What's new in production

	Vol. 229 No. 4
VICTOR SCHMIDT, DRILLING ENGINEERING EDITOR, schmidtv@worldoil.com

Jetting takes a new turn. Jets are a common technology in the oil patch. According to the Wikipedia dictionary, a jet is “a coherent stream of fluid that is projected into a surrounding medium, usually from some kind of a nozzle or aperture.”

In drilling, the concentrated pressure of downward-directed jets is useful for loosening lightly consolidated rock ahead of the bit and for cleaning cut rock from the bit face. When perforating a well, it is the power of the shaped charge’s explosive jet, directed perpendicular to the well, that opens a connection between the wellbore and the reservoir. In well maintenance, sideward-directed fluid jets are useful for cleaning scale and other deposits from the inside of tubing and other in-well equipment.

Taking a cue from the growing use of horizontal drilling, a relatively new form of jetting is helping to extend the life of older vertical wells. This process combines the reservoir-connection power of perforating with the jetting power of in-well cleaning by jetting lateral holes perpendicular to the wellbore. A 3-yr-old company, Well Enhancement Services, LLC, is applying this technology to keep older wells operating by opening new flow paths through near-wellbore damage remaining from the original drilling operation or caused by fines migration after years of production. The new paths may also connect the wellbore to virgin pressure in untapped areas of the field.

The process is relatively simple. Using a coiled tubing rig, a hydraulically operated anchor and orienting device are lowered into the well and locked at the desired depth and azimuth. A drilling device is then inserted through the anchor to cut a 1½-in. hole in the casing. Once that tool is withdrawn, the jetting head is inserted and begins cutting a 1-in. to 2-in. lateral hole into the reservoir. While the forward nozzle cuts rock, backward-facing nozzles clean the hole and provide thrust to move the tool forward-out into the reservoir as much as 150 ft.

The anchor can be reset as often as needed to jet new openings into the reservoir. Using this process, a single trip in the hole can open multiple laterals and more productive hole than a squeeze and re-perforation operation, because of the greater penetration depth, and all in one trip.

Projects. Iran and CNOOC signed a development deal to produce gas from the North Pars Field. The $16 billion contract will begin the development of 48 Tcf of the field’s 80 Tcf in-place reserves. Targeted production is 1.2 Bcfd.

Total Gabon is redeveloping Anguille Field in the Grand Anguille Marine concession 12.4 mi offshore Port-Gentil, Gabon. Water depth is 98 ft. The concession is 100% operated by the company and was renewed for a 25-yr term last year. The field began producing in 1966 and generated 7,500 bopd during 2007.

The company plans to improve the oil recovery factor to 23% from the present 13% by drilling more wells in the field’s northern section, and then fracturing and waterflooding the reservoirs. By the end of 2008, a dozen wells will be drilled.

From 2009 to 2011, the company will install new infrastructure and decommission obsolete process units, drill 30 more wells and build an onshore plant for power generation, fluid treatment and gas compression. This will eliminate gas flaring and produced water discharges.

BP hopes to extract an additional 2 billion bbl of oil from Prudhoe Bay in Alaska by producing the field’s heavy oil reserves. Advanced water injection technologies are expected to increase recovery rates, and drilling horizontal wells with coiled tubing will reduce development costs.

The field has been in decline since 1989, dropping about 10% per year. It has produced 11 billion bbl over the last 30 years, and the company hopes to recover around 13 billion bbl of the estimated 25 billion bbl in place. BP (26%) operates the field with partners ConocoPhillips Alaska Inc. (36%), ExxonMobil (36%) and six other companies hold the final 2%.

Chevron Australia Pty Ltd will develop Wheatstone Field as part of a new LNG project. The field was discovered in 2004, in 650-ft water depths of the Carnarvon Basin, 90 mi offshore northwest Australia. Initial development will bring 4.5 Tcf of natural gas to shore. The onshore facility will have at least one 5 million-ton/yr LNG train and provide gas to the local market. Design studies, site evaluation and field appraisal work continue with front-end engineering and design to begin in 2009. Chevron Australia is operator with 100% interest.

Elf Petroleum Nigeria Deepwater Ltd. and partners plan to develop Usan Field offshore Nigeria, targeting first production for 2011. The field is in OML 138 some 62 mi off the Niger Delta in 2,461-ft water depth. Production will flow to a 2 million-bbl-capacity FPSO. Associated gas will be conserved through reinjection. Elf Petroleum Nigeria Ltd. operates with 20% along with partners Chevron Nigeria Ltd. (30%), Esso Exploration and Production Nigeria (Offshore East) Ltd. (30%) and Nexen Petroleum Nigeria Ltd. holding 20%.

New output. Gran Tierra Energy Inc. has completed the Costayaco-2 well in Costayaco Field, Chaza Block, Putumayo Basin, in southern Colombia and turned it to production. A series of five drill stem tests produced a combined maximum flowrate above 6,600 bopd. Oil production will be moved by 6-in. flowline to a loading facility. From there it will be trucked to Uchupayaco and enter a pipeline. The discovery well, Costayaco-1, is producing 3,500 bopd. Both wells are completed in the Caballos and Villeta T sandstone reservoirs and additional field development is underway. Gran Tierra Energy is operator with 50%, and partner Solana Resources Ltd. holds 50%.

Petroiran began producing 20,000 bopd from Azadegan Field in southwestern Iran. The field holds some 42 billion bbl of oil.

Mariner Energy, Inc. began producing 60 MMcfd of gas from Bass Lite Field in the deepwater Gulf of Mexico. The field is a two-well project in 6,750 ft of water in Atwater Valley Block 426. The field is tied back to the Devil’s Tower spar by a 56-mi pipeline. Full production capacity is expected later this year after topside facilities upgrades on the spar. According to the company, the steel catenary riser tying the wells to Devil’s Tower is one of the first structures designed to meet the new MMS storm criteria. Mariner operates with 42.2% along with partners EOG (19.05%), ERT (17.5%), Deep Gulf (15%) and Eni (6.25%).