Step Change in Remote Exploration

Abstract

Remote Arctic onshore exploration can be very costly, frequently exceeding the cost of a deepwater Gulf of Mexico well. This paper reviews the reasons for these high costs and a possible combination of new proven technologies and rig designs to significantly reduce these costs Logistics, mobilization, demobilization and a limited drilling season are factors that combine to cause high costs. Operation time requirements and the short drilling season normally results in a rig drilling one well per season. A significant reduction in exploration final hole size is the primary driver in reducing costs as this leads to a major reduction in rig size. Downsizing does not limit well evaluation due to recent developments in downsizing evaluation equipment. The majority of the required information can be obtained with this finder well or "scratch and sniff" approach. This downsizing allows the use of an innovative rig design; hybrid coil tubing drilling unit; that has significantly reduced mobilization and demobilization times. The reduction in drilling and mobilization/demobilization time can result in one rig drilling multiple wells in the drilling season. Combining new technologies, such as casing drilling and coil tubing drilling, reduces drilling time and allows the hybrid coil tubing rig to drill deeper. Casing drilling and coil tubing drilling are areas where ConocoPhillips is an industry leader. A significant reduction in exploration cost is predicted, estimated at 50%. Introduction ConocoPhillips (COP) has significant Arctic onshore exploration acreage in Alaska, Canada, and Russia (through a (jJoint vVenture with OOOLUKoil Naryanmarneftegaz with Lukoil). The majority of the exploration prospects are far from existing infrastructure, 50 to 200 miles. Most remote exploration, greater than 570 miles from infrastructure, has been done using snow roads. Building ice roads for longer distances is not cost or time effective. The rigs are transported using low ground pressure vehicles, such as sleds, bull dozersRolligons, RolligonsTM (a), QuadTracsTM (a)Quadtracs, sleds, etc. In some cases conventional transportation equipment can be used but this requires highly packed snow roads. This delays mobilization until the packed snow essentially turns to ice and can accept a higher bearing pressure. The well pads are typically ice, built using water from local lakes. When drilling is completed and the pad melts there is no damage to the tundra. In Russia, sand or gravel pads, are built even for exploration wells. The rigs used are typically rated to more than 20,000 feet with 5-inch drill pipe. The rig components can be broken down to 8 ½ feet wide by 8 ½ feet tall and 50 feet long, maximum weight less than 50,000 lbm. This results in approximately 100 loads for the rig and 50 loads of associated equipment. Rigs in the Russian Arctic have large component pieces and are moved by skidding them on sleds1. Erection of the rigsequipment requires using cranes. This workErection is subject to weather related delays, blowing snow and low temperatures that shutdown crane operation. Thirty 30 days is a reasonable estimate of the time required to mobilize this type of rig. Stacking rigs close to the exploration well site has been done previously to reduce mobilization time. This however has not been very successfully in decreasing mobilization and rig up time. Rig moves in the Russian Arctic can take over three (3) months. Although rig components are large all the primary and auxiliary piping, ducting, insulation, etc. are fabricated onsite. Arctic conditions at initial mobilization are typically no daylight and low temperatures. During the Alaska 2006 season the time period, late January to early February 2006, had a minimum temperaturee of -55°F and a maximum temperaturee of -15°F. The average temperature during this time period was -35°F. At temperatures below -35°F all crane operations are essentially shutdown as booms may experience brittle fracture.