Well conditioning method for wireline logging using dedicated aqueous based drilling fluid composition
AssigneePetroleo Brasileiro S.A. - Petrobras
InventorsAngelo Marinho Vianna, Walter Francisco Cardoso Junior, Fabio Fabri, Sebastiao De Andrade Loureiro, Kaio Augusto Gonzaga, Leonardo Silva De Almeida
Life of this patent
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Abstract
The present invention addresses to a wireline logging method using an aqueous based drilling fluid with xanthan gum and polyols in order to improve the quality of the acquisition of geological data from wireline logging (final logging) in open hole and reducing the risk of the tool getting stuck. It can also be applied in well control situations and used in the integral drilling of the reservoir, but with different application bias of the multifunctional fluid.
Claims15
A well conditioning method comprising:
- preparing an aqueous based drilling fluid with polyols wherein preparing comprises:
- pre-hydrating filtrate viscosifying and reducing polymers water;
- adding NaCl brine to produce a mixture;
- adding polyol to the mixture;
- adding a precipitating additive of Ca++ and Mg++ ions, a buffer additive, an alkalizing additive, and a bactericidal additive, to the mixture;
- adjusting a pH of the mixture to be alkaline;
- densifying the mixture to a specific mass of 1,000 kg/m3 to 2,000 kg/m3;
- performing rheology, filtrate, and salinity tests;
- and
- adjusting a concentration of the filtrate viscosifying polymers and reducing polymers;
- conditioning a hole, previously formed by drilling, and pumping fluid, wherein conditioning the hole and pumping fluid comprises:
- pumping cushion into the hole and displacing the cushion with the aqueous based drilling fluid with polyols up to 100 m above a casing shoe of a previous drilling phase with a flow rate the same as a drilling fluid flowrate used during the previous drilling phase, wherein densifying comprises adjusting a weight of the mixture to match a weight of a previously used drilling fluid;
- withdrawing a drill string by performing backreaming by pumping the aqueous based drilling fluid with polyols to the hole;
- withdrawing the drill string from the casing shoe, with circulation and without rotation, by pumping the aqueous based drilling fluid with polyols at a reduced flow rate and controlled speed up to 200 meters above the shoe or according to an availability of the aqueous based drilling fluid with polyols;
- after pumping the aqueous based drilling fluid with polyols, pumping 15 to 32 m3 of a cushion and withdrawing the drill string in a section of the hole by pumping a fluid;
- after passing the cushion through a blowout preventer, turning on a booster;
- and
- from a pre-defined depth, completing the withdrawal of the drill string;
- and
- conducting, after conditioning the hole, wireline logging operations within the hole with a wireline logging tool.
Dependencies are inferred from the claim text.