Helium survey—identification of “sweet spots” locations for exploratory, appraisal and...
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Transcript of Helium survey—identification of “sweet spots” locations for exploratory, appraisal and...
Helium survey—identification of “sweet spots” locations for exploratory, appraisal and production drilling
November, 2009
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• During exploration, appraisal and development of oil and gas fields with complex geology, such as fracturing
permeability, low continuity of thickness and porosity formations, energy companies face an ever present
problem of low drilling success.
• Traditional exploration technologies such as seismic do not always accurately predict hydrocarbons
saturation.
• In a review of more than 2600 US and international wildcat wells – all drilled after completion of geochemical
or non-seismic hydrocarbon detection surveys- more than 80% of wells drilled on prospects associated with
positive hydrocarbon anomalies resulted in commercial discoveries; and only 11% of wells drilled on
prospects not associated with such anomalies resulted in discoveries*.
• Actual Geology can identify an active petroleum system in the exploration area, generate unique non-seismic
leads for further geological and seismic evaluation and identify “sweet spots”.
• Our methods are non-invasive and have a minimal environmental impact.
Executive summary
* presentation at 2008 AAPG International Conference and Exhibition, Cape Town, South Africa, October 26-29, 2008
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Outstanding track record
• 50 completed projects covering over 30,000 sq km in the last 8 years
• Strong in-house analytical team interpreting helium survey results for clients
• Clients: Gazprom, Rosneft, Lukoil, Yukos, Norilsk Nickel and many others.
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Our services
• Actual Geology services fit well into an integrated exploration strategy by detecting occurrences of
hydrocarbons’ by-products, such as helium, which serve as indicators to the location of undiscovered oil and
gas accumulations.
• Actual Geology provides:
− Mapping of helium concentration and subsequent forecasting of reservoir properties.
− Prediction of section saturation before drilling.
− Determination of areas with improved fractured permeability in prospective reservoirs or producing
deposits.
− Prediction of reservoir distribution, delineation of oil and gas accumulations.
− Determination of residual reserves at mature fields with declining production.
− Identification of prospective drilling targets, cut off of the low prospects and high risk zones.
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Service Data acquisition method Benefits
Helium survey
Field measurements of helium concentration at 1-1.5 m below earth surface and in near-surface air.
Scale 1:50000; 1:25000; 1:10000 (100x100m up to 25X25m grid)
1. Prediction of section saturation before drilling
2. Delineation of areas with better reservoir properties
3. Prediction of fracturing in reservoirs and producing
interval
4. Identification of “sweet spots” for drilling
Helium survey at well heads of producing wells
Measurements of helium concentrations at well heads 1. Identification and delineation of active reserves
2. Forecast of reservoir performance
3. Monitoring of well performance, recommendations
for well work over
4. Determination of residual reserves at mature fields
5. Identification of prospective zones for further
completion
Helium survey
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The process
Helium survey 300x300m grid,or 100x100m grid
Data processing Preliminary data interpretation
Data interpretation
Helium survey 100x100m grid,
or 25x25m grid
Identification of helium anomalies
Data processing Final mappingof helium anomalies
Preliminary stage(field):
Stage one(field):
Stage two: (analytical)
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Timeframe
• Once equipment and the team (20 detectors and 50 field specialists) are on site an average survey duration over an area of 100 km² is 60 days including:
− Deployment and deconstruction of field camp, testing of field equipment – 5 days
− Helium measurements on 100х100 m grid – 14 days
− Preliminary field data processing and planning of detailed grid – 4 days
− Helium measurements on detailed grid (15% of total area) – 7 days
− Final data processing and interpretation of the results –25 days
− Contingency work (10%) - 5 days
• Production rate of one team – 30-40 sampling points per day
Equipment example: PHD-4 Portable Helium Detector
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Field work logistics
1. Equipment and tools:• Helium leak detectors and gas analyzers • Computers and specially designed/developed
software for operational in-field quality control and processing
• Satellite communications between detectors and server holding central database minimizes human intervention and possible errors
• GPS- enabled equipment for accurate positioning and recording
2. Locally purchased (rented) equipment:• Cross-country vehicles• Field equipment (sleepers, office, kitchen,
generator, etc.)• Water, food and fuel supply tracks
3. Personnel• Initially – qualified Actual Geology specialists• Support personnel– locally hired• Future development – recruitment and training
of local staffMobile laboratory (a) and field equipment (b) versions
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Final results: Cheriomykhovskoye oilfield
Well #(heavy, high-viscosity oil)
Helium anomalyDaily production rate
Bbl/day
161 positive 645479 positive 64824 positive 64
5528, 5481, 5473 negative 11
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Well # Helium anomalyDaily production rate
Bbl/day
2034 positive 702035 positive 235
39 positive 2622024 negative dry hole
Final results: Galianovskoye oilfield
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Final results: Aprelskoye oilfield
Well # Helium anomalyDaily production rate
Bbl/day
6 positive 1645 negative dry hole
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Final results: Sredne-Shapshinskoe oilfield
Well # Helium anomalyDaily production rate
Bbl/day
7000 positive 3007002 negative <35
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Theoretical foundations
• All petroleum basin exhibit surface or near-surface hydrocarbon gases leakage.
• Helium on Earth is mostly created by the natural radioactive decay of heavy radioactive elements (thorium and uranium).
• Helium is a noble gas, chemically inert and is nonabsorbent into surrounding rocks and doesn’t form compounds. Helium’s ability for migration is greater than of other gases, with the exception of hydrogen.
• Helium migrates along the tectonic faults and through high-fractured zone. Seals, such as clay rocks, are not an obstacle for helium migration. Increased concentrations of helium in the near surface zone are the projections of zones with higher helium gas-saturation and improved permeability of geological section.
• The average helium concentrations are: 0.65 ml/l - in bottom water of hydrocarbon accumulations; 7 ml/l - in oil pools; 100 ml/l - in gas pools (ml/l – milliliters per liter).
Helium concentration - residual oil saturation relationship Oil saturation Helium concentration
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Theoretical foundations
Different vertical sections of helium concentration in the case of presence(b) or absence(a) of hydrocarbon accumulations within sedimentary cover.As helium solubility is so much greater in hydrocarbon pools than in water, reservoir is saturated by helium and it’s concentration increases (Fig.1, b). Near-earth surface helium concentrations is greater in case of hydrocarbon pool presence in geological section (b) in comparison with case where pool is absent (a).
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Conclusions
• The results of helium surveying leads to significantly better prediction, therefore risk and cost reduction
• Helium surveying is a powerful complement to conventional exploration methods.
• Further integration with available seismic, logging and production data can help companies to identify residual reserves, enhance potential of declining production or flooded fields, better plan drilling operations (especially horizontal wells) during exploration, appraisal and development stages
• In order to assess and prove effectiveness of its methods Actual Geology can conduct a pilot survey on an already explored field where a number of wells have been drilled in order to compare helium survey results with company’s existing information
• Helium surveying is a reliable and proven (by a number of successful projects in various geological settings) technique for accurate identification of the best drilling locations. Our experienced specialists are able to work in practically any complex terrain, traditionally off-limits due to restricted accessibility
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London
Vlad Sinani
Project Manager
Suite 3, Barkat House
116-118 Finchley Road
London, England NW3 5HT
Tel. +44 (0)20 7433 2512
Fax. +44 (0)20 7692 7957
E-mail: [email protected]
Contacts
St Petersburg
Viktor Chistiakov
General Director
36 Rubinstein street, office 35,
St. Petersburg
191002 Russia
Tel. +7 (812) 347 78 19
Fax. +7(812) 571 83 98
E-mail: [email protected]