Global was contracted to plug and abandon legacy wells at Treadwell 10 and North Star 815 sites near Summerland Beach, CA. Global dive teams had conducted assessments of the sites on separate prior occasions to determine the exact location and manner of the oil seepage. Two 4-person dive teams working 12 hour shifts located the …
Project Tag: Energy Services
In May 2015 Global commenced working on the Kitchen Lights Unit No. 3 project under Crowley Solutions for Furie Operating Alaska to install a monopod platform and pipeline in Cook Inlet,Alaska.
The Cook Inlet is one of the most challenging diving environments in the world with zero visibility,up to 30 feet differential between low and high tides and current speeds reaching up to 6 knots yielding an average bottom time of 30 minutes per tide swing
The project,installing a Monopod natural gas platform and 16 miles of 10″ concrete coated pipeline,involved at its peak a total of 25 dive crew members located on 3 different dive vessels in 3 different operational areas; where the gas line entered Cook Inlet on the south end,the Monopod location on the north end,and the 16 miles of pipeline in between. The project started concurrently at all three locations.
At the Monopod location,two dive teams worked the 4 slack tides each day. Tasks included the installation of a template over the well conductor in order to drive a “king” pile to aid in the proper alignment and setting of the Monopod platform,setting of the Monopod platform,connecting a 200ft spool piece to a flange exiting the Monopod and finalizing the connection from the pipeline to the Monopod.
The pipe lay operations utilized the DSV Sand Island to perform ‘span mitigation’ on any length of unsupported pipeline over 30 feet long. Over 300 pallets of Sea Crete bags were used to complete the span mitigation,all installed while liveboating with the DSV Sand Island. Once the pipeline was secured pipeline pigging operations commenced to clean and flush the pipeline of any impurities,in preparation of the installation of the closing tie-in spool and pipeline hydro test. The closing spool piece was installed successfully using both the pipe lay barge and the Sand Island,at which time the hydro test was conducted.
Global provided personnel,equipment and resources necessary to locate the source of a stain and sheen discovered offshore of the Bolivar Peninsula. A mystery pipeline was located offshore and thought to be the source of the pollutants. Specialized equipment was brought in to locate the pipeline where came ashore. Once exposed,it was the shore end was hot tapped and connected to a vac truck to remove the pollutants in the pipeline. It was determined by the USCG that the pipeline and its contents were not a significant environmental threat at which time the pipeline was plugged,sealed and reburied.
In early March of 2012,the north fender on the Christy Lee oil platform,owned and operated by Hilcorp,experienced mechanical failure which caused it to plunge into approximately 80’ of water in the Cook Inlet. The fender structure mechanically raised and lowered with the tide to keep visiting tankers properly fended during calls. The timeline for a prompt solution was critical,as delaying the arrival of tankers to the Christy Lee would subsequently result in substantial monetary loss.
Global used sonar equipment to determine the exact location of the damaged fender and its orientation on the sea floor. It was concluded that there was sufficient water depth above the fender to allow vessels to continue to call at the berth; however,a temporary system would need to be devised in order to keep the platform operational.
Global developed a plan to install a temporary fender,which consisted of assembling a Flexi-float barge system that would encompass both of the north legs of the platform and span the gap left by the missing fender. It was evaluated by our internal engineering staff and was verified by a third party engineering firm. Global successfully mobilized,fabricated,and installed the temporary fender system in just over two weeks,three days prior to the arrival of the next scheduled tanker.
In July,Global remobilized to the platform to recover the sunken fender. Constructed by a steel framework with a timber face and concrete counterweights,the fender is trapezoidal in shape and measures approximately 96’ long,30’ wide,and 8’ tall,and weigh 175 tons. Divers rigged the fender for removal,taking advantage of the short slack tide intervals between 3.5 knot flood and ebb currents. Global subcontracted Pacific Pile & Marine to provide a 500 ton crane,mounted on the barge “Salvation”. The 175.5 ton fender was lifted from the seafloor and loaded onto the deck barge “Mr. Ed”. It was then transported to the ASRC dock in Nikiski,AK where it was offloaded onto the pier,flipped over,and set down for repairs.
Upon completion of repairs,the fender was transported back to the site for reinstallation. Once onsite,the “Salvation” lifted the fender and set it into a ‘stored’ position on the platform,allowing the temporary fender system to be dismantled and removed. The repaired fender,already secured to the platform,was then lowered into its permanent place and the concrete counterweights reattached. The repaired system has been fully operational since mid-October.
“Not an easy feat for a project team to consistently rise and meet numerous challenges over many months. A remarkable project executed remarkably well by remarkable people across the board” said Bo York,Hilcorp Facilities Engineering Manager.
Operating from Global’s DSV Sand Island,divers performed an underwater survey of the spud cans on the Spartan 151 Jack-Up rig. Divers removed the well cap from the well head stub and then assisted in the installation of a overshot riser.
Work was completed in the Cook Inlet,an area notorious for up to 30-foot tidal swings and zero visibility water. Water velocity was measured using a Doppler Current Profiler and limited bottom times to 30 – 45 minutes per tidal swing.
Chevron has two product transfer moorings (PLEM),approximately 2 miles offshore of El Segundo. Global provided diving services and topside support for the replacement of hoses,buoys,and connecting components.
Global mobilized a four point mooring system and a deep air diving system onto a landing craft. The vessel was then moored 40ft from the leg of a production platform and directly over a sub sea oil and gas manifold. This required anchor operations to conducted in 3 pipeline corridors and near an active production platform. The project involved installing several hot tap installations and disassembling and re-assembling various spool pieces of the subsea manifold,which aid in the ability to utilitize cleaning pigs in both lines from the platform. All this was done without interrupting flow thought the manifold or operations on the production platform that it is connected to. This project was performed in Cook Inlet that is typical has zero visibility and tidal current in the excess of six knots
Mobilized surface dive spread and light construction vessel(s) to conduct site clearance operations on a leaking well at Main Pass 25. Conducted diver and sonar (Mesotech 1000) survey of bottom within 100′ radius of well center. Identified and removed (3) 2″ pipelines and misc. debris from bottom in preparation of lift boat arriving on site to perform well abandonment operations.
Working aboard the D/B Superior Performance,we provided mixed gas diving support to WWCI for the removal of an 8-pile platform jacket. Diving operations were conducted to a depth of 218 fsw. Due to internal obstructions,divers utilized diamond wire saw tooling to cut two of the jacket legs. The remaining legs were cut utilizing underwater burning rod.
We provided surface diving support aboard the D/B Superior Performance to assist,as needed,with the removal of the topside package and platform jacket. Dive work was performed down to 105 fsw using standard surface diving procedures.
The platform was initially cut free from the jacket then the legs were cut 15 feet below mud line using explosives. After all the legs had been severed,the platform toppled onto its side so that the D/B Superior Performance could pick up the structure,approximately 710 metric tons,and set it on the materials barge for transport to shore and proper disposal.