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Africa (Sub-Sahara) An 816-mile 2D seismic acquisition program was completed on the Ampasindava block, located in the Majunga deepwater basin offshore northwest Madagascar. The data will provide improved subsurface imaging of the large Sifaka prospect and will potentially mature additional prospects in the Ampasindava block to drill-ready status. Sterling Energy (UK) holds a 30% interest in the Ampasindava production sharing contract, which is operated by ExxonMobil Exploration and Production (Northern Madagascar) (70%). Asia Pacific The Jolly-1 well, located in the Otway basin onshore in South Australia, was spudded in petroleum exploration license (PEL) 495. The primary objective of the well, whose planned total depth is 4000 m, is to assess the unconventional oil and gas potential of shales within the Casterton formation. Beach Energy (70%) operates PEL 495, with partner Cooper Energy (30%).
Africa (Sub-Sahara) Bowleven began drilling operations at its Zingana exploration well on the Bomono permit in Cameroon. Located 20 km northwest of Douala, Cameroon's largest city, the well will target a Paleocene (Tertiary) aged, three-way dip closed fault block. The company plans to drill the well to a depth of 2000 m and will then spud a second well in Moambe, 2 km east of Zingana. Bowleven is the operator and holds 100% interest in the license. Asia Pacific China National Offshore Oil Company (CNOOC) has brought its Dongfang 1-1 gas field Phase I adjustment project on line ahead of schedule. The field is located in the Yinggehai basin of the Beibu Gulf in the South China Sea and has an average water depth of 70 m. The field is currently producing 53 MMcf/D of gas and is expected to reach its peak production of 54 MMcf/D before the end of the year.
Africa (Sub-Sahara) An 816-mile 2D seismic acquisition program was completed on the Ampasindava block, located in the Majunga deepwater basin offshore northwest Madagascar. The data will provide improved subsurface imaging of the large Sifaka prospect and will potentially mature additional prospects in the Ampasindava block to drill-ready status. Sterling Energy (UK) holds a 30% interest in the Ampasindava production sharing contract, which is operated by ExxonMobil Exploration and Production (Northern Madagascar) (70%). Asia Pacific Production began on the Liuhua 19-5 gas field in the Pearl River Mouth basin in the South China Sea. The field is expected to hit peak production of 29 MMcf/D this year. China National Offshore Oil Corporation (100%) is the operator. Drilling began on the YNG 3264 and the CHK 1177 development wells onshore in Myanmar.
A new methodology for a "Level 2" Seismic Hazard Assessment has been developed for a geothermal project. Geomechanical models were created to understand the thermo-mechanical effects in the lifetime of a specific geothermal operation. Two types of geomechanical models are used, a 3-D Mohr-Coulomb model using both a deterministic and a probabilistic methodology, and a 2-D elastoplastic finite element model, simulating the lifetime and the associated mechanical changes caused by the geothermal operation. The simulated results show that, under maximum production conditions, there is a 1% likelihood of induced seismicity. Using published correlations, the movement along a fault is used to calculate the maximum magnitude of the unlikely seismicity, projected to be the order of 1.5 to 2 M w . As a mitigation method, a Traffic Light System is proposed. This allows the geothermal operation to continue while staying within the expected safety margins.
Reservoir compaction in depleting gas fields can cause seismicity, as has been observed in a dozen countries (Foulger
For a few gas reservoirs, the evolution of potential fault slippage is simulated using the commonly adopted Mohr-Coulomb failure criterion. This shows that fault criticality is expected for reservoirs that showed seismic as well as non-seismic behavior. Apparently, some characteristic property is missing to explain the difference in behavior.
Using published pressure histories for seismically active gas fields, the relation is shown between seismic magnitude and relative depletion. It appears that in many cases, the first induced earthquake is relatively strong which suggests substantial cohesion of the faults. It is plausible from the geological history that in non-seismic regions, fault cohesion is larger, so that slippage is inhibited.
Veeken, Cornelis (Petroleum Development Oman) | Alawi, Ahmed (Petroleum Development Oman) | Ardia, Kusela (Petroleum Development Oman) | Naabi, Hajer (Petroleum Development Oman) | Janusz, Norbert (Petroleum Development Oman) | Al Abri, Ali (Weatherford Oil Tools) | Ghanem, Hassan (Weatherford Oil Tools) | Fadhl, Ahmed (Schlumberger Limited) | Thakur, Kapil (Schlumberger Limited)
Following second stage depletion compression, more than 100 deep onshore gas wells operated by PDO in the Sultanate of Oman started suffering from downhole halite deposition. Halite scale blocks part of production and reduces well capacity by 20-80% depending on well specific conditions. Fresh water bullheading treatments were introduced to periodically dissolve the halite scale but in many cases treatments were applied too late or are not effective in preventing permanent blockage. In those cases, a cleanout using a work string is required to restore wellbore access and production. Historically, coiled tubing was used to remove halite scale via milling and fresh water jetting. Recently, 1/4" and 3/8" capillary strings were successfully deployed to reduce the cleanout cost and the volume of water lost to formation. This paper describes the experience with fresh water bulheading and the novel use of capillary string to clean wells that suffer from halite scale.
Hadidi, Shahab (Petroleum Development Oman) | Boya Ferrero, Maria (Shell Global Solutions International) | Van Den Nouland, Casper (Petroleum Development Oman) | Nicholls, Christopher (Petroleum Development Oman)
The benchmark primary drainage Saturation Height Function (SHF) is a standardized dimensionless function that describes the expected saturation-depth profile for a specific rock type resulting from primary drainage. The paper's ambitious goal is to introduce the concept of creating an inventory of benchmark functions for every reservoir rock type. The benchmark function is the reference point to validate the fluid fill history and identify areas of primary drainage for a specific field. Furthermore, it can be used as a diagnostic tool to analyse changes in the reservoir rock type and pinpoint fluid fill variations. The benchmark function is a complementary model to constrain the SHF when there are insufficient data, especially in the transition zone. A key diagnostic criterion for a reservoir rock type is that it contains a consistent combination of pore types and hence has consistent (or predictable) capillary properties. Case studies on carbonate fields are presented from the Sultanate of Oman. The same concept is also applicable to clastic reservoirs.
The benchmark primary drainage function can be derived from the capillary pressure data. Conversion of this data into a normalized capillary pressure system is required. In this paper, we will introduce a workflow to utilize the saturation log data from different fields to build a benchmark function that is not influenced by reservoir fluids densities' and interfacial tension.
Benchmark primary drainage functions were created in different scenarios and rock types to aid saturation modelling in several fields. In one carbonate field, the saturation log data from an analogue field were used to constrain the transition zone due to data limitations. The benchmark function was also used to identify fluid fill variations and unlock a potential development.
The benchmark function of micro-porous rock, derived from several analogue fields, was the baseline for the saturation modelling workflow of a complex carbonate reservoir with a tilted contact and significant imbibition and it was a vital enabler in simplifying the saturation model.
Finding and starting a new career can be a fairly straightforward process for some or a daunting task for others. The transition may start in the mind when one begins to first foster thoughts about it. A significant change in direction, particularly when it breaks free of the status quo imposed by a peer group, often comes with its share of self-doubt lurking in the corner. However, when one does go through with the career transition, there are often rewarding results, although sometimes not in ways initially envisaged. You will read about how the transitions improved the careers and lives of the individuals, the motivation behind the change, and what had to be sacrificed to see it through. Read on to see how previous experiences help with career transitions, what sorts of resources were invaluable in managing the transition, and the soft skills that were relevant in ensuring that the career transition was a success. I believe that one of my biggest professional transitions, which set me onto my current path, was switching from film and physics studies to petroleum engineering. In 2004, I was attending university in Florida.
Bowleven began drilling operations at its Zingana exploration well on the Bomono permit in Cameroon. Located 20 km northwest of Douala, Cameroon's largest city, the well will target a Paleocene (Tertiary) aged, three-way dip closed fault block. The company plans to drill the well to a depth of 2000 m and will then spud a second well in Moambe, 2 km east of Zingana. Bowleven is the operator and holds 100% interest in the license. China National Offshore Oil Company (CNOOC) has brought its Dongfang 1-1 gas field Phase I adjustment project on line ahead of schedule.
Drilling hazards can lead to significant cost overruns during the drilling phase and might cause unsafe situations or potentially harm the environment. Often the local geology, when poorly understood, is the trigger of a drilling incident. By sharing past drilling experience and in particular observations on Geo-Drilling Hazards, via a suitable platform, well planning and risk assessment can be carried out more effectively. After analysing historic drilling reports, observations on drilling incidents have been compiled using a structured approach. Classification schemes allow systematic capture of key information in a format suitable for a database. In this process the observations (
The Geo-Drilling Events (GDE) database currently covers some 1000 boreholes from the Netherlands. Around 1400 geo-drilling events have been analysed systematically allowing to identify drilling hazard hotspots in a statistically meaningful sense. Examples of geo-drilling events include
Planned well trajectories can now be screened efficiently for geo-drilling hazards. The GDE Tool based on advanced classification criteria allows to share relevant well information across all operators active in the Netherlands. This includes newcomers, like geothermal operators who carry out a lot of drilling nowadays. The GDE Tool allows everyone to learn from the experience on drilling hazards gathered over the years by oil companies.