Method and Apparatus for Completion of Heavy Oil Unconsolidated Sand Reservoirs

Abstract

A method of completing a subterranean well having a well casing extending though an earth formation is provided, including the steps of: suspending an apparatus at a selected depth within the well casing; creating an unbalanced condition within the well casing; forming a lateral bore in the formation by jetting a pressurized fluid from the apparatus through a casing opening in the well casing and into the earth formation; receiving in the well casing through the casing opening fluid and formation debris created from forming the lateral bore; and lifting the fluid and formation debris received by the well casing upwardly through the well casing to the well surface.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is a continuation of International Application No. PCT / IB2011 / 054841, filed Nov. 1, 2011, which is a non-provisional of U.S. Application No. 61 / 409,622, filed Nov. 3, 2010.FIELD OF THE INVENTION[0002]The present invention relates generally to methods and systems for enhancing heavy oil productivity from unconsolidated sand reservoirs and, in illustrated embodiments thereof, more particularly relates to a method and apparatus for completion of heavy oil unconsolidated sand reservoirs.BACKGROUND OF THE INVENTION[0003]Heavy oil production with sand is becoming an increasingly used technique for certain types of heavy oil deposits. Allowing sand production can dramatically improve oil recovery compared to the non-sand production process. The advantage of allowing sand production is that the produced sand creates high permeability zones comprising of relatively small channels for the heavy oil to flow through. However, a chall...

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Benefits of technology

[0008]Embodiments of the present invention also provide for a low impact completion when compared to conventional explosive charge completions, which alleviate concern of damaging cement encasement that is critical in providing isolation from water zones above or below the productive formation.

[0009]Embodiments of the present invention further provide tools and methods for forming a large well-bore access area and a high permeability lateral bore or cavern deep within the reservoir providing enhanced connection between the well and reservoir. The large sand face or reservoir contact area provided by the high permeability bore reduces reservoir fluid velocities and is believed to minimize or eliminate problematic sand and clay production.

[0010]Embodiments of the present invention further provide tools and methods that can be implemented on existing completed wells that are experiencing problematic in-flow or poor production due to near well bore formation damage.

[0011]To achieve these and other advantages, in general, in one aspect, a method of completing a subterranean well extending through an earth formation is provided, including the steps of: creating an underbalanced condition in the well; providing a nozzle in the well; and pumping a pressurized fluid through the nozzle such that a jet of the pressurized fluid ejects from the nozzle and impinges on the earth formation creating a lateral bore in the earth formation.

Problems solved by technology

However, a challenge with heavy oil production with sand is keeping the sand moving freely and consistently into the wellbore.

This is attributed to experiencing in-flow problems caused by fine sand and clay migration or reservoir sand sloughing that plugs the small diameter casing holes created by the explosive charge perforation completion process.

However, each of these methods has achieved nominal success.

It is believe the low success is attributed to performing these methods in an overbalanced condition, that is, in a condition in which fluid pressure in the wellbore is maintained higher than the pressure of the reservoir.

It is believed this causes instability in the manufactured bores and results in eventual collapse or closure of the channel due to sand sloughing.

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