Run In Hole

Key Takeaways

• The mechanical sequence for running drillpipe in hole begins with picking up a single joint or a pre-racked stand (two or three joints pre-made up in the derrick setback) from the pipe rack or fingerboard using the top drive or traveling block elevator, stabbing the pin into the box of the last joint in the string held by the slips at the rotary table, spinning the joint to hand-tight engagement using the spinning wrench or iron roughneck, applying final makeup torque with the tong or iron roughneck torque head (verifying the torque-turn record is within the API RP 7G makeup specification for the specific connection), pulling the slips, lowering the string by a single joint or stand length, and resetting the slips to repeat the cycle; a single joint addition (approximately 9 meters) typically requires 3 to 5 minutes of rig time at a modern well-equipped rig, giving a tripping rate of approximately 100 to 180 meters per hour for single-joint running or 250 to 350 meters per hour when running three-joint stands (which have already been made up in the derrick during the previous POOH operation and stored in the fingerboard or setback, reducing the number of makeup operations per meter of string).
• Casing and liner running in hole follows a procedurally distinct sequence from drillpipe RIH because of the larger and heavier pipe, the single-use nature of the joints (which are not part of a reusable drill string and must be protected from thread damage), and the critical importance of achieving the specified installation depth within tight tolerance for zonal isolation: casing joints are picked up from the pipe rack using a single-joint elevator, the thread protectors removed and the pin-end threads cleaned and inspected, thread compound (API modified thread compound or premium thread lubricant for proprietary connections) applied to the pin threads, the joint stabbed into the preceding box, and made up with a hydraulic casing tong to the torque value specified by the connection manufacturer (for API buttress threads, typically 2,000 to 8,000 ft-lb depending on casing size; for premium connections such as VAM TOP or TenarisHydril, torque tables provided by the manufacturer govern); float equipment (the float collar and guide shoe pre-installed in the bottom of the casing string) is confirmed functional before RIH to ensure the casing fills with fluid at a controlled rate during running-in (preventing excessive buoyancy differentials that can cause the string to buckle or the float equipment to fail).
• Running speed limits during RIH are governed by surge pressure considerations: as the string is lowered into a fluid-filled wellbore, the displaced fluid must flow upward past the string in the annulus, generating a dynamic pressure increase (surge pressure) at the formation face that is superimposed on the hydrostatic mud pressure; if the surge pressure exceeds the formation fracture gradient, the wellbore can be fractured and lost circulation induced, causing a sudden reduction in pit volume that can be misinterpreted as a swab-induced kick; surge pressure is calculated using the Burkhardt (1961) method or more rigorous finite-element wellbore hydraulics models as a function of string OD, annular clearance, mud rheology, and running speed, with typical allowable running speeds of 0.5 to 1.5 meters per second for drillpipe in open hole and lower speeds (0.2 to 0.5 m/s) required for large-OD casing strings in tight clearance situations; rig crews are trained to slow the tripping speed whenever the string enters a known weak formation or a zone previously diagnosed with lost circulation, and modern top-drive systems incorporate automated speed-limiting controls that compare calculated surge pressure to a user-set fracture-gradient limit.
• Flow checks during RIH are mandatory best practice whenever the string passes through a permeable zone, the bit reaches a previously identified influx depth, or the mud logger observes elevated background gas readings: the flow check consists of stopping downward pipe movement, picking up off the slips, and observing the drill floor returns flowline for 3 to 5 minutes without pumping; if the wellbore is flowing (formation fluid entering the wellbore because the hydrostatic pressure has fallen below pore pressure due to swabbing during POOH or insufficient mud weight), the flowline will show continuous flow with the pumps off, indicating that the slips must be set and the well shut in for a formal kick control procedure; the risk of swabbing (creating a transient pressure reduction as the string is pulled upward during POOH that draws formation fluid into the wellbore) is highest in high-permeability formations with mud hydrostatic pressure only slightly above pore pressure, and the subsequent RIH after swabbing can encounter this formation-fluid influx unless a flow check is performed and the influx detected before it grows into a full well-control event.
• RIH time optimization is a primary focus of well planning and rig operations management because trip time in deep or complex wells can account for 20 to 40 percent of total rig time and cost: extended-reach wells require careful buckling analysis to ensure the drill string does not buckle in compression when the bit lands on bottom at the end of RIH (requiring sinusoidal or helical buckling calculations using Dawson-Paslay or Mitchell equations to specify the maximum compression the string can sustain before it contacts the borehole wall); deviated wells require friction modeling (using the soft-string or stiff-string torque-and-drag model) to ensure the hook load during RIH remains above zero (preventing the string from going to slack-side weight-on-bit, or "stacking off," in highly deviated sections where friction prevents the string weight from being transmitted to the bit); automated pipe handling systems (iron roughneck, automated pipe racker, dual-activity systems that allow tripping on one side of the derrick while coring or testing on the other) reduce the manual labor and cycle time of RIH, with modern high-performance drilling rigs capable of running 7,000 to 10,000 meters of drillpipe per day on a routine trip in a vertical or mildly deviated well.