October 2006 ///
Drilling ultra-deep wells places significant requirements on the drillstring. Lengthy drillstrings lead to high tensile loads, which lead to slip-crushing, hoisting issues and drill pipe collapse capacity concerns at the blowout preventer. BOP shear rams may also have difficulty cutting today’s high-strength, high toughness drill pipe. BHA connection failures pose greater risk and cost at ultra-deep well depths.
This article analyzes the many challenges of drillstring designs, specifically for ultra-deep drilling. It presents emerging drillstring technologies that are expected to increase depth capability for continued deep drilling advancement.
DEEP DRILLING TREND
Deep drilling trends in the US and throughout the world are increasing. Since 1995, the number of US wells drilled, greater than 15,000-ft TVD, has more than doubled, The number of annual, active US rigs drilling greater than 15,000-ft TVD has nearly tripled. The number of high-pressure, high-temperature (HPHT) completions in the US has nearly tripled since 2000.
Based on experience gained in a long career, the author presents his favorite five gripes about the accuracy of technical information, as he makes his plea for more professionalism in drilling.
With a large percentage of the world’s known hydrocarbon reserves located in carbonate reservoirs, the push to increase production has revealed a need to improve oil saturation calculations in carbonate transition zones.
Numerous attempts have been made to modify the famous Archie equation’s a, m and n parameters to derive a saturation that more closely matches core saturation measurements, but these have met with limited success. Rather than continue this approach, a different model of the pore and fluid distribution has been proposed and field proven. The latest model is to change the saturation evaluation to a volume measurement and acquire that measure prior to significant invasion. Adding sigma measurement to LWD enables this. Using this approach, recent field examples show more hydrocarbons than indicated by resistivity or pressure gradient methods.
Carbonate transition zones exhibit resistivity and pressure gradient phenomena that respond like water zones to resistivity and pressure gradient measurements.
During the 1960’s, US land operator GHK began pioneering efforts to explore the deepest areas of the Anadarko Basin. By the late 1970s, the company had extensive experience in deep drilling and had accumulated over 400,000 net lease acres. In 1981, GHK entered into a joint venture with Mobil to drill a series of ultra-deep exploration wells. One of those wells was the Robinson 1-1 well.
The expansive Hunton natural gas field was thought to be split into two distinct producing zones at 23,000 ft and around 29,000 ft. In 1981, drilling began on the Robinson 1-1 well near southwest Elk City, Beckham, OK. By late 1982, the well reached 29,241-ft TD in the Devonian Hunton formation. It was then cased to 28,581-ft MD.
When gas economics turned negative in 1983, the deep Hunton well was plugged and abandoned, to wait for higher gas prices that would make re-entry cost effective.
At one level, the business case for gender diversity is as simple and as obvious as not arbitrarily discarding resumes without looking at them. As the hiring executive, you would be outraged at the lost potential if half of your applicant pool were arbitrarily discarded. The price of ignoring gender diversity is high, and it is measured in lost potential, lost opportunities and lost credibility. It is so obvious that there seems little reason to discuss it in 2006, more than 30 years after women began entering the workforce in large numbers. Yet, women are still under-represented in the oil industry compared to other industries.
While women make up more than 46% of the overall US workforce, they are only 22% of the petroleum and coal production industry and less than 21% of the refining industry (see figure). This includes all levels; the percentage of women in management, especially in engineering roles, is even smaller.
More than 40% of horizontal wells encounter major unexpected structural geologic/ stratigraphic changes during drilling that result in wells being sidetracked or serious consideration given to this option. As the hole angle increases and measured depth of bed thickness becomes more distorted, correlation between predicted and actual geologies proportionately increases in difficulty.
Therefore, real-time correlation must be systematically planned in advance, and must identify key marker beds and decision points. Failure to recognize individual parameters within the reservoir of interest, such as stratigraphy, rock type, reservoir geometry and structure, fluid content, and formation petrophysical properties, can result in costly mistakes.
As witnessed during planning and executing horizontal drilling programs in the Hawiyah and Haradh fields of Saudi Arabia, the industry’s ability to drill horizontal and high-angle boreholes has improved with the aid of proper geological planning, execution and evaluation.
A potentially inexpensive method, Microbial Enhanced Oil Recovery (MEOR), may prove useful and economical. Most conventional oil recovery processes are only able to retrieve from 15 to 50% of the available oil in the reservoir. The utilization of this technology can extend the average well life without increasing excessive lifting costs. As MEOR effects chemical changes in the reservoir, it is an environmentally compatible method of carrying out tertiary oil recovery. MEOR will become increasingly economically feasible as genetic engineering develops more effective microbial bacteria that may subsist on inexpensive and abundant nutrients. This article will review how the microbe works to improve oil recovery, evaluating the potential gain in oil production versus treatment cost, and identify applications and potential advancement of MEOR.
Recovering oil usually requires three stages. Primary recovery typically recovers 10 to 35% of a reservoir’s oil-in-place. Secondary recovery, which most often involves waterflooding, can increase recovery by 20% or more.
Recent experimental works have demonstrated the benefits of adding nanofibers to microfiber nonwoven filter media. In this work, single fiber efficiencies and drag are applied to model filter performance for steady-state coalescence of oil drops from air streams. The model results show the same trends as observed in the experiments, namely that the addition of small amounts of nanofibers significantly increase the Quality Factor. New results from the model and experiments show that there is an optimum amount of nanofiber.
Recent work shows improved performance of nonwoven filter media by the addition of small amounts of nanofibers.1 The purpose of this work is to determine whether there is an optimum amount of nanofibers to add to the filter media.
Our approach to this project is to model the filter using single-fiber capture mechanisms and single-fiber drag forces.
Well-designed software is critical for a growing E&P company like Wichita, Kansas-based Vess Oil Corp. There is software available for all of the technical aspects of operations, including complex data analyses and geophysical interpretations. There are also accounting and back-office solutions. But there is very little available to tie the activities of people and the organization together, and managing projects of the many companies and partnerships in which Vess participates.
Vess describes each of the projects as a juggling act, where there are many different balls (tasks) in the air. The firm wanted to organize and manage the tasks better to gain productivity. Management needed capabilities for:
• Defining and scheduling projects and tasks, team members, and job responsibilities.
• Coordinating employees and contractor activities, regardless of whether they are in the office, at a well site or at any other location.
• Helping all project team members share information (communication and collaboration).
The anticipated debut of newly manufactured units has begun. This increased capacity is the primary factor impacting this year’s dynamic US rig fleet, according to the 53rd annual ReedHycalog Rig Census. The numbers of available rigs in the US, Canada, global offshore mobile, and international land rig markets all rose this year. Strong commodity pricing helped to put these new units and many previously idle rigs to work, and fleet utilization rose in most markets.
ReedHycalog continues to work closely with RigData to compile the US census, Nickle’s Rig Locator to monitor Canadian activity, and ODS-Petrodata to summarize the global offshore mobile rig fleet. The international land rig fleet will also be examined for the second year, as we expand our scope and refine our methodology to get a better picture of the global rig market.
The few, the proud, the drillers. In the past, leadership came from a group of individuals that proved their character though trials that would shame most of us today. We are simply not up to their standards. They were tough; really, really tough.
Drillers in our day personify the attributes of this group better than most. They stand silently on the rig floor in the rain, sleet, snow, mud, dirt and grease, exposed to objects falling from the derrick and abuse from self-centered bosses. They persist in all types of circumstances without argument or complaint. Their bodies and their character are staunch. They are truly tough; really, really tough.
So, what motivates us in the drilling industry? Is it the money? Hardly. We could probably make as much working for a chain store or changing oil.
A question of arrogance. Global warming is to writers as Bill Clinton was to late-night comedians. Here’s my take on how it works.
On the mythical Anti-Earth – that’s the planet that orbits opposite Earth on the other side of the Sun, so it can never be seen – everything is the opposite from what it is here, except human nature. On Anti-Earth, the problem is that a new ice age is approaching.
Almost all of the glaciers there have been growing for the past century or so, and the trend seems to be accelerating. There are pictures showing where the glaciers were a century ago, and video showing buildings slowly being crushed by the advancing ice. There are records of town meetings, where the subject was how soon and how far the town should be relocated, and these meetings continue to the present day.
High oil prices and the North Sea. High prices have had a considerable impact on North Sea oil and gas activities, with investment picking up noticeably. Other sources of encouragement are new discoveries and a reappraisal of prospectivity in Norwegian and UK waters. Exploration activity is rising, but it is hampered by a rig shortage. In any case, high oil prices, together with enhanced knowledge of the geology; progress in management, organization and technology; and a stable regulatory environment, give new life to an oil province hitherto considered mature and in decline.
In Norway’s 19th Licensing Round, in late March 2006, 17 companies were offered participation in 13 new production licenses. The smaller and medium-sized oil companies that have risen with geological maturity in the US Gulf of Mexico, and in UK waters, are now active in Norway.
Beyond SAGD. Canada’s heavy oil sands are producing and encouraging the industry to experiment with new ways to get more oil. Steam Assisted Gravity Drainage (SAGD) is the common production technology applied, but others are under development or in use.
However, there are some problems. SAGD uses lots of water and natural gas to generate steam. This is spurring research into new production forms that use fewer resources. While this editor has no direct experience with any of these efforts, he submits them to the reader for their consideration.
The Petroleum Technology Research Centre in Regina, Saskatchewan, Canada, is conducting research via Joint Implementation of Vapour Extraction (JIVE). This program is a collaborative effort between PTRC, Alberta Research Council, Saskatchewan Research Council, Nexen, Husky Energy, Canadian Natural Resources Ltd. and other heavy oil producers. The project is testing the effectiveness of a proprietary vapor extraction process, Vapex.
Microbial mystery. The non-biological origin of simple hydrocarbon gases is well accepted. Vast amounts of methane and ethane on Saturn’s moon, Titan, are believed to have formed in the upper atmosphere. But there is a connection to surface geology. Ponds and lakes (although not oceans) seem highly probable, as do subsurface reservoirs. Whether this has a corollary to Earth’s history is unknown.
Other theories hold that microbes could create hydrocarbons in commercial quantities as part of various processes that are mostly not understood. It is now believed that biogenic methane (as opposed to thermogenic), for example, could comprise as much as 20% of commercial natural gas reserves. It could be even more, with the discovery that some coalbed methane is not ancient, but instead, the result of more recent biological processes. The problem is that there are billions of microbes, and the food-metabolism-waste processes that are possible are vast.
News & Resources
Lankelma Marine SI acquired Andrews Survey, Great Yarmouth, to become Lankelma Andrews. Added to Lankelma’s CPT and sampling capabilities, Andrews brings extensive experience with geophysical data acquisition, interpretation and reporting, and a significant history of high-quality multibeam surveys and precise positioning and topographic services. The new company will have bases in the UK, The Netherlands, Singapore and Azerbaijan.
Whittier Energy Corp. has acquired three oil and gas fields in Mississippi and Texas from Imperial Petroleum, Inc., for $10.6 million. The company acquired 17 operated producing wells, minor interests in four additional non-operated producing wells, and four shut-in operated wells awaiting workover.
World oil supply fell 400,000 bpd in August to 85.8 million bpd, due to decreased output from Iran, Saudi Arabia and the North Sea. This comes after IEA revised July’s oil supply upward by 730,000 bpd, reflecting higher OPEC, North Sea and FSU output. In September, oil prices hit a five-month low at less than $70/bbl, while gas prices decreased by over 30%. IEA predicts that global crude will become heavier and sweeter between now and 2011.
As Argentina faces its ninth year of declining oil production, concerns abound that the country will become a net oil importer. In first-half 2006, Argentina’s oil exports fell 59%.
The World Rig Forecast – Short Term Trends predicts that despite new and reactivated rigs joining the fleet, worldwide offshore rig demand will continue to exceed supply over the next year, while current utilization hovers around 93%. Overall US rig count is at its highest level since early 1986.
Marine magnetometer for oil and gas surveys
Geometrics Inc. announced the G-882, a marine magnetometer for shallow and deep oil and gas survey applications. Others uses include pipeline mapping, geologic surveys, oceanographic research, and marine environmental investigations. The instrument features high sensitivity, low noise, and high sample rates for detecting small objects (0.004nT/ Hz-RMS at up to 50 samples per second), a compact and stable design that allows deployment and operation by one person, automatic hemisphere switching, and worldwide operation. It comes with processing software that provides data profiling or contouring for in-field or laboratory analysis. Its cesium sensor is designed for extreme reliability and ruggedness, and never needs recalibration or factory realignment.
The G-882 is designed to operate in any direction from small ships in shallow or deep water, and weighs only 50 lb with its 200-ft cable and sensor.
Knight Well Services, a division of Knight Oil Tools, named Bobby Crockett as general manager, where he will oversee all day-to-day operations for the division. Crockett has more than 27 years of experience in the well services business, most recently as Gulf Coast regional sales manager. Also, Randy Gibson was appointed operations manager. He will be based in the division’s new facility in Houma, La., and will oversee all operations and personnel at the facility. Gibson has been with Knight Well Services for six years, most recently as field manager.
Patriot Mechanical Handling Inc. has named Charles “Pat” Patrick as VP of products and rig packages. He brings over 30 years of equipment experience. Before joining Patriot, Patrick worked for Transocean Offshore Deepwater Drilling Inc. and also served as chairman of the IADC Maintenance Committee. Kal Karmous has joined the company as VP of operations.
Chevron, partners reveal major test in deepwater GOM
On Sept. 5, a consortium of Chevron (operator, 50%), Devon Energy (25%) and Statoil (25%) announced a record-setting production test on the Jack 2 well in Walker Ridge Block 758 of the US Gulf of Mexico (GOM). Jack 2 was drilled to delineate the Jack 1 discovery that encountered 350 net ft of pay in September 2004. Jack 2 was drilled and tested in about 7,000 ft of water and more than 20,000 feet below the sea floor, with a TD of 28,175 ft (Jack 1’s TD was 29,000 ft). Tested during second-quarter 2006, Jack 2 flowed more than 6,000 bopd, and the test represented about 40% of the well’s total net pay. Although the partners officially referred to Jack’s test results as “encouraging,” analysts are already estimating preliminary reserves at 3 billion bbl of oil on the low side and 15 billion bbl on the high side.
TABLE 1. Strength-to-weight ratio comparisons of many steel grades to non-steel alternative materials including attached steel tool joints.
Vol. 227 No. 10
1. Changes in the available US fleet
4. US regional census results