Showing papers in "Oil & Gas Journal in 1995"

Technology vital for horizontal well success

Abstract: Union Pacific Resources Co. (UPRC) has drilled more than 1,100 horizontal wells since 1987 and continues to operate about 15--20 rigs drilling horizontal wells. Technology has advanced the drilling, completion, formation evaluation, stimulation, and production of horizontal wells. Drilling break-throughs include dual-powerhead mud motors, retrievable whipstocks, and routine multiple lateral wells. Cost improvements have enabled UPRC to extend activity into deeper zones, which are hotter and more hostile. State-of-the-art drilling includes as many as four, 4,000+ ft horizontal laterals, horizontal wells at TVDs greater than 16,000 ft, and mud weights in excess of 15 ppg. In the Austin chalk, UPRC operates properties producing more than 480 MMcfd, 40,000 bo/d, and over 100,000 bw/d. The paper uses the wells of the Austin chalk to describe the technology used for formation evaluation, geological steering, muds, top drives, bit selection, mud motors, multiple laterals, retrievable whipstocks, water fracs, vapor-recovery units, artificial lift, automation, and surface facilities. Organizations, alliances, and corrosion problems are also discussed.

Synthetic-based drilling fluids have many environmental pluses

Abstract: Synthetic-based drilling fluids have several technological and environmental advantages over water-based and oil-based drilling fluids and can cut total well costs in many cases. Spent drilling fluids and drilling cuttings are among the most significant waste streams from exploration and development activities. They pose a serious and costly disposal problem for offshore operators who must barge spent mud and cuttings to shore for land disposal if the material does not meet U.S. Environmental Protection Agency (EPA) discharge limitations or permit requirements.

Frac pack technology still evolving

Abstract: Success of frac packs depends on candidate selection, treatment design, fluids and proppants, downhole tools, and treatment implementation. Current frac packing techniques have partially evolved from high-permeability stimulation in the Kuparuk field, Alaska. In the Gulf of Mexico (GOM), attempts were made as early as the mid-1960s to hydraulically fracture sands. These early treatments were not highly successful because of techniques, understanding of rock mechanical properties, and poor candidate selection. This article focuses primarily on frac packs in GOM wells, although this technique is also used in South America, Southeast Asia, Pakistan, Nigeria, Alaska, and Europe. Through mid-year 1995 in the GOM alone, there have been over 600 frac packs.

Method computes PVT properties for gas condensate

Abstract: A new simple method computes the black-oil PVT properties of gas condensates. The new algorithm represents a significant improvement over past approaches. The algorithm is a valuable tool for the reservoir engineer who analyzes gas-condensate reservoirs. To obtain the so-called black-oil PVT properties of gas condensates, this method requires only data normally available from a standard constant-volume depletion. The method is rigorous, direct, and simple and is ideally suited for a spreadsheet. Remarkably, no k-value or equation-of-state flash calculations are required as in previous methods. The calculations demand only a fraction of the time required by other methods. The black-oil PVT properties are routinely used in a wide variety of reservoir engineering calculations, ranging from material-balance calculations to finite-difference numerical simulations.

Impact of production and development RD and D ranked

Abstract: The National Petroleum Council (NPC) survey of the oil and gas industry`s research, development, and demonstration (RD and D) needs includes a wide diversity of production and development technologies. The NPC survey put 27 technologies in the production category and 34 in the development category. Deepwater production and development was a separate category with 16 entries. The paper discusses the ranking of technology needs for production, development, and deepwater operations. National laboratories and NIPER are involved in 90 projects categorized as primary technology needs and several of these are highlighted.

Oil history, potential converge in Azerbaijan

Abstract: Azerbaijan, the oldest known oil producing region in the world, still holds great potential for new discoveries and increased production. A multi-billion dollar production sharing agreement was recently signed with a consortium of primarily western oil companies to develop three oil fields in the Caspian Sea. Soon, Azerbaijan will offer new exploration acreage both offshore and onshore. This paper describes the history of oil production in Azerbaijan, offshore developments, tectonics, stratigraphy, petroleum traps, mud volcanoes, and short summaries of several oil producing areas. Current production is about 9 million tons/yr of oil and 7 billion cu m/yr of natural gas.

Rotating control head applications increasing

Abstract: Rotating control head technology has become an important tool for lowering drilling costs and increasing well productivity, especially in many hard-rock areas and mature oil and gas fields. Lower drilling costs are achieved primarily by the faster penetration rates, reduced nondrilling time, and reduced mud volume requirements associated with underbalanced drilling. Greater well productivity can sometimes be obtained because of reduced formation damage for mud. Recent advances in rotating head technology have increased the range of well conditions to which this technology can be applied. Even though the use of rotating control heads is growing rapidly, this topic has been largely neglected in most well control training programs. Many engineers are not yet familiar with this important emerging technology and some of the modern concepts and practices used. The paper discusses the high-pressure rotating head and its application to gas or air drilling, flow drilling, geothermal drilling, overbalanced drilling and workover operations. The paper also discusses operating guidelines and rig crew training.

German gas pipeline first to use new generation line pipe

Abstract: Ruhrgas AG, Essen, Germany, in 1992-93 installed a pipeline that used the world's first-ever GRS 550 TM (Grade X-80) line pipe. This X-80 Grade, specified as GRS 550 TM (TM = thermomechanically treated steel) by Mannesmannroehren-Werke AG (MRW), Muelheim, Germany, has a specified minimum yield stress (SMYS) of Rp (resistance proportional) 0.2 = 550 Newtons/sq mm (40 tons/sq in.) and a minimum tensile strength of Rm = 690 Newtons/sq mm (50 tons/sq in.). The project, a 163 mile (262.3 km), 48-in. (1.219-m) gas pipeline from Schluchtern in Hessen to Werne in North Rhine Westphalia, Germany, connects existing pipelines in new federal states in the former East Germany. The line began operating in late 1993. Use of GRS 550 TM steel in the pipeline allows Ruhrgas an operating pressure of 1,450 psi (102 kg/sq cm), compared to an operating pressure of 1,160 psi (82 kg/sq cm) for Grade X-70. This level permits considerably more gas to be transported over the same time. This article provides further details on the use of the X-80 Grade line pipe, including project planning, material and pipe properties, pipe bending, pipe delivery, field welding, downhill welding, coating and laying, and hydrostatic testing.

Shelf north of Falklands may be new S. Atlantic petroleum province

Abstract: Interpretation of new seismic data shows that all the elements of a favorable petroleum geology exist on the North Falkland shelf and therefore that the area will become an important petroleum province of the future. Spectrum Energy and Information Technology Ltd. acquired approximately 7,500 line km of speculative seismic data during 1993--94 over the continental shelf north of the Falkland Islands. These data have been interpreted geologically to determine the petroleum prospectivity of the area prior to the planned offshore Falkland Islands licensing round. In this article the authors outline this interpretation and show how it provides some important new information on regional geology and the break-up history of southern Gondwana. The paper describes plate tectonics and basin evolution; stratigraphy; basin structure; petroleum geology; source rock maturity; hydrocarbon generation; and petroleum prospectivity.

Geology, Murzuk oil development could boost S. W. Libya prospects

Abstract: With the recent involvement of Repsol, Total, and OMV in developing the 2 billion bbl oil-in-place Murzuk field complex, an infrastructure will be finally constructed in western Libya which will act as a precursor to more exploration activity and development projects in the Murzuk and Ghadames basins. Murzuk, an intra-cratonic sag basin, is a huge ladle-shaped structural basin covering more than 400,000 sq km and extending beyond the borders of southern Libya. The structure of the area is quite simple. The sub-horizontal or gently dipping strata are faulted and the faults are most frequently parallel to the anticlinal axis. Tectonic movements affected the basin to a greater or lesser degree from early Paleozoic (Caledonian) to post-Eocene (Alpine) times. The paper describes the exploration history; stratigraphy; the Ordovician, Silurian and Devonian, and Carboniferous reservoirs; source rocks; oil gravity and gas content; hydrogeologic constraints; aquifer influence on hydrocarbon accumulation; geologic structures; Murzuk field development; and acreage availability.

Exploration limited since '70s in Libya's Sirte basin

Abstract: Esso Standard made the first Libyan oil discovery in the western Ghadames basin in 1957. The Atshan-2 well tested oil from Devonian sandstones, and the play was a continuation of the Paleozoic trend found productive in the neighboring Edjeleh region of eastern Algeria. Exploration in the Sirte basin began in earnest in 1958. Within the next 10 years, 16 major oil fields had been discovered, each with recoverable reserves greater than 500 million bbl of oil. Libya currently produces under OPEC quota approximately 1.4 million b/d of oil, with discovered in-place reserves of 130 billion bbl of oil. The paper describes the structural framework, sedimentary basins of Libya, the Sirte basin, petroleum geology, play types, source rocks, generation and migration of hydrocarbons, oil reserves, potential, and acreage availability.

Heavy oil expansions gather momentum worldwide

Abstract: Cold production, wormholes, foamy oil mechanism, improvements in thermal methods, and horizontal wells are some of the processes and technologies enabling expansion of the world`s heavy oil/bitumen production. Such processes were the focus of the International Heavy Oil Symposium in Calgary, June 19--21. Unlike conventional oil production, heavy oil/bitumen extraction is more a manufacturing process where technology enables the business and does not just add value. The current low price spreads between heavy oil/light oil indicate that demand for heavy oil is high. The paper first discusses the price difference between heavy and light oils, then describes heavy oil production activities in Canada at Cold Lake, in Venezuela in the Orinoco belt, and at Kern River in California.

New correlations predict physical properties of elemental sulfur

Abstract: Until now, elemental sulfur`s physical properties have not been systematically correlated Simple tools for predicting these properties are necessary, especially for engineering calculations, because sulfur is widely used industrially Newly developed correlations use temperature to estimate sulfur`s density, specific heat, vapor pressure, viscosity, and thermal conductivity

Entrainment method enhanced to account for oil`s water content

Abstract: A method for estimating minimum oil-flow velocity in an oil-water multiphase stream sufficient to entrain all free water has been improved to account for water volume in the flowing oil Removing all free water in a flowing oil-water stream eliminates a separated settled-water phase which could cause corrosion damage to the transfer lines Such harmful oil field impurities as hydrogen sulfide and carbon dioxide dissolved in the free-water phase can contribute to the problem The method is reviewed here as a basis for presenting the improved approach for calculating the minimum flow velocity that takes into consideration water content already in the oil

The play that complements the petroleum system -- A new exploration equation

Abstract: The reasons for carrying out oil-and-gas-related investigations in a petroleum province are to find where to look for undiscovered commercial quantities of petroleum and to determine the related risk. To objectively determine risk, what is known should be clearly separated from what is unknown. When the play concept includes both the known and the unknown, however, the explorationist may not always separate these two types of information clearly when discussing risk with management. In contrast, if the petroleum-system concept is used to present only the known, then the play concept can be used to present the unknown. Thus, the play concept used in this manner complements the petroleum-system concept. The paper describes play and prospect, the petroleum system, complementary play, and exploration risk. By using the petroleum-system concept to present known information and the complementary-play concept to present unknown information, risk can be more objectively determined.

Equations help calculate surge and swab pressures in inclined wells

Abstract: This article analyzes the surge and swab pressures caused by clinging power during tripping in inclined wells. The calculation method presented here is for steady-state surge and swab pressures for axial flow of a Herschel-Bulkley fluid in an eccentric annulus. The accompanying charts show the application of this method to oil field operations.

Use of bicenter PDC bit reduces drilling cost

Abstract: The use of bicenter polycrystalline diamond compact (PDC) bit technology, dual-power-head down-hole motors, and oil-based drilling fluids helped save significant costs on a recent well drilled in the Gulf of Mexico. Not only has underreaming been eliminated, but the overall rate of penetration has been significantly increased. Directional control problems experienced during one phase of the well may limit use of the technique in difficult directional wells. This article discusses both the successes and the failures of this technique during the drilling of two phases of the same Gulf of Mexico well.

U.S. interstate pipelines ran more efficiently in 1994

Abstract: Regulated US interstate pipelines began 1995 under the momentum of impressive efficiency improvements in 1994. Annual reports filed with the US Federal Energy Regulatory Commission (FERC) show that both natural-gas and petroleum liquids pipeline companies increased their net incomes last year despite declining operating revenues. This article discusses trends in the pipeline industry and gives data on the following: pipeline revenues, incomes--1994; current pipeline costs; pipeline costs--estimated vs. actual; current compressor construction costs; compressor costs--estimated vs. actual; US interstate mileage; investment in liquids pipelines; 10-years of land construction costs; top 10 interstate liquids pipelines; top 10 interstate gas pipelines; liquids pipeline companies; and gas pipeline companies.

Microbes safely, effectively bioremediate oil field pits

Abstract: Natural and augmented bioremediation provides a safe, environmental, fast, and effective solution for removing hydrocarbon stains from soil. In 1992, Amoco sponsored a study with six bioremediation companies, which evaluated 14 different techniques. From this study, Amoco continued using Environmental Protection Co.'s (EPC) microbes for bioremediating more than 145 sites near Farmington, NM. EPC's microbes proved effective on various types of hydrocarbon molecules found in petroleum stained soils from heavy crude and paraffin to volatiles such as BTEX (benzene, toluene, ethylbenzene, xylene) compounds. Controlled laboratory tests have shown that these microbes can digest the hydrocarbon molecules with or without free oxygen present. It is believed that this adaptation gives these microbes their resilience. The paper describes the bioremediation process, environmental advantages, in situ and ex situ bioremediation, goals of bioremediation, temperature effects, time, cost, and example sites that were treated.

Horizontal well drilled into deep, hot Austin chalk

Abstract: Bent-housing steerable downhole motors helped maintain course for a deep, hot, horizontal well in the Austin chalk. The Navasota Unit No. 1 was planned as a B zone, single downdip lateral, Austin chalk horizontal well with a maximum departure from vertical of 3,767 ft and a planned total depth (TD) of 17,342 ft measured depth (MD)/14,172 ft TVD. The Austin chalk was found significantly deeper in this well than planned, which resulted in an actual TD of 17,899 ft MD/14,993 ft TVD, the deepest (TVD) horizontal well in the Austin chalk to date. The well was spudded on August 6, 1994, and took 52 days to reach TD. The static bottom hole temperature was almost 350 F. The paper describes the well plan, drilling results, and the lateral section.

Risk-based inspection improves safety of pressure equipment

Abstract: Refiners and petrochemical producers spend millions of dollars each year trying to improve the mechanical-integrity record of the processing industry. But the challenge lies in determining where to focus the industry's limited resources to effect the largest impact on equipment safety. A new risk-based inspection program has been developed to help processors determine the highest-risk equipment and design an inspection program that not only finds corrosion, but also reduces the risk of equipment failure. Engineers know that all equipment contains flaws. Fortunately, most flaws are innocuous and comprise what might be referred to as a ''fortuitous collection'' of flaws. The processing industry's equipment also contains many flaws: most are harmless, a few might lead to leaks, and extremely few may lead to catastrophic failures. The challenge is to cost-effectively find those few critical flaws that could lead to major failures. The paper describes this risk-based inspection method using a hypothetical case of a refinery gas fractionation plant.

Niger delta oil production, reserves, field sizes assessed

Abstract: The article presents tables and figures showing the reserve estimates and production histories of the 252 fields in the Niger delta, then makes forecasts of the likelihood of discoveries above a given size. The paper discusses oil reserves, development programs, drilling and 3D seismic surveying, secondary and tertiary EOR, reserve incentives, production facilities, capital spending required, Nigerian export blends, and the trend in these blends.

Drag reducing additives improve drilling fluid hydraulics

Abstract: The use of drag reducing additives helps drilling fluids develop a lower pressure gradient at a constant flow rate under turbulent flow conditions. At a constant pressure gradient a treated mud will flow faster than an untreated mud because turbulence is suppressed. The phenomenon, however, is unrelated to the lubricity functions of a drilling fluid. Drag reduction cannot be predicted from the description of mud rheology obtained with conventional API test procedures, and the phenomenon is unrelated to shear thinning behavior. Flow properties predicted from the Bingham, power law, Herschel-Bulkley, or Casson models will not correlate with this phenomenon. Simple pipe flow tests can provide a direct method for detecting and quantifying drag reduction activity (provided care is taken in selecting flow conditions). Drag reduction activity can be determined without introducing complicated rheological parameters. These pipe flow tests can be helpful in comparing different types of drag reducing additives. They are also valuable in analyzing the effectiveness of a drag reducer for a particular drilling application.

Better practices and synthetic fluid improve drilling rates

Abstract: Improved drilling practices, combined with the use of olefin-based synthetic drilling fluids, have dramatically reduced drilling time and costs in a difficult drilling area in the Gulf of Mexico. In the South Pass area, Marathon Oil Co. and other operators have had wells with long drilling times and high costs. In addition to the two wells with record penetration rates, routine drilling rates have also increased from the use of synthetic mud and careful drilling practices. Through application of these improved drilling practices, 2,000--3,000 ft/day can be drilled routinely. Marathon achieves this goal by applying the experience gained on previous wells, properly training and involving the crews, and using innovative drilling systems. Improved drilling practices and systems are just one part of successful, efficient drilling. Rig site personnel are major contributors to safely and successfully drilling at high penetration rates for extended periods. The on site personnel must act as a team and have the confidence and proper mental attitude about what is going on downhole. The paper describes the drilling history in the South Pass area, the synthetic drilling fluid used, cuttings handling, hole cleaning, drilling practices, bottom hole assemblies, and lost circulation.

Enzymes desulfurizing diesel fuel in pilot plant tests

Abstract: Energy BioSystems Corp., The Woodlands, Texas, is collecting data from a new 5 b/d, continuous-operation, biocatalytic desulfurization (BDS) pilot plant. Hurdles to commercialization are catalyst activity, stability, and fermentation yield. Since 1990, however, Energy BioSystems Corp. (EBC) has made great strides in improving all three of these factors. The BDS process uses enzymes to remove organically bound sulfur from petroleum streams at mild temperatures and atmospheric pressure. Objectives of the pilot plant studies include: validating and refining the computer simulations used to control the process and establishing the process design basis. So far, the results from pilot plant operations have met expectations. The projected 45% desulfurization rate has been achieved, within a few percent. This rate was simply the target for the initial evaluation experiments, and that the process is capable of desulfurizing almost to extinction.

Isolation profile liner helps stabilize problem well bores

Abstract: An expandable full-bore liner can cover long, lost circulation zones to eliminate the need for intermediate casing strings. This liner has also successfully repaired various casing problems in producing wells. The TatNIPIneft Institute, which is the largest oil and gas research institute in Tatarstan, has designed and patented an isolation profile liner, which was initially manufactured to eliminate the need for intermediate casing strings because of lost circulation or pressure depleted formations. To date, the liner has been successfully installed in approximately 850 wells throughout Russia. The isolation profile liner is constructed from a proprietary alloy that can be expanded from a collapsed state once the tool is run to the proper setting depth. To maintain the full working diameter of the well bore, the driller must underream the hole slightly above, below, and the across the problem zone. The liner is then expanded into the underreamed portion of the hole by using pump pressure an da specially designed expansion tool. An epoxy material applied to the outside of the profile liner adheres to the borehole wall, thus keeping the liner in place.

How unconventional gas prospers without tax incentives

Abstract: It was widely believed that the development of unconventional natural gas (coalbed methane, gas shales, and tight gas) would die once US Sec. 29 credits stopped. Quieter voices countered, and hoped, that technology advances would keep these large but difficult to produce gas resources alive and maybe even healthy. Sec. 29 tax credits for new unconventional gas development stopped at the end of 1992. Now, nearly three years later, who was right and what has happened? There is no doubt that Sec. 29 tax credits stimulated the development of coalbed methane, gas shales, and tight gas. What is less known is that the tax credits helped spawn and push into use an entire new set of exploration, completion, and production technologies founded on improved understanding of unconventional gas reservoirs. As set forth below, while the incentives inherent in Sec. 29 provided the spark, it has been the base of science and technology that has maintained the vitality of these gas sources. The paper discusses the current status; resource development; technology; unusual production, proven reserves, and well completions if coalbed methane, gas shales, and tight gas; and international aspects.

Project management improved multiwell shallow gas development

Abstract: Because of time and economic constraints, a multiwell shallow gas development project in southeastern Alberta required thorough pre-job planning and special drilling, cementing, and completions designs. The project took place during a period of peak industry activity, putting extra challenges on logistics and services.

North Dakota`s Dickinson Lodgepole discovery: A Preliminary exploration model

Abstract: Interest in the Mississippian Lodgepole formation of North Dakota has intensified since the successful completion of the Duncan Oil Inc. 1-11 Knopik flowing 2,707 b/d of oil and 1.55 MMcfd of gas 430 cu m of oil and 43,891 cu m of gas. The play began when Conoco drilled an in-field wildcat in an attempt to establish deeper production in Dickinson oil field. The discovery well, 74 Dickinson State, was completed in a clean lower Lodgepole limestone section that is thought to represent a Waulsortian mound. The most important questions asked concerning the Lodgepole play are whether or not it will step out of the Dickinson area, what are the factors that control the development of these mounds, what controlled the development of the reservoir and trap, and how it was charged with oil. Other than the reservoir section, the most significant feature observed from wireline logs of the area is the anomalously thick Bakken formation (Mississippian-Devonian). This observation is important to understanding the Lodgepole play and can be used to help explore for similar features elsewhere in the basin. The paper describes the regional setting, the Lodgepole stratigraphy, deposition, regional equivalents, and a salt collapse model that can readilymore » explain the features observed at the Dickinson field.« less

Spreadsheets generate reservoir uncertainty distributions

Abstract: Spreadsheets can quickly generate and graph normal, lognormal, and triangular distributions for analyzing prospects or problems involving uncertainty in the oil and gas industry. Monte Carlo simulation input distributions are specified in different ways, often by assigning the 10th and 90th percentiles, P10 and P90. Selecting the appropriate distribution (such as normal, lognormal, and triangular distributions) and justifying hat choice is critical to the believability of the model. The authors will show procedures for calculating parameters for normal, lognormal, and triangular distributions with a spreadsheet, and outline the proof that you always get a unique answer for a triangular distribution. The significance of the procedure is to avoid P10 and P90 inputs that yield a triangular distribution whose end points are clearly inappropriate. One such case would be if negative values are sampled to estimate net pay.