Coiled tubing injector apparatus

A coiled tubing injector apparatus for injecting coiled tubing into a well and for withdrawing coiled tubing therefrom, the coiled tubing injector apparatus comprising:

• a base;
• a pair of spaced apart separable carriages extending upwardly from the base, wherein each carriage includes a gripper chain for engaging the coiled tubing, the gripper chains defining a working length having an upper end and a lower end;
• and
• a support guide connected to each carriage, wherein each support guide substantially spans the distance between the lower end of the working length of the gripper chains and a lower end of the base.

A coiled tubing injector apparatus for injecting a coiled tubing into a well comprising:

• a base;
• a pair of opposed gripper chains positioned above the base for engaging the coiled tubing, wherein the gripper chains are movable laterally with respect to the base and define a working length having upper and lower ends;
• a wetting fluid basin for holding a wetting fluid positioned below the working length of the gripper chains, wherein the coiled tubing passes through the wetting fluid basin when the coiled tubing is injected into the well;
• and
• a support guide movable laterally with each gripper chain for engaging the coiled tubing, wherein the support guides extend downwardly into the wetting fluid basin.

A gripper chain system for use in a coiled tubing injector apparatus, the gripper chain system comprising:

• a linear beam having a bearing plate;
• a roller chain disposed about and supported by the linear beam, the roller chain comprising a plurality of rollers;
• and
• a gripper chain supported on the roller chain, the gripper chain comprising a plurality of gripper blocks, wherein the roller chain captures the gripper blocks to limit sideways movement between the roller chain and the gripper chain.

A coiled tubing injector apparatus for injecting coiled tubing into a well and withdrawing the coiled tubing therefrom, the coiled tubing injector apparatus comprising:

• a base;
• and
• a pair of carriages extending upwardly from the base, each carriage including a gripper chain assembly, each gripper chain assembly comprising:
• a linear beam;
• a roller chain supported on the linear beam;
• and
• a gripper chain for engaging the coiled tubing supported on the roller chain, wherein the roller chain comprises a plurality of rollers, each roller defining a pair of opposed shoulders, the gripper chains being received between the opposed shoulders.

A coiled tubing injector apparatus for injecting coiled tubing into a well and for withdrawing the coiled tubing therefrom, the coiled tubing injector apparatus comprising:

• a base;
• and
• first and second carriages extending upwardly from the base, each carriage having first and second outer plates, and each carriage including a gripper chain system mounted to the first and second outer plates, the gripper chain system comprising:
• a pair of spaced gripper chain drive sprockets mounted on a drive sprocket shaft for supporting a gripper chain, the gripper chain being adapted to engage the coiled tubing, the drive sprocket shaft having a centerline corresponding to an axis of rotation of the drive sprockets;
• and
• a pair of spaced idler sprockets mounted on an idler sprocket shaft positioned below the gripper chain drive sprockets for supporting the gripper chain, the idler sprocket shaft having a centerline corresponding to an axis of rotation of the idler sprockets, the centerlines of the drive sprocket shaft and the idler sprocket shaft having a first distance therebetween at first ends of the drive sprocket shaft and idler sprocket shaft and a second distance therebetween at second ends of the drive sprocket shaft and idler sprocket shaft,
• wherein the first and second distances are initially substantially identical so that the centerlines of the drive sprocket shaft and the idler sprocket shaft are parallel, wherein the initial substantially identical first and second distances may be established by noting the position of the first and second ends of the idler sprocket shaft relative to witness marks on the first and second outer plates, and wherein the position of the first and second ends of the idler sprocket shaft can be adjusted to maintain a parallel relationship between the centerlines of the drive sprocket shaft and the idler sprocket shaft if the position of the first or second end of the idler sprocket shaft moves during operation.

A method for maintaining a substantially parallel relationship between a drive sprocket axis of rotation and an idler sprocket axis of rotation in a coiled tubing injector, the coiled tubing injector comprising first and second outer plates and having a pair of drive sprockets and idler sprockets located therebetween, the drive sprockets being mounted on a drive sprocket shaft, the drive sprocket shaft having a centerline collinear with the drive sprocket axis of rotation, the idler sprockets being mounted on an idler sprocket shaft, the idler sprocket shaft having a centerline collinear with the idler sprocket axis of rotation, wherein a gripper chain is supported on the drive sprockets and idler sprockets, the method comprising the steps of:

• fixing the position of the drive sprocket shaft with respect to the first and second outer plates;
• positioning the idler sprocket shaft so that the centerline of the idler sprocket shaft is parallel to the centerline of the drive sprocket shaft and so that an initial distance between first and second ends, respectively, of the drive sprocket shaft and the idler sprocket shaft, is at a desired distance;
• placing a witness mark on the first and second outer plates to mark the position of first and second ends of the idler sprocket shaft relative to the first and second outer plates;
• monitoring the position of the first and second ends of the idler sprocket shaft relative to the witness marks;
• and
• adjusting the position of the idler sprocket shaft to maintain the parallel relationship between the idler sprocket shaft centerline and the drive sprocket shaft centerline if the first or second end of the idler sprocket shaft moves relative to the witness mark.