Baker Hughes Corporation

Kelvin D Smejkal

Michael H Johnson

Benn A Voll

Hang Nguyen

The present invention provides a method for efficiently packing proppant in an extended reach, horizontal, open hole annulus. For a given set of fixed parameters, such as the wellbore size, screen size and formation fracture pressure, the method provides a combination of critical parameter values, including the proppant density, the mixture ratio of proppant and liquid and the pump rate which will yield an efficient and effective placement of the proppant in the annulus.

Method of packing extended reach horizontal wells

A fluid system has been discovered using graded calcium carbonate particle sizes and a modified lignosulfonate. Optionally, a thixotropic polymer such as a welan or xanthum gum polymer is used to keep the CaCO.sub.3 and lignosulfonate in suspension. It is important that the calcium carbonate particles be distributed across a wide size range to effectively prevent filtration or fluid loss into the formation. Further, the lignosulfonate must be polymerized to an extent effective to reduce its water solubility. The modified lignosulfonate (lignin sulfonate) is necessary for the formation of a filter cake essentially on the surface of the well bore. Since the filter cake particles do not invade the well bore due to the action of the modified lignosulfonate, no high pressure spike occurs during the removal of the filter cake which indicates damage to the formation and well bore surface and typically reduces overall permeability of the formation. The rheological properties of the fluid allow it to be used in a number of applications where protection of the original permeable formation is desirable. The applications include, but are not limited to, drilling, fracturing and controlling fluid losses during completion operations, such as gravel packing or well bore workovers.

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Houston, TX, United States of America

Kelvin D Smejkal