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Journal of Australian Energy Producers
RESEARCH ARTICLE

Using the wellbore as a d/p meter to calculate gas rate

Chris Fair A , Ricardo Flores A , Eamonn Montague A , Bilal Hakim A , Soumitra Nande A , Venera Zhumagulova A , Analicia Caylor A and Paul Draper A
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Oilfield Data Services, Inc.

The APPEA Journal 55(1) 385-392 https://doi.org/10.1071/AJ14032
Published: 2015

Abstract

The common use of high-resolution tree gauges and downhole permanent pressure/temperature gauges has made it possible to use the measured pressure drop in the wellbore to directly and accurately calculate the gas rate. This is accomplished by first combining an equation of state with a dynamic heat transfer model to create a phase-thermal model (PTM). The PTM is then integrated with a direct solution to the mechanical energy balance (MEB) for flow in pipes.

The results obtained using this technique can be as accurate as, or in some cases more accurate than, conventional rate measurements. Since the wellbore may also be used for fluid density validation, the effective gas gravity (an input for many conventional flow rate calculations) may also be determined during shut-ins and used as an input to improve the accuracy of meter provers.

The purpose of this paper is to explain the physics behind the gas rate calculation and to present case study results from the implementation of this method in both real-time and historic data processing. The paper will also discuss the limitations of this method and the range of potential applications.

Chris Fair received his BSc in chemical engineering (1994) and his MSc in petroleum engineering (1997) from the University of Houston. During his time in school, he worked in various positions in the chemical industry and oil patch. These included roles in process operations, project/design engineering, PVT and fluid mechanics research, sales engineering, process control and instrumentation, downhole nuclear tool testing (both in the laboratory and in the field), laboratory instruction in process control, technical writing, and chemical engineering practices.

In 1997, Chris joined Data Retrieval Corporation (the SPIDR folks). While there, he worked on expanding the range and types of wells that could be effectively tested from the surface, and worked on increasing the company’s markets, both in the US and overseas.

In 2005, he started Oilfield Data Services, Inc. (ODSI), a reservoir/production engineering consulting firm that specialises in well test interpretation and field management of well flowbacks/exploration DSTs.

When not running around offshore or overseas, Chris is hard at work on a real-time well evaluation package, designed to track changes in reservoir, completion and wellbore parameters, and provide an early-warning system for petroleum engineers.

Outside of his day-job, he sings with the Houston Symphony Chorus.

Ricardo Flores received his BSEE (Bachelor of Science in Electrical and Computer Engineering), and his MSc in petroleum engineering, from the University of Houston. He began his oilfield career at Halliburton Energy Services, Sperry-Sun PSL while working on his MSc degree. Ricardo’s 12 years at Halliburton started with the Nuclear Physics Group, where he modelled the thermal drift of the density tool and modelled the environmental corrections for the neutron tool.

After obtaining his degree he became LWD field engineer. He then spent the bulk of his career at Halliburton in the R&D Electrical Group as an embedded programmer; he wrote the embedded software, and testing and calibration software for the next generation density, neutron, resistivity, and gamma logging while drilling tools.

Ricardo was a founding member of ODSI, where he has been the Chief Software Developer since 2006. Starting from scratch he developed the proprietary wellbore modelling and well test interpretation software used within the company, and then automated many of the processes to create a commercial real-time well evaluation software package that can automatically calculate rates, detect and analyse transients, and track changes in the reservoir.

In addition to developing software, Ricardo is in charge of sales and consulting in Europe.

Eamonn Montague graduated with an honours degree in petroleum geology from Adelaide University in 1989.

Confronted with limited opportunities for geoscience jobs, Eamonn embarked upon a career in reservoir/petroleum engineering, starting with a five-year stint at Santos in 1990, with a mixture of office and field work.

He then travelled to the UK and worked as a reservoir engineer with the Reservoir Management Ltd (RML) consultancy group out of Aberdeen, on a steep learning curve for a number of North Sea operators, spending the most of his time working with Oryx on the Murchison oil field.

In 1997 Eamonn returned to Australia and worked with Mobil (MEPA) in Perth; he developed an interest and skills in reservoir simulation modelling. After the Exxon-Mobil merger he spent four years from 2000–04 working at Curtin University as a lecturer, researcher and consultant, and has a partially completed PhD to complete one day in the future.

It was back to consulting in 2004, and then an opportunity to work overseas with Shell Brunei from 2005–08 presented itself. Eamonn returned to Adelaide in 2008, and spent some more time consulting, and then spent another four years back on staff at Santos.

In 2014 he moved back into the consulting realm, where he is now working with ODSI in a variety of roles including well/reservoir performance evaluation and field supervision.

Bilal A. Hakim is a reservoir/production engineer with ODSI, the Houston-based petroleum engineering consultancy.

He received his bachelor’s degree in 2012, and worked for various upstream and downstream companies.

After acquiring work experience he decided to pursue his masters degree in petroleum engineering (with an emphasis in smart oilfield technologies) from the University of Southern California (USC), while working part-time with ODSI. He completed his master’s degree in 2014.

Bilal’s primary focus is on well testing, reservoir engineering, reservoir characterisation, and completions evaluation.

In his spare time he enjoys travelling, photography and writing SPE papers.

Soumitra Nande received his bachelor’s degree in petroleum engineering in 2010 from India. He went to the US in 2011 and subsequently finished his master’s degree in petroleum engineering in December 2012 from the Missouri University of Science and Technology (Rolla, MO).

Before joining ODSI, Soumitra worked on a part-time basis with Reservoir Description Services as a reservoir engineer. He joined ODSI in December 2013 as a petroleum engineer, working from ODSI’s Houston office.

His primary focus is on reservoir and production engineering, and his job responsibilities at ODSI include well test analysis and interpretation, completions and reservoir evaluations, and reserves estimation using ODSI’s proprietary software. Soumitra is also responsible for frac evaluations and design, and managing the flowbacks/DSTs in field.

Venera Zhumagulova is a senior petroleum engineering student at the University of Houston. She has been interning with ODSI since December 2014.

Analicia Caylor is a senior in the petroleum engineering program at the University of Houston, and she is set to graduate in May 2016. She is presently interning with ODSI in Houston.

Analicia previously interned with Halliburton Landmark services during the summer of 2014, working with drilling engineering software, StressCheck and WellCAT. She also had the opportunity to intern with Boots & Coots during the summer of 2013. Her project was related to coiled tubing operations processes.

Prior to her internships, Analicia did research at the University of Wisconsin to develop a probe to measure thermal conductivity of in situ rock.

Analicia presently serves as the Society of Women Engineers’ University of Houston section President.

Paul Draper graduated from the University of Adelaide with Honours Degrees in mechanical engineering (1994) and science (petroleum geology and geophysics, 1995).

He joined BPB Wireline Services in 1995 and, as a wireline logging engineer in Australia, Pakistan, New Zealand and West Texas, gained invaluable experience with in-wellbore data acquisition, cased-hole and wellsite operations, and remote, extended duration wellsite projects.

In 1998 he joined Santos Ltd. Over 16 years, Paul gained significant upstream petroleum experience in exploration, petroleum/reservoir engineering, field/well operations and production, and regulatory compliance and supply contracts in onshore and offshore operated and non-operated settings, building an expertise in area/field appraisal and development, and reserves determination.

In 2014 he switched to consulting, working with ODSI, assisting early production implementation and analysis, and relishing the reservoir insights gained from comprehensive analysis of the data.

Complementing his interest in business and investment, in 2002 Paul completed a Graduate Diploma in Applied Finance and Investment with the Securities Institute of Australia.