bluuebunny/crossref_metadata_2025 huggingface dataset:
Advances in Parallel Reservoir Simulation Technology, Using Multi-Threaded Algorithms
Authors: Mohajeri Sina , Eslahi Reza , Bakhtiari Maryam , Zeinali Mostafa , Rajabi Hamed , Alizadeh Ali , Sharifi Ebrahim , Mortezazadeh Emad
Published: November 2018

The popularity of parallel reservoir simulation has increased in recent years due to availability of multi-core CPUs and the opportunity for run-time reduction, especially in complex and fractured reservoir models that include large amounts of data. However, the accuracy of classical domain decomposition techniques significantly decreases as the number of processing units increases. The scope of this work is mainly concentrated on development of multi-threaded algorithms to overcome the mentioned problem in parallel reservoir simulations. In this work, at first, a newly developed, parallel, three dimensional, fully implicit, three-phase black-oil reservoir simulator is introduced. For solving large scale linear systems produced in giant black-oil models, which are probable cases in real world reservoir models, BiCG-Stabilized linear solver, enhanced with various preconditioners including, Blocked Incomplete LU factorization, Constrained Pressure Residual using Algebraic Multi-Grid as its pressure smoother is constructed with a variety of parallelization techniques applied in each part. The presented multi-threaded algorithms can utilize any user-defined number of CPU cores. The algorithm has been evaluated by SPE10 with 1122000 grid blocks and a real data file containing 277875 grid blocks. The result indicates that increasing the number of CPU threads does not have any negative effect on the simulation performance in case of high memory bandwidth limits. For SPE10 data file, 1.70, 2.4, and 2.3 speedup ratios (in comparison with a single thread) has been observed for 2, 4, and 6 parallel threads, respectively. In the real case, the simulation speed is increased by a factor of 1.49, 1.74, and 1.75 for 2, 4, and 6 parallel threads, respectively. Using multi-threaded algorithms as a novel approach in parallel simulations, the solution configuration does not change from the single core case and follows the same exact path. This however is not the case for other simulators that use domain-decomposition techniques. These techniques insert numerical errors in the solution of linear systems, which lead to convergence problems in the whole system.
The Value of Integrated Borehole Image Analysis to Refine Geological Models: An Example From the Greater Burgan Field, Kuwait
Authors: Al-Enezi Bashar , Kostic Boris , Foote Nicolas , Filak Jean Michel , Al-Mahmeed Fatimah , Al-Shammari Obaid , Bertouche Meriem
Published: November 2018

Resistivity image logs are high-resolution tools that can help to unravel the depositional and structural organisation in a wellbore. They provide a particularly powerful dataset when calibrated against core, maximising their benefit for reservoir characterisation. This paper shows examples how very detailed image assessment from selected wells in the Greater Burgan Field has helped to constrain the stratigraphic model and depositional interpretations of the Cretaceous Burgan and Wara reservoirs.

A multidisciplinary study of 123 cored wells, integrating core sedimentology, petrography, bio- and chemostratigraphy, wireline well and resistivity image logs, has delivered a robust stratigraphic and depositional framework for one of the most important reservoirs in the world's largest siliciclastic oil field. A descriptive image facies scheme that has been calibrated against core and conventional well logs captures the lithological variation, sedimentary features and surfaces of the reservoir, providing a detailed proxy for the sedimentological evaluation of uncored intervals and wells.

The sand-rich lower Burgan (4S) comprises fine to very coarse-grained fluvial channel sandbodies that are locally separated by laterally restricted mudrock baffles. Image and core analyses suggest that the majority of the sandstones are high-angle cross-stratified and form stacked barforms within amalgamated channel sandbodies. Their consistent orientation towards the NE-E supports a low-sinuosity (braided) fluvial system resulting in a relatively simple, sheet-like depositional architecture across the field. Although slightly finer grained, the cored middle Burgan channel sandbodies (3SM) are similar to those in the lower Burgan. However, palaeoflow data from the imaged wells show a higher directional spread in the order of c.60-90° with a dominantly N to E orientation of the sandy barforms. Careful analysis of the orientation of the bounding surfaces between the sandstone packages indicates nearly equal proportions of obliquely and roughly parallel dip orientations in some wells. This suggests the formation of at least some lateral (point) bars and possibly the presence of higher sinuosity channels implying that sandbody architecture and fluid flow pathways could be more complex in the middle Burgan relative to the lower Burgan.

The examples from the Burgan and Wara Formations highlight the value of integrated image analysis for reservoir characterisation by delivering a consistent descriptive framework, embedding different datasets.
Basrah NGL: Best Practices for a New Sour Gas Processing Hub in Southern Iraq
Authors: Nour Tamir Abo , Bodewes Theo , Wharton Mark , Verlaan Cor
Published: November 2018

Overview

The objectives of the paper are to use the Basrah NGL gas processing project in the Basrah Gas Company JV (BGC) to demonstrate best practice application of industry solutions and appropriate technology selection, aligning with project value drivers whilst managing technical and non-technical uncertainties in decision making.

In mid-2018 contracts were awarded for the Basrah NGL gas processing hub in Southern Iraq that will set the competitive cost and schedule benchmark for new gas plants in Iraq. Embracing Shell and industry experience to deliver a standardized and replicable design was a key priority for the project team and JV partners. Technology selections were evaluated against project value drivers to support robust decision making for current and future operations, and contracting strategy selected considering synergies across the portfolio through bundling and building on in-country experience.

Two trains of 200 mmscf/d each have been awarded in the first development phase, however future expansion requirements are much simplified with the facility designed to be expandable to 5 replicated trains providing a total 1000 mmscf/d capacity in line with the upstream gas production forecast. The benefits of standardisation and replication lock in further cost and schedule savings for subsequent gas processing trains and continue to lower unit development and operating costs. In line with the future plans for the facilities, pre-investments were made for major infrastructure investments including gas and LPG export pipelines and high voltage power supply.

The BGC NGL processing train design is flexible to the range of gas qualities prevalent in Southern Iraq. Technology selections have been appropriately made to consider current and future requirements both in terms of ethane and LPG recovery but also acid gas removal and Sulphur recovery solutions. In the case of Sulphur recovery, a Shell and-Paques developed, Thiopaq technology is selected to provide the most capital efficient flexible solution, whilst also providing ease of scale-up to higher recovery rates as the upstream gas supply becomes progressively more sour (with higher H2S content) over time.
DCCD™ - A New Dual Column Cryogenic Distillation Technology for Natural Gas Sweetening: The Operations of a Laboratory Scale Pilot Plant
Authors: Picutti Barbara , Franzoni Guido , Vergani Paolo , Brignoli Fabio , Del Gesso Lucrezia , Rabino Francesca
Published: November 2018

This work presents the highlights of the results obtained from the operations of a laboratory-scale pilot plant, designed for the demonstration of an innovative gas sweetening technology. The theory behind the process, based on a dual-pressure cryogenic distillation, will be described and checked against the experimental results from the plant.

Experimental test runs with different feed gas compositions have been carried out: mixtures with a variable content of CH4, CO2, C2 and C3 have been tested. The design of the distillation columns of the laboratory-scale experimental plant allowed to process feed gas with a CO2 content up to 50 mol%, while C2 and C3 content has been limited to few percentages, aiming to reproduce the situation of a lean gas composition. Data from the plant have been used to cross-check predictions of commercial process simulators (e.g. Aspen HYSYS® V10).

The experimental results obtained from the laboratory-scale pilot plant allowed to successfully demonstrate the theoretical concept underlying the new dual-pressure cryogenic distillation technology. Adjusting the operating conditions of the pilot plant has allowed to treat gas mixtures with different contents of CH4, CO2, C2 and C3, and to study the effect of the operational parameters on the system. The presence of heavier hydrocarbons proved to be beneficial in avoiding solid CO2 formation, in accordance with available literature. The comparison between experimental data and predictions by commercial process simulators allowed to gather more information on the relevant thermodynamic framework, improving the overall degree of confidence in the models to be used during the design phase.

The increasing natural gas demand challenges the industry to find new solutions for the profitable exploitation of natural gas fields with a higher than ever CO2 and H2S content. In this scenario, cryogenic distillation represents a cost-effective alternative to traditional sweetening technologies. The concept of the new technology has been demonstrated through the operations of a laboratory scale pilot plant, confirming its capability to produce sweet gas while avoiding CO2 solidification.
Integrating Geomechanical Modeling and Production Data for Decision Support in Deep Gas Reservoirs in Oman
Authors: Dobroskok Anastasia , Al Zadjali Ruqaiya
Published: November 2018

Geomechanical modeling of hydraulic fracturing in deep gas reservoirs in Oman is complicated by high uncertainties in key parameters. This study aims to adopt a physics-based data analytics technique to model geomechanical behavior of rocks. The paper also presents the methodology of linking geomechanics with well performance. Finally, the integration of the results into a decision support system is discussed.

The majority of deep gas reservoirs in Oman are tight. The permeabilities are in the sub-millidarcy range. Hydraulic fracturing helps to unlock the reserves. Meanwhile, proper hydrofracture design is required to optimize the development of these complex reservoirs. Due to high stresses, unclear processes governing hydrofracture propagation, and complex depositional and diagenetic histories, the applicability of standard hydrofracture modeling techniques becomes questionable. Proper surveillance design and in-depth analysis of the monitoring data assist in testing the range of applicability of the modeling tools. The analysis also aids in characterizing the influence of the processes not captured within the models.

Recently the development of deep gas reservoirs in Oman started to benefit from horizontal well technology. Similarly to other horizontal developments, the question of proper well architechture and stimulation design was raised. In this study, the data pertaining to historical vertical wells was collated to understand the processes governing hydrofracture placement. The data indicated the presence of strong fracture barriers and of highly stressed zones which affect the ability to create sufficient fracture conductivity. Further, geomechanical models were calibrated to allow for realistic estimate of the contact area between the fracture and reservoir. Analysis of the production data indicated that productivity was often limited by the factors not captured in the models (e.g., suboptimal cleanup). For proper planning, risk factors may be chosen to reflect the loss of productivity. In the next step, the learnings from the vertical wells served for characterizing hydrofracturing in horizontals. Analysis of the data indicated that due to near-wellbore complexity and choking effect the productivity of an individual fracture in a horizontal well was only a fraction of that in a vertical well. As a final step all the data along with their interpretation are being incorporated into the library of hydrofracture scenarios. Future development will rely on searching for the analogs and selecting a design fitting all applicable scenarios. The paper presents an overview of the surveillance data analysis. The results of the analysis allow for creating a library of the development scenarios, which serve as a basis for a decision support system aimed at streamlining hydrofracture and well planning design.
New Approach to Fluid Typing Concepts in Tight Carbonate Source Rocks
Authors: Steiner Stefan , Mosse Laurent , Raina Ishan
Published: November 2018

Assessment of the porosity - fluid system, while challenging, is important in source rock oil plays. This is due to the wide range of hydrocarbon weight fractions, from bitumen to light hydrocarbon encountered in the source rock, along with the presence of both, the organic and the inorganic porosity systems, simultaneously. In such a play, while comparing zones of similar total porosity and water saturation, intervals with a better fluid type and porosity system will contribute more to the flow than other zones. In this paper an approach to poro-fluid typing a source rock is presented through examples from a carbonate source rock case study from the Middle East.

The following core measurements were acquired on two wells: 1. NMR T1-T2 measurements on as received, oil saturated and water saturated samples, 2. Retort measurements for effective and total porosity and saturation analysis 3. Solvent extraction saturations for quantifying total hydrocarbon saturation, and 4. Mercury Injection Capillary Pressure Analysis for estimating pore throat size distribution. TOC measurements were also acquired on all the samples. A classification technique called the Blind Source Separation analysis (BSS) is carried out on the combined dataset of NMR 2D maps and various classes are identified based on the typical signatures observed on the maps in different saturation states.

The classes identified using BSS were correlated to other core measurements to assign a physical meaning to each class. Based on the results, three key poro-fluid groups are identified. These groups are bitumen hosted porosity, porosity in the organics, and inorganic hosted porosity. By integrating results from MICP and SEM, we identify the typical pore sizes observed in the above groups and recommend zones that will bet better contributors to flow. Finally, we tie the results back to the limited measurements available in the log domain to predict zones with better flow potential.
Reactive Liner Perforating Technology used to Improve Efficiency of Hydraulic Fracturing Operations
Authors: Nunez Alvaro Javier , Molenaar Mathieu , Al-Salmi Masoud , Al-Farei Ibrahim , Gheilani Hamdan , Sayapov Ernest , Al-Shanfari Abdul Aziz
Published: November 2018

Deep exploration and gas wells with very tight formations to be hydraulically fractured in the Sultanate of Oman, have been preferably perforated with Abrasive Jet perforating systems in order to reduce the perforating skin and to be able to break down the formation compared to the regular deep penetration shaped charges which historically have been unsuccessful used. The complexity of the Abrasive Jet perforating operations requires Coil Tubing, Sand Management System (SMS), specialized perforator BHA, correlating devices, pumping and mixing equipment and a substantial quantity of fluids and sand per interval.

Perforating guns with reactive liner technology, conveyed with electric line, have been considered for these types of wells. This technology delivers enhanced perforations facilitating fracturing operations by reducing the break down pressures. Initially well data from three exploration wells "A", "B" and "C" were extensively evaluated with very high chances to succeed. The job execution was planned parallel to the Abrasive Jet perforation in case the formation would have not broken down after the gun perforations. In well "A" two stages were executed successfully using the reactive liner shape charge technology while in the well "B" the first stage was neither broke down after reactive liner charges nor after Abrasive Jet perforations; the second stage in well "B" was successfully executed after the reactive shape charge gun perforations. This initial success of these two exploration wells was replicated in another gas field also with tight formations which historically has been perforated with Abrasive Jetting near well "C".

As a result of this, the efficiency, the perforating accuracy and the cost savings are substantial improved; the HSE exposure is much less due to the fact that less resources are needed compared to the requirements for Abrasive Jet. This paper will go thru the design, planning, execution, results and the big step change in the fracturing operations in these types of wells in which Abrasive Jetting is not always the best preferred option.
Big Data-Driven Advanced Analytics: Application of Convolutional and Deep Neural Networks for GPU Based Seismic Interpretations
Authors: Haroon Sarblund , Alyamkin Sergey , Shenoy Ramachandra
Published: November 2018

The democratization of artificial intelligence began with the collection of large datasets and the ability to consume them for inferences and prediction by leveraging exponentially increasing computational power. This was further enhanced by the ability to parallel process datasets by breaking them up into independent units and applying fast computation to those units using Graphical Processing Units (GPUs). We discuss one such application in the area of seismic interpretation in the oil and gas sector. Seismic interpretation is particularly suitable since seismic datasets’ characteristics make them inherently amenable to parallel processing in post-stack format.

True big data in the oil and gas sector exists in the seismic arena, where up to one terabyte of data or more can be collected per hour. We show that while preprocessing is required for cleansing and quality checking the data, novel techniques can be applied from the medical and healthcare sectors, namely radiology, for image processing and anomaly detection in images. Further, we also show methods of preprocessing the seismic data, development of seismic images, and novel denoising techniques that lead to the construction of seismic cubes.

3D and 4D seismic cubes post-stack are today amenable to a plethora of neural network based parallel processing methods for anomaly detections. Using such techniques, the achievable speeds to detect anomalies are effectively above ten times what an experienced human being can do. These methods, at their very best, go far beyond human capabilities in terms of processing terabytes to petabytes of data. Such image processing is in use in image recognition, for example, in border control for person identification and verification, and satellite image analysis to discover the minutest of details. We showcase novel techniques based on Convolutional Neural Networks and Deep Neural Networks being utilized for subsurface geological and geophysical properties identification. Further developments of our current and future work are also discussed.

Our presentation specifically describes methods based on Convolutional and Deep Neural Networks to predict faults and salt domes in seismic images. The ability of Deep Neural Networks to continuously learn and self-optimize is the basis of our novel approach. A common criticism of machine learning methods is that most reported results describe results on field data where part of the field data has been used in training the neural network algorithms being used. In the work reported here, we describe the results of our algorithm on two completely blind field data sets – where none of the field data has been used in training the algorithms.
Gravity-Derived Borehole Azimuth through Gravity In-Field Referencing
Authors: Kim Jeong Woo , Rangelova Elena , Kabirzadeh Hojjat , Lee Gyoo Ho , Jeong Jaehoon , Woo Ik , Song Tae Han
Published: November 2018

Safe and economical determination of wellpath in directional drilling is traditionally achieved by the measurement-while-drilling (MWD) method which implements geopotential sensors, i.e., magnetometers and accelerometers. However, inaccuracies in determination of the wellpath arise because of random and systematic errors in measurements. In general, inclination is under good control with gravity measured by accelerometer, while azimuth requires a number of corrections as it also requires magnetic measurement which involves multiple sources of errors such as sensor errors, poorly-modelled crustal magnetic variation, drillstring magnetization, etc. These errors must be completely reduced or minimized to obtain an accurate wellbore position. A magnetic-free system and method to determine a borehole azimuth in the directional drilling is investigated in this study. We show that a borehole azimuth can be properly determined by using a system of coupled accelerometers mounted on measurement-while-drilling (MWD) sensors using Gravity in-Field Referencing (GiFR). In order to reduce errors due to relative oritation of the coupled drillstrings, we developed the Quaternion-based GiRF which considers the relative diaplacements and rotations between the two sets of accelerometer resulting in determining an improved azimuth.
Efficient Utilization of Existing Facilities and Energy in Gas Processing
Authors: Vyas Ajay
Published: November 2018

The objective of the Study was to recommend the most techno-economic option to maximize the NGL Recovery at existing Gas Processing Complex by assessing all the facilities in the complete processing chain from Offshore to Onshore and evaluating the potential options and their associated bottlenecks, production impact and business interruption in order to address the changes in gas supply to the existing Gas Processing Complex from various sources and developments.

The Study was conducted in 3 stages: Feasibility Study was carried out and recommended to install two NGL Recovery Trains with huge capital investment.Gap Analysis and Idea Innovation - The alternative idea of maximizing utilization of existing facilities and energy with minimum modifications was developed by re-distributing the feed streams based on their richness in NGL content within existing facilities so that the optimum NGL Recovery can be achieved.Pre-Feed Study – The developed idea along with other potential options were thoroughly evaluated by a Pre-FEED Study to select the most techno-economic feasible option.

The concept of maximizing utilization of existing facilities and re-distribution of gas according to their qualities offers outstanding benefits to its shareholders: Considerable saving in capital investment ~ 98.64% and energy saving of ~ 18 MWminimum modifications at Offshore Facilities and Existing Gas Processing Complex which could be carried-out during a planned Shut Down and without impacting the production targets.High Net Present ValueReversible design and operationNo long lead items

This paper represents the change in typical approach of installation of new facilities to accommodate the increase in gas supply to a holistic approach of efficient utilization of existing facilities and energy to generate more values to business by generating more revenues with minimum modifications and offering facilities which will be fit for purpose and potential future developments.
Integrated Optimization of the Overall Gas Mass Balance in a Deep-Water Production System
Authors: Brioschi Samuele , Cadei Luca , Del Monaco Luca , Raffone Marco , Montini Marco , Bianco Amalia
Published: November 2018

The current oil and gas market context is characterised by low prices, high uncertainties and a subsequent reduction in new investments. This leads to an ever-increasing attention towards more efficient exploitation of resources. This scenario underlines the need for existing assets production optimization, especially for deep-water applications. This paper presents the methodology of an innovative integrated production optimization tool and presents the results obtained in a real application on a deep-water asset.

The optimization tool aggregates in a single integrated platform all the different aspects of the asset, from well performances to topside process simulation through gathering system thermo-hydraulic calculations. It effortlessly orchestrates several pieces of software that model the different parts of the asset. Those are typically used by different disciplines, such as reservoir, well area, flow assurance, process and operations. Therefore, the tool promotes the essential collaborations between disciplines. The production optimization is based on genetic algorithms and is able to increase the production of an asset respecting all the operative and flow-assurance constraints.

The optimization was applied on a deep-water field, posing particular attention on the delicate ecosystem that is the gas lifecycle of an FPSO. In this case, a global and holistic approach is of paramount importance: in fact, the gas associated to the oil production plays a role in the hydraulics of the pipelines and after being dehydrated and compressed, is used as fuel gas, as gas for wells artificial lifting and for re-injection into the reservoir. The application resulted in a global optimisation of the gas utilization and had manifold impacts. Firstly, it resulted in an increase in oil production. Secondly, a reduction in the overall gas lift led to a more energy efficient use of the compressors. Finally, a higher use of the gas for re-injection resulted more effective for pressure maintenance. As a consequence of the theoretical study, the optimization actions identified by the tool lead to a successful application in the field.

This paper presents a novel approach to overall asset optimization that integrates different engineering disciplines. The approach accounts for the overall gas balance of an FPSO from bottom hole to separation, lifting and re-injection.
Use of Exogenous Bacteria to Improve the Bioremediation Process in the Caracara Field Colombia
Authors: Molano Jaime
Published: November 2018

CEPSA Colombia developed an improved technique for bioremediation; implemented since 2012 in the onshore Caracara field. This optimizes the processes of biostimulation and bioaugmentation by introducing exogenous bacteria, with efficiency (reduction of grease and oil) close to 90%.

The technique exceeds the performance of other published methods, as it has been used successfully for the biotreatment of soils and fluids impregnated with hydrocarbons at concentrations of fats and oil of up to 20 ± 2 wt%, equivalent to 200,000 ± 20,000 ppm (mg carbon/kg soil). Previous studies have suggested that oily sludges only with concentrations of fats and oils below approximately half that level can be bioremediated to achieve a compliance criterion standard close to 1 wt% as established in Chapter III of Louisiana Protocol 29-B and commonly adopted as an oil industry norm.

It is an ‘ex situ’ process since although applied at the field location the sludge is first collected and stored prior to batch biotreatment. The technique is most applicable to oily sludges that do not have an excessive asphaltene and resins content: asphaltenes are not biodegradable by microorganisms, given their structural complexity and resistance to the enzymatic attack produced by bacteria.

Our successful field pilot has been expanded to an industrial scale and has over a six-year period effectively treated the environmental liability of sludge ponds of approximately 12,000 m3 inherited when CEPSA assumed its interest in the Caracara field. Operations continue, treating ongoing generation of oily waste at an estimated cost saving of 54% relative to the treatment and transport costs of contracting an external bioremediation service provider.

We have developed simple criteria to screen the suitability of oily sludges for our process, which is simple, easy to implement and cost-effective, as it relies on bacteria generated from waste products readily available in the field at no cost. It should be applicable to other fields with similar environmental conditions.
Combined use of Optical-fiber DAS and a Permanent Seismic Source for Vertical Seismic Profiling Demonstrated at the Aquistore CO2 Storage Site
Authors: Nakatsukasa Masashi , Ban Hideaki , Kato Ayato , Shimoda Naoyuki , White Donald , Nickel Erik , Daley Thomas
Published: November 2018

Seimic reservoir monitoring is a method to monitor fluid displacement in the reservoir. Long-term monitoring to measure differences over several years has been successful recently. However, short-term monitoring to measure changes in nearly real-time is still challenging because the expected changes in such a short-term are small. Permanent reservoir monitoring might enable short-term monitoring because we can increase data repeatability since sources and receivers are permanently fixed at the same position. This method saves the acquisition cost once the equipment is deployed, but the number of sources and receivers is limited due to the high initial install cost. To address this challenge, we have demonstrated VSP monitoring with a combination of a permanent rotary source and DAS sensor. DAS can record a wavefield at very dense and extensive points along an optical fiber, but the quality is regarded as less than for conventional geophones. By comparing data recorded in 2015 and 2016, we investigated the improvement of the signal-to-noise ratio of DAS. Hourly repeatability was checked by arranging the waveforms by the acquisition time. The depth migrated image of the offset VSP extended the imaging are further away from the receiver well. Our study confirmed the complementary relationship between the permanent source and DAS acquisition. Combining these technologies might enable us to monitor small changes in the reservoir in the short-term.
Stress Testing with Improved Wireline Formation Tester in Low Permeability Unconventional Formation
Authors: Povstyanova Magdalena , Coscia Marco , Van Laer Pierre , Makarychev Gennady , Al Marzooqi Hassan , Leyrer Karl , Casson Neil , Cig Koksal , Desroches Jean
Published: November 2018

In preparation for the hydraulic fracturing campaign, the Unconventional Resources Team at Abu Dhabi National Oil Company (ADNOC) has carried out stress measurements both in open-hole and cased-hole in a number of recently drilled wells. The current paper demonstrates the results of the stress measurements in open-hole in two wells drilled in two different geological settings. The main target chosen was the unconventional Shilaif formation. One well was located on top of an anticline and the other well penetrated the Shilaif formation in a syncline. High breakdown pressures were expected (especially in the syncline).

In order to cope with the challenges expected during the stress testing in such environment, a wireline formation tester that included both single packer and dual packer was used to initiate breakdown and achieve measurement of fracture closure pressure. With the expected adverse rock properties, either natural fall-off or rebound technique was employed to obtain closure pressure. The single-packer module extended the differential pressure rating up to 12,000 psia in comparison to 4,500-psia rated dual packer. The single packer was used to initiate the fracture breakdown if dual packer was not considered sufficient. Formation pressures were measured at several depths with the dual-packer operations. The stress measurements were carried out not only in the Shilaif formation, but in the shale formations above (the Tuwayil formation) and below (the Mauddud formation) in order to check if the shales could be stress barriers for a large scale hydraulic fracture.

The current paper explains the procedure followed during the stress measurements and shows an example of interpretation of the pressure data acquired with wireline formation tester comprising the single-packer and dual-packer systems. The stress measurements were used to calibrate results of the geomechanical modeling.
Building a Robust Reservoir Model through Full Integration Workflow of Static and Dynamic: A Case Study from a Lower Cretaceous Carbonate Reservoir of a Giant Oil Field, Onshore Abu Dhabi, UAE
Authors: Pamungkas Setiyo , Flavien Maire , Baptiste Salley
Published: November 2018

An updated geological and dynamic model for a giant Middle East carbonate reservoir was constructed and history matched with the objective of creating an alternative model which is capable of replicating the reservoir production mechanisms and improving predictability, allowing optimizing the field development plan and water injection strategy. Giant Middle East carbonate fields often have long production history and exhibit high reservoir heterogeneity. It is always challenging to get a robust history matched model aligned with geological concepts and dynamic behavior understanding.

The objective of this paper is to present an improved and integrated reservoir characterization, modeling and history matching procedure for a giant Lower Cretaceous carbonate reservoir in the Middle East. The applied workflow integrates all available geological data (stratigraphy, depositional facies, and diagenesis), petrophysical data (RCA and minipermeameter data, Petrophysical Group definition, cut-off definition) and the extensive database of dynamic data (long production history, well test, RST, open-hole log saturation over more than 40 years of development drilling, and MICP). The process was initiated with the reservoir review by means of a fully integrated study that allowed having better understanding of the reservoir behavior and production mechanisms. The key heterogeneities (high permeability and intra-dense layers) which control the flow behavior were identified during this process. Geological trend maps were generated to control the distribution of high permeability and intra-dense in the model. Well test data, open-hole logs from development wells and time-lapse saturation logs from observation wells were used to calibrate the trend and permeability log data. A phenomenological model was constructed to test the main factors impacting the production mechanism as identified during the reservoir review. Multiple iterations were performed between the static and dynamic models in a way that allowed a quick and efficient work that is consistent with all disciplines assumptions.

Such continuous loop between the dynamic and geological models, with focus on the geological heterogeneities driving the dynamic reservoir behavior, has led to a more robust model capable of replicate the production mechanisms, which represents a major improvement compared to previous model in term of predictability.
New Technology to Assist Drilling to Improve Drilling Rate in Unconventional Gas Resources: Pulsed Arc Plasma Shockwave Technology
Authors: Cai Zhixiang , Zhang Hui , Li Jun , Zheng Jiadong , Yu Qing , Liu Kerou , Liu Yongsheng
Published: November 2018

The rate of penetration is very low during the development of unconventional gas resources such as tight gas and marine shale gas, owing to high rock hardness and strength as well as heterogeneities at all scales. To improve the efficiency and reduce costs of developing unconventional gas resources, this paper proposed a new technology to assist drilling, Pulsed Arc Plasma Shockwave Technology (PAPST).

This technology converts electrical energy into mechanical energy to generate dynamic loads shockwave which can assist rock-breaking. Firstly, based on the fluid mechanics and bubble dynamics, the mechanism of shockwave generation was analyzed. Then, to verify the feasibility of PAPST technology, this paper conducted rock breaking experiment with shale samples from Longmaxi formation, China. Meanwhile, based on impact and damage mechanics, the mechanism of rock damage caused by dynamic load was analyzed.

The results show that shale samples were destroyed and there were cracks and collapse pits on shale samples after the impact of shockwave. Therefore, the application of PAPST technology to assist drilling is feasible, and the greater the discharge energy, the higher the efficiency of rock failure. Through theoretical analysis, it is found that the radial cracks of rock are caused by the tangential tensile stress, which is caused by the shockwave impacting the rock. The secant cracks are caused by the resultant force of the three component forces: the tangential and radial components of the force on the rock particle caused by the shockwave and the radial tensile force generated by the reflection of stress wave at the rock-water interface. The collapse pits are most likely caused by stress concentration.

For the first time, this paper proposed an idea of applying shockwave generated by PAPST to assist drilling for increasing the ROP in unconventional gas resources. And it also provided a theoretical basis for the application of PAPST in the field of oil drilling by analyzing the mechanism of shockwave generation in drilling fluids and the mechanism of rock breaking by shockwave.
Using Similarity-Based Pattern Detection to Automate Pressure Transient Analysis
Authors: Suzuki Satomi
Published: November 2018

Automated pressure transient analysis (PTA) with real-time data feed from permanent downhole gauge (PDHG) enables continuous monitoring of well and reservoir that facilitates timely surveillance decisions. However, while robust automation of the process is critical to minimize the requirement of manual efforts, a challenge lies in automatic diagnostics of a log-log plot which is often contaminated by non-reservoir response such as wellbore dynamics. We propose a new automatic PTA method to enhance accuracy of diagnostics.

The method utilizes a pattern detection method based on similarity search and automatically identifies sequence of flow regimes, such as radial, spherical or linear flow etc., on a log-log diagnostic plot of pressure and derivative. To discover individual flow regimes, the algorithm scans a window on the plot and finds a pattern that is most similar to a ‘motif’ defined for the flow regime. Such motifs are known for individual flow regimes from analytical models. During the similarity search, the algorithm ensures that the discovered sequence of flow regimes is consistent with the flow scenario anticipated at the well.

The proposed method is implemented in fully automated PTA workflow. First, the system reads PDHG pressure and flow rate at a well. Then, pressure buildup intervals are automatically identified. Subsequently, a log-log diagnostic plot is automatically generated for each buildup and the proposed method is executed. Once a sequence of flow regimes is identified, the algorithm locates a horizontal line over the radial flow regime and calculates permeability, skin and extrapolated pressure p*. For horizontal wells, effective completion length is also computed by locating a half slope line on the linear flow regime. For hydraulically fractured wells, fracture length or fracture conductivity is estimated from the linear or bi-linear flow regime. The results are written on output files or to a database together with identified flow regimes visualized on plots for the review of reservoir engineers. The method is tested on oil producers with high water cut where significant fluid segregation or crossflow is impacting log-log diagnostic plots, as well as gas wells where a pressure leak during buildup is contaminating pressure derivatives. Despite such noise of non-reservoir responses, the proposed method successfully identifies flow regimes on most of buildups and produces PTA results comparable to manual analysis.

Compared to existing automatic PTA methods, such as automatic matching of model response or automatic semi-log analysis of radial flow regimes identified by user-specified criteria, the proposed method is particularly robust to use with pressure data which is significantly contaminated by non-reservoir responses. Such robustness of our method is achieved by a flexible pattern search for individual flow regimes rather than matching an entire model response all together or requiring rules specified by engineers.
Real-Time Slickline Production Logging: Technology Review
Authors: Alghamdi Abdullah , Yateem Rakan , Rajeh Rashed , Kadem Mohammad
Published: November 2018

Out of the many well intervention jobs conducted, the focus of discussion of this paper includes two well intervention operations using digital enabled slickline services in combination with production logging operations in fields whereby bi-directional telemetry is enabled using a proprietary plastic polymer insulating coating around a conventional slickline wire.

The smaller, lighter and easier slickline conveyance platform with its simplified stuffing box pressure control equipment enables direct and subsequent efficiency gains and risk reduction in providing both enhanced mechanical slickline services and an additional range of real-time downhole measurements. This combination enabled both services to be deployed in a single rigup with one digital enabled slickline unit used for both mechanical and measurement services on each well. This can reduce operational time and provide significant cost savings and a reduction in diverted and or delayed production. As an example, the real-time head tension readout was used to monitor the downhole tool movement and lift forces during the flowing survey allowing the well to be flowed at the optimal rate.

Two risk mitigation devices were incorporated in the toolstring, a real-time activated release device, and an interactive jar allowing mitigation of the associated risks should the toolstring become stuck in the well. The case studies described in this paper demonstrate the ability to provide a range of intervention services, specifically in the vertical logging operations, with the real-time surface readout measurement and control usually associated with electric line operations.

The surface readout capability and depth accuracy makes this system more a better fit than a conventional memory system, and due to the variety of sensors available it is comparable with an electric line production logging operation. Although the technology is for cased hole service, real-time data was also acquired in the openhole section. The operations conducted as described in this paper show that digital enabled slickline services are well on their way to becoming a proven service in enhancing operational efficiency and delivering a new level of complexity to real-time slickline deployed measurement services and control over the entire operation
Offshore Optimizations: EICT Systems, Installation and Footprint
Authors: Hage Safouan
Published: November 2018

The objectives of this paper are to highlight and discuss the role that Electrical, Instrumentation, Control and Telecom Systems (EICT Systems) can play in an optimization drive for offshore installation, let be on the footprint aspects, installation methodologies, mechanical completion and overall commissioning to first oil.

The Methodology being presented is based on converging the EICT Systems into an integrated approach in a homogenous EcoSystem building on the strength of the Systems Interfaces. This will cover the full lifecycle of those Systems from Engineering to Assembly and integration up to installation, testing and commissioning. The standard approach had been with these systems being addressed separately, while many of the design and implementation data and parameters converge into common interfaces that affects the overall aspect of Offshore installation like Ehouse Structures, back-up power supply systems and common Electrical, Process and Safety Control Interfaces and Platforms as examples.

We have been able to deliver a more optimized and efficient engineering with reference architectures, able to absorb variations without major impacts on delivery and commissioning schedule. Accordingly, we have better Systems Build-ups with optimized Interfaces and lesser footprints in Space and Energy consumption, i.e. Ehouse Structures (LERs and ITRs), Back-up Power Systems and Outdoor Equipment. Also, this has resulted in a more efficient installation and commissioning, i.e. less cabling and marshaling. This has led to a better offshore space allocation and Management, improved schedules for engineering, installation testing and commissioning and ultimately resulting in a better Cost of ownership at CAPEX and OPEX

This paper will discuss some of the critical interfaces mentioned above, like Ehouse and Integrated Process and Power Management and how the EICT Integrated approach will help deliver these Systems in an optimized and efficient manner to deliver the stated results and conclusion
Feasibility Study of Carbon Dioxide Methanation: Assessment of Various Supported Nickel Catalyst
Authors: Berahim Nor Hafizah , Abu Seman Akbar , Mohd Noh Mohammad Ghaddaffi
Published: November 2018

Carbon dioxide (CO2) management is vital for ensuring the economic and environment viability for monetization of high CO2 gas field. Apart from the great technical challenge in separating high concentration of CO2 in gas field economically, the management of separated CO2 is a fine balance between the sink-in value by sequestration and creation of value via conversion to product, constrained by the thermodynamic challenge in breaking the stable CO2 molecule. Conversion to methane is one the exploratory idea due to ease of integration to current product line-up of PETRONAS. Catalytic conversion of CO2 to methane are reported here over various supported nickel base catalyst, namely ZrO2, La2O3, and Al2O3 at temperature ranging from 300 to 400°C under atmospheric pressure. The catalysts with fixed Ni loadings were prepared by wet impregnation technique, characterized and their performances were evaluated in a parallel reactor under Sabatier-based CO2 conversion. Reaction temperature and GHSV were taken into account as two important parameters with fixed H2/CO2 molar ratio. Experimental results indicate that among all catalysts, Ni/Al2O3 give the highest CO2 conversion of 74% and high CH4 selectivity of 99% at temperature of 380°C and GHSV 10000 h-1. This asserted Ni supported on Al2O3 as a potential catalyst for CO2 conversion and promising methanation performance over a low cost catalyst.
Minimize Measurement Uncertainties to Gain More
Authors: Valasubramanian A
Published: November 2018

In today's competitive world, trillions of BTU's of energy through sales gas are traded every day. Natural gas values were considered not that high compared to that of Crude oil in the past, with the drive to use environmentally clean energy source more sales gas is being used now. This provided the opportunity to improve the gas custody measurement accuracy further. This paper discusses the gas flow measurement all the compnents contributed to the accuracy and the ways to minimize the measurement uncertainty.

Gas Custody Measurements are special applications, and different from the normal process measurements. Gas Custody measurement standard volume, mass flow and /or energy readings are not direct measurement value, rather it is a calculated output. It is a computed value based on several measurement data points with some underlying assumptions.

Typical sales gas metering systems with redundant meters for proving / standby is provided and the typical configuration is indicated in the Fig-1 below.