The Ingram Cactus Exact 15 Universal Slim-hole Drilling and Completion System was specifically developed for use with slim-hole casing designs suitable for installation through small bore BOP stacks (i.e. 7", 9" and 11" through-bore sizes).
One of the objectives in designing this system was to preserve all the design features developed in the standard Universal Wellhead Product Line. Specific care was taken to minimise the overall system height dimension so that in certain applications the need for wellhead cellars can be eliminated.
When used offshore, the system significantly reduces the height requirements for the wellhead deck area which can result in major structural savings in the platform design.
The main features of the slim-hole wellhead include:
- ·The low profile for the wellhead and tree combination (wellhead = 25.77", tree = 53.44").
- ·Through BOP installation of casing hangers and annular seals.
- ·Integral tubing hanger design with continuous control line options.
- ·A great reduction in the number of leak paths gained from the elimination of wellhead penetrations for tie-down bolts.
- ·Replaceability of all seal systems.
- ·Replaceability of the wellhead spool.
- ·External test facilities.
- ·Priced to compete with conventional systems.
The following documentation offers information about the Ingram Cactus slim-hole Universal Wellhead range suitable for use with either 11", 9" or 7 1/16" BOPs. Alternative casing programmes have been incorporated into the designs. Ingram Cactus Company intends to offer the Exact 15 Universal Slim-hole Product Group as part of its standard product line available from all its manufacturing locations.
1 System descriptions
1.1 7" Exact 15 Slim-hole wellhead
The 7" Slim-hole Wellhead System can be used below BOPs with a through-bore larger than 7".
The 7" system is designed to accommodate a 10 3/4" ´ 7 5/8" ´ 5 1/2" casing programme, completed with 3 1/2" tubing.
a. Constricting load shoulder
A specific design requirement of the system is to provide full bore access through the wellhead for the downhole assembly while at the same time providing an adequate landing shoulder for the 5 1/2" mandrel casing hanger. These conflicting requirements are met by a "constricting" landing shoulder. During the drilling operation, the landing shoulder is retracted into the body of the 7 5/8" casing head. Once drilling is completed, a torque tool is used to manipulate the actuation sleeve and force the landing shoulder into the casing head's bore.
b. Casing head and wellhead housing
The 7" Slim-hole Wellhead consists of two main parts (i.e. the 7 5/8" casing head {14.25" OD ´ 6.785" to 6.825" ID} and the 7" wellhead housing {14.22" OD ´ 6.938" ID}) connected by a right hand thread (RHT) connection. This design was selected to provide the following operational advantages:
- ·Independent installation of the wellhead housing with pre-installed and tested outlet equipment.
- ·Easy access for emergency hangers.
- ·Wellhead maintainability.
- ·Easy access for maintenance purposes.
A metal to metal seal is formed at the wellhead/casing head interface and a resilient seal is provided as a back-up and for external test purposes.
If run as a single unit, the wellhead housing/casing head combination utilises a hub-style full-bore running tool engaged to the wellhead upper speed clamp. Alternatively, the casing head can be run separately with a RHT, full bore running tool.
c. Stepped wellbore
The wellhead housing and the casing head provide a number of progressively smaller steps in their respective bores. This "stepping" technique helps to protect the seals used on the annular packoffs and tubing hangers from damage during installation. The final restriction in the casing head actuation sleeve can be used for an abandonment cap seal.
d. Wear bushing
To protect the bore of the wellhead housing during drilling, a bit retrievable wear bushing is used. This wear bushing has a restricted ID and is therefore run behind the BHA. The wear bushing is carried utilising an in-string J-type running tool. A wear bushing lock pin assembly which is temporarily installed in one of the lower wellhead outlets secures the wear bushing in the vertical position as well as preventing it from rotating.
e. BOP testing
A cup tester is used to perform periodic 7" BOP test procedures. Plug type test tools are provided for the larger systems which permit solid landing shoulders in the casing head.
f. Mandrel casing hanger
Prior to running the production casing string, a torque tool is used to manipulate the actuation sleeve inside the casing head. Rotation of the actuation sleeve forces the load shoulder into the wellhead bore and locks it in place. (See Constricting load shoulder).
The mandrel casing hanger is run with a right handed threaded full-bore running tool. If lockdown is required and the hanger lockdown ring is used, an extension is added to the running tool which compresses the hanger lockdown ring into the hanger body during installation. Once landed, the hanger running tool is partially backed off which allows the lock ring to engage the drive sleeve groove. Overpull will indicate if the latch has engaged properly. The running tool can then be retrieved.
g. Annular seals
Annular seals on the production hanger are available in two styles for the Exact 15 Slim-hole Wellhead System:
- ·Static
- ·Compression
The Static design uses self energising seals on the hanger and housing interfaces. No compression or injection is required. The unit is installed with a J-type running tool through right hand rotation. The unit can be externally tested. Provisions are made for injection for subsequent maintenance purposes.
The Compression design utilises dual static seals on the hanger interface and dual compression type seals on the wellhead interface. The seal assembly is installed with the same J-type running tool and makes up to the casing hanger in the same manner as the static seal. The unit can be externally tested. Provisions are made for injection for subsequent maintenance purposes.
h. Reusable drilling spool
The replaceable wellhead housing capability characteristic of all Universal Wellhead Systems allows the use of a low cost, reusable drilling spool for use during exploration work or for development drilling.
Just prior to completing the well, the reusable spool is removed from the casing head under the protection of a temporary abandonment cap. The short spool is then replaced with a completion wellhead which provides a location for the tubing hanger. In slim-hole drilling projects where relatively light equipment is subjected to the rigors of downhole rotation, this switch out capability can ensure that the production wellhead is always in top condition.
i. Temporary abandonment capability
The 7" Slim-hole System in accordance with the standards of the UniversalProductRange, offers wellhead replaceability under controlled conditions. This is accomplished through the use of a temporary abandonment cap which simultaneously seals off the production casing bore and the production casing annulus.
The abandonment procedure is detailed below:
1.Short drilling spool is used to drill the well to TD.
2.If the well is suitable for completion, the production casing hanger packoff is removed.
3.A temporary abandonment cap is installed over the production casing hanger neck, sealing the production casing bore and production casing annulus simultaneously. In those slim-hole systems where constricting load shoulders are used, an injectable seal between the actuation sleeve and the casing head ensures seal integrity once the T/A cap has been installed over the production casing hanger neck.
4.Once the T/A cap has been successfully tested, the BOP and reusable drilling spool can be removed.
5.At this stage a production wellhead housing can be installed on the casing head. This unit provides additional outlet ports for the tubing annulus and provides space for the tubing hanger.
6.The annular seal is replaced and the tubing hanger and completion tree installed.
j. Crossover options
Crossover spools can be provided to adapt specific slim-hole wellhead systems for use below larger BOPs.
k. Tubing hanger
The Exact 15 Tubing Hanger is landed and locked down through the BOP stack. During installation, an elongated running tool is made up to the external right hand thread on the OD of the hanger's neck. At the same time, an integral sleeve of the running tool holds the hanger lockdown ring in the retracted position. When the hanger is landed, the running tool is partially rotated to release the lockdown ring. Before disengaging the running tool completely, overpull is applied to the tubing running string to ensure that lockdown has occurred. The running tool is then retrieved.
As with conventional equipment, the tubing hanger can be provided with a variety of back pressure valve (BPV) profiles and control line options.
l. Control line exit option
The 9" and 11" Slim-hole Wellhead Systems can offer continuous control line configurations which exit through the wellhead housing. The design requires a longer wellhead housing and tubing hanger neck configuration - which will introduce additional costs in the system.
1.2 9" Exact 15 Slim-hole wellhead
The 9" Slim-hole Wellhead System has been configured to be used with two alternative casing programmes:
a. 13 3/8" ´ 9 5/8" ´ 7" casing program
As a result of the relatively large production casing size, this system has to use a constricting landing shoulder for the production casing hanger. In this respect, this system is very similar in design to the 7" system described previously.
Wellhead height25.46"
Xmas tree height51.01"
9 5/8" casing head15.818" OD ´ 8.813" to 8.125" ID
9" wellhead housing18.14" OD ´ 8.875" ID
9" speed clamp22.06" OD
7" casing hanger8.626" OD ´ 6.359" ID
9" ´ 7" packoff8.781" OD
9" ´ 7" annular seal8.864" OD (optional)
3 1/2" tubing hanger8.932" OD ´ 3.068" ID
b. 10 3/4" ´ 7 5/8" ´ 5 1/2" casing program
The smaller casing programme used with this 9" wellhead system allows the use of a solid landing shoulder in the casing head.
Wellhead height24.01"
Xmas tree height51.01"
7 5/8" casing head14.746" OD ´ 6.675" ID
9" wellhead housing18.14" OD ´ 8.875" ID
9" speed clamp22.06" OD
5 1/2" casing hanger8.626" OD ´ 4.891" ID
9" ´ 7" packoff8.781" OD
9" ´ 7" annular seal8.864" OD (optional)
3 1/2" tubing hanger8.932" OD ´ 3.068" ID
The two 9" systems utilise as many common components as possible to facilitate interchangeability
1.3 11" Exact 15 Slim-hole wellhead
As was the case with the 9" Slim-hole wellhead design, the 11" system is configured for two casing programmes.
a. 13 3/8" ´ 9 5/8" ´ 7" casing program
Unlike the 9" system, the 11" Slim-hole Wellhead System can provide a solid landing shoulder for the 7" casing hanger.
Wellhead height27.17"
Xmas tree height52.31"
9 5/8" casing head13.742" OD ´ 8.813" ID
11" wellhead housing18.14" OD ´ 10.875" ID
11" speed clamp25.00" OD
7" casing hanger10.594" OD ´ 6.359" ID
11" ´ 7" annular seal10.064" OD (static type)
11" ´ 7" annular seal10.781" (compression type)
3 1/2" tubing hanger10.932" OD ´ 3.068" ID
b. 10 3/4" ´ 7 5/8" ´ 5 1/2" casing program
The smaller casing programme for the 11" system requires change out of the casing head and the production casing hanger. All other components are interchangeable with the previously described large programme
Wellhead height27.17"
Xmas tree height52.31"
7 5/8" casing head13.742" OD ´ 6.785" ID
11" wellhead housing18.14" OD ´ 10.875" ID
11" speed clamp25.00" OD
5 1/2" casing hanger10.594" OD ´ 4.891" ID
11" ´ 7" annular seal10.064" OD (static type)
11" ´ 7" annular seal10.781" (compression type)
3 1/2" tubing hanger10.932" OD ´ 3.068" ID
2 Emergency equipment
The use of integral casing heads and mandrel casing hangers in the Universal Wellhead presents the risk that stuck casing prevents correct positioning of these components in the system. To provide an operational solution in these instances, a complete range of emergency equipment has been developed.
2.1 Emergency casing hanger
The Universal Slim-hole Wellhead System can accommodate an emergency casing hanger consisting of a split bowl and slip section, and an emergency pack-off unit. The emergency hanger can be installed through the BOP providing that no coupling is present above the hang-off point. The emergency pack-off unit can be installed through the BOP and is retrievable for maintenance purposes. This unit can be externally tested and injected.
The emergency hanger system maintains the same height tolerances so that the tubing hanger can be installed as if landed on the mandrel hanger.
2.2 Trulock starting heads
In those cases where the surface casing gets prematurely stuck, a hydraulically installed starting head which utilises casing slips to clamp the wellhead to the casing stub can be supplied. Automatic seals with injection capability provide for pressure integrity.
3 Low profile trees
As part of the effort to provide flexibility as well as reduce overall height dimensions, Ingram-Cactus have developed a composite block tree.
The tree comprises an integral master valve and tree adaptor unit which is studded upward, an upper master valve, a T-section, a swab valve and tree cap assembly. Long studs reach from the integral adaptor through the swab valve, clamping the block sections together to provide superior bending and shear resistance for the tree.
The composite block trees can be provided in various configurations in the complete range of valves and trims.
4 Speed clamp
The Ingram Cactus Speed Clamp, designed either for standard service or high pressure, high temperature applications, offers the following advantages:
Four configurations for:Conventional API hubs- Type X
ICC standard- Type U
High pressure/temperature- Type T
Economy- Type E
Greater bending capacity:Hubs mate face to face, providing greater resistance to bending moment than API clamps
Shear load resistant:Unique hub housing offers shear load resistance even when mated to a standard API hub
Rigid segment alignment:Clamp segments are rigidly retained on the hub housing even in the open position
Heavy duty construction:The Speed Clamp easily withstands stabbing loads on the segment section
Fire resistant configuration available.
Designed for all service conditions.
5 Universal BSM End Connection
The Ingram Cactus Universal "BSM" (Bending, Shear, Metal Seal) End Connection is designed with a metal to metal seal and built to provide safe, dependable service in pressure applications from 2000 to 15,000 psi. The BSM is available in standard bore sizes 11 3/16" to 21 1/4". Trims are available for all temperature and service conditions.
The BSM can also be furnished with ring grooves which will make it adaptable to either "BSM" or API flanges.
Face to face mating provide a stable connection more resistant to bending moment than API flanges. The internal seal profile provides a straight bore with a metal seal gasket creating a superior metal to metal seal.
A large cross-sectional diameter shear load offers maximum resistance to shear load.