Case History of Floating Mud Cap Drilling Techniques-Ardalin Field, Timan Pechora Basin, Russia

Abstract

SPE Member Abstract Floating Mud Cap Drilling Techniques have been used in the drilling industry since the early part of the 20th century. Rotating Heads have made this practice almost obsolete, but the practice is still used in areas where carbonate reservoirs and other highly permeable reservoirs experience either partial or full loss of returns. The objective carbonate interval in the Ardalin field often experiences full loss of returns that cannot be controlled by conventional western or Russian techniques. Field operations occur in an ecologically sensitive tundra environment, under arctic weather conditions, accessible by only helicopter in summer and snow road in winter. Rotating heads would have been costly and difficult to design for a Russian rig. Floating Mud Cap Drilling operations, though basically a simple procedure, required fore thought and planning in order to be successful under these conditions. This paper will present the thought processes and planning used to successfully drill through the objective interval with full loss of mud returns. Introduction Ardalin drilling operations are unique in scope. Multiple operational and technical factors needed to be considered when planning and implementing Floating Mud Cap Drilling Techniques. The Ardalin Field is located on the tundra in the Ti man Pechora Basin above the Arctic Circle in Russia (Figure 1). Drilling occurs on three drilling pads that are connected by an internal road system. The field is isolated on the tundra, and no permanent roads are available to the field from the existing Russian road system. Ground transportation is only available by ice road during four months of the year. Helicopter access is the only transportation means available at all other times. Ardalin drilling Operations utilized Russia Uralmash 3-D-86 rigs (similar to a 1930's western design) with selected upgrades of western drilling equipment and fell under the Russain Federation Safety Regulation. Though these rigs are more than adequate for drilling in the Ardalin field, rig capability was limited by western standards. P. 767