Well Services & Oilfield Equipment

INTEQ Proves Application of New Technology in the Middle East

INTEQ has successfully proven a number of new technologies to the Middle East which are changing the way operators approach their business as this technology presents new ways of drilling
by Ally Law & Robbie Kellas

CoilTrak in the Middle East
Historically, coil tubing drilling technology has been considered a high risk option by many Operators in the past because there have been relatively low experience levels compared to that of conventional drilling systems. However, the Sajaa Gas Field, operated by BP, required a unique solution to boost production in a mature, low pressure gas reservoir.

The Coil Tubing Unit in Operation in the Sajaa Gas Field

The Sajaa Field is located in the Emirate of Sharjah, United Arab Emirates. The onshore gas field is a Thamama limestone reservoir with 300F BHT and pressures of around 1000 psi.

INTEQ introduced the 3˝ CoilTrak Bottom Hole Assembly (BHA) in March 2003 to initially re-enter and sidetrack three trial underbalanced wells, which would test the reservoir productivity with this new drilling technique.

The 3˝ laterals drilled were approximately 2,500 ft in length, with 30-40 deg/100ft build up rates to horizontal. Each well had 3 or more laterals drilled from a single casing exit. The well completion was ‘barefoot’.

A number of challenges arose from this project, particularly because the reservoir has a very low pressure and is considered ‘hot’. The high temperature affects the downhole motors and tool electronics while the nitrogen injected through the coil affects the rubber elastomer used in the motors.

The trial wells were completed and the productivity improvements were so successful that a further 19 wells have been drilled. Initial production increases per well are in the order of 3 - 5 times higher than the original rate.

The unique feature of using CoilTrak is that, during underbalanced drilling, gas can still be produced and sent to the gas plant thus minimizing production downtime. Also, the effect of exposing more lateral hole in the reservoir can be assessed immediately by using the pressure sensors on the CoilTrak BHA to identify production increases. Using this technology, there is no need to wait until drilling is completed to perform a well test.

Since the start of the campaign, the Coil Tubing Unit has drilled over 190,000 ft and BP is planning further candidate wells based on the project’s outstanding success.

The CoilTrak Bottom Hole Assembly
The CoilTrak drilling system used to drill the Sajaa field wells is the result of 10 years’ of Coiled Tubing experience combined with expertise in closed-loop drilling systems.

The CoilTrak system can be used in both overbalanced and underbalanced applications and is available in 2 3/8˝ & 3˝ tool sizes for thru-tubing and re-entry through 3˝ & 4˝ completions.

CoilTrak represents the world’s first electirc-line controlled BHA with bi-directional communication.

The modular CoilTrak BHA design is flexible to meet multiple customer needs and brings together some of the industry’s most advanced drilling and evaluation technologies including high torque X-treme motors and Ultra Slim Multiple Propagation Resistivity Logging While Drilling (LWD).

CoilTrak incorporates an electrically powered hydraulic orienting system that can be adjusted rapidly via a closed-loop for precise wellbore placement. It provides accurate measurements of downhole Weight On Bit (WOB) as well as annular and bore pressure. CoilTrak continuously transmits this critical data to the surface in real-time via electric-line.

It also equipped with an Electrical Disconnect and Circulating Sub (EDC). The EDC offers an emergency disconnect functionality with the ability to re-direct mud flow directly into the annulus — permitting greater flow rates for improved hole cleaning while tripping. To avoid damaging downhole vibration CoilTrak Vibration Stick-Slip sensor package offers the industry’s most comprehensive real-time monitoring of downhole drilling dynamics

AutoTrak Rotary Closed Loop System
Just seven years ago, rotary steerable drilling systems were considered an exotic new technology commanding what some considered exorbitant daily costs. With a limited number of systems available on the market the service was almost exclusively reserved for projects in high cost, high activity areas with short supply chains. Today, the picture is much different. The technology has matured with a wide range of benefits and added value accepted by the industry and tremendous improvements seen in reliability.

The Middle East has seen an increasing trend in more complex horizontal well profiles with tight well placement tolerances. This has been driven by the need to drive more production from each well drilled. AutoTrak is an enabling technology that delivers the well placement accuracy needed with reduced drilling time, and the respective reduction in well cost. For this reason there is increasing demand for, and utilisation of, the technology in the Middle East.

The question often asked is how the AutoTrak service differs from drilling a directional profile with a conventional motor directional assembly. Motor directional drilling techniques require the use of bent housing downhole motors to be oriented in the borehole and “slid” along the borehole without rotation of the drillstring to achieve a change in the wells’ trajectory. Periods of this “slide” drilling are interspersed with periods of rotary drilling to achieve the desired three dimensional wellbore trajectory. The AutoTrak system enables full three dimensional directional drilling control to be performed while drilling with continuous drillstring rotation from surface. No time consuming “slide” drilling is necessary. From the many offset evaluations that have been made it has been found that, typically, slide drilling delivers a rate of penetration of 50 per cent of that delivered while rotary drilling. Through use of “state of the art” electronics and hydraulics technology, the BHA above the bit is bent in the desired steering direction by three hydraulic ribs housed in a non rotating sleeve. The steer direction and curvature magnitude can be controlled by messages transmitted from surface through the drilling fluid, without interruption to the drilling process. The system is even smart enough to transmit a confirmation of messages received back to surface, thus eliminating potential steering errors from a corrupted message. In addition to being able to steer in three dimensions while rotating ahead the AutoTrak BHA also has a steering hold mode where the system will seek and hold a target inclination to within +/- 0.2 degrees. Imagine the benefits of being able to drill a truly horizontal section. With AutoTrak technology this is no longer a dream but is reality. There have been a multitude of horizontal sections drilled, with AutoTrak, where the true vertical depth has been maintained to within a +/- 0.3m tolerance over thousands of metres drilled.

The AutoTrak system is not just a drilling tool, it is a fully integrated drilling and evaluation system. INTEQ has fully integrated its range of “Best in Class” Logging While Drilling technologies into the system. Near bit inclination, dual gamma, propagation resistivity, annular and bore pressure measurement, vibration, direction, nuclear density/porosity and acoustic measurement can all be integrated in the system with measurement transmitted real time and stored on downhole memory. The benefit of LWD system integration is that the logging sensors are placed closed to the bit allowing for earlier geological interpretation and immediate corrective directional changes to maintain the wellbore in the optimum position in the reservoir.

The benefits of running the AutoTrak system with continuous rotation are numerous and not always obvious. To name a few there is, elimination of slide drilling, smooth gauge hole without ledges, improved hole cleaning from continuous rotation, continuous curve with less tortuosity, superior reservoir navigation with sensors closer to the bit and precise well bore placement. The technology has also been used to drill profiles that cannot be drilled using conventional motor technology. INTEQ believe that the technology should only be deployed if the system can add value to the customer. If there is no added value, then run conventional motor technology.

INTEQ has not stood still since introduction of AutoTrak. The third generation of the system is now available which incorporates INTEQ’s new OnTrak MWD system. Hole size capability has been grown from the original 8˝ size to a full range of sizes from 18˝ down to 5 7/8˝. Most recent developments have been the introduction of the 3-1/8˝ rotary closed loop drilling system for through tubing applications, that won the 2004 Pipeline “Best in Industry Technology” award, and the AutoTrak X-treme service that incorporates an integrated precontoured X-treme motor power section. The AutoTrak X-treme system is “the ultimate drilling machine” delivering the precision and benefits of the AutoTrak rotary steerable system with the drilling horsepower of the X-treme motor technology.

Ally Law is INTEQ Operations Manager, Northern Emirates and Robbie Kellas is INTEQ Drilling Manager, Middle East. Acknowledgements: Sharjah Petroleum Council, BP in Sharjah