Geochemical Production Allocation – An Overview Paul Taylor
Oil and Gas Focus Group 2nd December, 2020
1 Introduction
Who am I? Who are Merlin? PhD Petroleum Geochemist 24 years’ experience in oil & gas operating companies Merlin Geochem Division Manager since April 2020
Practical experience of implementing geochemical allocation for reservoir management and export pipelines in North America and the Middle East
Today’s Talk An overview of the technology of geochemical production allocation How natural chemical tracers can be used to allocate commingled production streams, when other metering methods are not practical, are cost prohibitive, or have high uncertainty
2 Talk Outline
❑What is Geochemical Production Allocation (GPA) and what are the Potential Benefits?
❑How it Works ❑Natural Fluid Variation in Fields and Reservoirs ❑Analysis Methods ❑Fluid Mixing Calculations ❑Implementation Steps
❑Application of GPA in the UK
❑Future Developments
3 What is GPA, and what’s the benefit?
4 What is Geochemical Production Allocation (GPA)?
❑ GPA uses the chemistry of produced fluids as natural tracers to quantify the proportion of specified inputs into a mixture ❑ Allocate at reservoir, well, manifold, field or cluster scale
❑ It can be applied to oils, condensates, gases and Well R water mixtures Flowline 1 50:50 R:G ❑ Analysis of physical samples is required Export Well G 50:50 1&2 ❑ Multiple end-members can be allocated in a single Flowline 2 Well B mixture 100% B ❑ Up to six in commingled oils
❑ Typically provides allocation for hydrocarbon liquids with less than 5% error
5 Features of Geochemical Production Allocation (GPA)
❑ Low Cost ❑ Requires surface samples only ❑ No production deferment
❑ Low Risk and Low HSE Impact ❑ No well intervention required ❑ Low sample volumes at surface pressure ❑ No mobilisation of equipment or additional personnel required ❑ Can be incorporated into routine operations
❑ Widely Applicable ❑ Can be applied anywhere a sampling point is accessible ❑ Well Heads; Production Manifolds & Gathering Stations; Pipelines; Tank Farms
❑ Independent of Other Allocation Methods ❑ Provides validation of production models ❑ Support well test interpretation for sub-sea facilities without dedicated test line ❑ Back-up for sub-sea flow meters and down hole gauges ❑ Reliable oil allocation in high water cut flows
6 A Little Bit of History…
❑ Geochemical Production Allocation is not new technology ❑ First proposed by Chevron scientists in 1980’s ❑ Significant advancements in analysis and statistical treatments pioneered in Shell in the 1990’s ❑ Growth of vendor-supported projects in 2000’s
❑ Application high point in the North Sea led by Shell in 2000’s
❑ Local projects are in place around the world, but uptake is limited today – despite big improvements in technology in the last 20 years
7 How it works
8 Analysis of Oils & Condensates – Gas Chromatography
❑ Gas Chromatography of “dead” oil or condensates is the standard analysis employed ❑ Other analyses may be considered for enhanced sensitivity or speed
❑ The complexity of petroleum mixtures encodes a huge amount of information in each sample
❑ Statistical analysis may be carried out raw peak heights, areas or on ratios of adjacent peaks
9 Practicalities of Implementation
1. Desktop Scoping 3. Pilot Studies Define the flows to be allocated Ensure stability of end members Identify potential sampling points Validate mixing models with production Design sampling & analysis strategy samples
2. Feasibility Tests 4. Implementation Validate sampling points in the field Routine sampling, analysis and reporting Collect key end member samples Demonstrate chemical differences Create and test mixing models in the lab
10 UKCS Application
11 Potential Benefits and Contribution to MER UK
❑ GPA can be used as a cost-effective addition to metering and well test measurements
❑ It can provide robust information for fiscal settlement, meaning that individual producers can utilise common production facilities with reduced uncertainty
❑ The methods can contribute directly to MER UK by facilitating harmonious integration of multiple operators’ production in a cluster development, at low cost
12 Wrap Up
13 Summary & Take-Away Messages
❑ GPA can reliably allocate volumes for produced oil, gas, condensate or water ❑ Effective at the well, reservoir, field level ❑ Typically accurate within 5% of absolute volume (often 1-2% for oils or condensates) ❑ Can be used for fiscal calculations, and potentially for equity re-determinations ❑ A proven established technology that is getting ever better with improved analysis methods ❑ No production deferment, so no lost revenue ❑ Limited (or no) mobilisation of additional equipment and personnel - minimal HSE exposure ❑ Integrating GPA into metering and allocation activities can significantly reduce uncertainty and minimise costs associated with managing meters, gauges and flow tests
14 Future Developments
❑ In-line, “real time” methods
❑ Increasingly sensitive analytical tools ❑ Improved methods of water analysis and allocation
❑ Improved statistical methods and data processing
❑ The biggest opportunity for value addition is the deployment of existing technology…
15 References & Further Reading
Amendola, A., Caldiero, L., Cerioli Regondi, A. M. A., Dolci, D., Galimberti, R., & Nali, M. (2017). Production Allocation Without End Members: Now It Is Possible. In Offshore Mediterranean Conference and Exhibition. Offshore Mediterranean Conference.
Bazan, L. W. (1998) The allocation of gas well production data using isotope analysis. In SPE Gas Technology Symposium. Society of Petroleum Engineers. SPE40032
van Bergen, P. F., & Gordon, M. (2020). Production geochemistry: fluids don't lie and the devil is in the detail. Geological Society, London, Special Publications, 484(1), 9- 28.
Elsinger, R. J., Leenaarts, E. M., Kleingeld, J. C., van Bergen, P., & Gelin, F. (2010) Otter-Eider Geochemical Production Allocation: 6+ Years of Continuous Monitoring to Provide Fiscal Measurements for Hydrocarbon Accounting. AAPG Datapages 90110.
Hwang, R. J., Baskin, D. K., & Teerman, S. C. (2000). Allocation of commingled pipeline oils to field production. Organic Geochemistry, 31(12), 1463-1474.
Kaufman, R. L., Ahmed, A. S., & Hempkins, W. B. (1987). A new technique for the analysis of commingled oils and its application to production allocation calculations. Indonesian Petroleum Association, 16th Annual Convention Proceedings (Volume 2), 1987 Pages 247-268
Milkov, A. V., Goebel, E., Dzou, L., Fisher, D. A., Kutch, A., McCaslin, N., & Bergman, D. F. (2007). Compartmentalization and time-lapse geochemical reservoir surveillance of the Horn Mountain oil field, deep-water Gulf of Mexico. AAPG bulletin, 91(6), 847-876.
Schoell, M., Jenden, P. D., Beeunas, M. A., & Coleman, D. D. (1993). Isotope analyses of gases in gas field and gas storage operations. In SPE Gas Technology Symposium. Society of Petroleum Engineers. SPE 26171
Wright, S., Franks, S., Pantano, J., Kloska, M., & Wolters, J. (2019). Understanding Dynamic Production Contribution from Hydraulically Fractured Middle Bakken and Three Forks Wells in the Williston Basin, ND Using Time-Lapse Geochemistry. In Unconventional Resources Technology Conference, Denver, Colorado, 22-24 July 2019 (pp. 1200-1219). Unconventional Resources Technology Conference (URTeC); Society of Exploration Geophysicists.
16 For More Details Please Contact: [email protected]
Newberry House, New Street, www.merlinenergy.co.uk [email protected] Ledbury, HR8 2EJ, U.K. www.merlin-datawise.co.uk +44 (0) 1531 636000