How New Technology Offers One Solution To Low Oil Prices
There is no doubt that current oil prices are presenting a difficult challenge to the industry and stretching people' creativity when thinking of solutions. Slashing costs, which means people and equipment, makes for more dramatic headlines but simple efficiency gains also have their part to play as the industry adjusts to the new reality.
Extracting more from existing wells has an immediate effect on efficiency. A clear example is the migration of the shale operators to the most productive wells in the field that has seen production per well increase at the same time as the number of wells that are drilled dramatically decreases. Another way of increasing efficiency is to apply technological solutions that access more of the reservoir but from an existing wellbore or which provide more detailed well information which can optimize the amount of hydrocarbon extracted.
Two technologies which fit the bill are directional coiled tubing drilling and permanent monitoring with fiber optic sensors. Both of which were in their formative phase in the early 1990’s but which have now developed into established products.
Accessing more of the reservoir with Directional Coiled Tubing Drilling
The current sub 40 USD/bbl oil market is putting a huge amount of pressure on operators to maximize the returns on current assets and to minimize the operational and financial risk associated with accessing these reserves. Re-entering old wellbores and sidetracking to access new reserves in known reservoirs is a low risk way to increase cash flow and return on investment from an operators assets. Directional Coiled Tubing Drilling (DCTD) is a well-established technology for doing this. Over the last three decades significant advances in equipment reliability, metallurgy and the experience levels of personnel has made DCTD a very attractive method of re-entering wells. Operators and service companies can focus on delivering productive wells effectively rather than dealing with technology issues.
DCTD can also provide significant that are applicable to drilling new wells or for re-entry. One of the most significant advantages of DCTD is it’s suitability for – underbalanced drilling allows the formation to produce oil and gas while drilling which means that the formation is not damaged like it is in overbalanced drilling. This reduction in formation damage can lead to significant increases in the amount of oil produced from each well drilled.
Figure 1 - Example wellpath for a sidetracked well. The long horizontal section
increases the production of the well over that of a vertical well.
More complex operations such as multi-lateral branches, extension and larger hole sizes are being drilled, enabling operators to make the most of their existing reserves. Consequently, directional coiled tubing drilling BHAs are being deployed around the world in order to drill new wells and extend previous ones by accurately targeting pockets of oil and gas reserves. Successful drilling programs are ongoing in Saudi Arabia, Alaska and Australia as well as other places.
The Introduction of COLT and POLARIS
Ten years ago, AnTech combined mechanical, electronic and software engineers and the and DCTD Bottom Hole Assemblies (BHAs) were created. The COLT Measurement While Drilling (MWD) BHA is a 3.192” OD BHA which is steered magnetically. The POLARIS MWD/GWD BHA is a 5” OD BHA which is steered either using magnetic sensors or a gyro. The BHAs are run on Coiled Tubing with 7 conductor electric line inside the tubing (also known as e-coil). The connection to the BHA from surface via a cable allow real-time telemetry and very high data rates. This capability allows for extremely accurate wellbore placement thereby increasing the chance of success on a project.
The two BHAs are short – under 40ft in length – which allows them to be deployed above the blow out preventers. This means that the well can be closed in while the BHA is made up to the coil and pulled into the lubricator. The well is then only opened up once the complete pressure control envelope in place. This increases the safety of operations and allows for simple underbalanced deployment. The short BHA length also has the advantage of minimizing the distance between the bit and the survey tool meaning that the directional control is improved further.
Both BHAs recently demonstrated their technical and commercial viability in two recent projects. POLARIS was used in France to sidetrack a well and drill a new lateral to increase production from the well. COLT was used in the Appalachian Basin to sidetrack a vertical wellbore and drill a lateral to turn a dry well into a producer. Both projects were a success with the operators achieving their objectives.
Distributed Sensing with Fiber Optic Monitoring
Also in the early 1990’s permanent well monitoring started to become more widely used (price of oil at the time, $20). The systems in those days were electrical and provided point measurements of usually pressure, temperature and flow. These days, in addition to the electrical systems which have become cheaper and more reliable, a new generation or fiber optic sensors is available to operators. The nature of fiber optic sensor systems is that they can provide distributed measurements which means that if they are measuring a parameter such as temperature, the temperature can be recorded with a 3ft precision along the whole length of the cable. This provides a whole new dimension of visibility about the wellbore that was previously unavailable. Pressures, acoustic and seismic signatures can all be measured in this way.
When these fiber optic cables reach the surface, they need to be terminated and connected to the surface instrumentation. Keeping optical losses to a minimum is vital to ensure that the resolution of the sensors is not affected. Delicate optical fibers, no more than the thickness of a human hair present a challenge in an industry where a pipe wrench is a more common tool than a fusion splicer. As a result a whole new range of equipment has had to be developed to adapt super-precision assembly to the rugged environment around the well head. This is also a hazardous area environment were electrical equipment needs to conform to conform to international standards for use where explosive gases are present such as IECEx.
AnTech’s dedicated products division, is an expert and well-known supplier of Wellhead Outlets and has developed a whole new range of fiber optic products which continues to grow. Demands for equipment that can safely allow fiber optic connections to downhole gauges in high temperature and pressure environments can now be met.
AnTech has recently launched the Type-F range of fiber optic wellhead outlets which incorporates their proprietary feedthrough that is designed to API 6A standards. Additionally the Type-F range allow for excess fiber to be stored so that multiple attempts can be made at connecting, whilst protecting the delicate fiber. With in-house design engineers, AnTech can also deliver standard and customised fiber outlet solutions for most wellhead connections and downhole cables.
Figure 2 - AnTech's Type-F Wellhead Outlet
Furthermore, design and development on an explosive atmosphere certified Fusion Splicer has begun and this will in turn help complement the Type-F wellhead outlet range by safety splicing delicate fiber at the wellsite.
Change can be a challenge in an industry that is historically cautious about change. And this is for a good reason, the risks of failure with new technology are high so the benefits need to be significant. But the abrupt re-set of the industry means that doing the same thing and expecting a different result is not an option. and are two technologies that have shown their worth over time and now might just be the time when these innovations may offer an economic solution in a turbulent and challenging market.
Published in Hart's E&P Magazine - March 2016
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