DRILLING & PRODUCTION

Applying Schlumberger Oilfield Service's Maxpro technology, using the logging tool featured here, Mobil was able to record a memory production log while perforating a horizontal well in the northern North Sea.

Fugro designs riser monitoring system

Fugro Structural Monitoring has developed a new subsea instrumentation package (SIP) designed to provide real-time information on the performance of deepwater risers. The device was presented at a recent seminar in London by Mike Savage, Senior Instrumentation Engineer for Fugro Structural Monitoring.

The sensors include strain gauges to directly measure the loading on a component. These gauges can eliminate the need to make assumptions about the interaction between, for example, the motion of risers and the stresses induced by this motion. These gauges are pre-installed on the component before it is deployed subsea. But, if necessary, the gauges can be connected to the logger using an ROV mateable connector.

Accelerometers are used to measure the motion of the subsea component. Unfortunately, these tools have the drawback of being sensitive to the rotation in the gravitational field. So movements that also include rotation will be overestimated by the accelerometers. It is, however, possible to set an upper boundary for this error when it occurs. The SIP biaxial accelerometer package is independent of the logger. It is connected to the logger by a conventional underwater mateable connector or by an ROV mateable connector.

The SIP, configured for riser monitoring, uses eight strain gauges installed in a T configuration at 90° intervals to measure the axial stress and bending stress in two orthogonal planes. This allows for the monitoring of the total axial load on the riser. Changes in tension, applied by the vessel as well as the constant tension control system, can thus be verified. Constant currents introduce static loads and bending stresses into the riser. By measuring these stresses on a regular basis, an operator can evaluate the condition of the riser. Vortex-induced vibrations create dynamic stresses, that can in turn affect the integrity of the riser. The SIP can continuously calculate the statistics of these dynamic stresses and the stress cycle can be logged. By regularly collecting this data, an operator can evaluate the fatigue performance of the riser.

The accelerometers can be used to measure the rotation and motion of the riser in a quantified format that can be integrated into the definition of riser motion limits.

Power Plan software optimizes well design

Schlumberger GeoQuest has just released its version 3.0 of the Power Plan well design software package. The program assists drilling engineers with setting and meeting drilling programs by providing a common application that can be shared and accessed by all the members of the well design team. The common program allows engineers to share geological, geophysical, and petrophysical information. This sharing of data is said to reduce drilling program failures and allow engineers to make the most of large discoveries.

The program allows asset teams to produce real-time well plans, reducing cycle times and increasing efficiencies. There are a number of modules in the program that give engineers a variety of options to integrate in designing a drilling program. The various applications allow users to standardize their drilling procedures across the globe. Key modules in the system include the well design application that can generate a geometrical well plan for geological targets, DrillSAFE application, which offers torque and drag analysis hole cleaning and pressure losses for planned and actual well trajectories, Close Approach, an application to minimize anti-collision risks, Bottomhole Assembly (BHA) Editor, which allows engineers to quickly design a bottomhole assembly, Survey Editor to compare well progress with the proposed trajectory, and DataBrowser, which gives engineers easy access to drilling data. It's no surprise that the program is endorsed by Schlumberger-owned Anadrill and Integrated Project Management at the wellsite and planning office. The software is Y2K compatible.

Weatherford dives into new technology the old-fashioned way

Last month Weatherford announced it will take a more aggressive position in the area of intelligent completions. Its route to this new posture took the form of a merger between Subsurface Technology, a Norwegian-based company partially owned by Weatherford, BEI Technology, and DataLine Petroleum Services. The three will be rolled into one integrated intelligent completions powerhouse called Subtech Intl. The combined company will then participate in a joint venture with Weatherford's Completion segment, which will hold controlling interest in the new company. The goal will be cost-effective intelligent completion systems. Weatherford has also retained an option to buy out the company over the next five years.

So what has Weatherford put together with this merger? BEI designs and builds solenoids, motor drives, motor controllers, valves, pumps, single wire communication systems, and transducers for drilling, completion, and subsea applications. These tools are designed for pressures of 25,000 psi and temperatures of 400° Fahrenheit. Dataline Petroleum Services is a developer of proprietary data acquisition and analysis systems for reservoir evaluation, description, and management. These systems enhance field production economies. The company has also developed a proprietary delivery system for electronic downhole measurement systems that can install and retrieve monitoring packages in all types of wells, including highly deviated wells. These products have obvious applications in intelligent completion programs, but are also designed to optimize gas lift wells through surface monitoring and control at the injection point.

Subsurface installs permanent downhole monitoring systems and has designed permanent gauge installations using Dataline's delivery system. So with the stroke of a pen, Weatherford has not only entered the intelligent completion space race for a cost-effective solution, but does so while holding only 51% of the risk, not bad in a low oil price environment.

Mobil first production log while perforating horizontal well

Applying Schlumberger Oilfield Service's Maxpro technology, Mobil was able to record a memory production log while perforating a horizontal well in the northern North Sea. The logging tool was run ahead of 250 ft of coiled tubing-conveyed perforating guns to obtain virgin reservoir data. This new technology was an outgrowth of the Maxpro concept, which maximizes well productivity by integrating key personnel with new technology. Using a tool manufactured by Schlumberger Lee Tool and Dowell Coiled Tubing the technology delivers substantial savings in rig time, eliminates the need for a separate production logging run, and provides the first accurate reservoir measurement immediately after perforating.

The tool was first used on Mobil's Nevis Field in June of 1998. Mobil North Sea estimated running the Memory Production log in conjunction with the coiled tubing-conveyed perforating gun saved about a day's rig time compared to running a stand-alone production log. In addition, the results met the data acquisition objectives of Mobil and confirmed that perforation had been achieved.

These logging tools are built to withstand extreme downhole conditions and still report accurate information. Mobil reportedly has plans to use the technique in future North Sea production testing operations. The technique was used on the 9/13b-N4y well of the Nexis field in the Northern North Sea. The well began production in late November of last year. It contains reserves of 3.4 million bbl and 3.6 Bcf. It is owned by Mobil, 50%; Amerada Hess, 22.222%; Enterprise Oil, 22.778%; and OMV, 5%.