Dashti, Qasem M. (Kuwait Oil Company) | Al-anzi, Ealian H.D. (Kuwait Oil Company) | Al- Doheim, Aref (Kuwait Oil Company) | Kabir, Mir Md Rezaul (Kuwait Oil Company) | Acharya, Mihira Narayan (Kuwait Oil Company) | Al-Ajmi, Saad (Kuwait Oil Company)
Robustness of measurement while drilling (MWD) and logging while drilling (LWD) tools is laboratory-tested and rigorously field-tested for the expected operating and measurement specifications. Such tools have been used in the industry for decades with proven track record of stability. However, a typical tool string deployed as a part of bottom-hole assembly (BHA) has recently failed to withstand the unexpected BH conditions during drilling of the pilot hole using potassium formate mud (KFM), a heavy water based mud. The failure occurred within a deep-fractured calcareous kerogen section (CKS).
The tools had multiple surface communication failures; the first one was resolved as debris was found obstructing the rotor-starter part before drilling the CKS. The second failure occurred in the back-up tools, after drilling into the CKS and remained unexplained throughout drilling with the expectation of BH data recorded on memory. Inspection of the tool components, once the drilling was completed, revealed two major findings: First, some parts of the BHA, specifically the components of the CuBe tool had "vanished??. Secondly, the recovered tool parts had further damage due to corrosion and pitting. In addition, an unexpected color change in metal body parts was observed.
In the paper, the authors explain the unique mystery of tool eating "down-hole ghost??. Similar tools were previously used without an issue at comparable high pressure and temperature conditions and in geological sections alike in Kuwait in drilling with oil-based mud. The service provider's operational experience elsewhere has failed to explain the bizarre outcome, as they had not encountered similar incidents of vanishing tool parts and down-hole color change. The claim was that similar tools were successfully operated in water-based mud drilling including KFM. This claim was confirmed prior to the field execution with metallurgical compatibility tests carried out by the mud supplier.
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 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.
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.
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.
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.
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.
Shipilova, O. (Det Norske Veritas AS) | Kulyakhtin, A. (Norwegian University of Science and Technology) | Tsarau, A. (Norwegian University of Science and Technology) | Libby, B. (Det Norske Veritas AS) | Moslet, P.O. (Det Norske Veritas AS) | Loset, S. (Norwegian University of Science and Technology)
Marine icing (or, 'sea spray icing') is a well-known threat for commercialfishing craft and other relatively small vessels. However, larger vessels, suchas supply ships, where localized icing can primarily be a safety or operationalhazard, are less well studied. The MARICE project is a multi-year effort by DetNorske Veritas (DNV), the Norwegian University of Science and Technology(NTNU), Statoil and the Research Council of Norway (NFR) to study this issue. Athree-part simulation system has been designed to study the amount of waterlifted from different types of ship bows in different weather conditions andestimation of the movement of droplets over, and their impingement with, thesuperstructure of vessels, neglecting the possibility of droplet break-up orcoalescence. It was found that areas where the icing potential might be thegreatest are not necessarily intuitive, as the movement of water and air isturbulent. Attempts were made to validate the model for water freezing on ametal unit against land-based spraying measurements conducted on Svalbard innatural weather conditions. The results of this study would be of greatestinterest in the design and operation of vessels for cold conditions where seaspray icing might pose a hazard.
Due to the increasing interest in commercial operations in cold marineenvironments, the process and dynamics of sea spray-generated ice accretion onmoving vessels is a high priority area of research. For smaller vessels, suchas many commercial fishing boats, the general threat posed by spray-generatedicing to the stability of the craft is widely acknowledged. However for vesselssuch as those in the 100-meter (300-foot) length range, where the rightingability is less likely to be compromised, the primary concerns regarding vesselicing are more localized, specifically interference with normal operations dueto hindrance of the motion or functionality of equipment, loss of equipmentaccess and obstruction of walkways, icing of sensors, work burden associatedwith ice removal, threat to the safety of the working environment and abilityto conduct emergency operations.