Schlumberger

Performance Report: IFE Reduces Waste Volume, Drilling Cost and Improves Drilling Performance

Challenge:

Shallow wells, many rig moves, mob/demob times minimization. Small rig, inefficient and old SC equipment. Increasing disposal and total project costs. Limited waste disposal site capacity and no further allowance for a new waste disposal site. Need for shale inhibition but environmental restriction on chlorides, increasing cost to drill due to fluids and waste disposal. No fluids reusage.

Drilling sensitive, depleted sand formations, restrictions to mud weight (max. 1.12 S.G.). Drilling performance m/hr was showing a decreasing trend line. Lack of communication. No HSE plan. Corrosion problems due to existing mud system.

Solution:

INTEGRATED FLUIDS ENGINEERING (IFE) approach to address fluids performance and waste disposal volumes. This included a different type mud system and new equipment as well as an on site Solids Control Engineer and a 24 hour mud engineering service. Benchmarking, pay for performance contract.

SILDRIL/Potassium Carbonate as substituted for KCl polymer drilling fluid (mud system was changed to Potassium Carbonate/Polymer after 10 wells drilled, to lower the fluid related costs – OMV’s decision after a trial showed good results). The Solids control system was upgraded after an IFE Rig evaluation to 2 BEM-300 shakers and upgraded in second half of 2002 to 3 BEM-300 shakers, SWACO Type Desander/Desilter Unit, two variable speed Centrifuges (in noise protected 20ft container), in conjunction with a fully automatic drypolymer Midcofloc 7 dewatering unit.

Result:

  • Reduced wastes: 23,5% in first year of operation, or 4423 mto of waste otherwise discharged into OMV fs disposal sites.
  • Reduced wastes: 32,83% in year 2002 operations, or 5716 mto of waste otherwise discharged into OMVfs disposal sites.
  • Disposal Factor reduction (Plan vs. Actual) ranged from 50%-4%.
  • Faster drilling: Increase average drilling rate more than 50%.
  • Footage costs reduced by 13%.
  • Reduced fluids and waste costs: The complete fluids and waste related cost showed 11% savings. This included Fluids, equipment, Engineering and Disposal cost.
  • NO fluids disposal; reuseage/recycling of all fluids, including spud-mud.
  • More for Less. Improved drilling performance for less total dollars.
  • Other customers interested to implement IFE (MOL, POGO, INA).
  • Start of IFE in Hungary, MOL, in first half of 2003.

Well Information
Location Lower Austria
Spud / Completion March 2001 – March 2003
Wells / Footage Drilled 43 wells – 3 rigs (1 contractor [only in 2001], 2 operator rigs)
8,823 ft of 17½”
71,383 ft of 12¼”
179,792 ft of 8½”
3,037 ft of 6⅛”
143,586 ft of total hole drilled
Average well depth – 6,508 ft

The Details

The driving forces of IFE for OMV have been: make cost savings potential visible, use most efficient SCE, minimize overall waste volume and waste disposal costs, use environmentally friendly drilling fluids system, reuse all fluids, no HSE incidents – no spills, no accidents, reduce time to TD/shorter time to production/increase ROP, lower total project costs, pay for performance, higher production rates, lower costs per unit produced.

For OMV a driving part for a new type of contract was also to show contractor’s performance reflected by cost reductions, reduced day rates or rewarding a Bonus. A “pay for performance” Incentive contract was established and benchmarks defined on a well-to-well basis (max. mud weight; hole cleaning efficiency; drilling fluids, engineering and SCE costs; SCE efficiency, amount of waste disposed ).

The difficulties of drilling in the Vienna Basin Area are drilling sticky shale formations , where excellent inhibition is needed and also drilling depleted, sensitive sand formations (underhydrostatic – high potential for differential sticking), where max. mud weight is limited to S.G. 1,12 (9,3 lb/gal).

Costs were increasing due to the following reasons: increasing waste disposal costs and waste disposal site costs – dump and dilute was common, due to max. MW of 1,12 S.G. and inefficient SCE, no dewatering, no recycling or reuseage of fluids; everything also directly relates to increasing fluids and logistic (trucking etc.) costs.

3 rigs have been used for the 24 wells drilled until end of February/beginning of March 2002. 2 OMV rigs and 1 contractor rig.

43 wells have been drilled without any HSE incidents (accidents or spills) or downtime of M-I/SWACO equipment. M-I Austria received a Bonus on 42 of 43 wells.

Prior to the IFE process at the end of 2000, the average ROP was 4.2 m/hr. (Drilling rate is based on total project time and total meters drilled). The first six months of 2001 showed an increase to 4.7 m/hr. Final results for 2001 improved the ROP to 4.9 m/hr. Wells drilled in the first half of 2002 had an average of 6.4 m/hr (no records from second half).


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