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Environmentally acceptable wellbore fluids for optimising reservoir productivity


The objective is to develop methodologies and fluid systems
for drilling hydrocarbon reservoirs in ways that maximize
production or fluid injectivity. The approach is to improve
understanding of the reactions occurring between drilling
fluids and hydrocarbon-bearing reservoir rocks by studying the filtration behaviour of selected drilling fluids under
temperature, pressure and flow conditions typical of North Sea wells. Particular attention will be given to open hole
completions in highly deviated and horizontal wells (these
wells are not perforated and damage due to drilling fluids is not easily bypassed).
Technical Approach
Drilling fluids are mixtures of salts, polymers and solids in an aqueous or oil base fluid. In addition to the materials
deliberately added to give desired properties (e.g. rheology, density, filtration behaviour, lubrication), contaminants such as rock solids, brines and gasses accumulate in the system.
This produces complex fluids whose fundamental properties and reactions with rocks under the prevailing high temperatures
and pressures are not understood in detail. The work will
improve this understanding and apply it to the formulation and engineering of improved fluids. It will focus on:
- The structure of mud filtercakes formed on rock substrates; investigation of how cake structure can be influenced by
changing the fluid composition (e.g. polymer type & molecular weight, and solids type, size & shape).
- The invasion of mud components (polymers, surfactants,
solids and salts) into the rock, and the consequence of
invasion on rock permeability.
- The formulation of fluids to optimize the formation of the mud filtercake and minimize permeability damage.
- Development of remedial treatments which effectively remove filtercake and any permeability damage.
Expected Achievements and Exploitation
The project is expected to produce:
- An improved understanding of the relationship between
drilling fluid properties and their performance in filtration control and formation damage.
- Novel polymers and other additives which improve fluid loss and filtercake characteristics.
- Techniques for remedying formation damage.
This will lead to:
- Guidelines, novel additives and techniques for the
successful limitation of formation damage.
- Technologies to improve oil recovery and well performance. - New methods for safer, cheaper drilling and production.
- Reduced environmental impact and improved efficiency of the drilling operations.
The new technology developed by the project will be evaluated in carefully controlled field trials.

Funding Scheme

CSC - Cost-sharing contracts


Schlumberger Cambridge Research Ltd
High Cross Madingley Road
CB3 0EL Cambridge
United Kingdom

Participants (3)

Rue Boussingault 6
67083 Strasbourg
Institut Français du Pétrole
1-4,Avenue De Bois Préau
92506 Rueil-malmaison
Statoil R&D Centre

7005 Trondheim