bluuebunny/crossref_metadata_2025 huggingface dataset:
Interval Density Analysis From a Distributed Absolute Pressure Array
Authors: Hewlett Richard , Pink Stephen , Goswami Jaideva , Debrosse Daniel , Wright Charles
Published: September 2021

The objective of this paper is to evaluate the effectiveness of a distributed pressure sensor array along the drillstring in identifying and quantifying fluid influx into the wellbore.

As part of a real-time wired drillpipe (WDP) network, distributed sensors can be spaced along the network at varying intervals. In the fall of 2020, a test well was drilled where such a WDP network was utilized, involving 11 discrete sensor packages. These distributed sensors consisted of absolute annular and internal pressure transducers. From these distributed sensors, analysis of various intervals was examined for fluid effects including density analysis. This paper summarizes the findings of the tests and analyses.

The WDP network (Craig, et al. 2013) is the underlying technology that allows for the distributed sensor array and the real-time processing of measured data. Each discrete sensor package is a node on the network. The industry-leading telemetry bandwidth of the WDP network allows for many sensor nodes. The test well drilled in the fall of 2020 gave an opportunity to place 11 sensor nodes along the drillstring. The real-time absolute pressure data collected from these nodes was analyzed for various intervals, calculating differential pressure between pressure sensor nodes and further calculating interval fluid density.

The results of the distributed absolute pressure data provided many interesting observations. The effectiveness of the interval density for quick-look monitoring was greatly enhanced from the more traditional view of the raw pressure data alone. The effects of sensor spacing and sensitivity were easily observed. Tracking variations in fluid density as it transitions through the wellbore can provide insight into fluid mixing, fluid velocity, and transmission time. Transmission time through the various intervals can further provide insight into wellbore conditions. The slope and peak of interval fluid transitions help understand volumetric and specific density details of fluid transitions from events such as drilling mud pills and influx materials.

This novel dataset showcases the power of a real-time distributed sensor array. Multiple intervals of interest can be examined, leading to a new level of wellbore understanding. Information concerning the wellbore fluid can aid in real-time decision making to optimize the wellbore and associated operations, while providing a new level of risk avoidance and safety factor.
Mitigation of Gas Condensate Banking Using Thermochemical Fluids and Gemini Surfactant: A Comparison Study
Authors: Hassan Amjed , Mahmoud Mohamed , Kamal Muhammad Shahzad , Al-Majed Abdulaziz , Al-Nakhli Ayman , Shakil Hussain Syed Muhammad , Patil Shirish
Published: September 2021

Accumulation of condensate liquid around the production well can cause a significant reduction in gas production. Several methods are used to mitigate the condensate bank and maintain the gas production. The most effective approaches are altering the rock wettability or inducing multiple fractures around the wellbore. This paper presents a comparison study for two effective approaches in mitigating the condensate bank. The performance of thermochemical fluids (TCF) and gemini surfactant (GS) in removing the condensate liquid and improve the formation productivity is studied.

In this work, several experiments were carried out including coreflooding, capillary pressure, and relative permeability measurements. The profiles of condensate saturations show that GS can mitigate the condensate bank by 84%, while TCF removed around 63% of the condensate liquid. Also, GS and TCF treatments can increase the relative permeability to condensate liquid by factors of 1.89 and 1.22 respectively, due to the wettability alteration mechanism. Capillary pressure calculations show that GS can reduce the capillary pressure by around 40% on average, while TCF leads to a 70% reduction in the capillary forces.

Overall, injection of GS into the condensate region can lead to changing the wettability condition due to the chemical adsorption of GS on the pore surface, and thereby reduce the capillary forces and improve the condensate mobility. On the other hand, TCF injection can improve rock permeability and reduce capillary pressure. Both treatments (GS and TCF) showed very attractive performance in mitigating the condensate bank and improving the formation production for the long term. Finally, an integrated approach is presented that can mitigate the condensate damage by around 95%, utilizing the effective mechanisms of GS and TCF chemicals.
Naturally Fractured Basement Reservoir Characterization in a Mature Field
Authors: Akbar Muhammad Nur Ali
Published: September 2021

Characterizing the naturally fractured reservoir in a mature field is always a challenging task due to minimal subsurface data availability and the technology was not as advanced as nowadays. Therefore, this paper is proposed to provide an alternative solution to identify the presence of the fractures, classify them into the fractured quality related flowability, and distribute them vertically within the well interval and propose a lateral distribution method for reservoir modeling.

This research was conducted based on a case study of basement fractured carbonate reservoir in Hungary. I used more than twenty development wells which mainly drilled during 1980-2000's. The fractures presence is simply identified by using gamma-ray and density logs. The relative movement of density log to the defined fractured baselines was directed to classify the fracture quality within three groups of macro-fracture, micro-fracture, and host-rock. These groups were validated by core data and the acoustic image log from the newest drilled wells. Furthermore, I implemented the self-organizing map (SOM) for distributing the fracture group to other wells which having limited subsurface data.

Since the fracture classes were distributed along the well depth interval, then the well test (DST) results and production flow test data validated the flowability of them. As a result, the main flow contribution intervals of the fracture can be well-recognized. The macro-fracture consistently indicates the fracture class showing the main contribution of the liquid flowrate more than 10 m3/d along the perforated intervals. The rock properties of this class have porosity range around 1-2% with permeability dominantly more than 100 mD. In contrast, the host-rock class is defined as a protolith/non-fractured rock. The porosity and permeability are extremely low (tight rock). This class does not give any flow contribution due to the high content of the marl or clay, the absence of the fracture, or the fractures had been re-cemented by calcite or quartz minerals. Meanwhile, the micro-fracture denotes the group of rock with porosity range around 2-10% and permeability average between 1-10 mD. In general, the flowrate coming from this fracture class was lower than 10 m3/d of liquid during the flow-test.

As a novelty, this proposed approach with the machine learning of SOM-clustering effectively assists us to recognize the fracture presence and its quality along the well-depth interval from the absence of the advanced technologies of image logs and production logging (PLT) measurement. Also, the defined fracture class here can take a role as a fracture facies or rock typing in terms of 3D reservoir modeling and distributed laterally based on fault-likelihood attribute and fault zone defined by distance-to-fault.
Model Comparison for Esp Run-Life Prediction: Classic Statistics Vs. Machine Learning
Authors: Celemín Alejandro , Estupiñan Diego A. , Nieto Ricardo
Published: September 2021

Electrical Submersible Pumps reliability and run-life analysis has been extensively studied since its development. Current machine learning algorithms allow to correlate operational conditions to ESP run-life in order to generate predictions for active and new wells. Four machine learning models are compared to a linear proportional hazards model, used as a baseline for comparison purposes. Proper accuracy metrics for survival analysis problems are calculated on run-life predictions vs. actual values over training and validation data subsets. Results demonstrate that the baseline model is able to produce more consistent predictions with a slight reduction in its accuracy, compared to current machine learning models for small datasets. This study demonstrates that the quality of the date and it pre-processing supports the current shift from model-centric to data-centric approach to machine and deep learning problems.
Foam Generation in the Presence of Residual Oil in Porous Media
Authors: Almajid Muhammad , Kovscek Anthony
Published: September 2021

This paper studies the effect of trapped, emulsified oil on the requirement for the geometrical Roof snap-off for foam generation in a porous medium. We extend an existing hydrodynamic pore-level model to describe the liquid accumulation in an appropriately-sized pore in the presence of oil. The effect of oil is simulated by adjusting the pore shape to be asymmetrical as observed in microfluidic experiments with residual oil. We alter the boundary and initial conditions of the problem to test various scenarios. Specifically, four cases are presented. The liquid accumulation is presented when the amount of wetting liquid volume connected to the pore is altered through changing the boundary conditions (cases 1 and 2). Moreover, the effect of drier surrounding medium and/or drier pores is also tested by increasing either the capillary pressure surrounding the pore or the capillary pressure of the pore itself (cases 3 and 4). We find that the presence of residual oil affects the liquid accumulation times when there is no external liquid pressure gradient applied. Additionally, residual oil presence makes the Roof snap-off criterion for liquid accumulation stricter. To augment our pore-level study, we use a statistical pore network to observe the effect of the microscopic changes observed in our pore-level model macroscopically. Our results indicate that a stricter Roof snap-off criterion leads to fewer germination sites for lamellae generation. Our pore network analysis computes the generation rate constant to be as much as four times larger in the absence of oil than in its presence. Results suggest that changes to the shape of pore constrictions by emulsified oil reduce the effectiveness of foam generation.
Application of a Novel Analytical Technique to Monitor Corrosion Inhibitor Residual in Oilfield Samples
Authors: Jin Peng , Liu Zhengwei , Jani Jagrut , Murugesan Sankaran , Jackson Tracey , Liu Ya , Ramachandran Sunder , Wronska Malgorzata , Huang Lei
Published: September 2021

Accurate and in-time monitoring of corrosion inhibitor (CI) residual concentration is a key factor in asset integrity management for oil and gas operations. However, the natural variability of CI residual due to field conditions is usually convoluted with the error introduced by sampling and analytical techniques. In traditional analytical techniques, it is typical to encounter error of over 100%. Recently, a novel nanoscale technique (TrueDetect™, TD) was developed to accurately measure CI in the field. This technique is based on a proprietary spectrometry technique and allows quick and accurate analysis of CI residual at the ppm level. The portable instrument allows field samples to be analyzed on-site without the need for shipping them to a centralized laboratory. In the current study, the TD technique was applied to analyze field samples from various fields. Moreover, the TD technique was capable of analyzing CIs at low dosages and could be used as a method to qualify CI products in the lab and in the field.
A Curious Case of Addressing Well Integrity Issue with Production Logging
Authors: Agrawal Gaurav , Kumar Ajit , Verma Vibhor , Mishra Alok , Gualti Vikram , Mahajan Varun
Published: September 2021

The productive life of a well can be affected by deterioration of the well integrity which can be due to casing/tubing corrosion, casing damage during drilling/ work over, packer failure, plug failures, cement integrity issues etc.

Remedial measures can be executed if the nature of problem is diagnosed. One can receive early warning of a potential problem and obtain data for determining a specific restoration program by running well integrity diagnostic tools. There are various well integrity tools available to cater evaluation needs at present times with different working principles and targeting different well integrity problems such as casing/tubing and cement integrity. However, in challenging situation and complex environments, the tools may not provide complete diagnostics.

Production logging can be an effective tool in such scenarios by mapping the flow behaviour in the wellbore and can provide a better idea of the wellbore problems.

The well "A" is a development well which was drilled (max angle~ 27º) and completed in the interval X345-X349m and X362-X368m to exploit gas from the reservoir ABC. During initial testing it produced @ 1, 67,000 m3/d with FTHP of 2348psi. Later after acid job rate increased to 2,20,000 m3/d but later well had frequent water loading problem and required frequent activation / stimulation. The well has good reservoir zones as identified on the OH logs, hence, to diagnose the reason for water production, PLT was planned in the well in 2015. The well was producing 1,00,000 m3/d of gas at an FTHP of 1181psi during that time. Annulus pressure build-up was also observed in the well suggesting integrity issue with packer/tubing.

During the PL run, it was observed that the packer has fallen and settled across one the perforation and the flow was observed to be ongoing from inside as well as outside the packer element making the flow interpretation tricky.

A proper interpretation was carried out taking into consideration all available data and water entry point was confirmed. Based on the results, a well intervention was carried out and after the job, well started producing 1,50,000 m3/d of gas with 0% water cut whereas before it was producing 1,00,000 m3/d of gas with 1900 BPD of water. Thus, the intervention resulted in production enhancement by 50% and reduction in water cut by 100%.

This paper highlights the proper analysis of the recorded data for diagnosis of the flow condition in an adverse and complex scenario and finding out the water entry point for a proper remediation of the well integrity and production issue.
Mitigation of High Temperature Challenges in Limestone Acidizing through the use of Chelating Agents
Authors: Khan Mandeep , Qamruzzaman Mohammed , Roy Dhirendra Chandra , Raman Ravi
Published: September 2021

Acid jobs with conventional acid systems like hydrochloric acid in high temperature conditions is challenging on various fronts. Enhanced reactivity of strong acids results in poor penetration and severe face dissolution. Also, it aggravates the issue of corrosion of downhole equipment and may also result in sludge formation/asphaltene deposition. Worldwide, chelating agents has emerged as a standalone stimulation fluid for high temperature acidizing. Their unique attributes and properties have been proved very useful for acid jobs at elevated temperatures. However, the chelating agents-based formulations need to be carefully evaluated on various acidization parameters for a fruitful stimulation.

Mumbai Offshore field has been encountering the above-mentioned problems in acidizing of its high temperature (>275°F) limestone reservoirs. The paper presents innovative solutions devised for high temperature matrix acidizing. Two chelating agents viz., EDTA (Ethylenediaminetetraceticacid) and GLDA (L-Glutamic Acid N, N-diacetic acid) were explored and evaluated with meticulous laboratory studies. The performance of the chelating agent-based stimulation fluid was compared with acetic acid. Slurry tests were performed to quantify the dissolving power of each acid. Consequently, core flooding tests were carried out to to find the optimum pH of the chelating agents from stimulation point of view. Core flooding studies were performed at anticipated injection rates on representative core samples from a payzone A, with BHT 275-290° F, from Mumbai Offshore. pH optimized formulations were tested against N-80 metallurgy coupons at reservoir temperature for corrosion potential estimation. Also, sludge, asphaltene and emulsion formation tendencies were analyzed with representative oil samples.

The results convey that both EDTA and GLDA were able to mitigate the challenges encountered at elevated temperatures. EDTA and GLDA were found to stimulate the cores with wormholes formed at wide pH range with no face dissolution observed. Chelating agents enjoyed good dissolving power with negligible corrosion rates, absence of sludge and asphaltene deposition, compatibility with formation fluid and excellent iron control properties.
Hydrocarbon Field Re-Development as Markov Decision Process
Authors: Sieberer Martin , Clemens Torsten
Published: September 2021

Hydrocarbon field (re-)development requires that a multitude of decisions are made under uncertainty. These decisions include the type and size of surface facilities, location, configuration and number of wells but also which data to acquire. Both types of decisions, which development to choose and which data to acquire, are strongly coupled. The aim of appraisal is to maximize value while minimizing data acquisition costs. These decisions have to be done under uncertainty owing to the inherent uncertainty of the subsurface but also of other costs and economic parameters. Conventional Value Of Information (VOI) evaluations can be used to determine how much can be spend to acquire data. However, VOI is very challenging to calculate for complex sequences of decisions with various costs and including the risk attitude of the decision maker.

We are using a fully observable Markov-Decision-Process (MDP) to determine the policy for the sequence and type of measurements and decisions to do. A fully observable MDP is characterised by the states (here: description of the system at a certain point in time), actions (here: measurements and development scenario), transition function (probabilities of transitioning from one state to the next), and rewards (costs for measurements, Expected Monetary Value (EMV) of development options). Solving the MDP gives the optimum policy, sequence of the decisions, the Probability Of Maturation (POM) of a project, the Expected Monetary Value (EMV), the expected loss, the expected appraisal costs, and the Probability of Economic Success (PES). These key performance indicators can then be used to select in a portfolio of projects the ones generating the highest expected reward for the company. Combining the production forecasts from numerical model ensembles with probabilistic capital and operating expenditures and economic parameters allows for quantitative decision making under uncertainty.
Retrospective Analysis of Geological Exploration 2010 - 2020
Authors: Mostovoy Pavel , Safarov Ildar , Tumanov Evgeniy , Zaytseva Maria , Aksenov Maksim , Vorobyev Vladimir
Published: September 2021

Oil and gas companies’ future production profile is shaped by their exploration strategy and resource base development. Gazprom Neft's production profile will include 40% of current exploration projects by 2030. Geological exploration, on the other hand, is a high-risk business because it involves a lot of uncertainty due to the geological complexity of the targets being explored, as well as a lot of risky capital.

Taking these factors into account, the Company will need to expand its exploration function as well as its approaches to managing exploration projects in order to meet its lofty aims. To determine the key areas of growth and a strategy for the exploration function development in the coming years, it was decided to first analyze the geological exploration activity in the Company in 2010 – 2020 period.

The knowledge of achievements, success stories, and development areas is the fulcrum for future victories. Therefore, retrospective analysis is an important tool for the development of any system of activity - individual, organization, or state.
Rate/Pressure Transient Analysis of a Variable Bottom Hole Pressure Multi-Well Horizontal Pad with Well Interference
Authors: Chu Hongyang , Liao Xinwei , Wei Cao , Lee John
Published: September 2021

Multi-well horizontal pads are common in unconventional reservoirs. With addition of infill wells and hydraulic fracturing, interference between multiple multi-fractured-horizontal wells (MFHWs) has become a serious issue. Current RTA workflows assume a single MFHW in the unconventional formation. This paper presents a new multi-MFHW solution and related analysis methodology to analyze targeted well rate performance in a multi-MFHW system.

In this work, a semi-analytical equation describing multi-well pad in the Laplace domain with well interference is proposed. The proposed semi-analytical model can simulate the rate performance of a multi-well horizontal pad with variable BHP for a targeted well in the pad and different initial production durations for the offset well. From the constant BHP condition and Laplace transforms, we obtained multi-MFHW solutions for transient flow. We used superposition of various constant BHP solutions to study interference among various fractures and MFHWs. The variable BHP of the targeted well is achieved by a variable dimensionless BHP function in the Laplace domain without any convolution or deconvolution calculations. A systematic validation for the proposed method is conducted using a commercial numerical simulator for cases of different initial production times for offset MFHWs, multi-MFHWs with variable BHP. Through the total material balance of the multi-MFHW system, we can analyze a target well in the pad with this multi-MFHW analysis. Interference by offset wells often appears after pseudo-radial flow in the target well's hydraulic fracture. It causes the pressure derivative curve during elliptical and infinite-acting radial flow (IARF) to rise, as does the RNP derivative. The inverse semi-log derivative has the opposite trend. Well interference also makes the rate/pressure drop functions to deviate from initial straight lines in later stages. Sensitivity analysis of well spacing shows that "transition flow" will change from elliptical to formation linear flow between wells as well spacing increases and it can show the transitional flow characteristics in more common cases.
Experimental and Modeling Studies on Pressure Gradient Prediction for Horizontal Gas Wells Based on Dimensionless Number Analysis
Authors: Luo Chengcheng , Wu Ning , Dong Sha , Liu Yonghui , Ye Changqing , Yang Jianying
Published: September 2021

Accurate prediction of pressure gradient in gas wells is the theoretical basis of gas well performance analysis, production optimization and deliquification technologies design. Experiment is the best access to characterize the flow behavior of gas wells. For low-pressure experimental investigation and gas wells, the most difference is the pressure (gas density), which could lead to totally different flow behavior. Dimensionless numbers are often used in the flow pattern maps to account for the flow similarities at different conditions, which means liquid holdup in the high pressure can be also predicted at low pressure conditions if we choose proper dimensionless numbers for pressure scaling up. However, no studies have focused on this point before. Besides, gas wells have high GLR, most empirical models were intended to developed for oil wells, which have greater weight in low GLR, decreasing the accuracy in gas wells.

In order to predict the pressure gradient in horizontal gas wells, an experimental investigation of gas-water flow has been conducted. The experimental test matrix was designed to cover all the flow patterns. The experiment was conducted in a 5-m long pipe. The liquid holdup and pressure gradient were measured. Subsequently, the effect of gas velocity, liquid velocity, pipe diameter, and inclined angle on liquid holdup was analyzed. Then the dimensionless numbers proposed in the literature have been investigated and analyzed for pressure scaling up. Finally, a comprehensive model was established, which is developed for prediction pressure drop in gas wells. Some field and experimental data were provided to evaluate the new model. The results show that the Duns-Ros dimensionless number was not proper for pressure scaling up while the Hewitt-Robert Number performs best. Compared to widely used pressure gradient models with field data, the new model with Hewitt-Robert Number performed best, which shows that it is capable of dealing with prediction of pressure gradient in gas wells.
Cementless Well Construction Opens the Full Control on Well Integrity for the Life of the Well
Authors: Teodoriu Catalin , Bello Opeyemi , Vasquez R. R. , Melander Ryan M. , Esquitin Yosafat
Published: September 2021

Well construction has relied on two main elements, casing and cement, to achieve the well goals while maintaining the highest possible well integrity. Can cementless well construction achieve similar goals? This paper is investigating the various well construction concepts proposed over the years and will analyze the cement's ability to withstand long term well loads.

First, a review of various well construction concepts such as slimhole, conventional, pre-salt and horizontal wells. We will normalize the casing to cement thickness ratio by validating and proposing a simple mathematical calculation for establishing this ratio. Our calculations have shown that in the case of slimhole well concept, the thin cement sheath cannot serve as a strong well barrier as defined by current standards, and thus a new solution might be necessary.

The second part will look at current new trends in wellbore construction that include external casing packers and other solutions such as metallic wellbore isolation solutions. Hydraulically expanded metal packers are a robust and reliable alternative to cement. They are each mounted to a casing joint and can be rotated while running in hole. They have a proven deployment track record of high diametrical expansion, conforming to the wellbore geometry, while isolating differential pressures more than 15,000psi. Exploration of load carrying capabilities will be completed using Finite Element Analysis (FEA), simulating the different well scenarios as described in the previous paragraph. This will enable us to establish which well types can use this novel technology for the replacement of cement.

The paper will conclude with one possible solution that could be used to mitigate cement problems by shifting the well construction concept to a cementless new era. Also, understanding that the cement manufacturing process is highly CO2 intensive, emissions per well could be reduced through the newly proposed concept.
The Use of Augmented Reality and 3D Visualization in Petroleum Engineering Education
Authors: Alyafei Nayef , Fadlelmula Mohamed , Sheharyar Ali , Idris Mohamed , Retnanto Albertus
Published: September 2021

The objective of this paper is to showcase the applications of augmented reality and 3D visualization to enhance the learning process of petroleum engineering concepts. In this study, an educational magazine covering various components of an offshore drilling rig with embedded 3D models is used. In addition, the magazine includes simplified text describing the definition and functionality of various drilling components.

The prototype of this magazine was sent to both current and former students of Texas A&M University at Qatar and was accompanied by a survey designed to evaluate the efficacy of the magazine. The participants showed a significant favor towards the use of augmented reality and 3D visualization in petroleum engineering education through the survey. Overall, the augmented reality experience provided has given the participants a new dimension in the interactive-learning field. Also, the magazine provides a unique experience to visualize petroleum engineering operations and concepts in the midst of COVID-19, where many trips and experiences are limited.
Top-Down Approach to Area Development Plan Maturation
Authors: Muhammad Yasin Muhammad Yazuwan Sallij , Muhammad Ir. Suhana , Wan Mohd Zamri Wan Fatin Izyan , Mohd Radzi Shahrul Nizam
Published: September 2021

In maturing an Area Development Plan (ADP), most of the data used are incomplete, too fragmented, or sometime due to time constraint; need to be deduced down to assumptions. Due to this fact, an ADP is bound to have updates, even during the course of maturing it. This is where the issue starts. Since the conventional approach is "bottom-up", room to accommodate changes is limited; at times require the whole proposal to be reworked. This is because it focuses on getting the best development concept for a given field first before rolling it up to study the network/interrelationship between fields.

A "top-down" approach in maturing an ADP intends to better assist any given team to be agile whilst focusing on value added solutions from a strategic bird's eye point of view. The approach in discussion was adopted and tested to a regional ADP study in year 2020 which initially involves more than 1000 fields (discovered, prospects, and leads). This approach allows for any changes throughout the course of maturing the ADP because, its main focus is to get the best network/interrelationship between fields first, before focusing on the development concept of each of the fields.

Other benefits that can be observed by adopting the approach in discussion is a shorter study duration. Based on the case study, the study duration was reduced from 10 months to 6.5 months. With shorter duration too, can help the Company in better manage its manpower resources to focus on things that matters.
Achieving Uniform Fluid Distribution with a Custom-Designed Organic Solvent Maximizing Coiled Tubing Reach During Matrix Acid Stimulations
Authors: Saiood Hussain , Duthie Laurie , Aybar Umut , Molero Nestor
Published: September 2021

The success of stimulation fluid placement in openhole extended reach wells (ERWs) through coiled tubing (CT) is highly dependent on the depth achieved. Friction forces and helical buckling typically cause early CT lockup, which limits the reach. Organic deposits in the wellbore increases frictional forces causing premature lockup or in some cases even complete blockage. Efficient removal of organic deposits enables CT to reach maximum depth to perform the matrix stimulation.

Analysis of these organic deposits was conducted and following a thorough comparative test, a new solvent-external phase emulsion inhibitor was selected to treat the wellbore prior to matrix stimulation. Optimum cleanout methodology was identified for the CT run with a high-pressure jetting nozzle (HPJN) combined with a chemical dissolution effect of the chosen solvent. Focused, high-energy fluid streams loosen any compacted deposits, while the high rate of fluid passing through the tool allows for an efficient cleanout. A matrix stimulation treatment with CT was then executed in the openhole section of the ERW with a TD of 18,773-ft (9800-ft horizontal lateral section) with HCl and emulsified acid systems.

By using a solvent-external phase emulsion, only the external phase of the emulsion containing the dissolver is in contact with organic deposits; the remaining internal phase fluid is not. This therefore allows a reduction in total solvent volume. The proposed wellbore cleanout treatment with HPJN reduced the friction coefficient between CT and the completion by 10%. In turn, it was verified that during the operation, an additional 3,320 ft of reach was achieved in the openhole section. Combined with other extended-reach techniques (i.e., mechanical agitator tools, friction reducers), it allowed the 2.0-in CT pipe to reach the TD of the well (18,773 ft). These efforts together maximized the reservoir contact during the matrix stimulation in the openhole section with HCl and emulsified acid systems. Distributed temperature sensing (DTS) methodology was used with the aid of fiber optic installed CT, and the intake profile of the openhole section was mapped. Analysis of the data was applied to optimize the pumping schedule to obtain uniform production contribution across the openhole section.

The systematic engineering workflow presented includes the organic deposit diagnostic procedure, laboratory testing, chemical selection, and treatment application. This yields a wellbore treatment that minimizes friction for the remainder of the operation and enables maximum CT reach. This provides more insights of integrated matrix stimulation treatment with CT to overcome the serious challenges present in extended reach openhole wells.
A Methodology that Enables Real Time Large Volume Reservoir Testing for Deeper Reservoir Targets in Old Wells Without Damaging the Existing Upper Reservoir Layers
Authors: Karacali Ozgur , Bellabiod Sofiane , Theuveny Bertrand
Published: September 2021

Pressure transient testing has been significantly revamped and various types have been applied for numerous motives over the past decades. In this paper, a methodology and adapted technology have been discussed in detail for enabling downhole testing operations with existing open perforations above the test packer. This methodology enabled successful downhole testing operations where conventional annulus hydraulic pressure pulse system was ruled out for numerous reasons, such as existence of perforated zones above zone of interest and/or well integrity constraints.

The proposed method is based on an acoustic, wireless, bi-directional downhole to surface communication telemetry system. The process utilizes acoustic signals to control downhole tools and transmits downhole measurements in real time through a secured network connection. The procedure used in this well testing methodology is proven successful in numerous well test operations for exploration and appraisal wells in Algeria. The continuously unfolding downhole data has enabled end users and stake holders to take actions and decisions that maximized the value gain while optimizing the test durations and drilling rig utilizations.

The successful application of this proposed methodology has enabled parameter estimation during the execution phase of the well testing operations. Data measured in real time is coupled with reservoir engineering interpretation to ensure meaningful sub-surface evaluation. Wellbore dynamics and several other inherent noise sources have been successfully identified to avoid snags of misinterpretation. Wells needing stimulation treatment or longer clean-up durations to enhance the well to reservoir communication quality have been handily identified in real time. The methodology has proven hydrocarbon existence in unexplored layers while enabling incorporation of additional test objectives with further assessments of zones of interest. Real time data greatly reduced uncertainties in well behavior and assisted in informed-decision-making process to adapt well test programs in real time. All well testing objectives were achieved by addressing various challenges that are inherent to conventional memory mode downhole testing operations.

The methodology presented will enable the downhole testing operations through drill stem testing (DST) in complex wellbore geometries where conventional well testing approaches were rendered unattainable. The proposed solutions will warrant downhole testing of previously un-appraised formation layers that are overlain by perforated producing reservoirs. The methodology is described in detail and systematically so that the procedure and learnings from Algerian hydrocarbon producing basins can be adapted and applied to other well tests elsewhere around the globe.
Mud Motor PDM Dynamics: An Analytical Model
Authors: Samuel Robello , Baldenko Fedor , Baldenko Dmitry
Published: September 2021

In a fast drilling environment, suchas shale drilling, refining advanced technologies for preventing downhole toolfailures is paramount. Challenges are still very much associated with complex bottom-hole assemblies and the vibration of the drill string when used with a downhole mud motor. The mud positive displacement motor with various lobe configurations and designs becomes an additional excitation source of vibration. Further, it affects the transient behavior of the performance mud motor. Unbalanced force exists because the center ofmass of the motor rotor does not coincide with the axis of rotation.Further, the vector of full acceleration of the center of the rotor can be decomposed into two perpendicular projections—tangent and normal—which aretaken into account and integrated intothe full drill string forced frequency modelas force and displacement at the motorlocation. The paper includes two models, first one to predict the critical speeds and the second one to see the transient behavior of the downhole parameters when the mud motor is used.The model also considers the effect of the stringspeed. The unbalanced force is more pronounced at the lower pair or lobe configuration as compared to the higher pairlobe configuration because of the larger eccentricity. The unbalance is modeled in terms of an equivalent mass of therotor with the eccentricity of the rotor. Also, the analysis provides an estimation of relative bending stresses, shear forces, lateral displacements and transient bit rpm, bit torque, and weightone bit for the assembly used. Based onthe study, severe vibrations causing potentially damaging operating conditionswhen transient downhole forcing parametersare used for the vibration model.It has been found that when a mud motor isused using static forcing parameters may not provide the conservative estimation of the critical speeds as opposed totransient parameters. This is because coupled oscillations fundamentally can create new dynamic phenomena, which cannot be predicted from the characteristics of isolated elements of the drilling system.
Corrosion Challenges on Electrical Submersible Pump Wells in the North Kuwait Field
Authors: Al-Majdli Abdullatif , Martinez Carlos Caicedo , Al-Dughaishem Sarah
Published: September 2021

Oil production in North Kuwait (NK) asset highly relies on artificial lift systems. The predominant method of artificial lift in NK is electrical submersible pump (ESP). Corrosion is one of the major issues for wells equipped with ESP in NK field. Over 20% of the all pulled ESPs in 2019 and 2020 in NK field were due to corrosion of the completion or the ESP string. With an increase in ESP population in NK, a proactive corrosion mitigation is essential to reduce the number of ESP wells requiring workover. Historic data of the pulled ESPs in NK revealed that most of the corrosion cases were found in the tubing as opposed to the ESP components. Although there are multiple factors that can cause corrosion in NK, the driving force was identified to be the presence of CO2 (sweet corrosion). Corrosion rates have been enhanced by other factors such as stray current and galvanic couples. In this paper, multiple methods have been suggested to minimize and prevent the corrosion issue such as selecting the optimal completion and ESP metallurgy (ex. corrosion resistant alloy), installing internally glass reinforced epoxy lined carbon steel tubing, and installing a sacrificial anode whenever applicable.
The Role of Pre-College STEM Education in Student Enrollment in Petroleum Engineering
Authors: Alyafei Nayef , Shaikh Afsha , Gharib Mohamed , Retnanto Albertus
Published: September 2021

Final-year high school students are faced with a difficult decision when selecting their undergraduate major of choice. Often, the decision is made even more difficult by uncertainty about what different majors entail. Petroleum engineering in particular is a discipline that is generally not explored within high school classrooms and therefore students lack understanding about the roles of engineers in the oil and gas industry. To combat this uncertainty, this paper explores the potential of running pre-college project-based learning programs to increase high school students’ interest in and familiarity with pursuing various undergraduate STEM disciplines and careers. More specifically, this paper provides an insight into two case studies of novel STEM education programs, developed to enhance a group of high school students’ understanding of petroleum engineering.

The programs were designed to increase students’ interest in learning about the selected petroleum engineering concepts, namely polymer flooding to enhance oil recovery and multiphase fluid flow in porous media, while simultaneously providing an understanding of the current global challenges faced by the oil and gas industry. The program also aimed to engage students in learning and applying fundamental engineering skills to relatable real-world issues. These project goals will help facilitate the desire, commonly seen in recent years, of developing countries to increase their oil and gas production. This program was applied during the Summer Engineering Academy program offered by Texas A&M University at Qatar, which provides an innovative educational space for high school students. The program was conducted with the main objective of allowing the students to understand the basic concepts of petroleum engineering via short lectures as well as laboratory experimentation. Students in Grades 9-11 spent 10 days learning about petroleum engineering applications that integrated science, engineering, and technology where they designed, built, and tested an experimental setup for understanding various processes in petroleum engineering. Students were expected to solve a common problem faced in the petroleum industry. At the end of the program, the students gained an understanding of the issues and recommended unique solutions to these problems in the form of oil-recovery based projects presented to a panel of experts. This program attempted to build bridges between the STEM education pipeline of rapidly developing countries, such as Qatar, and the new demand for talent in the oil and gas sector. The details of this novel program are presented, including the content, preparation, materials used, case studies, and the resulting learning outcomes.
Using an Adjustable Cone Meter to Measure Wet Gas
Authors: Mahalingam Sakethraman , Munro Gavin , Arsalan Muhammad , Gawski Victor
Published: September 2021

When the gas flow rate of a well significantly changes, the flow rate can fall below that of the operating range of a traditional fixed size Venturi meter, necessitating the replacement of the original meter with one of a smaller size. However, with an adjustable cone meter, the internal reconfiguration feature allows it to automatically switch from high operating flow range to low operating flow range and there is no requirement to disassemble the meter from the flow line assembly. Adjustable cone meters were designed, developed and tested at the wet-gas flow loop at National Engineering Laboratory in East Kilbride, Scotland. After calibrating the meter with dry nitrogen gas, the meter was tested with increasing amounts of liquid being injected into the flowline, upstream of the meter. The liquid caused the differential pressure measurement on the meter to over-read. Based on the differential pressure measurements under varying flow conditions, algorithms were developed to measure the dry gas and liquid fraction. The data obtained from the tests such as differential pressure, pressure, temperature, liquid density were used to build an over-reading model of the meter and a liquid fraction estimation model based on pressure loss ratio derived from an additional differential pressure measurement. The model was used to not only to quantify the gas and liquid flow rates but also the estimated error in each measurement. The measurements show that the Adjustable Cone meter is able to provide low uncertainty in both dry and wet gas conditions and offers a turndown ratio of up to 54:1 in dry gas conditions. In addition, the automatic adjustment of the meter from high flow to low flow positions avoids the need for manual intervention that involves additional risk and cost.
Corrosion and Wear Resistant Boronizing for Tubulars and Components Used Down-Hole
Authors: Machado Roger , de Sales Bastos Paola Andrea , Socorro Royero Danny Daniel , Medvedovski Eugene
Published: September 2021

Components and tubulars in down-hole applications for oil and gas production must withstand severe wear (e.g. erosion, abrasion, rod wear) and corrosion environments. These challenges can be addressed through boronizing of steels achieved employing chemical vapour deposition-based process. This process permits protection of the entire working surfaces of production tubulars up to 12m in length, as well as various sizes of complex shaped components. The performance of these tubulars and components have been evaluated in abrasion, erosion, and corrosion conditions simulating the environment and service conditions experienced in down-hole oil and gas production. Harsh service conditions are very common in the oil industry and the combination of abrasion, friction-induced wear, erosion, and corrosion environments can be quite normal in wells producing with the assistance of artificial lift methods. The boronized steel products demonstrated significantly higher performance in terms of material loss when exposed to harsh operating conditions granting a significant extension of the component service life in wear and corrosion environments. As opposed to many coating technologies, the boronizing process provides high integrity finished products without spalling or delamination on the working surface and minimal dimensional changes. Successful application of tubulars and components with the iron boride protective layer in oil and gas production will be discussed and presented.