Casing Alignment Tool

When engaged in the drilling process, periodically, the vertical pipe (casing) will lean over inside the well head thus coming out of alignment. In order to provide vertical alignment, the casing must be moved inside the wellhead until equal distances between the two has been achieved. It is necessary to maintain alignment in order to properly set the casing hanger slips. Casing hanger slips are used to hold up and seal the casing inside the well head. Once the slips are set and the excess casing is removed, a casing adapter spool is added on top of the well head and bolted down tight. This structure forms the bottom portion of the christmas tree. Drilling then continues until they reach a point where another string of casing is run in the hole either to complete the oil well or to isolate a zone that might cause trouble in the completion of drilling operations. Again, the casing must be aligned to set the casing slips to complete the well or to drill deeper. The above process creates prevents a safety risk and an increase in operational cost due to lost rig time.

The current method presently used to address this challenge creates numerous safety concerns. While operating on a jack-up rig, there can be a big air gap (approx. 90 feet) between the well head and the bottom of the jack-up barge. This compounds the problem of trying to align the casing and the well head, due to the natural bow in the casing. In order to align the casing with the well head, roughnecks must rig-up chains and air-tuggers to move it. This process becomes an immediate safety issue, since the rig has only limited hard points (legs of the derrick) to secure a cable and to pull the casing into alignment. The pulling and pushing of the casing using air-tuggers is dangerous to the operators of the air winches. In most cases they come into close proximity of the cables and chains which are used in this procedure. In an environment where communication is crucial, confusion during this time is common. This is created when the air-tug operator is on the drill floor and can not see the roughnecks under the rig floor. The entire crew puts themselves in danger when they use unorthodox measures to align the casing and set the slips.

Additionally, along with the obvious safety issues, there is often times a significant loss of rig time which comes at great expense to the operator. First, the hard points on the rig are seldom in the right place as to pull the casing into alignment. Secondly, the angle of the casing sitting off center very seldom lines up with the hard points available on the rig. The short distance that the casing can be moved in the rotary table creates one more obstacle and adds to the loss of rig time.

The challenge faced by both the operator and the drilling contractor is to find a solution which addresses both the safety and the financial issues. Quality Rental Tools has developed the first hydraulically operated tool specifically designed to solve this problem. By using the hydraulic operated Casing Alignment Tool (CAT), the old method of alignment is eliminated. The base plate of this tool is bolted to the casing well head flange in the vicinity of the casing lean. The hydraulic jack is inserted on to the back plate of the CAT and bolted down. With the v-block attached to the hydraulic jack saddle, the casing can be moved into the correct position. The back plate has a milled slot cut across its back to allow for small adjustments in the jacking mechanism. This allows the v-block to sit in the exact position it needs to be, in order to move the casing over to center. The well head service technician then operates the hydraulic jack and moves the casing into its proper place. The casing slips can then be set in place without the use of unsafe and unorthodox methods thus allowing the drilling operation to continue in a timely manner.

This cost effective and safe method of providing proper casing alignment can permanently eliminate the old unsafe and costly process. Upon reviewing the CAT with drilling rep’s, project engineers, and well head personnel (Cameron Iron Works, Vetco Gray and Woods Group), this solution to the alignment of casing with the well head has been found simple, cost effective, and the safest way to accomplish the task. It is clear that a better way of aligning casing in relation to the well head was needed. The Casing Alignment Tool, provided by Quality Rental Tools, is the right solution.