Frank Hartley • Houston
Optimizing reservoir performance
StatoilHydro and Schlumberger Information Solutions (SIS) joint R&D-collaboration on technologies for production and process optimization, initiated two years ago, has resulted in solutions that will improve reservoir performance, the companies say.
StatoilHydro and SIS have developed and tested new technologies and practices to optimize StatoilHydro’s Water Alternating Gas (WAG) processes. Integration of proprietary and commercial technologies from Schlumberger enabled optimization of the WAG cycle with respect to all reservoir and surface constraints as well as business objectives. The resulting WAG schedule indicates potential for increased production, based on optimization that supports operational decision making. The new process incorporates real-time data and third-party technologies via PRODML.
“The technologies and workflows developed through our collaboration on this initial project have the potential to allow optimization beyond WAG processes to control and optimize a number of production management systems,” says Astrid Jørgenvåg, vice president research and development, increased oil recovery, StatoilHydro. “We are encouraged by work on the project thus far and look forward to promising results. Many of our fields use WAG processes to enhance recovery, and we expect material production increases from implementing similar work processes on other fields going forward.”
“This success represents a key milestone in achieving the ambitions of our collaboration with StatoilHydro. The joint pilot project delivers a material solution towards the realization of the digital oil field,” says Olivier Le Peuch, president of SIS. “We are pleased to have achieved such positive results and for the opportunity to test these technologies in an operational setting. We look forward to continuing our collaboration with StatoilHydro to deliver additional production innovations and accelerate industry adoption of these digital oilfield technologies.”
Other key deliverables developed by StatoilHydro and SIS include new “coarse” reservoir models that provide high resolution around the wells that support rapid reservoir simulation and automated real-time data management processes. Automated calculation and monitoring of key performance indicators, 24/7, allow field engineers to focus on diagnostic tasks and required actions.
Intelligent well completion system installation
Baker Oil Tools says it has installed an optimized natural gas lift intelligent well completion system in the Zuluf field offshore Saudi Arabia. The system combined the Equalizer optimized openhole completion with a cased-hole intelligent completion system controlling gas injection into production tubing to enhance heavy oil lift. The system uses the Equalizer ICDs with 4 1/2-in. (11.4-cm) MPas packers in the 6 1/8-in. (15.6-cm) openhole section. The upper completion used 7-in. (17.8-cm) feed thru Premier packers and HCM-ATM valve. The valves are placed facing the gas zone and hydraulically actuated to control lift gas injection. The completion provides isolation, mitigation, and control of water/gas production, enhanced oil production, and recovery with minimized well intervention.
Also used was the reservoir-optimized completion system that integrates well screen technology and an inflow control device to balance, or equalize, flow along the entire length of a lateral wellbore to ensure uniformly distributed inflow without cementing and perforating. The system achieves sustainable optimized production, including delayed water and gas coning, extended well life, increased recovery, reduced rig time, and reduced risk, the company says.
Combining these tools allows commingled production in wells that exhibit permeability contrasts, multiple zones, or varying reservoir pressure.
According to Baker, the system has the following advantages:
- Optimizes production and delays water coning in low-drawdown, high-rate horizontal wells
- Balances longitudinal flow along the entire length of the wellbore to ensure a uniform production or injection profile
- Equalizes pressure drawdown seen by the reservoir
- Provides more uniform reservoir depletion, increasing net present value.
Expandable casing patch
TIW (UK) says it has installed its first XPatch expandable casing patch system in the UKCS. Specifically, the XPatch system was installed on behalf of CNR International (UK) in the northern North Sea to provide a cost-effective method to isolate perforations and reduce workover costs. The system was installed in a well on the CNR’s Ninian platform 175 km (108.7 mi) offshore the Shetland Islands, Scotland, UK.
TIW (UK) has installed its first XPatch expandable casing patch system in the UKCS.
When CNR began researching alternative technologies for use in a forthcoming workover, its objective was to find one that would isolate two sets of perforations and convert the well from an oil producer to a water injector. In addition, CNR wanted to ensure that it would have the option of re-perforating one of the straddled zones at a later date, if required.
CNR selected the system for its simple design, metal-to-metal sealing capability, ease of installation, and cost, which was less than that of competing workover systems.
To achieve these objectives for CNR, TIW installed the system in a three-step configuration. First, three XPatch packers were set in separate trips to straddle the lower and upper perforations with 4 1/2-in. (11.4-cm) and 4-in. (10.6-cm) tubing. The system was designed to be flexible, allowing CNR to change from 4-1/2-in. (11.4-cm) and 4-in. (10.6-cm) tubing, as needed. All three system runs were installed successfully.
“Overall, the patch was set from 14,260 ft (4,346.5 m) MD to 12,627 ft (3,848.7 m) MD at an 80° well angle, which was extremely impressive,” says Rob Spears, completion engineer for CNR. “I am happy to report that the system met and exceeded our expectations in both performance and ease of deployment. The entire installation by TIW was flawless.”
CNR is planning to install another one on its Ninian development in the North Sea, and is examining others as possible candidates for installations.
The system can be run in any type of wellbore inclination, from high angle and horizontal to monobore and slim hole. It also has proven successful in high pressure and temperature downhole. The first system was tested successfully for geothermal application.
The system features an expandable packer to provide high pressure, gas tight metal-to-metal annular seals and a PBR designed to receive a metal-to-metal seal nipple. The expandable packer allows for close tolerance casing design, and can be manufactured to suit nearly any casing or tubing combination. The system uses standard API tubular sizes and material, including P110, L80, and CRA.
