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Case Studies

Case Study: Tartan Field- OMF, Offshore North Sea

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Overview

Carogas Services was contracted by TalismanSinopec UK to undertake a review of the potential of the brown field development Tartan field located in the Outer Moray Firth,North Sea.
The Tartan Field is a mature multi pay zone oil field development that has been in production since 1978 using a dilapid

Objectives

The objectives of the study were:
  • Review the existing field data
  • Revise the geological & simulation field models
  • Identify future development & near field options
  • Identify gas source for gas lift purposes
  • Review the facilities integrity, upgrade evaluation
  • Identify the LTRO on the main Tartan field
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Carogas Services Role

Carogas Services undertook the following activities in completing the project:

  • Review the regional geology and tectonic evolution
  • Revisit all core data (56 wells), sedimentological,sequence strat & facies model incorporated into the reservoir model
  • Generated a paleogeographic map for entire area
  • Reviewed and reinterpreted the existing seismic data
  • Review and define the hydrocarbon contacts and reservoir parameters
  • Update volumetric analyses
  • Identify infill drilling opportunities
  • Populate well hopper
  • Identify work over opportunities
  • Identify secondary recovery options
  • Compile a prospect inventory with associated chance of success analysis
  • Review and verify the production data
  • Generate forward production estimates for existing and potential new well locations
  • Identify options for nearby gas resources for gas lift required for Tartan re-start
  • Assess the facilities status and impact on future development options
  • Review operating costs and identify cost reduction opportunities
  • Undertake economic analysis
  • Provide a series of recommendations to the operator

Outcome & Client Benefits

Abcreste’s work resulted in full field evaluation that identified a series of infill well opportunities for future growth, it also brought to bare the risks associated with the opportunities.
Talisman acquired a comprehensive field review that was long overdue and provided a basis for it to decide on a desired future
course of action for the entire Claymore/Tartan area in the Outer Moray Firth basin.

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Case Study: York Field

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Overview

Carogas Services consultant was involved in the field review and development planning of the York gas field.

The York gas field is located in the Southern North Sea (SNS) area of the United KingdomContinental Shelf (UKCS). Presence of many intra-faults , particularly the intra-fault located south-west of the field makes the development of the field challenging.

Objectives

The objectives of the study were:
  • Review available field data
  • Review existing development plan
  • Build a new dynamic model
  • Identify development options
  • Recommend optimal development plan
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Carogas Services Role

Carogas Services Consultant undertook the following activities in completing the project:

  • Review available Reservoir Engineering data
  • Liaise with in-house G&G and Petrophysics discipline staff towards ensuring dynamic considerations were reflected in the static model build
  • Build dynamic model
  • Investigate different development well types
  • Identify optimal number of wells for developing the field
  • Generate production profile for the field based on identified development options
  • Undertake economic analysis
  • Recommend optimal development options for the field

Outcome & Client Benefits

Provided the company with two optimal development options and a flow chart showing the dependence of option two on option one .

Operator drilled wells in the field based on work carried out and FDP submitted by Carogas Services ’ Consultant

The operator put the field to production with production within prognosed rates

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Case Study: Sand production and Water Hammer Study

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Overview

VJN Engineering Consultancy UK Limited, along with LR Senergy was contracted by an Oil & Gas Producing Company operating in Caspian Sea to investigate the potential for water hammer effect emanating from abrupt valve closure during water injection.

The study also evaluated the potential for sand production in producer wells along with determining minimum flowrates for optimal production with minimal solids production and transportation.

Objectives

The objectives of the study were:
  • Determine maximum pressure pulse for varying valve closure times.
  • Provide input to geo-mechanics for formation fracture analysis.
  • Determine sand transportation and bedding pattern.
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Carogas Services Role

VJN Engineering personnel undertook the following activities in completing the project:
  • Reviewed the production profiles (oil,water, gas and solids production rates).
  • Determined study basis to best simulatevarious life of field operating conditions of the asset
  • Built OLGA models of both production and injection wells.
  • Simulated and evaluated water hammer effect in injection wells.
  • Simulated and evaluated sand production and deposition during production.
  • Identified areas of sand bedding in pipeline.
  • Identified sand accumulation rates topsides
  • Determined maximum attenuation expected for various valve closures times
  • Advised optimum valve shutting time to minimise risk of water hammer and formation damage.
  • Assessed the topsides facilities capacity and impact of sand production on future tie-back options
  • Generated a technical report detailing findings of the study.
  • Provided recommendations relating to optimising production whilst limiting sand production.

Outcome & Client Benefits

The study performed by VJN & LR Senergy has resulted in identifying possible sand deposition locations essential for pigging operation. Best practises for valve closure have also been advised.

The study also provided an avenue for a subsurface/subsea multi-disciplinary collaboration, where expertise from both fields provided the client with an optimum solution.

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Case Study: Feasibility study across 2 ultra deep offshore blocks

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Overview

Carogas Services ’ was mandated by Sonangol to carry out an independent review on the economic feasibility in doing a Cross Block Development between 2 Ultra deep offshore blocks (block 16 &3 1)

Both blocks had 16 associated oil and gas fields were located offshore Angola and the two different operators had been unable to make the economics stack up. As a result the developments were declared contingent and shelved. Sonangol in a bid to move things forward wanted an independent view on the commerciality of a cross block development to keep the CAPEX down and restart conversations.

Objectives

The objectives of the study were:
  • Quick screening for compatibility of all Blk 31 SE & Blk – 16 oil and gas fields
  • Validate and Re-evaluate reserves, by providing ZAIL independent view
  • Phased drilling by rigorous well optimisation (location, timing and count)
  • Facilities flexibility and scalability
  • Economics- Reducing upfront CAPEX, maximising facilities Ullage, maintaining production plateau as long as possible
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Carogas Services Role

Carogas Services undertook the following activities in completing the project:

  • Data review and update
  • Fluid compatibility (PVT), DST’s, Geology e.t.c
  • Model review and update
  • Network model review and update
  • Volumetrics, production rates and production profiles (P10,P50 & P90)
  • Economic models
Development concept (Facilities)
  • Desktop study of existing documentation and review analogue developments
  • Prepare design study basis and agree report format
  • Identify design cases based on P10, P50, P90 resource and production
  • Identify feasible concepts including options and sub-options
  • Determine engineering quantities for conceptual reference case
  • Preliminary safety and environmental considerations
  • Preliminary risk, reliability and availability considerations
  • Development schedule
  • CAPEX and OPEX estimates
  • Economic evaluation

Outcome & Client Benefits

Provided the company with an optimal phased development option, delaying upfront CAPEX by $700m and CAPEX savings up to $2 billion

Study results proved that development could break even at much lower oil prices (<$30/bbl savings)

Sonangol was more informed in reviewing IOC’s request to adjust PSC terms to favour their blk 31 and blk 16 standalone development concepts

A more detailed FDP was initiated amongst the contractor group as a result of ZAIL study

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Case Study: Partial Sale of Zarat Block

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Overview

PA Resources (PA) engaged Carogas Services to support its Tunisia offshore permit Farm-Out process. Carogas Services was brought on site to provide technical, strategic and commercial support working alongside an assigned team and external advisors.

Objectives

The objectives of the study were:
  • Engage a financially strong and competent technical partner to technically participate alongside PA in the operation and development of both permits.
  • Cover a portion of the cost of on-going exploration and development funding via cash and development carry.
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Carogas Services Role

  • Participated in a peer review of the draft plan of development to identify and resolve gaps in advance of launching the farm-out process.
  • Developed sales materials including the information memorandum & management presentation in association with other disciplines.
  • Sourced an appropriate dataroom provider and prepared a virtual data room in support of the marketing of the assets.
  • Provided strategic and commercial advice during the negotiation of the sale to Enquest. This included advice on negotiation tactics, commercial review of terms and input to the Sale & Purchase Agreement.

Outcome & Client Benefits

Carogas Services assisted PA in attracting a high quality license partner and in achieving financial and contractual terms for the sale which compared favourably with recent benchmark deals in Tunisia.

PA announced its successful farm-out of the Didon and Zarat offshore permits in Tunisia. The divestment related to the transfer of a 70% share in each permit and operatorship of both permits to Enquest. The Zarat permit contains the undeveloped Zarat and Elyssa fields and a number of exploration targets, whilst the Didon permit contains the producing Didon Field. The terms of the sale were:

  • An upfront cash consideration of USD 23 million;
  • Additional cash payment of USD 93 million contingent on development of the Zarat field;
  • Contingent payments of up to USD 133 million following successful project developments upon achieving certain targets.
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Carogas Services is an upstream oil and gas Services, Consultancy, & Training
group that delivers tailored solutions and sustainable value through a blend of local
expertise and global technical support.

Contact

Block 7, Building 4, Mobolaji Johnson Place, Lekki Phase One, Lagos, Nigeria.

395, road 14, Nad Al Sheba Villas, Meydan, Dubai, UAE

  • +234 906 713 2405
  • +234 916 649 4226
  • +971 588 923 138
  • info@carogasservices.com

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