JPT

Vol. 59 No. 8

August 2007

Technology Applications

Dennis Denney, JPT Technology Editor

Lightweight Subsea Intervention

Expro International Group has announced commercialization of its AX-S lightweight subsea wireline-intervention system (Fig. 1). The system is designed to diagnose production problems and improve production from subsea wells. The goal is to reduce the reserves-recovery gap between subsea wells and those managed from platforms. The system comprises well-control, tool-storage, and wireline-winch packages, all contained within pressurized housings. This rigless deepwater intervention system will be able to perform several services without bringing the tools to the surface for changeout. Up to eight wireline tools can be stored in the storage package and can be changed out at the seabed within the system. All tools (logging, perforating, tool setting, tractor, and others) will be preloaded into the storage package before lowering the system to the wellhead. A remotely operated vehicle (ROV) will be used to install the system on the production tree. System control will be through its own umbilical from a computer on the surface vessel, which can be off location. The system will use electrical and hydraulic controls to power and control the system. The stuffing box is eliminated because the winch is part of the system on top of the production tree and under wellhead pressure. The result is that no hydrocarbons are exposed to the sea. The winch will contain 25,000 ft of 9/32‑in. monoconductor wireline. The system will have complete ROV backup.

For additional information, visit www.exprogroup.com.

Fig. 1—Artist’s impression of Expro’s Deepwater AX-S System installed on a template (not to scale).

Real-Time Viscosity

The Brookfield Engineering Laboratories’ TT-100 in-line viscometer (Fig. 2) is used for continuous real-time drilling-fluid-viscosity measurement. This instrument provides data that enable determining real-time annular hydraulics. This information can help prevent well-control problems. With Couette geometry, the instrument provides a way to create and communicate a new level of data for rig operators and drilling-fluid suppliers. The viscometer, combined with a data-logging system, can provide real-time yield-point, plastic-viscosity, and apparent-viscosity information, enabling continuous power law and other calculations. Typically, the instrument mounts in line, supported by connections, in a bypass from the main flowline. The measurement zone is protected from the main flow, allowing accurate, repeatable measurement under variable conditions. It can be operated at shear rates of 511 sec-1 as required by the American Petroleum Institute.

For additional information, visit www.drillingfluidviscosity.com.

Fig. 2—Brookfield TT-100 in-line viscometer.

Casing Inspection

Halliburton’s fast circumferential acoustic scanning tool, FASTCAST, provides measurements for cement evaluation or pipe inspection at speeds up to five times that of previous tools. The data-acquisition system is programmable at the wellsite to optimize for speed on the basis of the customer’s requirements and borehole characteristics. The tool can provide complete borehole coverage in both open and cased holes. With a vertical (horizontal) resolution improved up to 12 (3) times in pipe-inspection mode, the tool can provide 100% coverage of casings up to 20 in. in diameter. Factors that influence the logging speed are horizontal coverage, borehole size (smaller holes are logged faster), and vertical resolution (lower resolution implying higher speed). In cased holes, ultrasonic pipe inspection and cement evaluation can be obtained simultaneously. In cement-evaluation mode, the tool is used primarily to determine cement bonding and to image channels in the cement directly behind casing. It also can be used to measure casing characteristics such as thickness and internal and external diameters. Images can be oriented either to tool body or to the high side of the hole in any operating mode. When combined with a cement-bond log, the cement evaluation can be acquired between 60 and 120 ft/min (depending on well conditions), which is possible because of the use of the company’s proprietary processing. In pipe-inspection mode, the tool is optimized to provide hole coverage suited to the application. The vertical resolution can be the traditional 3 in. but can be refined down to 0.2 in. Similarly, the number of waveforms per scan can be adjusted to provide full horizontal coverage down to the beam footprint of the transducer. Once optimum coverage is identified, a job-planner program allows the engineer to acquire data at the maximum logging speed suited for the application.

For additional information, visit www.halliburton.com.

Fluid Additives

Benchmark Energy Products will distribute EcaFlo equipment and fluids (anolyte and catholyte) to the oil and gas industry. These fluids are for managing bacteria, viruses, fungi, and other microorganisms in fracturing fluids and the water produced in conjunction with oil and gas. The anolyte fluid is produced in the anode chamber of a proprietary electrolytic cell, by passing an electric current through the cell containing a very weak saltwater solution. The pH of the produced anolyte is controlled at 6.2 to 6.5 so that the predominant specie of available chlorine in the anolyte is hypochlorous acid. Hypochlorous acid is recognized as a powerful antimicrobial agent, yet is not harmful to humans or animals.

For additional information, visit www.benchmark-research.com.

Seismic Technologies

Schlumberger announced the release of three new technologies to complement its WesternGeco Q-Technology services. For offshore surveys, Dynamic Spread Control is an automated vessel-, source‑, and streamer-steering technology. This technique enables repeatability for 4D studies and increased accuracy in over/under and rich- and wide-azimuth surveys. For onshore surveys, the Desert Explorer DX-80 vibroseis unit was developed specifically to complement the Q-Land integrated acquisition/processing system. This vibroseis unit generates an 80,000-lbf peak hydraulic force with low distortion across a broad bandwidth. The MD Sweep design enables a vibrator to produce more-energetic low frequencies than a traditional sweep-design approach. Historically, lower frequencies in the seismic bandwidth have been over-looked because conventional geophones attenuated them. Field tests demonstrated that this technology could extend the bandwidth of the vibrator operating at full power by half an octave.

For additional information, visit www.westerngeco.com.

Oil-in-Water Monitor

The Roxar Oil-in-water monitor (Fig. 3) is an in line, oil-in-water monitoring technology that provides real-time information about the amount of sand and oil in produced water. The monitor uses ultrasonic back-scattering technology with pulse-echo measurements to measure dispersed oil droplets and sand particles. The monitor can be fitted on pipes larger than 3 in., can be inserted and extracted without shutting down the process, and is suitable for installation in hazardous areas. A highly focused acoustic signal is -transmitted directly into the produced-water stream in the focal region. Individual solids, oil droplets, and gas bubbles will reflect the acoustic energy, and each reflected signal holds particle-specific information. From the large number of measurements, the monitor calculates full-size distributions for oil and sand. From the size distributions, corresponding concentration values are calculated. The method is based on physical models and feature-extraction techniques. The large number of direct measurements enables accurate results, even in the extremely low-size and ‑concentration range. The monitor enables optimizing production through the monitoring and controlling of solids and oil droplets in reinjection water, both debottlenecking and increasing the capacity of water-treatment facilities, and reducing the amount of oil emissions into seawater by monitoring oil-in-water discharge accurately.

For additional information, email roxarinfo@roxar.com.

Fig. 3—Roxar Oil-in-water monitor.

Plotting Software

Techplot has released its Techplot RS 2007 Release 2, an integrated plotting tool designed specifically for oil- and gas-reservoir modeling. This release has the ability to compare well data on a bubble graph. It also has a new plot type for creating complex x-y plots and new functionality for controlling the color legend for grid variables. The software was developed for reservoir engineers and allows data from multiple sources to be loaded and displayed in graphics ranging from x-y graphs to complex 3D renderings. This software manages data from multiple reservoir-simulation applications, as well as observed data such as production rates and formation tests. The redesigned bubble-plot functionality includes a new option to display delta bubbles that represent the difference between two data sets of well properties (e.g., the results from a simulator run and the observed data). Users can specify x-y mapping interactively for each frame on a page and can create multiple pages of graphs, which they can step through and edit at any time. New controls for the grid-variables color legend allow users to specify the range for each variable and to enter the number of levels for dividing the color legend and the number of labels to display on the legend. Users can select the cells to include or exclude individually or as a group (defined by a polyline, rectangle, or circle). Users can select two solution files interactively for one reservoir grid, then create a file that contains the difference between the solution values at each matching timestep to be viewed in the plotting software.

For additional information, visit www.techplot.com.