bluuebunny/crossref_metadata_2025 huggingface dataset:
Integrated Thermodynamic Digital Twin for Energy Performance Monitoring of Large Compression Units
Authors: Sajjad Saqib , Al Jenaibi Eisa , Hakki Praveen
Published: November 2020

The compression units installed on sales gas network face wide range of operating modes owing to the varying supply & demand scenarios and the associated network dynamics. It is very challenging to ascertain the real performance in such applications due to changing specific energy consumption. The paper presents development of a novel and robust monitoring system, enabling realtime energy performance monitoring of dynamic compression and revealing realistic opportunities for energy savings.

The methodology comprised review of design and OEM data for the compression units, followed by review of operating envelope. Subsequently, developed a thermodynamic model of compression units encompassing all the operating modes. Then embedded the actual performance curves from OEM in the thermodynamic digital twin and validated the model with actual operating data. Carried out site visits and held discussions with technical teams as part of the comprehensive approach. A mathematical model additionally developed, in addition to the thermodynamic model, to enable operators for off-line monitoring of the compressors performance during unavailability of thermodynamic digital twin.

Detailed performance analysis of centrifugal compressors is essential to ascertain their condition and functioning. A decrease in performance can be an indication of internal wear or fouling, which if allowed to continue, may result in reduced throughput or excessive energy consumption or even unscheduled outages. Thus, the performance is not just an indication of energy or operating cost but also reflects other vital aspects like reliability. The integrated thermodynamic digital twin developed for large sales gas compression units, with total throughput capacity of more than 500 MMSCFD, has enabled and demonstrated effective energy performance monitoring even with changing operating scenarios. It facilitated real-time comparison of actual performance (specific energy consumption) with model based expected performance. It also aided real-time trending of polytropic efficiency as well as real-time display of potential energy savings opportunities. The digital twin has proven to be a reliable and low cost tool to predict compressor performance for various operating modes on real time basis. The data from the compression digital twin can be tied into process simulation models for process optimization. The model can complement supervisory capabilities, diagnostics, control capabilities and even facilitate in predicting failures ahead of time.
Psychological Risks in Professional Activities of Oil and Gas Workers in the South and North
Authors: Korneeva Yana , Simonova Natalia , Degteva Galina
Published: November 2020

The purpose of research is to perform a comparative analysis of psychological risks in professional activities of the oil and gas workers in the south and north. The study was conducted on the offshore ice-resistant platform, the Caspian Sea (April 2019), 50 employees took part in it (fly-in-fly-out duration - 14 days) and in the oil production in the Far North, where 70 employees took part (fly-in-fly-out duration: 30 days). Research methods are questionnaire, psychological and psychophysiological testing. Assessment of professional risk was carried out by comparing objective functional state indicators of employees and assessing their performance. We studied both the personality traits of employees and the characteristics of their adaptability, depending on their relevance to various professional groups. The question was solved which employees who successfully perform their work on land (oil field) will be able to be successful while working at sea (oil production platform) in the context of climatic conditions. Results, For the first time, a variable model of psychological risks of oil and gas personnel was developed, including a differential assessment of environmental and personal resources and focused on isolation, control and reduction of psychological risks in professional activities.

Peculiarities of the environmental oil production resource during fly-in-fly-out work organization taking into account risk factors when working on land and at sea are revealed. The professionally important qualities of oil and gas of personnel were identified and differentiated under the conditions of various comforts of professional activity and life in the fly-in-fly-out camp and on the oil production platform. For the first time, a study was conducted to identify the psychological risks of workers of the offshore ice-resistant oil platform in the Caspian Sea through a scientific expedition. The data obtained as a result of this expedition are unique and are of great scientific and practical value.
Accuracy Prediction of Zero-Survey Time Definitive Dynamic MWD Surveys
Authors: ElGizawy Mahmoud , Lowdon Ross , Edmunds Michael , Breen Michael , Ekwue Winner
Published: November 2020

Wellbore surveying is essential to deliver the objectives of a well; it is, however, time-consuming, increases the risk of differential sticking, and due to its costs, may not often be done enough to describe the wellbore architecture adequately. Measurement While Drilling surveys are taken traditionally while stationary. A new surveying tool featuring Definitive Dynamic Surveys (DDS) allows the same or better levels of accuracy to be achieved when drilling, eliminating the need for stationary surveying time, working the drillstring, or taking additional time to plan the next directional move. Definitive surveys are delivered to the directional driller in real-time to allow them to focus on the efficient delivery of the wellbore trajectory. This provides a step-change in drilling performance, eliminating surveying time and reducing drilling risks. Additionally, this paper describes the framework for determining the accuracy of DDS surveys in terms of wellbore positioning. As measurements are taken while rotating, the standard stationary MWD error model does not apply in all respects.

An analysis of drilling efficiency savings is conducted, looking at the rig time savings from eliminating static MWD surveys, directional improvements compared to similar previous well, and the reduction in open hole pumps off time giving an indication of the improvement in stuck pipe risk mitigation. Furthermore, the tool accuracy mapping to position accuracy is quantified, and it involved three steps. First, identify the error sources that corrupt the measurements and their propagation modes. Second, mathematically deriving partial derivatives that map these error sources to uncertainty in the direction of the wellbore. Finally, determining the appropriate magnitude of such error sources.

In deriving the error model magnitudes, this provided the minimum viable parameters that the DDS survey had to meet, notably in terms of sensor misalignments, shock and vibration parameters, eddy current compensation, and phase shift corrections. DDS surveys have been tested and verified, and this paper outlines how this has been done, and the magnitudes for the final derived errors in terms of bottom hole positioning errors compared to stationary MWD surveys. The savings in rig time, directional control, and the reduction in stuck pipe risk are significant and critically reduce time spend off bottom, which is becoming a larger portion of a well's AFE.

DDS surveys offer much more efficient rig operations, improved borehole quality, trajectory control, and higher survey density than traditional stationary MWD surveys. The efficiency improvements DDS provides are a step-change in the drilling process. DDS surveys are completely unique in offering stationary MWD survey quality while drilling; being unique, they have some unique error terms that have to be derived, populated, and verified, which are presented in this paper.
Automated Connection Integrity Beats Traditional Tubular Running by Delivering Zero Rejected Joints, Efficiency Enhancements, and Personnel Reductions
Authors: Mihalic Goran , McIntire Scott W.
Published: November 2020

The automated connection integrity system known as Vero employs computer-controlled makeup and autonomous evaluation algorithms to run and pull completion strings. Results from automated and traditional (non-automated) equipment on similar jobs shows the difference.

This paper compares thread inspection reports after running and pulling completion strings using both types of equipment. The automated jobs included three completion runs and pulls; the traditional job included one completion run and pull with the same type and size of tubulars in the same well configuration. Comparing additional data on personnel reduction and operational efficiency, including joints per hour and rig and rig down time, provides insight into overall system efficiency, safety, and well integrity benefits of the automated system over traditional ones.

The thread inspection results from 761 connections after completion pullout show 77% of tubulars passed with the automated system; however, zero passed with traditional equipment. In addition, the automation system reduced rig up and down time by 25% and personnel up to 50% during heat stress periods, which required six instead of 12 people. Over the nine jobs for this customer, Vero helped to make up more than 1,200 connections with zero rejected and laid-down pipes. The precise torque control enables operators to achieve the final torque at liner maximum torque and the allowed higher torque while reaming the liner string to total depth (TD) on drillpipe. With computer control of rotations per minute (RPM) and torque, Vero delivers a 2% variance of final torque, which enables operators to target the higher end of the maximum torque recommended by the original equipment manufacturer (OEM) without exceeding the limit. These higher makeup values enable applying higher torque while reaming the liner string to TD on drillpipe in challenging wellbores.

The Vero system uses computer-controlled processes for automating the makeup, breakout, and evaluation of premium connections. This solution controls the makeup and breakout parameters to reduce thread damage caused by rig-floor conditions while consistently achieving and thoroughly evaluating OEM criteria. Through automation, Vero improves operational performance while enhancing safety risk management and well integrity assurance.
Removal of Oil From Oily Industrial Wastewater Through Resin Technology
Authors: Tejero Àngels , Das Supriyo , Gómez Verónica , Pandya Hardik
Published: November 2020

Produced water and industrial waste water contamination is given by a combination of the creation of stabilized oil emulsions and the presence of soluble oil components. Typical components include alkanes, BTEX (benzene, toluene, ethylbenzene and xylenes), high amounts of dissolved solids, suspended solids, heavy metals, high content of biochemical oxygen demand (BOD) and chemical oxygen demand (COD). Failing to clean-up this oily water before disposal can have severe environmental consequences. Since most conventional water-treatment technologies are also negatively impacted by the presence of emulsified oil, development of appropriate oil removal technology is also in the best interest of any water reuse scheme. This paper includes several trials that have been carried out with industrial wastewater water containing both emulsified and dissolved oil for the evaluation of performance of two polymeric resins.

The present study has tested synthetic oil emulsions in a controlled environment to evaluate the impact of typical operating conditions on removal efficiency. Bench testing and piloting have been carried out with real wastewater originated from various sources in the Tarragona industrial petrochemical complex (Spain). Samples with oil content ranging from 10 to 1000 mg/L of Total Petroleum Hydrocarbons (TPH) have been tested. Results show that a coalescer-type resin can effectively target emulsified oil, and in the correct operating conditions can achieve up to 90-98% removal. Furthermore, this is a technology that is not negatively affected by high concentrations of oil. On the contrary, results indicate that higher concentrations of insoluble oil contribute to improving overall efficiency. It has been identified that residual TPH can be attributed to water-soluble species, because a second pass does not improve performance. A polymeric adsorbent can remove dissolved oil components-such as phenols, BTEX and PAH-with an efficiency of over 99.9%. However, rapid saturationa and its fouling problems when confronted with emulsified oil indicates ideal solution for treating oily waters would be successive treatment with a coalescer and an adsorbent resin. This study shows, through testing of real-life samples from industrial wastewater that polymeric resins are able to remove both the emulsified and dissolved oil from oily water, and how composition has a significant influence on its removal.
New Methodology for Quantitative Cement Evaluation Using Sonic Logging while Drilling: First Application in Middle East
Authors: Al-Fawwaz Abdullah , Alsenan Duaa
Published: November 2020

Well Integrity is a major concern and a crucial step during the life cycle of the well. That is especially the case after the Macondo incident that changed the perspective of well integrity and proved how misinterpreting the data can lead to severe consequences to the safety of people, financial and environmental impacts. With the new innovations and technologies that we have nowadays, the oil and gas industry has expanded and entered more complex and challenging environments. The technological development of directional drilling allowed better reach and better oil and gas production from the reserves by using multiple angles while drilling. In Saudi Arabia, thousands of wells drilled each year where numerous cement integrity challenges faced especially in high angle wells. Wireline (WL) developed their tools over many years to provide an advanced assessment for cement bond evaluation with a reliable measurement. However, many local cases where observed where cement evaluation through WL was not a possible option due to some challenges such as well control issues and downhole condition. As a result, we needed to implement an alternative solution that can provide a quantitative cement evaluation through different means to address client challenges in cases where the WL service is not a valid option.

Due to the high demand for real-time logging and rig time saving, Logging While Drilling (LWD) expanded its service offerings to address client challenges related to well integrity. In 2004, LWD started to provide top of cement (TOC) service utilizing its sonic tool that indicates qualitatively the presence or absence of cement in the annulus. However recently, LWD developed the first algorithms that delivers a quantitative cement evaluation through an LWD sonic tool utilizing a hybrid methodology. This new approach is a combination of two different types of interpretation which are amplitude-based and attenuation-based methodologies.

This paper will present a successful trial test of the quantitative cement evaluation through LWD that was done in Hout Field in Saudi Arabia and verified with conventional WL cement bond log. The results of this test proved that LWD cement evaluation can be a viable alternative solution to running WL logs. Especially when the conveyance of WL is not feasible or even as a cost-effective solution to save tripping time.
Highly Efficient Modified Activated Carbon as Shale Inhibitor for Water Based Drilling Mud Modification
Authors: Arfaj Mohammed K. , Rana Azeem , Saleh Tawfik A.
Published: November 2020

Maintaining wellbore stability while drilling is critical to mitigate operational problems and reduce well construction costs. This is clearly evident in the case of drilling troublesome intervals such as shale formations. The current study describes the effect of diethylenetriamine modified activated carbon (DETA-AC) on the swelling inhibition of shale samples with high clay content and rheological features of water-based muds (WBM). DETA-AC provides a huge surface area, a prominent number of functional groups, and a relatively non-toxic nature that makes it suitable for environment-friendly additives to drilling fluids. In the current study, the DETA-AC was utilized as an environment-friendly swelling inhibitor. Rheology tests were conducted by hot rolling the WBM at 212°F temperature and 500 Psi pressure for 16 hours. The inhibition features were assessed by dispersion recovery test, shale inhibition stability test, and linear swelling test. The outcomes revealed that DETA-AC modified WBM (DETA-AC-WBM) showed high shale recovery (93.3 %) in dispersion test as related to unmodified WBM (73.6 %), the aqueous solution of KCl (51.5 %), and commercial shale inhibitor mud (74.9%). shale cuttings treated with DETA-AC-WBM displayed stable behavior and resistance against water for up to 2 days. Bentonite in DETA-AC-WBM demonstrated a prominent decrease in linear swelling 58 % as compared to bentonite in water. While the rheological characteristics of DETA-AC-WBM remain almost the same after hot rolling. To confirm the adsorption of DETA-AC on the surface of the clay, its inhibition mechanism was explored by several characterization techniques such as Fourier transforms infrared spectroscopy (FT-IR) analysis, thermogravimetric analysis, scanning electron microscopy, and energy dispersive X-Ray spectroscopy. The proposed inhibition mechanism suggests that DETA-AC carries functional groups that can disturb the hydrogen bonding among H2O and shale material. Subsequently, the clay surface is protected against the adverse effects of clay-water interactions.
Benchmarking of Ultimate Recovery Factor Across Kuwait: Unlocking Additional Potential
Authors: Al-Ghanemi Mohammad , Dhote Prashant , Bora Anup , Al-Bahar Mohammad , Walker Jake , Dharnidharan Bala , Hornbrook John W.
Published: November 2020

A countrywide benchmarking of ultimate recovery factor (URF) for oil reservoirs in Kuwait is presented in this study. The results of this study have been useful to support identification of long-term opportunities and have influenced the creation of conceptual development plans for some of the newly discovered prospects of the company.

The Kuwait Oil Company (KOC) has a diverse inventory of petroleum reservoirs having a wide range of geologic age, depth, reservoir complexity, and development maturity. This study focused on the reservoir complexity index (RCI) method and global analogs to identify development opportunities and improvements to the URF in the brown and green fields of Kuwait.

A customized benchmarking workflow was developed to assess the URF of approximately 100 conventional oil reservoirs. First, a detailed 17-parameter RCI factor and a simplified 7-parameter RCI factor were developed. These two RCI methods were then validated against simulation-estimated URF from waterflood development for the study reservoirs. Next, the two RCI factors were used to benchmark URF for study reservoirs against the company's peers and against global analogs having best practices in operations. Finally, a set of benchmarking dashboards were refined to identify reservoir-complexity concerns, comparisons of company and global peers, and identification of potential upsides or risks in URF.

Comparison of higher performing global analogs to the company's reservoirs with similar RCI resulted in identification of additional development opportunities and upsides in URF.
Assessing Reservoirs' Viability for Long Term CO2 Sequestration Using Cuttings Volatiles
Authors: Smith Michael
Published: November 2020

We present methodology to evaluate long term sequestration viability of CO2 reservoirs using drill cuttings.

Cuttings volatile data was obtained from 2 parallel horizontal wells, drilled along the same vertical trajectories, separated by 400 meters in 2019. One horizontal well drilled within 100 meters of a 1994 vertical oil well. The already produced section shows very low CO2 compared to the rest of this lateral and the entire length of the twin lateral. Oil production from the 1994 vertical well reduced reservoir pressure, caused CO2 loss from formation water, and produced CO2 to the surface, lowering reservoir CO2 contents. This example shows cuttings volatiles analyses can detect past CO2 reservoir loss, and is a valuable tool for evaluating long term storage viability of CO2 reservoirs.

Another horizontal well, different location and formation, produced about one third of the expected oil. Cuttings volatiles indicate that the heel third of the lateral was oil productive, but that oil in the two thirds of the lateral towards the toe had been lost along a major fault. The CO2 contents in the oil pay zone are normal, but in the oil depleted zone CO2 is very low. Loss of oil from the reservoir along the fault reduced reservoir pressure, resulting in dissolved CO2 loss from formation waters, and CO2 loss along the fault.

Cuttings from ten wells from the same limestone formation in a two county area in Oklahoma were analyzed. Nine of the wells show normal CO2 contents. The tenth well drilled across a major fault has 10 to 100 times less CO2 than the other 9 laterals. CO2 in interstitial waters was lost from the reservoir via the fault. Rock Volatiles data indicate the zone drilled by this well is not adequate for long term CO2 sequestration.

A two mile high temperature gas horizontal well was analyzed crosses a major fault near the toe. Very high CO2 contents are observed at the fault. The CO2 is generated in a deeper formation and is migrating out through the penetrated formation. Neither formation is adequate for long term CO2 sequestration.

Cuttings from two CCS wells drilled by the Kansas Geological Survey were analyzed for cuttings volatiles CCS reservoir viability assessment. Both wells show no signs of CO2 depletion, and are considered by us to be low risk for long term CO2 loss.

Rock Volatiles CO2 analyses of cuttings and core is a powerful tool for assessing long term CO2 sequestration viability before new wells are drilled.
A Micro/Nano Scale Fluid Flow Model in Tight Unconventional Reservoirs
Authors: Aldhuhoori Mohammed , Belhaj Hadi , Ghosh Bisweswar , Fernandes Ryan , Alkuwaiti Hamda , Qaddoura Rabab
Published: November 2020

Diffusion forces have been ignored when modeling fluid flow in porous media with a consent belief that viscous transport is the predominant controller. This work introduces a new comprehensive flow model suitable for tight UCRs including viscous, inertia and diffusion forces to account for the transport of fluid in the three scales. A new model addressing multiphase 1-D radial flow in tight UCRs has been mathematically derived and numerically solved, tested and verified against real cases using MATLAB software. A detailed parametric analysis and verification has been carried out and a very clear profiles and flow patterns of the main flow parameters were identified. It has been established that, with lower permeability of the porous medium and lower viscosity of the flowing fluid, the diffusion mechanism becomes more predominant in controlling flow velocity. The results of the newly derived equations that includes the diffusion term have significantly shown the contribution of diffusivity to the flow in the nanoscaled pore spaces as suspected and proven by the numerical models created and the comparison between the suggested equation to other equations and correlations that are used in the field to describe the behavior of the flow in low permeability and low porous medium was established.
Improving Drilling Rate of Penetration Modelling Performance Using Adaptive Neuro-Fuzzy Inference Systems
Authors: Hamdi Zakaria , Haldavnekar Aditya , Momeni Mohammadsadegh , Bataee Mahmood
Published: November 2020

Rate of penetration (ROP) modeling is one of the most important objectives of any drilling program. Penetration model depends on different criteria such as mud weight (MW), weight on bit (WOB), rotary speed (N), and so forth. It is a complex process, because of the high number of variables and uncertainties. Different mathematical models and evaluation methods were developed to solve this problem but they were unable to attain desirable accuracy. Adaptive neuro-fuzzy inference systems (ANFIS) could be used in these cases to predict the rate of penetration. ANFIS is a combination of neural networks and fuzzy logic networks and could be used to create a robust ROP model. The objective of this study is to apply the ANFIS method and compare the modeling results with conventional artificial neural network models. ANFIS trains the model using a set amount of data and then validates it against random data to measure the error. Drill bit record from a certain field has been taken as training data and testing data for the program. The selection process uses the Sugeno model for generating the fuzzy model and the backpropagation and gradient descent method for recognizing the patterns. The data was normalized and sorted out to remove the incomplete values. Tests were done by applying 2 and 3 membership functions to a 4 input interface and a 5 input interface. The accuracy of the results depends on the numbers of inputs and membership functions. Each input was tested with different membership functions to test the data. The output generated from the training process showed that sigmoid function and Gaussian function with grid partitioning and linear output function yielded the best results for 4 and 5 inputs using 2 and 3 membership functions each. The training error recorded was about 3 percent with a checking error of 20 percent for most cases.
A Laboratory Investigation of Factors Affecting Polymer Retention in Carbonate Reservoirs
Authors: Chacko Thomas Nithin , Alfazazi Umar , W. Al-Shalabi Emad , AlAmeri Waleed
Published: November 2020

Polymer flooding is one of the widely used chemical enhanced oil recovery techniques. Polymer retention is one of the key factors that affects a successful polymer flooding application at field-scale. This paper evaluates polymer retention of two potential synthetic- and bio-polymers in carbonate reservoirs under harsh conditions. Static retention of the two potential polymers was evaluated through studying different potential parameters that govern polymer adsorption rate, namely soaking time, liquid/solid ratio, rock surface area, polymer concentration, temperature, and sulfate spiking. Pulverized carbonate outcrop samples were used as rock surface medium. The initial and final concentrations of polymer solutions were measured using UV-Spectro Photometer and Total Organic Carbon (TOC) analyzer for the synthetic- and bio-polymers, respectively.

Results from the static tests showed that the liquid to solid ratio is the most influential parameter affecting polymer adsorption. Effect of time on biopolymer adsorption is negligible and instantaneous, whereas it took about 6 hours for the synthetic polymer to reach an equilibrium adsorption state with rock powders. Although polymer retention increases with increasing the salinity of the makeup water, acceptable adsorption levels of 250 and 310 µg/g were obtained at a high salinity of 167,000 ppm for synthetic- and bio-polymers, respectively. Polymer concentration is directly affecting the adsorption rate. In addition, the synthetic polymer showed less retention with more promising results as opposed to the biopolymer.

The study evaluates several potential parameters affecting static adsorption of potential synthetic- and bio-polymers in carbonate reservoirs under harsh conditions. The paper provides more insight into the effect of sulfate spiking on polymer retention that has not been investigated thoroughly before. The approach used is much simpler than the dynamic retention measurements, but still can be used as an initial screening step before polymer injection tests.
Well Integrity Flow Detection Using Novel Acoustic Pattern Recognition Algorithms
Authors: Noble Lilia , Langnes Tommy , Thiruvenkatanathan Pradyumna , Jones Curt , Fletcher Samantha , Saisbhan Anil , Ali Jinnah-Marie
Published: November 2020

This paper discusses a new technology that helps to identify and differentiate multiple downhole well integrity events - tubing leaks, casing leaks, flow behind casing and overburden integrity, using unique algorithmic pattern recognition capability based on acoustic measurements from Distributed Acoustic Sensing (DAS) data. Here, we demonstrate application of this technology to identify flow behind casing and effectively build remediation strategies for Plug and Abandonment (P&A) of one of the wells in a BP operated field.

Applying DAS for tubing leak detection has been discussed in prior publications. The approach has however, relied on simple data processing methods ‘listening’ for zones of increased noise when wells are shut in. In this paper, we discuss results from the application of a novel real time pattern recognition based approach to processing data from DAS that:

Denoises data to decouple fluid movement ‘signals’ from background noise Uses signature recognition to constructs fluid ‘flow logs’ across the entire length of the well bore every second; Displays evolution of the fluid noise through depth and time

The technology has been deployed across several assets for identifying well integrity events through different stages of well life – starting from drilling, production through to abandonment.

In this paper, we demonstrate the application of the new capability for identifying flow behind multiple casing strings on one of the BP operated wells. The system was deployed to identify and pattern the evolution of fluid movement noise behind multiple casing strings through time and depth which was then used in conjunction with a tailored operational workflow to inform effective remediation strategies for plug and abandonment of the well. The fluid flow logs generated were used to conclude on the source of flow, flow propagation and pathway and facilitated an informed decision on extending the well’s first lateral barrier into the formation and adjustment of the position of the planned second barrier. The results showed the effectiveness of the capability in the field and demonstrated its unparalleled value for the operator, allowing for well abandonment.

The technology offers a new method of acoustic data processing on DAS that extracts valuable and often hidden insights to identify the source of fluid flow and flow pathways, providing an ability of capturing events behind multiple casing strings – all fundamental challenges that the industry has been looking to solve for several decades.
Theoretical Aspects and Practical Implementation of Study of Drilling Fluid Level in the Annulus While Drilling with Total Losses
Authors: Ruzhnikov Alexey
Published: November 2020

Many of the matured fields across the Middle East have formations with below-hydrostatic pressure, when drilling is completed without return to a surface. Most of the losses while drilling across vugular, fractured or weak formations happens suddenly, and a fluid level is not visible at the surface. Further the continuous mud cap is applied while drilling to maintain the constant bottom hole pressure. However, the mud cap flow rate and mud weight (MW) most of the time are based on local best practices and not supported by any engineering study, for example using 1.5 ppg at the rate of 1.5 BPM. To have a proper understanding of the fluid level the bottom hole assembly (BHA) is equipped with an equivalent static density (ESD) sensor was used. As continuous mud cap is required while drilling a special procedure was developed to allow tool application.

This study was performed initially across the surface section (which together with an intermediate section often has losses in the Middle East), where based on offset well analysis a single lost circulation zone present and the chance of the well control is low. Based on the result of the study the fluid level was clearly identified. Further, to understand the effect of the mud cap flow rate the section was drilled by changing this parameter. The data obtained allowed to understand the effect of a flow rate on the fluid level in the annulus. Having this information the bottom hole pressure can be maintained with lower and constant mud cap flow rate, avoiding risk of wellbore instability or well control, as well as positive financial impact as expensive mud was not used at a high rate to top up the annulus.

The obtained information and knowledge explore further the underground behavior of the depleted, fractured and vugular formations across the Middle East. The manuscript can be used by anyone across the world aiming to improve the service quality and reduce the cost related to mud cap as well as have better knowledge to present the well control risk.
Quantification and Correction of Lateral Motion Effects on NMR Logging While Drilling
Authors: Haji Abdullah , Tisdale Colin , Muslem Mohammed , Abouzaid Ahmed
Published: November 2020

Monitoring downhole drilling dynamics is an essential element to quality check the measurements provided in logging while drilling (LWD). LWD nuclear magnetic resonance (NMR) is sensitive to the motion induced from the bottom-hole assembly (BHA) during drilling, therefore, quantifying the motion effects becomes important to understand how to correct the measurements. Quantification and correction of lateral motion effects on NMR LWD are the objectives of this paper.

Data was collected from various BHA combinations with LWD NMR to model the responses, which were compared with actual downhole conditions to assess the need for the lateral motion correction (LMC). Vibrational assessment criteria are utilized to assign a severity level, which dictates the level of the LMC. The LMC applies an algorithm to differentiate true formation signal responses from the vibration signal response. Specifically, the motion effect function was integrated into the forward matrix of the NMR joint inversion, and a nonlinear optimization algorithm was used to determine the four motion parameters, and if present, compensate for lateral motion effects.

In wellbores with severe motion vibration there were large discrepancies between real-time and memory data, which resulted in mismatches with the measured partial porosities. Investigations were conducted on the BHA design, well trajectories, and wellbore environment to quantify the lateral motion effect on the NMR measurement. This information was then compiled to incorporate all aspects of BHA design techniques to mitigate the lateral motion effects on the NMR measurement. The LMC algorithm gives added confidence to ensure all data collected is consistent and reliable even in more challenging wellbore environments, which could be subjected to unanticipated lateral motion.

This paper highlights an approach to integrate BHA simulation principles to anticipate severe motion effects during drilling. This knowledge, coupled with the LMC, creates a platform to enhance NMR data quality.
Self–Sealing Cement System as an Abandonment Solution for Wells with Gauge Cables: A Case Study from North Sea, UK
Authors: Rublevskyi Anton , Johnson Carl , Tay Chuang Hwee , Main Darren , Herrera Axle
Published: November 2020

With an increasing number of wells transitioning to their abandonment stages, associated operational efficiency and cost cutting have become a major focus in the industry. An operator had an objective to permanently abandon an offshore well that was suspended in 2016. The key challenge was to develop a long-term well abandonment solution leaving the completion tubing and gauge cables in the well. All the associated operations had to be completed utilizing a lightweight well intervention vessel.

Traditionally, retrieving the entire 5 ½-in. production tubing during plugging and abandonment operations has added operational complexity and costs and increases the risk of exposure to health, safety, and the environment (HSE) hazards. Alternatively, a sealant technique placing cement through and around the completion tubing with gauge cables in-situ exists. However, this technique is associated with a heightened risk of leak path development over time. Ongoing experimental work suggested that enhancements to the conventional cement sealant systems would be beneficial to improve long-term sealing; thus, an active self-sealing cement system that would seal microannuli or small fissures around the tubing and gauge cables was designed. The set cement sealant characteristics include low Young's modulus to resist failure from wellbore stresses and the ability to regenerate the original seal upon contact with any hydrocarbons that may seep through any isolation defects through the life of the abandoned well. To achieve proper cement placement, advanced fluid simulation software and carefully tailored fluid density and rheology profiles were used.

During the operation, a plug of the self-sealing cement sealant was pumped through the production tubing and squeezed into the perforations to create a permanent barrier across the reservoir section. Next, a mechanical plug was set inside the production tubing to isolate the lower section, and the tubing was perforated to provide access to the A-annulus above; subsequently, a balanced plug of self-sealing cement (SSC) system was spotted above. After 30 hours, the plug passed a 3.4-MPa [500-psi] verification pressure test. The operator estimated the operation saved 2 to 3 days of rig time, valued at approximately GBP 400,000 to 600,000. The operator also avoided the risk of leaving the well on long-term suspension with mechanical plugs while waiting for a rig to complete the isolation, and the operation minimized the number of intervention steps required for abandonment, thereby limiting scope growth.

Operators are constantly looking for ways to increase reliability, improve efficiency, and minimize risks, and therefore, abandonment techniques are evolving. The developed solution is a novel and robust alternative to conventional well abandonment using an advanced cement sealant technology for the first time and an innovative placement technique.
One ADNOC – ADNOC Gas Processing Innovative transformation from Local to Global Optimization
Authors: Ghanayem Nidal , Kumar M. Suresh
Published: November 2020

Unique within the ADNOC Group, Real Time Optimization (RTO) has transformed the operation of NGL trains by optimising all 12 NGL trains of one of ADNOC Gas Processing gas facilities. This enables flexibility such as selectively diverting feed to high yield plants.

The objective of the RTO is to achieve optimal distribution of feed gas and condensate RVP across various processing units of the facility in order to maximize the overall C2 and C2+ recovery, minimize energy consumption, reduce emissions and reduce overall operating cost.

Successfully proven, this is a good case for rolling out to similar complexes. Initiatives are now being taken up for other ADNOC Gas Processing sites and a ONE ADNOC RTO.
Digitalization in Oil and Gas Industry - A Case Study of a Fully Smart Field in United Arab Emirates
Authors: Arif Muhammad , Al Senani Abdulla Mohammed
Published: November 2020

Digitalization, artificial intelligence and cutting-edge technology are considered the building blocks of oil and gas 4.0 industrial revolution. In line with this vision, comes the implementation of strategies to unmanning of oil fields around the world. One of the first oil fields in the United Arab Emirates, fully operated remotely, is located in the South East region 250 km away from Abu Dhabi emirate.

This paper discusses the success story of oil field that was developed and commissioned in 2017 making it the first smart field in the ADNOC Onshore. Moreover, the adopted designed and applied technology facilitated unmanned operation of field from downhole to export.

The development of the digitalization solution involved several components: the installation and connection of sensors, the development of engineering models, development of algorithms and man machine interface integrating all this data.

This paper details the use of state-of-the-art algorithms for identification of well flow conditions, deployment of advanced analytics for surveillance and optimization of ESP wells. This paper shares major challenges, solutions and benefits of the digitalization. Compared to conventional fields, smart field sets an example for enhancement of operations efficiency, profitability, and environmental safety.

The application of digital technology, combining in field measurement devices, real-time data, simulation models, and advanced algorithms to maximize productivity by automating best practices has made this field really Smart.

The main success stories include: the extension of the lifetime of the ESPs; reduction in well downtime; significant time savings for repetitive tasks; improved reservoir management accuracy; the ability to more readily meet production targets; facility management and optimization; and improvement in oil quality.

Due to the initial lack of digitalization in the oil fields, this project can be considered a blueprint for modernization of fields in challenging environment where very little digital infrastructure is initially available.
Delivering A Simple Convincing Saturation Model with Infinite Rock Type Using Iterated Fractal Function System
Authors: Sugiharto Yudiyoko Ega , Ralphie Benard , Johare Dzulfadly
Published: November 2020

The purpose of this paper is to design a saturation height function which can overcome the measurement insufficiency and can also be applied to the reservoir models where core measurements are not available at all for all kind of siliciclastic reservoirs.

This paper adopts a quantitative approach. The data is collected from the integration of core and log data. This approach is based on the assumption that sandstone reservoirs having similar Rock Quality Index (RQI), has similar capillary pressure behavior as regards water saturation. Universal capillary pressure curves were generated from 22 core plugs in Malaysia, using actual core data. Empirical relations between curve fitting parameters and core plug RQI values were developed. The universal capillary pressure curves were then used in other wells to calculate water saturation which has no core data. For those wells, the pseudo RQI values were calculated using the porosity and permeability derived from the log. A water saturation function was derived, as a function of RQI and HAFWL, with these pseudo RQI values and height above the Free Water Level.

The results of this study portray that saturation modelled through this saturation height function matched very well with resistivity derived saturation. Water saturation resulting from generalized capillary curves was contrasted in wells without core data to that computed from resistivity logs. These water saturation results were found to be more realistic than those calculated purely from resistivity logs. The results confirmed the assumption that the universal capillary pressure curves can be used without core data to predict water saturation in wells. A well that has intercepted a hydrocarbon accumulation effectively represents a massive core sample of the reservoir. It is now possible to calculate the saturation reliably in any well. RQI is known over the entire hydrocarbon column. At the saturation anywhere in a reservoir can be determined, and the FWL known or estimated with reasonable certainty. It is in principle viable to evaluate Sw directly based on the drainage capillary theory.

This study provides an insight into the universal saturation height function as a basic formulation in designing, developing, and appropriate strategies to model water saturation.

This study not only helps subsurface study team in modelling water saturation, but it also offers new insights concerning the ability and capability of the strong direct relationship among rock quality index, height above free water level, and water saturation.

This study uses an extended concept of Cuddy et al. (1993) to describe how water saturation varies with height above the free water level (FWL). Cuddy proposed the relationship of bulk Volume of Water vs Height above the FWL to derive water saturation. This approach requires conversion from BVW to SW. The proposed function, called K-function does not require the conversion.
Accelerated Pressure Restoration in a Green Field by Implementing Best Reservoir Management Practices
Authors: Zivanov Dragoljub , Kuramata Hideaki , Furuta Tetsuto
Published: November 2020

In one of the green fields in Abu Dhabi a large unanticipated drop in reservoir pressure was observed just after initial production was started. Consequently, it was decided to conduct a comprehensive investigation in order to understand the field's complexity and the reason behind the pressure decline. Solutions for such challenging developments requires solid cross-discipline efforts.

Field A has 3 stratified reservoirs producing for several years. Production started with natural depletion anticipating water aquifer will have strong impact on production. Although experiences from neighboring fields suggest that aquifer might play a key role in development mechanism, unfortunately a large pressure decline of around 600 Psi was observed after one year of production which would eventually approach facilities pressure thresholds. An integrated reservoir management team was established to give quick response in the shortest possible time implementing reservoir management best practices into an "Accelerated Pressure Restoration" WI project. The clear objective of WI implementation was to resurrect reservoir pressure with improved sweep efficiency extending plateau rate and increasing recovery factor, thus allowing wells to produce as per designed rate with natural lifting as long as possible.

Based on the gathered data, new reservoir simulation results were obtained. Subsequently a ranking of the different production forecast scenarios were created. Various scenarios were generated including assessment of different production levels on natural depletion and water injection including implementation of artificial lift at a later stage of development. Based on technical feasibility, economic evaluation, reserves recovery, production plateau and facilities utilization, the well trajectories/completions were designed and hence proposed the most adequate water injection scheme for implementation. The water injection project follows a simplified VAP (Value Assurance Process), reducing the overall timeline of the project delivery and accordingly improving economics. Implementing water injection scheme at an earlier stage significantly increases NPV (Net Present Value) of the overall project and RF (Recovery Factor) when compared with the base case FFDP (Full Field Development Plan). Furthermore, drilling the water injection wells will give a clear picture of the structure and reservoir properties in the flank shedding light on just how complex these reservoirs are. During this study, major risks and uncertainties were recognized aiming to de-risk any further field development.