respective correlation times. NMRD affinity or wettability index was obtained from the time scales of the molecular translation and chemical exchange based on the dipolar interactions in the proximity of the paramagnetic spins. Only limited NMRD results of fluid/rock systems and saturation states were reported currently. This work utilizes a wide bore FFC NMR relaxometer to obtain NMRD on more fluids and rock samples of different mineralogy and analyzes their NMRD features with spin relaxation models.

The current study obtains the NMRD curves and qualitative affinity/wettability estimation for different fluid/rock system, including brine, mineral oil, crude oil, sandstone, limestone, and carbonate reservoir rocks. The dynamic patterns of liquid molecules are evaluated through NMRD features for their adhesive degree one the pore surface. The comparison with supposed wettability property indicates that they correlate well, and the wettability states are better understood through their molecular dynamics.

The NMRD measurement and interpretation of various fluid/rock systems extend its application; the determination of microdynamic patterns and parameters explains different wettability states from the molecular level. This study set the foundation for its application extended to fluid/rock systems at various saturation states and wettability alteration monitoring and optimizing during different oil mobilization processes.
Evolution of Limited Entry Multi Stage Stimulation Completion Technology for Improved Acid Stimulation in Tight Carbonate Reservoirs
Authors: Rodoplu Rasim Serdar , Abdulaziz Ahmad Azly , Malik Ataur R. , Gardiner Colin
Published: October 2018

Acid stimulation is an excellent method to increase hydrocarbon production and long-term formation drainage from carbonate formations. However, the stimulation effectiveness largely depends on pertinent placement method. Besides the necessity for optimized treatment design and fluid recipe, homogenous acid distribution is one of the most critical aspects for treatment success. For this purpose, a novel completion method has been deployed that allows for effective acid stimulation by maximizing formation contact in the openhole horizontal wellbore.

An improved Multistage Stimulation System (MSS) that has been developed to distribute acid homogenously across the lateral is utilized, where multiple sleeves are deployed in clusters as part of a single stage, and opened with a single size ball without being limited to pump rate. It was considered imperative to have positive indications of the balls landing on the seats and the sleeves being shifted open within the zone of interest. The previous MSS system was based on severing part of the nozzles for fluid access which needed to be upgraded for better operational efficiency and production enhancement.

The new completion technology is suitable for carbonate formations which are tight, heterogeneous and require stimulation to improve gas production and recovery. Wells drilled in the maximum horizontal stress direction to mitigate hole stability risks and geosteered to maximize the formation contact makes it difficult to stimulate effectively. Therefore, an improved MSS system is required to homogenously distribute the acid across the lateral during the stimulation. This novel MSS completion design was undertaken standardized, well established trial test procedure and was applied in a candidate well and included three stages where two of the stages utilized four sliding sleeves while the remaining stage was integrated with five sliding sleeves. Each stage was isolated by hydro-mechanical packers in the 5.875 in openhole.

Each stage was then monitored using a new surface mounted real-time downhole monitoring system, an electronic device that enables live verification of completion operation events while being independent of pressure. The data gathered from different sources indicated that the sleeves functioned as per design. The production results exceeded the expectations.

This paper describes a novel approach that enhances acid stimulation effectiveness and fulfills stimulation objectives using advanced openhole MSS completion technology. Evolution of the technology and comparison with its predecessor is discussed. It also demonstrates the use of a new surface monitoring system that supplies real time data during sleeve activations enabling clear and accurate detection of downhole events.
Development of low density rigid gels/composites for ESP packer penetrator protection
Authors: Zhao Weishu , Huang Jin , Zoraia Ghanem H. , Xiao Jinjiang
Published: October 2018

Electric Submersible Pumps (ESP) are commonly used artificial lift equipment in production wells. The ESP packer penetrator system is designed to carry the electric power cable that connects the electric motor in ESP to the surface control panel. Various chemicals downhole make up highly corrosive and hostile environments to the metal wires and their insulation materials for electric connectors. Many ESP failures could be attributed to packer penetrator failure due to corrosion of the electric connector beneath the ESP packer.

A method is developed to generate a low density gel system that isolates the electric connector from downhole chemicals in order to provide prolonged protections of electric connectors against corrosive atmospheres and chemical attacks. Mixture of low-density materials/composites are prepared on the surface and then pumped into targeted place through the bypass tubing. The mixture has low density so that it travels upwards in the wellbore and floats on the top of downhole fluids. Under a given well temperature, a rigid gel/composite system forms between the electric connector and the downhole fluids, isolating the electric connector from the hostile chemicals thus providing a better protection. We have developed the low density settable material and demonstrated its performance in the lab scale. It is also scaled up to a mocked up physical simulator to observe the flow dynamics and chemical reaction in realistic geometry.
Reduce the Rate of Abandoning Radioactive Sources in Oil and Gas Wells
Authors: Shhub Abdu Naser , Amer Mustafa
Published: October 2018

Data collected over 12 years indicated an average of 19 radiation incidents per year, related to stuck radioactive sources in well logging. On average 61 % of these stuck radioactive sources have been retrieved, and the remainder sealed in as per protocol.

The goal of this Lean Six Sigma project is to reduce the percentage of abandoned stuck radioactive sources from 39% to 30%.

Analysis of past data shows five parameters with the greatest effect on the percentage of abandonment.

These parameters are: location, onshore/offshore, LWD/wireline, company and fishing duration.

Lean Six Sigma Methodology (5 DMAIC phases) is used to manage this project and two workshops have been conducted to determine root causes and recommendations.

We are currently in the process of implementing 13 recommendations for 13 root causes. Corrective actions have been assigned to stakeholders with an estimate date for completion.
Use of Polymer Resins for Surface Annulus Isolation Enhancement
Authors: Elyas Odai , Alyami Abdullah , Wagle Vikrant , Alhareth Nasser
Published: October 2018

Cementing is an extremely important task in oil/gas well drilling operations to ensure integrity of the well, and to prevent gas and oil migration through the cement matrix for an extended period. This could lead to sustained pressure in the casing annulus (CCA). Sometimes, cements or chemicals are injected from the surface to improve wellbore isolation. Two parameters control this surface operation success; injectivity and pressure.

The objective of this paper is to demonstrate the ability of different types of resins in shallow remedial operations at different parameters of injectivity and pressures to improve wellbore isolation. Examples of these resins are epoxy resin system and polyester resins. Epoxy based resin is prepared by mixing an epoxy resin with an aromatic amine-curing agent. A polyester resin system is made by mixing polyester resin, norpol peroxide curing agent, filler, and silicon dioxide.

Intensive lab testing and pilot testing were performed at shallow conditions to assess the limitation of each type of resin and to optimize on operational procedures. For such surface operations at low injectivity profile, it is expected to have solids free resin for deeper penetration. Short setting resins are desired over extended ones to allow for proper isolation and quick sealing.

The paper will discuss best practices to perform the surface operations and will highlight limitations and benefits of both resins supported by intensive lab testing and field applications.
Semi-Analytical Three-Phase Relative Permeability Model for Gas-Condensate
Authors: Abdul-Latif Benson Lamidi , Abdul-Rashid Bawah
Published: October 2018

Modeling three-phase flow in gas-condensate systems requires the relative permeability of each fluid as a function of the fluid saturation. The Coreflood laboratory and experimental measurement of three-phase relative permeability (3-PRP) data is much complicated, more time consuming and relatively expensive when compared to forecasting two-phase relative permeability data.

Owing to this, many three-phase relative permeability correlations have been proposed in the petroleum industry for estimating three-phase relative permeability using geometric or arithmetic summation and interpolation of two-phase relative permeability data. After comparing results of most of the existing three-phase models to Oaks experiment, we realized that most of the existing three-phase models fail to incorporate the physical mechanisms underlying multiphase flow in gas-condensate systems.

This paper aims to fill this knowledge gap by proposing a novel 3-PRP model to forecast three-phase relative permeability in gas-condensate systems. Three-phase interactions between fluids and fluid saturations are fully incorporated in this model by introducing three-phase characteristic coefficients. Using these coefficients, the total two-phase oil saturation relative to water is not only a function of the three-phase oil saturation relative to water but it is expressed as a function of the three-phase oil saturation with respect to both water and gas.

The proposed 3-PRP model is successfully validated against experimentally measured three-phase relative permeability data.
Success Stories of a Green Chemistry Based Stuck Pipe Solution in Saudi Arabia's Challenging Top Holes Facing Total Losses to Production Holes with High Overbalance
Authors: Hegazy Mohamed , Sharma Sunil , Fares Khaled , ElBatran Ahmed
Published: October 2018

Historically, stuck pipe has been one of the biggest causes of non-productive time (NPT) in Saudi Arabia, resulting in loss of tools, reduced hole footage, and potentially endangering well objectives. Stuck pipe still tops the list of costly non-productive time events worldwide, ahead of items such as well control incidents, waiting on weather, lost circulation, equipment failures, and rig associated problems (Hunter et al., 2014).

In Saudi Arabia, stuck pipe incidents occur in all drilling sections. While drilling top hole sections, they are generally coupled with partial to total losses; in deeper sections, they are induced due to high overbalance. Stuck pipe in top hole sections requires a solution that is environmental friendly, as many aquifers used by local communities are also present in these sections. Since the presence of aquifers limits the use of conventional hydrocarbon-based solutions, a novel non-hydrocarbon-based pipe freeing agent was developed. This new technology eliminates the need to isolate the stuck pipe pills at surface after circulating them out; they can be incorporated into the circulating system because of their excellent environmental footprint. When added in the drilling fluid, these pills improve system lubricity.

This paper presents an overview of successful applications of this novel chemistry in both the top-hole section with total losses and in the production section with overbalances up to 4,400 psi. Performance-based results and advantages of using this solution to improve overall drilling performance will also be discussed in detail. Best practices and lesson learnt for mixing, pumping, displacement, and soaking will also be covered in detail to provide a guideline for operators in similar conditions across the Middle East.
High-Fluid-Loss, High-Strength Lost Circulation Solution for Total Losses Zones in Saudi Arabia
Authors: Hegazy Mohamed , Sharma Sunil , Fares Khaled , ElBatran Ahmed , Dave Alok , Megally Fady
Published: October 2018

Lost circulation is a prominent problem in almost all fields of Saudi Arabia. Losses can vary from partial to total and sometimes also initiate other drilling related issues, such as stuck pipe, kick, and wellbore instability. These complexities make it paramount to cure losses as fast as possible to minimize non-productive time.

Conventionally, discrete pills formulated using a material blend with broad particle size distribution (PSD) are employed first as one of the more popular approaches for curing severe lost circulation. The lost circulation material concentration and PSD are increased in the pills based on loss rates, thus under severe and total loss conditions the pills require use of specialized pumping equipment, by-pass tools, and even the removal of the BHA. Unfortunately, dealing with severe losses in the Kingdom, success rates with these pills are very low. A solution for severe to total losses pumpable through a BHA was the operator's wish.

In this paper, successful field applications proving the advantages of a new high-fluid-loss, high-strength (HFHS) lost circulation solution in different fields, formations, and sections will be covered in detail. The paper will also include operational best practices for mixing, pumping, spotting, and squeezing HFHS pills, lesson learnt, and recommendations for future applications.
Prediction of Inflow Performance Relationship of a Gas Field Using Artificial Intelligence Techniques
Authors: AL-Dogail Ala S. , Baarimah Salem O. , Basfar Salem A.
Published: October 2018

The Inflow Performance relationship is considered one of the diagnostic tools used by Petroleum engineers to evaluate the performance of a flowing well. An accurate prediction of well IPR is very important to determine the optimum production scheme, design production equipment, and artificial lift systems. For these reasons, there is a need for a quick and reliable method for predicting the well IPR in gas reservoirs.

This study presents back propagation network (BPN) and fuzzy logic (FL) techniques for predicting IPR for a gas reservoir. These models involved 489 data points from published literature papers and conventional PVT reports.

Statistical analysis was performed to see which of these methods are more reliable and accurate method for predicting the inflow performance relationship for the gas reservoir. The FL model outperformed the artificial neural network (ANN) model with least average absolute error, least standard deviation and highest correlation coefficient. The proposed fuzzy logic well inflow performance relationship model achieved an average absolute error of 4.303%%, standard deviation of 18.891% and the correlation coefficient of 0.995.

The developed technique will help the production and reservoir engineers to better manage the production operation without the need for any additional equipment. This technique will reduce the overall cost of the operation and increase the revenue.
Evaluating the Effects of Surface Tension and Viscosity on Two-Phase Flow in Horizontal Pipes
Authors: AL-Dogail Ala S. , Gajbhiye Rahul N. , Mahmoud Mohamed , ElKatatny Salaheldin
Published: October 2018

Two-phase gas/liquid flow in pipes is a common occurrence in the petroleum, chemical, nuclear and geothermal industry. In the petroleum industry, it is encountered in the production, transportation, and processing of hydrocarbon from oil and gas field. In designing these systems, accurate prediction of pressure drop is imperative which is determined from flow regime map. Unfortunately, most of the flow regime maps were developed for the air-water system and widely used for the gas/oil system. In spite of the practical importance the general applicability of these maps is not addressed. In order to improve the generality of flow regime maps it is necessary to evaluate the effect of fluid properties such as surface tension which differ by great magnitude (air/water = 72 dyne/cm and gas/oil = 35 dyne/cm) and viscosity (viscosity of water 1 centipoise and for oil 10 centipoises at standard condition) on the flow regimes. Thus, this study aims to evaluate the effects of surface tension and viscosity on the flow regimes in horizontal pipes.

The most flow regime maps are generated using the air-water system and widely applied to the oil-gas system. In addition, the empirical equations based on flow regime maps are not accurate with relatively high error (20-30%). So that the applicability of these maps is limited due to the lacking knowledge of fluid properties effect. Evaluation of these properties will address the applicability of these maps for other systems.

The objective of this study is to evaluate the effects of surface tension and viscosity on flow regimes in horizontal pipes and investigate its effects on boundary transition. The experiments were conducted on horizontal pipe flow-loop (length 30' and diameter 1") with two-phase air/ water. The range of superficial gas velocity is 0-60ft/s and superficial liquid velocity is 0-10ft/s. The effect of surface tension has been introduced by reducing the surface tension with the aid of a surfactant, and the effect of viscosity has been introduced by increasing the viscosity with aid of glycerin. Four different surfactant concentrations (0.02, 0.05 0.1, 0.5%) and four different glycerin concentrations (5,10,20,30%) have been selected to evaluate the effects of the surface tension and viscosity.

The experimental data were utilized to generate flow pattern map and the effect of surface tension and viscosity were evaluated based on the variation in the boundaries of different flow patterns.
New Technology to Evaluate Equivalent Circulating Density While Drilling Using Artificial Intelligence
Authors: Elzenary Mahmoud , Elkatatny Salaheldin , Abdelgawad Khaled Z. , Abdulraheem Abdulazeez , Mahmoud Mohamed , Al-Shehri Dhafer
Published: October 2018

The equivalent circulation density (ECD) is a very important parameter in drilling high pressure high temperature (HPHT) wells and deep water wells. In formations where the margins between the formation pore pressure (PP) and the formation fracture pressure (FP) is narrow, ECD is a key parameter. In these critical operations, the ECD is used to control the formation pressure and prevent kicks. The recent approaches in oilfield depend mainly on using expensive downhole sensors for providing real time values of ECD. These tools also have operational limits which may prevent using it in all downhole conditions.

The objective of this paper is to present a new technique for predicting ECD values while drilling without the need for downhole tools. The technique uses surface drilling parameters in a model to evaluate the ECD values precisely using artificial intelligence (AI) techniques. The model was developed using two AI techniques; artificial neural network (ANN) and adaptive neuro fuzzy inference system (ANFIS). Using this technique will save cost and time by eliminating needs for using expensive, complicated downhole tools like measurement while drilling (MWDs) and pressure while drilling (PWD).

The results obtained showed that the accuracy of the developed model is very high with error factor less than 0.22 % comparing the actual to predicted ECD values. Implementing this model in well design will have great impact in accurately choosing correct mud weights to safely drill the well. It will also minimize the drilling problems related to ECD such as losses or gains especially in critical area where margins between pore and fracture pressure is very narrow.
Dynamic Fluid Pulsation: A Novel Approach to Reservoir Stimulation Improves Post-Stimulation Gains
Authors: Davidson Brett , Kolli Koti , Spanos Tim , Akar Ahmed Abu , Omari Mazen Al , Djelliout Mohamed Amine , Shanoun Djilali
Published: October 2018

One of the major challenges to maximizing recovery of reserves is that every oil or gas reservoir rock is more or less heterogeneous at all scales (micro, mega, and pore) which leads to disproportionate production and injection outcomes. Generally, the higher the level of reservoir heterogeneity the more difficult it becomes to achieve maximum fluid distribution or conformance. Improving conformance in a non-homogenous material such as a hydrocarbon reservoir inherently means improving flow through lower permeability regions. Ideally, during a conventional well stimulation using a treatment fluid such as acid, we wish to move the fluid through the majority of the rock volume but the physical constraints of fluid flow negatively impact that ideal outcome.

Dynamic fluid pulse technology provides for high inertial fluid momentum which improves the flow efficiency of fluids injected into the wellbore, the near wellbore region, and the reservoir. The nature of fluid displacement energy ensures that pulsed fluid will penetrate the matrix proximal to where the tool is placed thus achieving enhanced fluid distribution. Prior to a stimulation operation a dynamic mathematical model associated with fluid pulse technology is employed to generate a precise well program (pumping schedule) to maximize the contact volume of the treatment fluid along the completed interval. Compared with conventional stimulation dynamic fluid pulsation has been demonstrated to bring significant financial benefits to well stimulation without impacting results including: reduced chemical costs; improved post-stimulation sustainability; and, better overall post-stimulation well performance as a greater volume of the completed interval hence matrix is contacted by the treatment fluids.
Cost Estimation of Fire Protection Requirements During Bidding Phase Through Simplified Risk Assessment Methods For Oil & Gas Facilities
Authors: Srikanth Mellachervu , Prabhakaran Abhilash
Published: October 2018

Projects with accelerated engineering, procurement, and construction (EPC) schedules are becoming common in the oil and gas industry with Oil Majors keen on quick and guaranteed returns on investment. EPC contractors involved in the bidding process face the task of submitting ‘qualification free’ techno-commercial proposals within a short time frame which provides challenges to the tenderer for a package having a level of design not mature enough for the estimation purpose. The objective of this paper is to demonstrate a practical approach to the cost estimation of fire protection systems during bidding stage using Simplified Risk Assessment (SRA) methodologies.

The methodology adopted was to conduct a risk assessment for a typical bid to arrive at the sound cost estimate for the fire protection systems. Typically fire protection requirements come in form of recommendations from safety/risk studies, hence cost attached to fire protection requirements were estimated based on the results from SRA for a typical bid. The Fire Risk Assessment (FRA) was performed using DNV-GL PHAST software to carry out consequence analysis to identify the extent of fire impacts. Subsequently, frequency analysis was conducted using parts count methodology to cumulate the frequency of fire scenarios. The most prominent leak scenarios for the study were considered as a part of the simplified approach in lieu of considering exhaustive scenario combinations based on different leak sizes, weather parameters, leak directions, etc., which traditionally forms part of detailed QRA. The selection of prominent leak scenarios was based on the good practice followed in the industry supported by the requirements specified within Operator Standards as well. The Fire Risk Assessment (FRA) results for different time intervals formed the basis for fire protection requirements.

The study has helped to identify fire protection requirements for specific system/equipment/structure and further has helped in the submission of ‘qualification free’ techno-commercial proposals. The advantages of adopting this methodology based on SRA approach are deemed to be well-suited for bidding phase, where the time and cost of carrying out detailed risk analysis is not feasible.

Application of such methodology would also provide benefits to the operators in receiving quick and reliable fire protection cost estimate.
Trailblazing Unconventional Exploration: Out-of-the-Box Solutions Result in Elimination of NPT and Faster Delivery of Challenging Unconventional Horizontal ERD Wells
Authors: Hegazy Mohamed , Sharma Sunil , Fares Khaled , ElBatran Ahmed
Published: October 2018

Drilling unconventional horizontal extended reach wells has always been challenging; coupled with geological and drilling challenges of an exploratory field, they present the perfect combination for non-productive time (NPT). To maximize production, it is paramount to reach the whole reservoir and extract hydrocarbon resources efficiently. Moreover, to increase profits, the well should be drilled in minimal operating time, which in turn reduces operating expenses. This paper presents a detailed study and outline of neoteric practices used to drill four such wells in an unconventional field that resulted in the elimination of NPT and reduced drilling and completion time to less than one-third.

Thirteen wells have been drilled under an unconventional gas exploration project since 2007 with a historical average drilling and completion time of 95 days (and best record of 60 days). Numerous challenges associated with the field (i.e., loss of circulation, hole instability, stuck pipe, bit balling, casing held up) led to an average NPT of 40 days. To eliminate NPT and improve operational efficiency, a detailed study of the offset wells' drilling and mud programs was conducted with the operator. After an in-depth review and analysis, a revised mud program was adopted containing a holistic approach to encounter the challenges faced in offset wells, as they were all interconnected. The use of a novel rate of penetration (ROP) enhancer and proprietary software for precise hydraulics management resulted in improved ROP, elimination of bit balling, and excellent hole cleaning. A modified bridging strategy, using software simulations validated by lab testing and changes in sweeping procedures to avoid wash out and removal of filter cake, cured losses successfully and improved overall hole condition. A totally new composition for mud mixed on location in the event of total losses and use of innovative polyamine inhibitor for reactive formations eliminated hole instability and stuck-pipe incidents. Implementing these customized solutions, combined with precise operating strategy, led to zero NPT and a reduction of average drilling and completion time to 29 days; this saved a total 245 days and an overwhelming cost savings in drilling fluid services cost for the four wells drilled to date.

This paper discusses the outstanding performance achieved while using the existing setup by modifications in operational procedures and inventive techniques. It also describes cost effectiveness, overall performance-based results, and challenges while implementing the strategies. A detailed

comparison of all the challenges that occurred while drilling and the proper troubleshooting steps are also discussed. Finally, the paper compares the existing results with previous drilling techniques, which may help operators with the future development of their respective fields.
Case Study: Innovative World's Slimmest Coiled Tubing Tractor for Stimulation of Extended Reach Wells
Authors: Saeed Abubaker , Saiood Hussain , Arsalan Muhammad , Moore Bruce
Published: October 2018

In extended Reach wells, existing coiled tubing (CT) technologies were unable to pass narrow downhole restrictions and reach target depth (TD) for stimulation operations. Overcoming current limitations in extended reach downhole tools resulted in the development and field use of a slim, compact, and record-setting high pull-force tractor that enables rig-less stimulation, thereby maximizing production and cost effectiveness.

A development project evaluated multiple tractor design concepts, yielding a new generation of an ultra-slim (2-1/8 inch OD) and high pulling force tractor. Exhaustive shop, yard, and flow loop testing verified the tractor's ability to reliably pull in both cased and open hole, employ multiple layers of failsafe technologies, and facilitate rigging up with simpler and less expensive operations. A series of wells with increasing depth and difficulty were used to demonstrate the technology for field use.

The design process verified that the new generation tractor efficiently moves in an accordion-like motion, grips the roof of the hole with an eccentric gripper assembly, and is powered by differential pressure created by pumping fluid down the CT centerline. Shop and Flow Loop testing verified that the eccentric gripper automatically orients itself to engage the high side of the hole, thereby providing an excellent and debris-free surface for traction. Flow Loop testing verified that tractor's ability to circumnavigate high dog leg severity well bores. In one field demonstration, the tractor successfully passed a 2.44 inch restriction, conveyed coiled tubing 2400 feet past lockup reaching well TD of almost 21,400 ft, and averaged 15 feet per minute while running in hole. The benefits of this technology come in the successful operation of a tractor that produces up to 3500 lbs. pulling force, collapses to 2-1/8 inch outside diameter, and operates in 6-1/8 to 7-1/2" inch diameter open hole.

The paper summarizes the research and development of this innovative world's slimmest coiled tubing tractor for stimulation of extended reach wells. It discusses a recent field trial operation including the yard and function surface tests to prepare for this field trial. The paper also explains in details how this technology was successfully deployed, in addition to the broad implications resulting from production engineers having this technology in their tool box, which will permit them to ensure cost efficient operations, maximize production, and will enable rig-less intervention of restricted extended reach wells all over the world.
Optimization of water consumption of hydraulic fracturing treatment by utilizing recycled flowback fluidse
Authors: Al-Arnous Ahmed , Al-Qahtani Nasser , Al-Sugair Bader , Al-Arfaj Ayman
Published: October 2018

As the hydraulic fracturing activities are dramatically increasing in Saudi Arabia, the demand of fresh water supply for stimulation jobs is also growing. Conventional acid/proppant fracturing stage normally acquires 80,000 to 100,000 gallons. In areas where water source is over a large scattered distance, delivering water to locations becomes logistically complex. Therefore, a solution to overcome the dilemma of fresh water scarcity is vital to preserve the resources and save the cost on the long-term.

This paper analyzes the solutions implemented to preserve the fresh water utilization in fracturing applications in the kingdom and the other proposed solutions in the upcoming future. Two methods have been approved successfully into preserving fresh water consumption and alternate the utilization of fresh water resources: Sea-water Nano filtration, and CO2 fracturing fluid. Both applications have been implementing in Gauwar field into gas bearing zones as an acid or proppant treatments. However, delivering sea water from water injection plant, then filtrate it makes the process even more complex than utilizing a fresh water sources. Moreover, such a practice was not economically viable and requires an infrastructure for long term plan. In addition, remote areas and scattered gas fields won't benefit much of this alternative. On the other hand, utilization of CO2 as a base fracturing fluid reduced the usage of fresh water as a current solution. Thus, it is still depending on the formation compatibility and the CO2 quantities in hand.

As a result, a new solution is proposed to overcome the fresh water scarcity especially with the expansion of gas fracturing operations in the kingdom. The need to find a sustainable cost effective alternative is crucial, such as Recycling Flowback fluid to be reused as a base fluid for the next stages on the same well. The process will save fresh water resources, transportation of water from the source to the desired well in the front end and waive the need to treat the flowback fluid and dispose it into the waste disposal area on the back end.

In the gas fields of the kingdom, most of onshore gas wells require fracturing operations to economically produce. More than 50 % of the new wells acquire 3-5 stages to be hydraulically fractured in order to produce commercially and sustain production. In the meantime, 40-60% of fracturing fluid returns back during the flowback operation after each stage where 10% of that fluid is mixed with gel and the rest is a gel-broken fluid. The concern is filtering the fluid after the gel is broken to simplify the process.

In summary, this paper comprehensively reviews the benefit of using a robust fracturing fluid that can utilize 100% produced/flowback instead of freshwater for fracturing operations; that should become the norm as we move into a more environmental friendly paradigm.
Geomechanical Property Computation from Digital Rock Models and Comparison with Core Measurements
Authors: Saad Bilal , Jin Guodong , Ali Shujath Syed , Alshanqaiti Elham
Published: October 2018

Rock mechanical properties are critical to reduce drilling risk and maximize well and reservoir productivity. This paper present a methodology of predicting mechanical properties (Young's modulus and Poisson's ratio) from 3D rock models generated using laboratory measurements or downhole logging data. The 3D rock model provides the microstructure and boundary to simulate rock elastic properties. Mechanical properties are computed from rock models using the finite element method.

Laboratory measurements were conducted on four Berea sandstone samples to determine the mechanical properties for comparison and other properties as input in rock modeling, such as bulk and grain density, porosity, mineralogy, and grain-size distributions. Numerical results from rock models generally match the core measurements of the corresponding samples. The methodology proposed in this study could potentially be applied downhole for predicting the mechanical property profile along the wellbore, as all input parameters to generate rock models can be derived from logging measurements.
Nanoparticle-based chemical treatment for preventing loss circulation
Authors: Wagle Vikrant , Kalgaonkar Rajendra , Al-Yami Abdullah S.
Published: October 2018

This paper provides development of a novel nanoparticle-based chemical treatment composition for its potential use a loss circulation material. The novel loss circulation material is based on a delayed activation chemistry to gel up an environmentally friendly nanomaterial based dispersion. The chemical treatment composition comprises of two major components viz. nanoparticle based dispersion and a chemical activator. A major advantage of the activator used to gel up nanoparticle-based dispersion is its ability to place the treatment composition in to the target zone before the nanoparticle based dispersion gels up thus avoiding premature setting of the treatment fluid. The newly developed system can be used effectively up to 300°F. The gelation times were evaluated at different temperatures up to 300°F. The effects of pH and different concentration of activators on gelation times of the new treatment fluid has also been studied. The effectiveness of the newly developed composition as a loss circulation treatment was also evaluated by performing permeability plugging tests to test the plugging capacity of this novel system.

The novelty of the newly developed treatment composition is to have a controllable gelation time under a variety of downhole conditions to allow accurate placement of the treatment fluid inside the wellbore without premature setting of the fluid. It was shown that the gelation time of the treatment composition could be controlled by adjusting the concentration of the activator. The system gives a predictable and controllable pumping time, ranging from a few minutes to several hours at over a wide range of temperatures. This is an important advantage of as it allows the treatment composition to remain pumpable for sufficient time for placement and develops the network structure that leads to gelation, over a predictable period of time. The set gel, which appears as a crystalline solid, could remain homogenous and stay in place thereby preventing loss circulation.
Advances in near-surface characterization and deep imaging with smart DAS upholes
Authors: Bakulin Andrey , Golikov Pavel , Smith Robert , Erickson Kevin , Silvestrov Ilya , Al-Ali Mustafa
Published: October 2018

A smart distributed acoustic sensing (DAS) uphole system is proposed that utilizes a cost effective, permanently installed fiber as a seismic sensor embedded in the shallow subsurface. Using this system, uphole velocity surveys for near-surface characterization can be acquired with a single shot by recording all depth levels simultaneously. Dense grids of on-demand smart DAS upholes produce more accurate long-wavelength statics than conventional approaches, reducing uncertainty in the interpretation of low-relief structures. Connecting multiple upholes with a single fiber enables seismic surveys to be acquired with buried vertical arrays. These can provide robust images of the deeper subsurface like surface seismic, but with much improved accuracy due to the elimination of most of the near-surface complexities. The system comprising a carpet of surface shots and a dense grid of smart DAS upholes provides a complete dataset for near-surface characterization as well as imaging for oil and gas exploration of low-relief structures.

The proposed smart DAS uphole acquisition scheme was successfully tested on an onshore field in Saudi Arabia. The field test demonstrates the validity of the components and the entire system. Smart DAS uphole data was found to be of excellent quality, while recorded seismic data with buried vertical arrays showed clear reflection signals and produced images of the deeper subsurface.

This paper presents the smart DAS uphole system for near-surface characterization and deep imaging, including a discussion of the processing results from the data acquired during the field tests. We show how the novel acquisition system can be used in the petroleum industry to decrease the risks associated with the exploration of low-relief structures.