A new full well stream pump has increased production by more than 700 b/d on Nexen Petroleum's Eugene Island block 257 D platform, resulting in a gas surplus from wells that previously had to borrow gas for artificial lift. The RamPump, a hydraulically operated, plunger style, multi-phase pump by Weather-ford International Inc., was installed in March 2001. The pump has been operating continuously in parallel with a gas lift compressor to lower the backpressure of four wells producing to that platform.
Prior to installation, the wells produced into a platform separation system operating at 230 psi – the pressure needed to move the liquids approximately 1.5 mi downstream to platform C for final separation. Evaluation indicated that increased production rates could be obtained by lowering the pressure to 50 psi. Additionally, since conventional types of pumps in the past caused sand or gas-locking problems and emissions normally associated with having to degas the liquids, this pump was a prime candidate due to its handling capabilities.
The RamPump, a hydraulically operated, plun-ger style, multi-phase pump by Weatherford, was installed at Eugene Island block 257.
The pump was moved offshore in March and installed. Start-up was quick, and pumping began without difficulties. The pressure was lowered to approximately 45-55 psi, and the pump began moving the liquids with entrained gas to platform C. The free gas from the platform separator was diverted to the compressor, where it was recycled for gas-lifting the wells. Nexen is now evaluating other properties that may capitalize on this method.
Additional installations are planned, with units of varying capacity – from 10,000 boe/d to 150,000 boe/d – and functionality at discharge pressures as high as 1,250 psi. Special models can increase the discharge capability to well over 3,000 psi. The ability of the pump to manage the full well stream across a broad pressure range has led to expanding the role to include well kick-off and well stimulation applications, unlocking production potential from wells that have been shut-in, or have had difficulty responding to standard stimulation practices.
An alternative to conventional methods of cleaning the interior of tubes and pipes has been introduced and patented by AIMM Technologies Inc. (Aimmtech). According to the company, the hydrokinetics process, based on sonic resonance, offers a more efficient, cost-effective, ecological, and safer method of clearing fouled pipes and tubes as compared with traditional methods such as hydro-blasting, baking, chemical cleaning, drilling, or brushing.
The technology is based on the induction of "sonic resonance" into the cleaning water stream or medium. Sonic resonance travels through the water stream (medium) and safely transfers to both the tube and the fouling material. Because of the different compositions of the tube and the fouling material, they resonate at different frequencies, breaking the bond between them and allowing the fouling to be expelled. Fouling material is generally seen extruding from the end of the tube in large snake-like pieces rather than particulates, as in conventional hydro blasting.
The process can often perform work that cannot be accomplished by hydro-blasting, lancing, drilling, baking, acidizing, or other methods, the company says. It works best in situations where traditional cleaning methods fail: U-shaped tubing or piping, tight workspaces, and totally blocked lines. In addition, the process can clear lines and/or pipe that have 45°, 90°, and 180° bends, regardless of whether the line is above or below ground. Process units achieve optimum service for a longer period of time because tubes and pipes are cleaner, thus extending the time between costly shutdowns.
Record bit run
A record-breaking bit run with the Weatherford BBL technology was achieved for Shell UK Exploration and Production. A polycrystalline diamond compact bit was run on well PL08 in the Barque field, in block 48/14 in the UK southern North Sea. The 8 1/2-in. BB657XT bit, drilled 6,806 ft through the Zechstein Supergroup to TD at an average rate of penetration of 62.4 ft/hr in one run. In conjunction with a 6 5/8-in. Neyrfor FBS turbine, all directional objectives for the well were fulfilled.
This is the longest distance achieved through the Zechstein sequence with a single bit in the southern North Sea gas basin. The Permian age Zechstein group is a long sequence of inter-bedded halites, anhydrites, and hard dolomites, which require a unique combination of bit aggression and durability to optimize drilling performance and to complete the section.
The latest run builds on the previous record run of 5,319 ft on a single bit achieved with the 8 1/2-in. BB657 bit style on the Barque PL06 well. The relationship with GlobalSantaFe, responsible for southern North Sea well engineering on behalf of Shell, enabled the development of the BB657 bit design with features specifically suited to the application.
The process has improved the performance over the course of the Barque field development since the first BB657S run on the Barque PL04 well made 3,435 ft at 49.3 ft/hr in 1995. The collaborative approach with Shell and GlobalSantaFe in the southern North Sea has enabled improvement of bit design, stretching the performance envelope.
First corrosion-resistant expandable
Nederlandse Aardolie Maatschappij B.V. and Enventure Global Technology have successfully installed the world's first corrosion-resistant alloy (CRA) solid expandable tubular (SET) system in a well located in The Netherlands. The cooperative effort among Shell International Exploration and Production B.V., NAM, and Vallourec Mann-esmann (VAM) resulted in the expansion of a 6-in., 13% chrome (Cr13) cased-hole liner inside 7 5/8-in. casing. Proprietary gas-tight CRA expandable connections and tubulars, jointly developed by Shell and VAM, were also used for the first time in the SET system installation.
The increased durability of Cr13 tubulars in corrosive environments will dramatically reduce the limitations on how deep a well can be drilled, according to the companies.
The 710-ft CRA cased-hole system, installed in a gas well in the Wanneperveen field, was expanded in 7 5/8-in. 39-lb/ft, 33.7-lb/ft, and 29.7-lb/ft casing, with elastomer seals in each section. Combined mechanical and hydraulic forces used to expand the chrome pipe by 9.8% averaged approximately 92,000 lb. Post-expansion inside diameter of the 6-in., 18.6-lb/ft CRA liner was 5.92 in., compared to a pre-expansion diameter of 5.39 in., while post-expansion burst and collapse were estimated at 7,000 psi and 4,000 psi, respectively. Overall liner length was reduced from 730 ft to 710 ft as a natural result of the expansion process.
The test is in preparation for the installation of a 5,500-ft expandable CRA system to re-line production casing so it can be used as the production conduit. The ability to expand Cr13 tubulars will allow far greater production deliverability from highly corrosive wells.