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Papua New Guinea

Dow M.,Oil Search Ltd. | Florence A.,Halliburton Co. | Babu J.V.,Halliburton Co.
Society of Petroleum Engineers - SPE/APPEA Int. Conference on Health, Safety and Environment in Oil and Gas Exploration and Production 2012: Protecting People and the Environment - Evolving Challenges | Year: 2012

While water-based fluids are generally preferred for drilling in environmentally sensitive locations, many are formulated with potassium chloride (KCl) to achieve good inhibition of reactive clays. The chloride ion however can be defined as a contaminant in land operations, with the potential to inhibit the growth of vegetation, and it can also be considered a potential pollutant to aquifers. In the rain forest region of the Southern Highlands of Papua New Guinea (PNG), an alternative to the KCl high performance water based fluid (HPWBF) was needed to mitigate environmental concerns, affirm the operator's commitment to sustainable operations and provide continuous improvement as required by ISO 14001. The fluid design team examined a range of alternatives and determined that potassium acetate (KAc) could replace KCl in the drilling fluid as a more environmentally acceptable inhibiting salt. Laboratory testing confirmed that the drilling performance properties of the fluid would not be impeded by substituting KAc for KCl. Experience using KAc fluids in other geographical areas was also examined to back up the laboratory testing. The original KCl-based HPWBF had historically helped reduce issues related to the longer step-out wells, directional complexity, rock tectonics, and wellbore stability in the area. The new KAc system was used equally successfully to drill seven challenging wells. Both the technical and environmental objectives of the wells were achieved without sacrificing drilling performance. The change to KAc increased the fluid cost by approximately 10% when compared to the KCl-based system, but the operator concluded that this was a good investment, considering the distinct environmental benefits. In a comprehensive review of the background to, and the successful implementation of the KAc HPWBF in to PNG Southern Highlands drilling, this paper firstly discusses the purposes of a drilling fluid. It will show how the presence of the potassium ion is regarded as essential within the drilling fluid, but the chloride ion has no discernible benefit. It considers the unique PNG Highland rainforest environment were the drilling operations occur, the local communities who live and interact with the operation, and how the operator has successfully protected this area. The drilling fluid disposal and discharge solutions in use in the Highlands operating area are discussed, how appropriate disposal solutions are selected, and how drilling fluid discharge is controlled to minimise any environmental impact. In the second half of the paper, the methods used to develop the new chlorides-free KAc HPWBF system will be discussed. Results will then be presented from the seven wells drilled with KAc HPWBF, with two previous KCl wells used as reference. It will demonstrate that along with the improved environmental acceptance, drilling fluid robustness was maintained, as was on bottom drilling performance. Finally a review of material usage and costs indicates the change to the new KAc fluid did not have as significant an impact as first assumed, as KAc concentrations within the HPWBF were optimized. Copyright 2012, SPE/APPEA International Conference on Health, Safety, and Environment in Oil and Gas Exploration and Production. Source

Voordouw G.,University of Calgary | Menon P.,University of Calgary | Pinnock T.,University of Calgary | Sharma M.,University of Calgary | And 4 more authors.
Frontiers in Microbiology | Year: 2016

Microbially-influenced corrosion (MIC) contributes to the general corrosion rate (CR), which is typically measured with carbon steel coupons. Here we explore the use of carbon steel ball bearings, referred to as beads (55.0 ± 0.3 mg; Ø = 0.238 cm), for determining CRs. CRs for samples from an oil field in Oceania incubated with beads were determined by the weight loss method, using acid treatment to remove corrosion products. The release of ferrous and ferric iron was also measured and CRs based on weight loss and iron determination were in good agreement. Average CRs were 0.022 mm/yr for eight produced waters with high numbers (105/ml) of acid-producing bacteria (APB), but no sulfate-reducing bacteria (SRB). Average CRs were 0.009 mm/yr for five central processing facility (CPF) waters, which had no APB or SRB due to weekly biocide treatment and 0.036 mm/yr for 2 CPF tank bottom sludges, which had high numbers of APB (106/ml) and SRB (108/ml). Hence, corrosion monitoring with carbon steel beads indicated that biocide treatment of CPF waters decreased the CR, except where biocide did not penetrate. The CR for incubations with 20 ml of a produced water decreased from 0.061 to 0.007 mm/yr when increasing the number of beads from 1 to 40. CRs determined with beads were higher than those with coupons, possibly also due to a higher weight of iron per unit volume used in incubations with coupons. Use of 1 ml syringe columns, containing carbon steel beads, and injected with 10 ml/day of SRB-containing medium for 256 days gave a CR of 0.11 mm/yr under flow conditions. The standard deviation of the distribution of residual bead weights, a measure for the unevenness of the corrosion, increased with increasing CR. The most heavily corroded beads showed significant pitting. Hence the use of uniformly sized carbon steel beads offers new opportunities for screening and monitoring of corrosion including determination of the distribution of corrosion rates, which allows estimation of the probability of high rate events that may lead to failure. © 2016 Voordouw, Menon, Pinnock, Sharma, Shen, Venturelli, Voordouw and Sexton. Source

Bailey B.T.,Macquarie University | Bailey B.T.,Oil Search Ltd. | Morgan P.J.,University of Canberra | Lackie M.A.,Macquarie University
Antarctic Science | Year: 2015

A gravity survey was conducted on the Windmill Islands, East Antarctica, during the 2004-05 summer season. The aim of the study was to investigate the subsurface geology of the Windmill Islands area. Ninety-seven gravity stations were established. Additionally, 49 observations from a survey in 1993-94 were re-reduced and merged with the 2004-05 data. A three-dimensional subsurface model was constructed from the merged gravity dataset to determine the subsurface geology of the Windmill Islands. The main country rock in the Windmill Islands is a Garnet-bearing Granite Gneiss. A relatively dense intrusive charnockite unit, the Ardery Charnockite, generates the dominant gravity high of the study area and has been modelled to extend to depths of 7-13 km. It has moderate to steep contacts against the surrounding Garnet-bearing Granite Gneiss. The Ardery Charnockite surrounds a less dense granite pluton, the Ford Granite, which is modelled to a depth of 6-12 km and creates a localized gravity low. This granitic pluton extends at depth towards the east. The modelling process has also shown that Mitchell Peninsula is linked to the adjacent Law Dome ice cap by an 'ice ramp' of approximately 100 m thickness. © 2016 Antarctic Science Ltd. Source

Eisemberg C.C.,University of Canberra | Rose M.,Flora and Fauna International | Yaru B.,Oil Search Ltd. | Georges A.,University of Canberra
Biological Conservation | Year: 2011

Papua New Guinea has astonishing biological and cultural diversity which, coupled with a strong community reliance on the land and its biota for subsistence, add complexity to monitoring and conservation and in particular, the demonstration of declines in wildlife populations. Many species of concern are long-lived which provides additional challenges for conservation. We provide, for the first time, concrete evidence of a substantive decline in populations of the pig-nosed turtle (Carettochelys insculpta); an important source of protein for local communities. Our study combined matched village and market surveys separated by 30. years, trends in nesting female size, and assessment of levels and efficacy of harvest, each of which was an essential ingredient to making a definitive assessment of population trends. Opportunities for an effective response by local communities to these declines needs to consider both conservation and fisheries perspectives because local communities consider the turtle a food resource, whereas the broader global community views it as a high priority for conservation. Our study in the Kikori region is representative of harvest regimes in most rivers within the range of the species in Papua New Guinea, and provides lessons for conservation of many other wildlife species subject to harvest. © 2011 Elsevier Ltd. Source

Wilson P.,Corrosion Risk Management Pty. Ltd. | Hancock P.J.,Oil Search Ltd. | Krouse D.,Callaghan Institute
NACE - International Corrosion Conference Series | Year: 2014

Non destructive Testing (NDT) is commonly used to assess the extent of corrosion within plant, including vessels, piping and pipelines. In particular measuring instruments using ultrasound are used to find locations where loss of wall thickness has occurred and to determine the extent of the loss. Inherent in the measurement of wall thickness is the assumption that from a limited set of measurements it is possible to infer the condition of a vessel, heat exchanger tube bundle or section of piping. The determination of corrosion rate then requires a reassessment of the wall thickness at a later date. For old plants, the variability in corrosion damage both in a spatial sense and in depth of loss causes a difficulty in finding the worst case losses in wall thickness and in determining remaining life. It is also necessary to recognize that the measurement error depends on the skill applied by the inspector during the inspection. This paper discusses the use of probability of detection concepts for finding corrosion damage and illustrates it for a corroding vessel inspected over a 2 year period. It also describes the use of distributions of wall loss to characterize the condition of corroding vessels and pipelines. The incorporation of statistical principles into data analysis is required because of the inherent variability of corrosion damage. © 2014 by NACE International. Source

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