The oil-water interfacial tension (IFT) is by all means important in capillary pressure estimation and fluid-fluid and fluid-rock interactions analysis. Observations from experimental data indicate that oil-water IFT is a function of pressure, temperature, and compositions of oil and water. A reliable correlation to estimate oil-water IFT is highly desire. Unfortunately to our best knowledge no correlation that uses the compositions of oil and water as inputs is available. Our work is to fill this gap.
In this research, we collected data from former studies and investigations and developed a correlation for oil-water IFT. In the proposed correlation oil-water IFT is a function of system pressure, temperature, and compositions of oil and water. Error analysis was conducted to check the accuracy of the equation by comparing the calculated values with the experimental data. The results indicated that the new correlation predicts reliable oil-water IFTs. Our correlation calculates the oil-water IFT from system pressure, temperature, and compositions of oil and water. It addresses the effect of composition of oil on IFT, which is not presented in existing correlations. Therefore it can not only be applied in the calculation of capillary pressure in the compositional simulation, but also be used in daily petroleum engineering calculation such as waterflooding analysis.
Hassan, Hany Mohamed (Petroleum Development Oman) | Al-hattali, Ahmed Salim (Petroleum Development Oman) | Al Nabhani, Salim Hamed (Petroleum Development Oman) | Al Kalbani, Ammar (Petroleum Development Oman) | Al Hattali, Ahmed (Petroleum Development Oman) | Rubaiey, Faisal (Petroleum Development Oman) | Al Marhoon, Nadhal Omar (Petroleum Development Oman) | Al-Hashami, Ahmed (Petroleum Deveopment Oman)
A cluster area "H" consists of 4 carbonate gas fields producing dry gas from N-A reservoir in the Northern area of Oman. These fields are producing with different maturity levels since 1968. An FDP study was done in 2006 which proposed drilling of 7 additional vertical wells beside the already existing 5 wells to develop the reserves and enhance gas production from the fields. The FDP well planning was based on a seismic amplitude "QI" study that recommended drilling the areas with high amplitudes as an indication for gas presence, and it ignored the low amplitude areas even if it is structurally high. A follow up study was conducted in 2010 for "H" area fields using the same seismic data and the well data drilled post FDP. The new static and dynamic work revealed the wrong aspect of the 2006 QI study, and proved with evidence from well logs and production data that low seismic amplitudes in high structural areas have sweet spots of good reservoir quality rock. This has led to changing the old appraisal strategy and planning more wells in low amplitude areas with high structure and hence discovering new blocks that increased the reserves of the fields.
Furthermore, water production in these fields started much earlier than FDP expectation. The subsurface team have integrated deeply with the operation team and started a project to find new solutions to handle the water production and enhance the gas rate. The subsurface team also started drilling horizontal wells in the fields to increase the UR, delay the water production and also reduce the wells total CAPEX by drilling less horizontal wells compared to many vertical as they have higher production and recovery. These subsurface and surface activities have successfully helped to stabilize and increase the production of "H" area cluster by developing more reserves and handling the water production.
The time taken to safely optimise a reservoir produced by artificial lift can be measured in weeks or months.
Typically the well by well process is as follows:
• Well testing
• Amalgamation of the well test data with down hole gauge and ESP controller data
• Analysis of the data to find the existing operation conditions
• Analysis of the ESP pump curve operating point and optimisation limitations
• Sensitivity studies in software to assess the optimum frequency and WHP
• Notification for the field operations to action the changes
• Further well tests to verify the new production data.
• Analysis of the data to ensure the ESP and well are running optimally and safely at the new set points
New technology enables this process to be performed in real time across the entire reservoir or field, significantly shortening the time to increased production and enabling real time reservoir management.
Each artificially lifted well in the reservoir was equipped with an intelligent data processing device programmed with a real time model of the well. The processors were linked to a central access point where the operation of field could be remotely viewed in real time.
Each well's processor was provided with a target bottom hole flowing pressure to enable the optimum production of the reservoir. The real time system automatically compared the desired target drawdown values with the capability of the pumping system installed in each well, and automatically suggested the optimum operating frequency and well head pressure to achieve the target. Where the lift system was not capable of producing to the target bottom hole pressure, a larger pump was automatically recommended. As production conditions change the system adapted its recommended operating points to compensate and maintain target production.
This paper discusses three case studies where real time optimisation and diagnosis lead to improved production from the reservoir.
Blunt, J.D. (ExxonMobil Upstream Research) | Garas, V.Y. (ExxonMobil Upstream Research) | Matskevitch , D.G. (ExxonMobil Upstream Research) | Hamilton, J.M. (ExxonMobil Upstream Research) | Kumaran, K. (ExxonMobil Corporate Strategic Research)
Safe and economic hydrocarbon exploration, development and productionoperations in the high arctic deepwater require a nuanced understanding of thesea ice environment. Robust image analysis techniques provide methods bywhich this nuance can be more objectively characterized and used for decisionmaking while in operations. Morphological segmentation and windowedstatistical analysis are proposed as two approaches that provide usefulinformation on the tactical scale by rapidly characterizing floe fieldmorphology and relative surface roughness. Their use is demonstratedwithin the context of actual high arctic field program data. Results fromthe method application are shown and the benefits and limitations of their useare discussed.
The purpose of this paper is to introduce various offshore platform conceptsthat can be employed in ice infested waters, particularly shallow waters,depths varying from 65 ft to 500 ft. The paper illustrates five innovativeplatform concepts that for arctic drilling. The proposed platform conceptswould have ability to withstand extreme ice, wind, wave and temperatureconditions to extend the drilling seasons either near to winter sever storm orfor round the year operation. The platforms are designed to operate indifferent water depths in different part of the arctic by accommodating thedrilling structures and equipment on the deck. The emphasis is on theefficient of breaking, moving ice sheets around the structure and withholdingthe topside loads. Some of the platform concepts are fixed and others aredeveloped from the floating solution and the technical details are presented inthis paper.
This paper will describe the state of art in active acoustic detection ofoil and gas in the water volume as well as the seafloor. Examples of real datawill be described with the relevance to the leakage detection challenges wheresurveillance and early detection is crucial. Active acoustic data will bepresented from several trials from various parts of the world, examples hereofis California natural seeps, Brazil leakage detection, Norway plume mixingphenomenon's and more.
Applications: Leakage detection on subsea assets, Site surveys of leakages,Oil response capabilities, Oil recovery capabilities, Dispersant efficiencyespecially sub surface, Quantification of leak flux both gas and fluid.
Results, Observations, and Conclusions: Expedition results will be reviewedbased on several real life tests and deployments of active acoustic systems.Conclusion of expected performance of active acoustic systems will be drawn.Miniaturization and adaptation of power requirement as well as uplink demand,combined with sufficient processing to avoid false alarms will bediscussed.
Significance of Subject Matter: Early subsea leakage detection is absolutelykey to any arctic project, quantifiable flux rates is an important key input toall decision-making during operation of oil fields in all regions.
Saleem, Saad (Pakistan Petroleum Limited) | Sattar, Suhail (Pakistan Petroleum Limited) | Shahzad, Atif (Weatherford Oil Tools M.E. Limited) | Ziadat, Wael (Weatherford Oil Tools M.E. Limited) | Sabir, Shahid Majeed (Weatherford Oil Tools M.E. Limited)
The name "Sui?? has become synonymous with natural gas in Pakistan. Sui is Pakistan Petroleum Limited's (PPL) flagship gas field. Commercial exploitation of this field began in 1955.
Two major reservoirs of this field are Sui Main Limestone (SML) and Sui Upper Limestone (SUL). Both the reservoirs have become highly depleted by time. Conventional drilling technologies in these formations result in complete loss of drilling fluid, stuck pipe and severe formation damage issues.
Pakistan Petroleum Limited (PPL) planned to drill a horizontal well Sui-93(M), where target reservoir was Sui Main Limestone (SML). Drilling a horizontal well with conventional drilling techniques can cause a complete loss of drilling fluid. Underbalanced Drilling integrated with electromagnetic telemetry transmission was successfully used to drill this well to a target depth of 2200m MD with complete directional controls. Electromagnetic transmission modeling was performed on the resistivity data of offset wells to determine signal attenuation for Sui-93(M) Well. Based on modeling results it was decided to run an extended range set-up with a downhole antenna.
The main reason for using EM-MWD was to provide real time data for annular pressure (APWD sensor) and directional controls in UBD environment. The APWD (annular pressure while drilling-real time ECD) sensor was considered mandatory to monitor and ensure underbalanced condition while drilling, thereby avoiding significant problems such as lost circulation and stuck pipe.
This paper discusses the planning, results, problems and lessons learned during the first application of the Extended Range EM-MWD (Electromagnetic-Measurement while drilling) technology in Sui-93(M) well.
The application of EM-MWD along with UB technology represents a stepwise progression for improving PPL's ability to exploit mature reservoirs, especially those that are severely depleted like in Sui Gas Field, Pakistan.
In August 2010 a 265 km2 ice island calved from the Petermann Glacier innorthern Greenland. Soon after the initial calving event the mass broke intoseveral pieces, some of which exited Baffin Bay and drifted south toward theLabrador coast. By June 2011 PII-A, a large fragment of the initial PetermannIce Island, was situated offshore Labrador and in one week it had moved 225 kmdown the coast. Concern arose that if PII-A continued its trajectory it couldreach the Grand Banks by August 2011, posing a potential risk for existinginfrastructure in the offshore region of Newfoundland. To properly assess thepotential risk a realistic estimate of ice mass was necessary. This in turnrequired field measurements of the ice islands thickness.
A three-day field program was carried out on the Petermann Ice Islands,PII-A and PII-A-a, from June 17-19, 2011. At this time PII-A and PII-A-a weresituated offshore Labrador, Canada, approximately 100 km northeast of the townof Rigolet. Geophysical survey methods, including Ground Penetrating Radar(GPR) and Seismic Reflection, were used to identify the base of the islands andobtain ice thickness measurements at various locations. Eight satellitetracking beacons were deployed on PII-A and one was deployed on PII-A-a.Ablation data, photographs and video footage were also obtained during theprogram. On July 22, 2011, PII-A was revisited while it was situated off thesouthern Labrador coast. GPR measurements were acquired at the pre-existingstations; the measurements allowed for deterioration rates due to surface andbasal melting to be calculated for PII-A. Results of the field measurementsindicate that ice thickness varied between 50 to 80 m on PII-A; the thicknessof PII-A-a was 30 m at a single survey location. Surface melt rates of 2.7-6.3cm day-1 were observed over a 1-day period in June. For the 35-day periodbetween June and July visits, average surface and basal melt of 5.0 cm day-1and 3.4 cm day-1, respectively, were calculated.
Modern active acoustic multibeam sonars have the last 1.5 years achieved amajor breakthrough in terms of performance, physical size, power consumption,uplink flexibility, processing and not least price. This now allows the tool tobe used in a much wider context during arctic subsea hydro carbonate (Oil/gas)detection, quantification and visualization. As the new generation sonar is soflexible it will easily integrate to any platform, AUV, ROV, Gliders, permanentinstallation, ship borne etc. The multibeam sonar will be capable of monitoringlarger areas and perform various tasks in an arctic oil explorationsetting.
Active acoustics can be used for various applications such as A) Reservoirfault monitoring, a good example of such an event was the Frade field spillNovember last year, under ice this would have been disastrous B) Natural seeps,this is instrumental to monitor during exploration but also during operation ofthe field C) Leakage detection on infra structure, naturally this is of greatconcern to have real time detection of leakages from critical infra structureD) Oil spill response, detection of hydro carbonate suspended in the watercolumn as well as under the ice, on seafloor E) Dispersant mixing efficiency,real time 3D monitoring of the mixing process during application of dispersantF) Major events such as the deep water horizon it is important to be able tomonitor hydro carbonate in the water column Results, Observations, andConclusions: Active acoustic test data will be shown, this will be a mix ofreal offshore data as well as laboratory based data sets. Examples of datarelevant to all the application areas described will be given Significance ofSubject Matter: Obviously those applications are highly relevant for the articexploration area.
Experts from the oil and gas industry are sure that the "easy oil" is nearlygone. Due to that the oil and gas industry has to face more and morechallenging deposits like those in ultra-deep waters or in the Arctic. To copewith these challenges, thinking out of the box will be required in some cases.To find the most effective solution, to shorten development time and to avoidunnecessary failures technology transfer from other industries can be ashortcut to unlock the Arctic reserves in a safe and economic way.
A potential technology provider can be the military submarine industry. Thispaper postulates submarines and their technology portfolio as a potentialsource of solutions for some of the future oil and gas challenges in the Arcticenvironment. Todays' non-nuclear submarines operate in a cost efficient waywith minimum risks to the crew, the operator and the environment.
To prove this, after a short introduction into the submarines historyshowing their development and today's capabilities, the not obvious parallelsbetween the vessels and systems from oil and gas industry and the conventionalmilitary submarines will be carved out by comparing their basic designrequirements. A selection of technologies developed for conventional militarysubmarines will be introduced and the potential usage of these technologies tofulfill the oil and gas needs, occurring especially but not only in the Arcticenvironment, will be presented afterwards. Finally submarine concepts will beintroduced providing the ability to perform operations for the oil and gasindustry weather independent and beneath the ice in the Arctic Ocean.