October 2004 ///
Highly complex and faulted geology in southern Oklahoma, coupled with the high dip angles, creates a challenging drilling environment. The inclination-building tendencies of these formations compel operators to use a steerable motor with a bend angle to construct boreholes that are intended to be nearly vertical. To address these issues, Chesapeake Energy recently applied VertiTrak (VT), a sophisticated straight-hole drilling device, together with a new-style, reduced-exposure Genesis PDC bit, to enable the operator to save considerable rig time and increase ROP while delivering quality wellbores, resulting in minimal casing wear, reduced torque and drag, and improving casing-cement jobs.
The impact of damage from imbibition-induced water trapping in exploration wells at Alaska's Alpine field has been minimized by an alternate drilling fluid system.
Recent field tests determined just how many lost circulation problems can be traced to reduced fracture gradients, due to cooling around the wellbore.
Reservoir simulation studies require good knowledge of permeabilities, but reliable measurements are only available from laboratory core tests. These are usually taken from a small percentage of wells. Frequently, this information is extrapolated to calculate permeabilities over the field, but insufficient data points usually cause unreliable predictions. This article proposes a method to estimate formation permeabilities from standard well logs and core data. The method should be applicable to any reservoir as long as sufficient core and log data are available. The method assumes that the Carman-Kozeny equation holds for the reservoir rocks, which is a fairly reasonable assumption, and that the available well logs contain intrinsic information on tortuosity, sand size distribution, cementing characteristics, etc., which ultimately determine flow performance.
This hypothesis is usually strong because the available logs are not able to fully read the physical phenomena that cover the complex dynamics of flow through reservoir rocks. The method was tested in a sandstone formation in Chihuido de la Salina, Neuquen basin, Argentina. Some core data points were not used to train the neural network and were subsequently useful for validation and comparison. In spite of certain drawbacks, the method was shown to outperform both standard-regression and hydraulic-flow-unit approaches.
To understand costly, abnormal geopressures and wellbore instability, a large, experiential database has been applied to integrated basin modeling.
Noting that more money is spent on processing water than all other major services, the authors look at ways in which this major expense can be reduced.
Simulation and physical testing led to development of a flotation cell that has been test-operated successfully on floating and fixed platforms.
Looking at the attractive remaining reserves and property life, operator Oak Resources, Inc. (Unit now operated by Phoenix PetroCorp Inc.) elected to replace the injection lines and continue the waterflood using coiled, continuous, composite pipe instead of carbon steel pipe (internal and external coated) or jointed fiberglass pipe. While the overall installed cost would have been about the same for the different systems evaluated, the deciding factors were the ease of installation, the short downtime of wells and roads, and the projected long-term reliability. After trenching, it took only 1-1/2 days in April 2003 to install about one mile of mixed 3-1/2- and 2-1/2-in. OD lines, including pressure testing. The total installed cost was less than $8 per foot. Only two failures (within 14 days and 10 ft of each other) were experienced within one year of installation, and both were attributed to localized damage during installation. Otherwise the system has performed very well, as expected.
In addition to describing the improved US fleet characteristics, this year's census adds new information on the Canadian and global, mobile offshore fleets.
This month, we share a tongue-in-cheek gem, written by Les Skinner of Energy Personnel International. As Les says, “Most of this stuff comes from sad personal experience. Fishing and undergoing a root canal are my two favorite activities (right along with owning a drilling rig and discussing any topic with an attorney).”
How to Foul Up a Fishing Job. History has shown that a good many people don't know the correct way to really mess up a fishing job, so here's some advice on how it's done.
Friendly and unfriendly immigration
Chávez won the referendum, so perhaps PDVSA will focus on oil production and not politics. International observers may have affirmed President Hugo Chávez's win on Aug. 15, but the opposition is likely to continue challenging the results. Another key day will be Oct. 31, when regional elections take place, and the opposition may challenge Chávez again.
The opposition, a loose coalition of political parties, business and labor leaders, and civic groups, has struggled to present a united front after the referendum defeat. They are split over whether to challenge Chávez on Oct. 31. Unless the opposition finds a way to challenge him successfully, Chávez will stay in power until December 2006.
Petroleum industry technology leaders Cameron, Baker Hughes, Halliburton, Lufkin Industries and Weatherford are charter members of a new initiative to strengthen hands-on instruction in drilling, completion and production at Texas A&M University, College Station, Texas. The new Program in the Harold Vance Department of Petroleum Engineering aims to increase exposure to oilfield equipment and procedures. Students visit professional labs and well sites, interact with working professionals, who visit campus weekly, and develop a working vocabulary of the industry based on practical experience.
With the emphasis on equipment and hands-on lab experience shrinking on campuses across the nation, the department's new initiative counteracts this trend. The program supports the Department's Drilling and Production Systems course for junior-level students. The class introduces nomenclature and methods used in drilling, completing and producing oil and gas wells. Amazing, they're learning there's more to this business than sitting all day in front of a computer.
Crude biodegradation. Biodegradation of crude in petroleum reservoirs is an important exploration risk with major economic consequences. World Oil presented a paper by (Alan Yu, et al. April, 2002) that attempted to quantify that risk through integration of temperature and hydrocarbon-charge histories modeling. At and near the surface, this alteration process by aerobic degradation of petroleum is well documented. It has long been thought that oxygen- and nutrient-bearing surface waters percolate into reservoirs, and that this flow was necessary for in situ oil biodegradation.
However, biodegraded oils are found in reservoirs where aerobic conditions are unlikely. This, together with the recent identification of several anaerobic microorganisms in oil fields and the discovery of anaerobic oil-biodegradation mechanisms, means that anaerobic biodegradation processes could also be responsible. Such anaerobic degradation in deep petroleum reservoirs has thus far been strongly contested. Moreover, no single organism has yet been isolated that has been proven to degrade hydrocarbons under the conditions found in deep petroleum reservoirs.
News & Resources
First Reserve Corp., a private equity firm specializing in energy industry investments, agreed to acquire the Dresser-Rand Co., a business unit of Ingersoll-Rand, for about $1.2 billion. This is First Reserve's third acquisition from a major multinational corporation in 2004 and its second billion-dollar transaction in the past six months. Dresser-Rand is a leading supplier of infrastructure equipment, including compressors, gas and steam turbines, to the worldwide energy industry.
Heartland Oil and Gas Corp. appointed Philip S. Winner as COO. He will be primarily responsible for directing and advising the board on exploration, development and production of the company's Kansas CBM lands. Winner has 25 years of experience in the oil and gas industry, including the development CBM assets in the Piceance, Sand Wash and Green River Basins. Previously, he was VP of HS Resources.
BJ Services appointed Brad Pellegrin area manager, North America, for BJ Tubular Services. Pellegrin will manage operations in North America, and be responsible for budgeting, forecasting and implementation of the division's processes. He has 16 years of experience in the oilfield service industry.
Two deepwater drilling rigs arrived last month to fulfill drilling commitments at Chinguetti field and elsewhere off Mauritania for Woodside Petroleum. The presence of two rigs allows for wells to be batch drilled, whereby one rig performs the same operation on a number of wells in order, rather than drilling a single well from top to bottom. The West Navigator will drill the top hole sections of several exploration and appraisal wells. Following completion of the top holes, the wells will be temporarily suspended before the bottomhole sections are drilled by the Stena Tay . This tandem drilling arrangement will achieve increased efficiency.