bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigating the Performance of Various FCD Geometries for SAGD Applications
Authors: Gohari Kousha , Ortiz Julian , Abraham Anson , Moreno Oscar Becerra , Irani Mazda , Nespor Kristian , Sanchez Javier , Betancur Andres , Bilic Jeromin , Duong Khoi , Bashtani Farzad 
Published: February 2021

Abstract
Steam-Assisted Gravity Drainage (SAGD) is a complex process that often requires more control relative to conventional applications during production operations. Flow Control Devices (FCDs) have been identified as one of the technologies that offer improved downhole steam utilization and injection/production efficiency. The first FCD completions, with a helical geometry, were installed in SAGD wells at the ConocoPhillips Surmont project over a decade ago. The installations have shown improved steam chamber conformance and reduced steam-oil ratio (SOR) while accelerating bitumen production. Since then, various FCD geometries have been investigated and used, with several of them explicitly designed with a steam blocking capability. This study used a numerical simulator to investigate the performance of these various FCD geometries.
This comprehensive study started testing several geometries in a flow loop and using the data obtained to develop a mechanistic model to characterize the flow performance of the FCDs and finally evaluating their performance in a holistic manner via a numerical simulator.
By using mechanistic modeling, it was ensured that the performance of the devices was accurately represented, and the physics of the process were considered. The analysis used a commercially available numerical simulator to evaluate the performance of the various FCD geometries in SAGD operation. Three sector models representing different reservoir qualities observed in Surmont were used for the analysis. Additionally, various operating strategies were investigated for each sector model to ensure that a comprehensive understanding of each FCD geometry was achieved.
The results of this study showed that FCD flow resistance setting or nozzle size played a significant role in the production performance of the wells in liner deployed FCD applications. Additionally, the steam blocking geometries resulted in increased cumulative production and lower SOR relative to other geometries. The FCD geometry did also impact the development of the steam chamber.
Nevertheless, if the FCD completions are configured with the proper flow resistance setting or nozzle size, they provide a proactive measure, which leads to significantly better performance compared to a non-FCD completion. With lower subcool, the geometry of the FCD has a greater impact on the performance of the well. It was also confirmed that an aggressive operating strategy results in better performance of the FCD completions.
Analysis of the Performance of Various Well Liner Completion Strategies in Surmont
Authors: Gohari Kousha , Ortiz Julian , Nespor Kristian , Sanchez Javier , Betancur Andres , Irani Mazda , Bashtani Farzad , Sabet Nasser , Ghannadi Sahar , Abraham Anson , Bilic Jeromin , Becerra Moreno Oscar 
Published: February 2021

Abstract
ConocoPhillips operates Surmont, which is the first Steam-Assisted Gravity Drainage (SAGD) project to implement Flow Control Devices (FCDs) in producer wells. This study was conducted to evaluate the production performance of different liner completion strategies. The analysis compared well pairs completed with slotted liners (SL) to producers completed with FCDs, both liner deployed (LD-FCD) and tubing deployed (TD-FCD), and investigated the impact of FCDs in injectors.
An extensive analysis was conducted using available production and temperature data along the wells. The wells were completed using various fixed-resistance FCD settings, while some wells were completed using variable setting designs. As time went on, several of the slotted liner producer wells were retrofitted with tubing-deployed FCD completions. One of the key objectives of the study was to determine the success rate of tubing-deployed FCDs and their performance relative to liner-deployed FCD wells. Another objective was to evaluate the impact of retrofitting slotted liner SAGD injectors with tubing-deployed FCD completions.
In this study, a grading system was established based on the reservoir quality along the well for both injector and producer. For similar graded well pairs, LD-FCDs had better production performance than TD-FCDs. Considering similar graded reservoir quality, FCDs consistently performed better than slotted liners, in both conformance and production acceleration. The production analysis showed that the FCD flow restriction was a major controller of the conformance, but considering the self-choking phenomenon of the reservoir, most FCDs can perform positively in different circumstances. In this study, the self-choking effect of the liquid pool is discussed and explained for different reservoirs and variable subcool.
Generally, if erosion is not a factor, FCDs can create a more controlling system than liquid-pool dominant systems. In these cases, both conformance and production acceleration is enhanced if operators yield lower subcools and greater draw-down pressures.
Field Evaluation of Improved Oil Recovery Methods in a Libyan Oilfield
Authors: Ifelebuegu Augustine O. , Zydan Zydan H. 
Published: February 2021

ABSTRACT
Intisar A oil field is a Libyan field located in Concession 103 and has been in production since 1968. In this paper, we report the field evaluation results of the various productions enhancement techniques and initiatives applied for incremental oil production. The impact of improved recovery by various waterflood optimisation processes including infill well drilling, installations of ESPs, current well re-completion, and conversion wells were evaluated taking into consideration surface facility constraints. An incremental total daily production of 9872 STB/D was achieved in the overall optimisation projects with infill horizontal well drilling producing the highest incremental recovery. The internal rate of return for the overall project was 72% and a payback period of 3.4 years. The lessons learned, and recommendations for future development of the field were established.
Petroleum Geochemistry of the Loperot-1 Well in Lokichar Basin, Kenya
Authors: Katithi David M. , Opar David O. 
Published: February 2021

ABSTRACT
The work reports an in-depth review of bulk and molecular geochemical data to determine the organic richness, kerogen type and thermal maturity of the Lokhone and the stratigraphically deeper Loperot shales of the Lokichar basin encountered in the Loperot-1 well. Oil-source rock correlation was also done to determine the source rocks’ likelihood as the source of oil samples obtained from the well. A combination of literature and geochemical data analyses show that both shales have good to excellent potential in terms of organic and hydrogen richness to act as conventional petroleum source rocks. The Lokhone shales have TOC values of 1.2% to 17.0% (average 5.16%) and are predominantly type I/II organic matter with HI values in the range of 116.3 – 897.2 mg/g TOC. The Lokhone source rocks were deposited in a lacustrine depositional environment in episodically oxic-dysoxic bottom waters with periodic anoxic conditions and have Tmax values in addition to biomarker signatures typical of organic matter in the mid-mature to mature stage with respect to hydrocarbon generation and immature for gas generation with Ro values of 0.51 – 0.64%. The Loperot shales were shown to be possibly highly mature type II/III source rocks with TOC values of 0.98% – 3.18% (average 2.4%), HI of 87 – 115 mg/g TOC and Ro of 1.16 – 1.33%. The Lokhone shale correlate well with the Loperot-1 well oils and hence is proposed as the principal source rock for the oils in the Lokichar basin. Although both source rocks have good organic richness to act as shale gas plays, they are insufficiently mature to act as shale gas targets but this does not preclude their potential deeper in the basin where sufficient gas window maturities might have been attained. The Lokhone shales provide a prospective shale oil play if the reservoir suitability to hydraulic fracturing can be defined. A basin wide study of the source rocks thickness, potential, maturation and expulsion histories in the Lokichar basin is recommended to better understand the present-day distribution of petroleum in the basin.
Research on the Tectonic Evolution of the North Africa from Morocco to Libya as the Controlling Factor on the petroleum basins’ Hydrocarbon Accumulation
Authors: Liping Xiong , Yanli Liu , Danni Shi 
Published: February 2021

ABSTRACT
This paper focuses on the tectonic evolution of the North African petroleum basins as the controlling factors on the major basins’ formation, evolution and the hydrocarbon accumulation, analyzing the petroleum enrichment conditions and proposing hydrocarbon accumulation mode. The analysis concludes that the distribution of North Africa Basins is in regular east-west direction, clear depression associates with highland structure. The basins becomes gradually older from the west to the east, corresponding to the Western Paleozoic basin, the Middle part Paleozoic and Mesozoic superimposed basin and the Eastern Mesozoic-Cenozoic rift basin. Petroleum in the Middle-West basins is mainly controlled by western Hercynian tectonic movement with obvious NE – SW distribution character, while petroleum in the East basins controlled by the Alpine tectonic movement, showing NW-SE distribution. Experienced a number of north-south direction reversals, the Paleozoic basin developed in the South and the Mesozoic-Cenozoic superimposed basin overlaying the Paleozoic Basin located in the North. The basins have two different accumulation models, which are younger source rocks associated with the older reservoirs and the older source rocks with the younger reservoirs.
A Review of the Leading Technologies that Can Make a Difference in the Search for and Production of Hydrocarbons
Authors: Engelder Terry , Zhou Yaneng 
Published: February 2021

ABSTRACT
As industry evolves in the 21st Century in Africa, there are fundamental questions that are in the best interest of industry to solve in exploration for and production of new prospects and in the revitalization of partially depleted fields. Many of these questions may be addressed using technologies that have evolved during the gas shale revolution of the past decade. This talk will review some of these leading technologies in briefly discussing the following ten questions. What is the state of stress in basins? What information comes from a microseismic survey? How does knowledge of a depositional environment guide the placement of a lateral? How do natural fractures evolve in shales? What information is available when sonic logging is coupled with conventional logs? Where does water go when injected into shale? What are the major subsurface structures that can be detected in multichannel seismic? How does a project deal with the smaller scale (sub-seismic) structures? How is organic carbon distributed in reservoir rock? What are the mechanisms for the development of overpressure in basins?
Slim-hole Drilling – De-risking Exploration in Remote Locations
Authors: Soquar Emmanuel , van der Westhuyzen Chris 
Published: February 2021

ABSTRACT
Onshore exploration – both oil and gas and geothermal – typically involves the mobilisation of full sized conventional rigs. The support package includes back up and auxiliary parts, capable of drilling and fully evaluating deep large diameter conventional holes. In early stage exploration programs conducted in remote and frontier locations, the operating costs can approximate those of an offshore operation. This standard approach may be an unnecessary expense and lessons can be learned from the mining industry, which has been operating in a lower cost environment in frontier locations for over 125 years. A slim well approach is adopted not just to the well design but to team size, civil works, evaluation requirements and logistics. A smaller rig capable of drilling slim wells to the desired terminal depth (of up to 4,000 m), with complete logging and core sampling, can provide exploration companies with a cost effective solution.
Regionally Connected Structural Systems: The Power of the Big (Continental-Scale) Picture
Authors: Granath James , Dickson William 
Published: February 2021

ABSTRACT
Beyond offshore West Africa where modern densely-sampled data from ships and satellites have played a key role in current understanding of passive margin evolution, Africa is in general rather unevenly known, especially in the subsurface in more remote areas. The GIS-based Exploration Fabric of Africa (EFA, the &lsquo;Purdy project&rsquo;) was designed to address that problem. It includes structural features such as faults and basin outlines but at a very high and often generalized level, divorced from their underlying genetic linkages. We have undertaken to compile a more detailed tectonic synthesis aimed to integrate understanding of the oceanic margins with the continental realm. This is an overlay to EFA with a variety of public domain, published, non-exclusive, and derivatives of proprietary work at a closer and more detailed level, importantly guided by known patterns of structural styles. Potential field (gravity and magnetic) data provide guidance in locating, extending, and connecting key mapped features; we then rely on the kinematic patterns to predict missing details in a testable interpretation. The result is a detailed structural features map that can function as a framework within which to target and prioritize both conventional and unconventional activity by operators and licensing/regulatory organizations. We illustrate the process in theory and in practice along the Central African Rift System (CARS), where data is sparse. This fault linkage systems approach has flagged underexplored areas where unmapped structure is likely that could, for example, be targeted with hi-resolution geophysical data. A similar system to CARS appears to cross southern Africa from Namibia to Tanzania – a &ldquo;Southern Trans-African Rift system&quot; or STARS. Exploration in the eastern Owambo Basin resulted in the mapping of a pull-apart basin from depth-to-basement inversion of high-resolution magnetic data and subsequently studied with structural modeling. Thinking in terms of such fault and structural systems, this &lsquo;Kavango Basin&rsquo; can be related along strike to the Karoo Basins in Eastern Africa via features such as the Omaruru lineament, implying the possibility of a fairway of extensional basins and shears across the continent that are not obvious in existing low-resolution data. STARS represents a blue-sky frontier concept for both conventional and nonconventional exploration potentially offering new exploration leads, the ultimate objective of big picture work.
Increasing Plug and Abandon Efficiency in East Africa: Challenges and Solutions
Authors: Joneja Galen , Awalt Michael , Johnson Carl , Bogaerts Martijn , Alsam MHD Tareq 
Published: February 2021

ABSTRACT
In line with an escalation of drilling operations in East Africa, operators and service contractors are increasing their focus on how to make operations more efficient in challenging market. One operation for which a robust, safe, and effective tool was utilized to increase efficiency is the plug and abandonment of deepwater exploration wells in Tanzania and Kenya.
Traditional abandonment of a well is accomplished by stacking multiple cement plugs to achieve zonal isolation. The plugs covering reservoir sections are normally independently verified in keeping with best practices applicable to well barriers. By setting longer plugs to cover multiple zones, rig time and operating costs can be significantly reduced. However, there are limitations to cement plug length when set conventionally without significantly increasing the risk of stuck pipe. The Hydraulic Tubing Release Tool (HTRT) was introduced during a deep-water exploration campaign in East Africa. It has been used successfully during the abandonment of five different wells where seven plug and abandonment operations placed long abandonment plugs, ranging from 405m to 1787m, in a single operation.
The utilization of the tubing release tool system in well abandonment operations has proved to lower the risks and operational costs through the reduction of necessary cementing operations. With the sacrificial tubing being left in the cement, there is less risk of plug contamination which occurs as a result of pulling out of the plug. It also allows for longer plugs to be set in a single operation as opposed to stacking several cement plugs to get the required length, saving additional time.
It has been used successfully on five deepwater wells in East Africa to set long abandonment plugs in open holes ranging from 700m to 1800m MD. The main objective of the disconnect system is to shorten the time taken to perform a well abandonment program as well as reducing the associated risks, thereby saving rig time and money.
Comoros – New Evidence and Arguments for Continental Crust
Authors: Milsom John , Roach Phil , Toland Chris , Riaroh Don , Budden Chris , Houmadi Naoildine 
Published: February 2021

ABSTRACT
As part of an ongoing exploration effort, approximately 4000 line-km of seismic data have recently been acquired and interpreted within the Comoros Exclusive Economic Zone (EEZ). Magnetic and gravity values were recorded along the seismic lines and have been integrated with pre-existing regional data. The combined data sets provide new constraints on the nature of the crust beneath the West Somali Basin (WSB), which was created when Africa broke away from Gondwanaland and began to move north.
Despite the absence of clear sea-floor spreading magnetic anomalies or gravity anomalies defining a fracture zone pattern, the crust beneath the WSB has been generally assumed to be oceanic, based largely on regional reconstructions. However, inappropriate use of regional magnetic data has led to conclusions being drawn that are not supported by evidence. The identification of the exact location of the continent-ocean boundary (COB) is less simple than would at first sight appear and, in particular, recent studies have cast doubt on a direct correlation between the COB and the Davie Fracture Zone (DFZ). The new high-quality reflection seismic data have imaged fault patterns east of the DFZ more consistent with extended continental crust, and the accompanying gravity and magnetic surveys have shown that the crust in this area is considerably thicker than normal oceanic and that linear magnetic anomalies typical of sea-floor spreading are absent.
Rifting in the basin was probably initiated in Karoo times but the generation of new oceanic crust may have been delayed until about 154 Ma, when there was a switch in extension direction from NW-SE to N-S. From then until about 120 Ma relative movement between Africa and Madagascar was accommodated by extension in the West Somali and Mozambique basins and transform motion along the DFZ that linked them.
A new understanding of the WSB can be achieved by taking note of newly-emerging concepts and new data from adjacent areas. The better-studied Mozambique Basin, where comprehensive recent surveys have revealed an unexpectedly complex spreading history, may provide important analogues for some stages in WSB evolution. At the same time the importance of wide continent-ocean transition zones marked by the presence of hyper-extended continental crust has become widely recognised. We make use of these new insights in explaining the anomalous results from the southern WSB and in assessing the prospectivity of the Comoros EEZ.
High Expansion Technology Opens the Way for Enhanced Recovery
Authors: Masson Graham 
Published: February 2021

ABSTRACT
The objective of this paper is to examine the recent improvements in High Expansion packer and plug design, while minimizing packer element extrusion. Changes that provide operators with more intervention options at reduced risk.
For thirty or more years, extrusion gap has been controlled primarily by the use of a "Gauge Ring" as a packer back up. While successful, this approach dictates a large OD packer or plug to minimize extrusion gap. As our industry has developed more tortuous wellbore geometry, large ODs have led to running and pulling problems. These designs have also prevented many operators from recovering failed zones. Water encroachment, gas migration and failed sand screens have often been dealt with by re-completion. Options were limited to inflatable systems, long elastomer or umbrella-type plugs. Horizontal completions further reduced that to only Inflatable solutions, due to umbrella systems dependency on cement. Recent developments in High Expansion products have opened up new opportunities to recover from these types of problems.
High expansion elastomers and new design packer back-up systems allow for actual V-Rated packer, plug and straddle systems. With this benefit comes the added value of a retrievable system.
The Role of Neo-Tectonics in Oil Migration, Lake Turkana Region, Kenya
Authors: Witte Jan , Trümpy Daniel , Babies Hans Georg 
Published: February 2021

ABSTRACT
Numerous oil seeps have been documented in the Turkana Basin, western Kenya. However, no commercial oil has been found here to date. Recently discovered substantial oil fields in the nearby Lokichar Basin indicate that oil migration can be complex in these rift basins and may pose an exploration risk. We present a new fault and lineament map of the Turkana-Lokichar Basins, integrated with present-day stress data, oil seeps and known prospects.
Digital terrain data, satellite images, geological maps, seep and gravity data were integrated into a GIS-database, to superimpose the data and to test it for spatial correlations. Digital terrain data, satellite images, gravity and structural maps were used to conduct detailed mapping of the fault and lineament network. The seep and prospect maps are based on the integration of different public data sources.
Four main fault sets are recognized in the basin (~N-S, W-E, NW-SE and SW-NE). Careful analysis of topographic data along both shores of Lake Turkana reveals numerous fault scarps, indicative of recent tectonic activity (particularly the N-S and NW-SE set). The area is presently under NW-SE oriented extension, implying that most of the rift-parallel N-S faults are under oblique dextral transtension. The majority of the documented oil seeps and slicks are found to be associated with rift-parallel faults but also occasionally with the W-E trending set. Recently published neo-tectonic and isostatic uplift data indicate that the highest level of recent fault activity is presently found close to the rift axis and dominantly on the rift-parallel fault sets.
We conclude that ~N-S and W-E oriented faults are the most conductive pathways for hydrocarbons in this region under the present-day stress field (and likely throughout the Mio-Pliocene). We further observe that several prospects of the NW-SE trend have seepages associated with them, which could be indicative of breached traps, especially close to the rift axis where faults are most active. Our assessment should help to better understand migration pathways and exploration risks in the Turkana Basin. We encourage explorers to carefully map fault networks, investigate active fault scarps, age-date them where possible, test them for spatial correlation with oil seeps and evaluate them within the context of the present-day stress field. In consequence these workflows will help mitigate exploration risks in the Turkana-Lokichar Basins and similar tectonic settings.