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Shale inhibition is considered to be the most important factor to prevent hole problems when drilling with water based drilling fluid (WBM). Some components are believed to be vital for well bore inhibition like KCl, glycols and designed polymers. The effect of the products is largely based on the cuttings quality seen in the return flow at the rig. When new systems are introduced they are often tested in relatively simple wells and performance are evaluated based on results form that well.
Some incidental observations where systems not regarded as inhibitive outperformed the state of the art water based drilling fluid systems. This observation trigged of a larger survey on drilling efficiency with respect to water based drilling fluid system. Water based drilling fluid systems used in Statoil's operations over the last 15 years in the North Sea were compared with respect to hole quality. Data from the survey shows that today's highly inhibitive systems do not perform any better than systems used for 15 years ago. The survey raises a question around the way drilling fluid systems are designed today. Are we using the right methods for designing the drilling fluids?
The paper describes the result from the survey. In the paper a method using different "indicators" to measure the hole quality is used. Such indicators include: stuck pipe frequency, tripping time, drilling progress, caliper data and cuttings quality. As a result of the first part of the survey, the drilling fluid chemical composition was altered both when drilling through non-reactive and reactive formations in a series of wells. An increased drilling efficiency was observed. The paper describes how the drilling fluid composition could be optimized dependent on the smectite content of the formation.
Shales consist of a very complex compsition of different minerals. This composition varies with depth and age. The interaction between the drilling fluid and the complex mineralogy is very often the cause of hole problems while drilling a well. Finding the optimum drilling fluid to safely drill in such changing environment is challenging. Drilling fluid suppliers are constantly working to improve existing and to develop new and better drilling fluids. When new products or drilling fluid systems are tested it may be difficult to measure the improvement due to the influence of many other well design parameters. Especially the interaction between shale and drilling fluid and the resulting effect on hole stability and condition is difficult to evaluate. Presently, there is no direct measurement of hole stability and several hole condition indicators must be used instead. Using indirect measurement such as stuck pipe frequency, tripping time, drilling progress, caliper data and cuttings quality is only valuable if the data is sufficient to establish a trend. As a result any new drilling fluids or modifications must be tested and monitored over more than one well or section to verify a positive effect. We often fail to do such a long-term evaluation. More commonly drilling fluid systems and products are evaluated based on data from one or two wells. Another weakness, the lack of a historical database of hole quality indicators, it is making it difficult to benschmark drilling fluid modifications. The lack of historical data and the short test period of products or new fluid systems result in an evaluation with many unsertanties and are easily leading to incorrect conclusions.
Abstract The International Association of Oil and Gas Producers (OGP) has collated and published environmental performance data since 2001. This Environmental Indicator Performance programme has continued and a new set of data for activities in 2006 has been produced. The five main indicators gathered are gaseous emissions, aqueous discharges, non-aqueous drilling fluids on drill cuttings, oil and chemical spills and energy consumption. Performance results are presented on a global and regional basis, onshore and offshore, and normalised to hydrocarbon production. Results are shown, for ease of comparison, alongside the previous years' published results. The report will address the emerging trends in environmental performance as well as factors that underpin the data. 31 OGP member companies took part in the survey representing about a third of known world production. Contributing companies provided data from 55 countries worldwide; however regional coverage is uneven, ranging from 98% of known production in Europe to 17% in the Middle East and 5% in the Former Soviet Union. Introduction Since 1998, the International Association of Oil and Gas Producers (OGP) has collected information from its members worldwide on a range of environmental performance indicators. The key objectives of this programme are to allow the member companies to compare their individual performance with other companies in the sector and thus to lead to overall improved environmental performance in the upstream sector. The programme also contributes to the industry's general wish to be more transparent about its operations. For over 20 years, OGP has collated and published information on safety performance in the upstream sector and by providing an international focus for the industry, this initiative hassled to substantial improvements in the performance of operators and their contractors. A parallel initiative on environmental performance was first considered in the mid 1990s but made little progress as companies debated questions of common definition, the representative nature of any data collected and the problems of maintaining effective anonymity for contributors. Nonetheless, the 1997 conference of international experts on the upstream oil and gas industry held in Noordwijk, the Netherlands, proved to be a watershed for the industry. The conference was jointly organised by the governments of The Netherlands and Brazil under the banner of the United Nations Commission on Sustainable Development (CSD) and addressing undertakings from the world Summit on Environment and Development held in Rio de Janeiro 5 years previously. The conference provided a unique opportunity to bring industry together with a broad range of industrial and societal stakeholders. These groups delivered a clear message to the industry to go further than saying how well it conducted its business, but to show that delivery was achieved. In response to this challenge, OGP members established a mechanism for collecting and collating information on environmental performance in the upstream sector as the basis for an annual sectoral report. The first summary of globally aggregated data from an annual reporting cycle was produced in 2003 for data representing performance in 2002; a more extensive report showing globally and regionally aggregated data representing performance in 2003 was published in 2004. Annual reports have been published in successive years.
Abstract The International Association of Oil & Gas Producers (IOGP) has collected environmental data from its member companies on an annual basis for the past 16 years. The programme was set up in response to the industry's wish to be more transparent about its operations and to enable IOGP member companies to compare their performance with that of other companies in the sector. The ultimate aim is to provide a representative statement on the environmental performance in the upstream oil and gas industry. This paper will discuss the analysis of submissions by participating member companies for the years 2013 and 2014. Data were reported by participating companies in the following 6 environmental indicator categories: gaseous emissions; energy consumption; flaring; aqueous discharges; non-aqueous drilling fluids retained on cuttings discharged to sea; and spills of oil and chemicals. The data represent oil and gas wellhead production of 2.1 billion tonnes. Forty three companies took part in 2013 and 2014, operating in more than 80 countries worldwide, and the database now represents what is probably the most comprehensive set of reliable information on cross company performance in the industry. Performance results are presented on a global and regional basis, onshore and offshore, and normalised to hydrocarbon production. Results are shown, for ease of comparison, alongside the previous year's published results.
A new indicator is presented which allows major local tectonic features to be determined from a single well. The only measurement required, besides mud filtrate resistivity and temperature, is the SP log. The information which can be determined from this indicator includes: 1. Location of fault zones. 2. Location of compaction stress changes. 3. Location of abnormal pressures. 4. Location of permeable sands of significant extent. The method is simple and may be cross-checked with the density or travel time log. It involves several simple principles: A. (water salinity) (shale porosity) = constant B. (shale porosity) = (overburden-hydraulic pressure) Water salinity may be accurately determined from clean sands, and a complete well profile is needed to make an analysis. Several analyses are made, where the various stresses have been confirmed. Mathematical theory and laboratory results are also presented. 34