Sparse Water Fracture Channel Detection from Subsurface Sensors Via a Smart Orthogonal Matching Pursuit

Water front movement in fractured carbonate reservoirs occurs in micro-fractures, corridors and interconnected fracture channels (above 5 mm in size) that penetrate the carbonate reservoir structure. Determining the fracture channels and the water front movements within the flow corridors is critical to optimize sweep efficiency and increase hydrocarbon recovery. In this work, we present a new smart orthogonal matching pursuit (OMP) algorithm for water front movement detection in carbonate fracture channels. The method utilizes a combined artificial intelligence) AI-OMP approach to first analyze and extract the potential fracture channels and then subsequently deploys a deep learning approach for estimating the water saturation patterns in the fracture channels. The OMP utilizes the sparse fracture to sensor correlation to determine the fracture channels impacting each individual sensor. The deep learning method then utilizes the fracture channel estimates to assess the water front movements. We tested the AI-OMP framework on a synthetic fracture carbonate reservoir box model exhibiting a complex fracture system. Fracture Robots (FracBots, about 5mm in size) technology will be used to sense key reservoir parameters (e.g., temperature, pressure, pH and other chemical parameters) and represent an important step towards enhancing reservoir surveillance (Al Shehri, et al. 2021). The technology is comprised of a wireless micro-sensor network for mapping and monitoring fracture channels in conventional and unconventional reservoirs. The system establishes wireless network connectivity via magnetic induction (MI)-based communication, since it exhibits highly reliable and constant channel conditions with sufficiently communication range inside an oil reservoir environment. The system architecture of the FracBots network has two layers: FracBot nodes layer and a base station layer. A number of subsurface FracBot sensors are injected in the formation fracture channels to record data affected by changes in water saturation. The sensor placement can be adapted in the reservoir formation in order to improve sensor measurement data quality, as well as better track the penetrating water fronts. They will move with the injected fluids and distribute themselves in the fracture channels where they start sensing the surrounding environment’s conditions; they communicate the data, including their location coordinates, among each other to finally transmit the information in multi-hop fashion to the base station installed inside the wellbore. The base station layer consists of a large antenna connected to an aboveground gateway. The data collected from the FracBots network are transmitted to the control room via aboveground gateway for further processing. The results exhibited strong estimation performance in both accurately determining the fracture channels and the saturation pattern in the subsurface reservoir. The results indicate that the framework performs well; especially for fracture channels that are rather shallow (about 20 m from the wellbore) with significant changes in the saturation levels. This makes the in-situ reservoir sensing a viable permanent reservoir monitoring system for the tracking of fluid fronts, and determination of fracture channels. The novel framework presents a vital component in the data analysis and interpretation of subsurface reservoir monitoring system of fracture channels flow in carbonate reservoirs. The results outline the capability of in-situ reservoir sensors to deliver accurate tracking water-fronts and fracture channels in order to optimize recovery.

Innovative High Permeability Streak Characterization and Modeling Utilizing Static and Dynamic Data in a Complex Giant Mature Oil Field in the Middle East

This paper proposes an integrated approach to model High Permeability Streaks (HPS) using the case study of heterogeneous carbonate Reservoir B, utilizing static and dynamic data. Modelling the HPS is critical as they play an important role in fluid dynamics within the reservoir. The impact is observed from 60 years of development, where flood front movement is captured by rich density of Pulsed Neutron and recently drilled open hole logs. Injection water is overriding from tighter lower subzones (injected zones) to permeable upper subzones of the reservoir, thereby leaving the tighter lower subzones unswept. Gas cusping down to the oil zone occurs through the HPS resulting in non-uniform gas cap expansion, which leads to early gas breakthrough in producers near the gas cap. The problem with characterizing HPS is associated with their thickness- in Reservoir B it ranges from 0.5 to 2.5ft and occur in multiple subzones in the upper part of the reservoir. The standard triple combo suite of logs does not have the resolution to detect these thin HPS. In addition, the cored interval of the HPS is mainly disintegrated which is attributed majorly to well sorted grain-supported lithofacies. Therefore, sampling for porosity & permeability via Routine Core Analysis (RCA) and Capillary pressure as well as pore throat distribution using Mercury Injection Capillary Pressure (MICP) method is extremely difficult. This results in a gap in the input dataset for the static models, where the higher permeability samples are not captured in logs or cores and are therefore under-represented. Current approach to unify this gap is to use permeability multipliers, which does not honor geological trends. The HPS in Reservoir B has added complexities when compared to other regional HPS. Not only are they multiple and distributed across subzones, there is also preferential movement of water through the HPS within the same area. Of the 3 upper subzones that have HPS, in some areas, water injected in lower subzone will override the HPS in the middle and move right to the HPS in the top subzone, thereby ignoring the hierarchical flood front movement from bottom to the top. A robust workflow was developed in order to address and resolve the above mentioned uncertainties related to High Permeability Streaks. The proposed integrated workflow consisted of five stages: Developing a robust geological conceptual model Mapping spatial distribution & continuity Capturing the vertical presence in cored & uncored wells (depth & thickness) Permeability Quantification of HPS using Well Test Measurements Modelling High Permeability Streaks The paper highlights the utilization of a range of static (core, Routine Core Analysis (RCA), image logs, OH logs) and dynamic data (Pulse Neutron Logs (PNL's), later drilled Open Hole Logs, Production Logging Tools (PLTs) and well test data). Quantitative (HPS depth indicated by water saturation profile indicated by waterflood movement) and Qualitative (Flooding observed but HPS depth is uncertain) depth indicators/flags were generated from the data set and became the foundation of the modelling the HPS. The first step in the workflow is to establish a robust geological conceptual model. For Reservoir B, certain facies contribute to HPS, which are mainly leached Rudist Rudstones and Coated grain Algal Floatstones as well as well sorted Skeletal Grainstones. Based on core observations, they have confirmed vertical stratigraphic presence in each subzone (top, mid, base) which is attributed to storm events. These were consequently mapped using average thickness from core descriptions and revised using contributing facies trend maps and qualitative dynamic observations. These maps served as basis for probability trend distribution for static rock type models. The vertical presence of HPS was increased from 10% to 30% by re-introducing them in the missing core intervals using quantitative dynamic flags and thickness from isochores. Consequently, permeability were assigned in the missing section using the proposed permeability enhancement technique that honors the verified well test measurements. Based on the above improvements, the HPS intervals were mapped to the static rock type with best reservoir quality (SRT 1), which is also linked to certain geological attributes (i.e. lithofacies, diagenetic overprint & depositional environment). The enhanced permeability in the identified HPS intervals is also reflected as upgraded SRT (from lower SRT 2 to best SRT 1). The overall impact is observed by improvement of poro-perm cloud, with added control points for HPS SRT (1), which is vital for permeability modelling. The updated permeability model, captures high perm streaks in terms of vertical presence and magnitude. By introducing higher permeability in the upper subzones of the reservoir, the water overriding/gas cusping phenomena could then be mimicked in the dynamic model. The proposed methodology is an integrated workflow that maximizes the input from each disciplines (G&G, Petrophysics and Reservoir Engineering) to create a robust static model through incorporation of high permeability streaks. The use static and dynamic data, has helped to establish HPS existence/preference, which then could be used to upgrade the permeability/SRT. This will in turn lead to a better static model and a better history match in the dynamic model. It will also led to better remaining in place prediction and enable accurate prediction for future field development, especially where EOR is involved.

Experimental investigation of a line plume in a filling box

A series of experiments were conducted to quantify the dynamics of a filling box driven by a line plume that spans the full width of the enclosure. Three configurations were tested namely symmetric (centrally located plume), wall-bounded (plume attached to an end wall), and asymmetric. The front movement for the symmetric and wall-bounded configurations was well described by the standard filling box model. The front movement results indicate that the typical value of the entrainment coefficient $$ \left( \alpha \right) $$ α for an unconfined plume ($$ \alpha = 0.16 $$ α = 0.16 ) could be used to accurately predict the front movement for both the centrally located plume and the wall-attached plume. This is in contrast to other studies that suggest that wall-bounded plumes have a significantly lower entrainment coefficient. The standard filling box model broke down for the asymmetric configuration. As the plume was closer to one wall than the other, the plume outflows that spread out and reflected off the end walls returned to the plume at different times. This created a pressure imbalance across the plume that caused the plume to bend sharply toward the nearest wall. Analysis of the plume outflow as a constant flux gravity current showed that the outflow velocity scaled on the cube root of the plume buoyancy flux per unit width $$ f $$ f , a result confirmed by further experiments. This result was used to quantify the time at which the plume bends and the standard filling box model breaks down.

"Onze toestand dwingt ons tot spreken." Brief van Cyriel Verschaeve an kardinaal Mercier — 6 augustus 1917

De brief heeft van 1917 tot 2017 een merkwaardige geschiedenis gekend met betrekking tot de teksteditie. In deze bijdrage wordt de laatste, wetenschappelijke editie in de Open Brieven (Antwerpen, 2017) gevolgd.Een van de belangrijkste documenten uit de voorgeschiedenis van de brief is het essay 1830-1908, een ongepubliceerde tekst die door Lodewijk Dosfel in februari 1918 te Gent werd uitgegeven. Dit essay openbaart de opvattingen van Verschaeve over natie en staat, geheel verschillend van die van Mercier. De kapelaan volgde hier de Zuid-Afrikaanse generaal uit de Boerenoorlog, Christiaan De Wet, en de Luikse hoogleraar Emile de Laveleye. De voorbereidende stappen tot de brief zijn merkbaar in de dagboekaantekening van 25 januari 1915, gewijd aan de beroemde Patriotisme et Endurance (verzet tegen de Duitsers) en in die van 18 september 1916, over de twee politieke objectieven van Verschaeve: de vernederlandsing van de Gentse universiteit en de inrichting van de bestuurlijke scheiding.De eerste week van augustus 1917 voelde kapelaan Verschaeve zich bedreigd. Hij maakte zich zorgen over het uitblijven van het antwoord van koning Albert I op de Open Brief van 11 juli door de leiding van de Frontbeweging aan de vorst gestuurd en bij de soldaten verspreid. Bovendien was aan de top van de regering De Broqueville een wissel doorgevoerd: het Ministerie van Oorlog kwam in handen van Armand De Ceuninck, een hardvochtig generaal. Verschaeve vreesde het ergste voor hem en voor de soldaten.In die omstandigheden nam hij het initiatief om op eigen houtje een (tweede) open brief aan de koning te schrijven en een oud plan uit te voeren: een brief gericht aan paus Benedictus XV en een aan kardinaal-aartsbisschop Désiré Mercier.In het eerste deel van zijn brief sprak de kapelaan zijn grote bewondering uit voor de kardinaal en zijn verzet tegen de Duitse overweldiger. Vervolgens herinnerde hij aan de homilie van 21 juli 1916 in Sint-Goedele te Brussel over de betekenis van de soldaten aan de IJzer: ils sont nos sauveurs. En dat bracht hem vanzelf tot de beklagenswaardige situatie van de Vlaamse piotten, de spanningen in het leger en het repressieve optreden van de overheid. In het tweede deel trok Verschaeve scherp van leer tegen de aartsbisschoppelijke maatregel, met betrekking tot het activisme, de Duitse maatregel voor de vernederlandsing van de Gentse universiteit en het doorvoeren van de bestuurlijke scheiding in België en de autonomie van Vlaanderen. Het zijn uitgesproken politieke statements van de kapelaan over de Vlaamse beweging.Met deze brief heeft Verschaeve Mercier willen counteren maar is daar niet in geslaagd. De brief is in oktober 1917 in Londen afgegeven aan de vertegenwoordiger van de kardinaal, Mgr. Antoon De Wachter. Of hij Mechelen heeft bereikt weten we niet. Wel werd de tekst aan het front verspreid. Verschaeve dacht daarbij een keerpunt te bewerkstellingen in de Frontbeweging en in de Vlaamse beweging in het algemeen.__________ “Our situation compels us to speak.” Cyriel Verschaeve’s Letter to Cardinal Mercier, 6 August 1917 From 1917 to 2017, this letter has had a noteworthy publishing history. This article follows the latest, scholarly edition in Open Brieven (“Open Letters”, Antwerp, 2017).One of the most important documents from the prehistory of this letter is the essay 1830-1908, an unpublished text that was issued by Lodewijk Dosfel in February 1918 in Ghent. This essays reveals Verschaeve’s views on nation and state, quite different from those of Mercier. Here, the chaplain follows the Afrikaner Boer War general, Christiaan De Wet, and the Liège university professor Émile de Laveleye. The preparatory steps toward the letter can be gleaned in his journal entry of 25 January 1915, dedicated to the well-known Patriotisme et Endurance (“Patriotism and Endurance”, an address of Mercier’s relating to resistance to the Germans) as well as in the entry pf 18 September 1916, about Verschaeve’s two political objectives: transforming the University of Ghent into a Dutch-speaking institution and establishing administrative separation.In the first week of August 1917, chaplain Verschaeve felt himself to be under threat. He worried about the lack of a response from King Albert I to the Open Letter of 11 July, which had been sent to the sovereign by the leadership of the Front Movement and spread among the soldiers. In addition, a change had recently taken place in the ranks of the De Broqueville government: the War Ministry came into the hands of Armand De Ceuninck, a stern general. Verschaeve now feared the worst for himself and for his soldiers.In these circumstances, he took the initiative on his own accord to write a (second) Open Letter to the king and to put an old plan into action: a letter to be sent to Pope Benedict XV and Cardinal-Archbishop Désiré Mercier.In the first half of his letter, the chaplain spoke of his great admiration for the cardinal and his resistance to the German usurper. Subsequently, he remembered the homily of 21 July 1916 at the Cathedral of Saint Gudula about the soldiers on the Yser: “they are our saviours”. This brought him right to the pitiable situation of the Flemish infantrymen, the tensions in the army and the repressive conduct of the government. In the second half, Verschaeve very angrily attacked the archbishop’s attitudes on topics such as Activism, the German measures for the transformation of the University of Ghent and the implementation of administrative separation in Belgium and autonomy for Flanders. These were outspoken political statements from the chaplain about the Flemish Movement.Verschaeve had wanted to counter Mercier but did not succeed in doing so. In October 1917, the letter was handed to the representative of the cardinal, Mgr. Antoon De Wachter. It is unknown whether it made it to Mechelen. The text was, however, spread at the front. In doing so, Verschaeve intended to bring about a turning point in the Front Movement and in the Flemish Movement in general.

Het oorlogsjaar 1917, de IJzersymbolen en de relativiteit van de IJzermythes

Oorlogsjaren zijn op zichzelf erg belangrijk, maar het oorlogsjaar 1917 was dat in het bijzonder, zowel internationaal als vanuit Vlaams perspectief. Voor de Vlaamsgezinden aan het front betekende 1917 een scharnierjaar: tegen de achtergrond van de eindeloos aanslepende stellingenoorlog enerzijds en de Vlaamsgezinde agitatie van activisme en frontisme anderzijds, werd het oorlogsoffer van een aantal Vlaamsgezinde soldaten nadrukkelijk een sterven-voor-Vlaanderen. Hun offerbereidheid voedde de hoop dat het politieke initiatief na de oorlog in de handen van de Vlaamsgezinden zou komen. Maar tegelijk groeide het gevoel van verlatenheid ten opzichte van de hoogste kerkelijke en politieke overheden, in de eerste plaats tegenover kardinaal Mercier en koning Albert, op wie men vruchteloos beroep had gedaan om de Vlaamsgezinde aspiraties in te wil-ligen. De aura van het sterven-voor-Vlaanderen ontwikkelde zich vooral rondom een aantal gesneuvelde Vlaamsgezinden: deze IJzer-helden werden IJzersymbolen. Onder hen verwierven vooral de (in 1917 gesneuvelde) gebroeders Edward en Frans Van Raemdonck en Renaat De Rudder een iconische en ten dele mythische betekenis.__________ The War Year 1917, the Symbols of the Yser and the Relativity of the Yser Myths Years of war are very important on their own, but the year 1917 was unusually so, in an international as well as Flemish perspective. For Flemish-minded individuals on the front, 1917 was a turning point: against the background of the endlessly persistent war of position on the one hand, and the Flemish-minded agitation of Activism and the Front Movement on the other, the wartime sacrifice of a number of Flemish casualties was emphatically one of ‘dying for Flanders’. Their willingness to sacrifice fed the hope that the political initiative would come into the hands of the Flemish-minded after the war. But at the same time, a sense of abandonment grew regarding the highest ecclesiastical and political authorities, in the first place Cardinal Mercier and King Albert, to whom a fruitless appeal had been made to accede to Flemish demands. The aura of ‘dying for Flanders’ developed largely around a number of fallen Flemish-minded soldiers: these ‘Yser heroes’ became ‘Yser symbols’. Among these, the brothers Edward and Frans Van Raemdonck and Renaat De Rudder, who all died in 1917, developed a particularly iconic and partly mythical significance.

't Volk is voogd en meester moede

Tot hij in april 1916 in de buurt van Diks-muide gewond raakte, was de dichter August Van Cauwelaert als broer van de politicus Frans Van Cauwelaert de man die soldatenklachten aanhoorde en die de spanningen tussen Franstalige bevelhebbers en de Vlaamse manschappen registreerde. Maar door de informatie die hem tijdens zijn her-stel in het Zuid-Franse Cannes bereikte, stond Gust Van Cauwelaert gaandeweg dichter bij de Frontbeweging dan zijn broer Frans. Dat blijkt uit een drietal hekeldichten die hij tijdens en na de oorlog schreef aan het adres van de Belgisch regering in Le Havre en aan koning Albert.Gust achtte zijn broer te goedgelovig in zijn contacten met de Belgische regering en met koning Albert. Meermaals waarschuwde hij Frans dat hij op het punt stond zijn prestige te verspelen. Eind december 1916 schreef hij hem: “Het feit dat gij geloofd hebt in de beloften die van hogerhand gedaan werden aangaande onze zaak, en dat vertrouwen hebt meegedeeld, heeft u kwaad gedaan, geloof me”.De verdeeldheid binnen de Vlaamse beweging die Gust had voorspeld was een feit toen hij in augustus 1919 werd gedemobiliseerd.__________ ‘Volk is voogd en meester moede Until he was wounded in the vicinity of Diksmuide in April 1916, the poet August Van Cauwelaert, as the brother of the politician Frans Van Cauwelaert, was the man who listened to soldiers’ complaints and who kept a record of tensions between French-speaking commanders and Flemish enlisted men. But, due to the information that reached him during his recuperation in Cannes in the South of France, Gust Van Cauwelaert gradually moved closer to the Front Movement than his brother Frans. This can be seen in three satirical pieces that he wrote during and after the war, directed at the Belgian government in Le Havre and to King Albert.Gust considered his brother to be too credulous in his contacts with the Belgian government and King Albert. On several occasions he warned Frans that he was about to forfeit his prestige. In the end of December 1916 he wrote to him: “The fact that you have believed in the promises that were made from on high regarding our cause, and that you have made that confidence known out loud, has done you harm, believe me.”The division among the Flemish Movement that Gust had predicted was a fact by the time he was demobilized in August 1919.

"Een ruim veld voor de Studentenbeweging ligt open." Inzake oorsprong en aard van de Vlaamse 'Frontbeweging'

De geschiedschrijving die de ‘Vlaamse Frontbeweging’ tot onderwerp nam, heeft tot dusver te weinig het oog gericht naar de voorgeschiedenis die in nauw verband staat met de afschaffing van de loting en de veralgemening en uitbreiding van de dienstplicht vanaf 1909. Daarbij kwam ook nog eens de eerste taalwet van 1913 die door de strijdkrachten zou moeten toegepast worden. Dit leidde tot een veel sterkere betrokkenheid binnen de Vlaamse beweging. Daarbij werd uit de aard der zaak vooral gerekend op de jonge mannen die nog naar het leger zouden moeten. Zij zouden in staat moeten zijn om de volksjongens zonder veel scholing mee in het ‘Vlaamse’ bad te trekken en zo stapsgewijs het Nederlands een plaats te geven in de strijdkrachten.Al even belangrijk voor een goed begrip is het feit dat de vooroorlogse elite er bijzonder goed in was geslaagd om het leger dienstbaar te maken bij de start van de carrière van wie hoger onderwijs kon volgen via de ‘compagnies universitaires’. In 1909 werd bovendien de categorie van de brancardiers gecreëerd die bestond uit seminaristen, novicen en student-onderwijzers. Zij moesten enkel een cursus volgen in hun vrije tijd.Er werd dus een elite geschapen die amper in contact kwam met de werkelijkheid in het leger en die mijlenver afstond van het beroepskader. Dat leverde de nodige springstof waarop de Frontbeweging kon groeien als een voortzetting van de vooroorlogse katholieke studentenbeweging. Deze jongemannen vonden dat zij hun vooroorlogse agitatie op taalvlak moesten verder zetten in oorlogstijd. Omdat de Duitse Flamenpolitik en de toenemende uitzichtloosheid leidde tot verbittering betekende dit een bedreiging voor de machtspositie van het militaire kaderpersoneel en de koning-opperbevelhebber.De hoop en de verwachting dat de Vlaamse oud-strijders zich na afloop van de oorlog en masse achter de Frontbeweging haar eisenprogramma zou scharen, bleek echter ijdel.__________ “A Wide Field for the Student Movement Lies Open.” On the Origin and Character of the Flemish Front Movement The historiography which takes the ‘Flemish Front Movement’ as its subject has so far paid too little attention to the historical background which is closely tied to the abolition of the conscription lottery and the generalization of the service requirement from 1909. In addition to this was the first language law of 1913 that the armed forces were supposed to follow. This led to a greater participation in the Flemish Movement. This obviously included in large part the young men who still had to go into the army. They had to be up to the task of bringing boys from the common folk who did not have much schooling into the ‘Flemish’ sphere and thus work step-by-step to give Dutch a place among the armed forces.Just as important for a good understanding is the fact that the prewar elite was unusually successful in making the army a stepping stone in the career of those who could follow higher education, through the “compagnies universitaires” (university companies). Most importantly in this regard, in 1909 the category of stretcher-bearer was created, which was made up of seminary students, novice priests and student teachers. They only had to take a course in their free time.Thus, an elite was formed that was nearly never in contact with the day-to-day life of the army and which was miles away from the traditional professional circles. This provided the necessary spark from which the Front Movement could grow as an extension of the prewar Catholic student movement. These young men found that they had to continue their prewar agitation regarding language matters in wartime. Because the German Flamenpolitik (policy of coopting the Flemish Movement) and growing hopelessness led to embitterment, this constituted a threat to their position of power of the military senior staff and the king as commander-in-chief.The hope and the expectation that Flemish veterans would range themselves en masse behind the Front Movement’s list of demands after the end of the war turned out to be in vain.