Abstract

A one-piece aluminum inner barrel liner system has been employed to protect and containerize core material during coring operations with conventional and wireline core barrels. The system offered enhanced safety features and improved core handling on the rig floor. The integral one-piece liners securely containerized the core during acquisition. Vent holes allowed expelled gas to escape during recovery to the surface, improving safety during core retrieval and handling. The companion Non-Rotating Inner Tube Stabilizer system will ease separation of the 30-foot liner joints, thus improving wellsite handling procedures and safety during extended core runs. The design allowed the liners to be opened quickly and easily at the surface for rapid examination and sub-sampling of the core material.

Introduction

Conventional core barrels collect and containerize a column of core material in an inner barrel that can be made of non-disposable steel or disposable materials such as aluminum, fiberglass, or thin-walled steel (Baker Hughes 1999). Disposable aluminum inner barrels are perhaps the most widely used method of containerizing core material today. Thin-walled plastic and aluminum liners inserted inside of steel or aluminum inner barrels also can be used to containerize the core material (Baker Hughes 1999). While not as rigid and supporting of the core as standard inner barrels, the liners are used in low-cost coring operations or to provide rapid access to the core material at the wellsite.

Traditional thin-walled aluminum liners consist of one piece extruded tubes or a two-piece split system incorporating an extruded liner that has been cut in half along the longitudinal axis (A. Anis 2001). This paper describes the use of a new aluminum liner system for conventional and wireline core barrels. The new liners are run-in-hole as single one-piece 30-foot long units that, brought to the surface filled with core, can be split in half along laser-cut perforations. This offers two advantages over the traditional liners. First, in comparison to traditional one-piece liners from which core must be extruded, the new liners are easy to split open at the surface for simplified access and examination of core material. Second, the new design is less likely to jam when compared to two-piece liners that may shift or twist around each half during the coring operation.

The new liners are designed to be used with a Non-Rotating Inner Tube Stabilizer System for extended coring runs. Extended core-filled liners are easily separated at the surface by insertion of a hydraulically-driven guillotine blade into a window on the inner tube stabilizer (Fig. 1). Then the inner barrel connections are broken at a torque lock (Fig. 2). This prevents damage to the core that can be induced in systems that require the backing-off of the box and pin threads connecting inner barrels.

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