Issue: September 2011
Special Focus
The concepts of net reservoir (good-quality reservoir rock) and net pay (good-quality hydrocarbon-bearing reservoir rock) are intrinsically related. A knowledge of net pay is important for the volumetric estimation of hydrocarbon resources. Yet there is no universal definition of net pay, no general acceptance of its role in integrated reservoir studies, and no recognized method for evaluating it, and there are disparate views on how to make use of it.1 Partly for these reasons, net pay constitutes a major source of uncertainty in volumetric reserves estimates, second only to gross rock volume. This article examines the state of the industry with regard to quantifying net pay using determined formation properties and promotes an improved methodology that avoids drawbacks of traditional approaches. A specific aim is to reduce subjectivity, so that different subsurface teams can deliver more closely aligned net-pay estimates. These matters are especially important during the early stages of field life, when uncertainty in estimated petroleum resources is greatest.
Surface geochemistry is a relatively routine exploration method used to investigate issues of hydrocarbon generation and charge.1–6 The presence of near-surface migrated petroleum provides strong evidence that an active petroleum system is present as well as critical information on petroleum source, maturity and migration pathways.6–8 This article summarizes results from the multiphase Surface Geochemistry Calibration (SGC) study conducted by the Energy and Geoscience Institute (EGI) at the University of Utah.
In recent towed EM research over Statoil’s Troll complex, the data obtained corresponded well with previous seismic and stationary EM results, confirming the concept’s viability as an exploration method.
Features
CGGVeritas is celebrating its 80th anniversary this year. The international geophysical services provider was founded as Compagnie Générale de Géophysique (CGG) in 1931 and conducted its first survey in West Africa in 1932. CGG began conducting 3D seismic exploration in 1971 and acquired its first 4D survey in 1994. The company assumed its present name in 2007 by combining with Veritas. CGGVeritas includes legacy companies such as the US-based Digicon and Canadian software company Hampson-Russell. Sercel, the seismic equipment manufacturer, also operates within CGGVeritas’ corporate umbrella. CEO Jean-Georges Malcor provided his perspective to World Oil Editor Pramod Kulkarni on the outlook for the seismic industry and the current state of technology advancement in acquisition, data processing and interpretation.
Having already expanded its portfolio of events this year with the inaugural Arctic Technology Conference in Houston, the Offshore Technology Conference organization is continuing the trend of highlighting up-and-coming oil and gas provinces with the first-ever OTC Brasil conference.
Applying a new conceptual model to presalt wells and subsea systems in the Santos basin allowed the identification of initiatives that will yield major capex savings for Petrobras.
Wired or networked drill pipe incorporating distributed temperature and pressure sensors has potential to transform the management of downhole incidents. When used in conjunction with managed pressure drilling, incidents can be immediately identified and controlled by application of additional pressure on the annulus in a closed-loop system.
With oil reserves second only to the Middle East and a rapidly expanding natural gas sector, Latin America has become an increasingly important focus of exploration and production efforts in recent years. Brazil’s massive presalt discoveries have attracted an influx of foreign and domestic investment that is widely expected to propel that country within the next few years into the ranks of the world’s top five crude oil producers. Other Latin American countries are also welcoming the technology, capital and expertise of foreign companies, but under terms and conditions that vary greatly from country to country. Meanwhile, investors are carefully monitoring the effects on the energy sector of this year’s presidential elections in Peru, Guatemala, Argentina and Nicaragua and 2012 elections in Mexico and Venezuela. At present, the latter country’s politics, economy and oil and gas industry are shadowed by uncertainty due to President Hugo Chavez’s ongoing battle with cancer (see column on p. 25).
Subsea oil/water separation has been used for years to lighten high-watercut wellstreams such as at the mature Tordis field in the North Sea, and pumps on the seafloor—both single-phase electrical submersible pumps (ESPs) and multiphase boosting systems—have helped lift hydrocarbons that low pressure or deep water would otherwise put beyond reach. In the future, resources in Arctic waters, for example, will almost exclusively require subsea developments, as floating ice in the region poses a serious hazard to surface facilities. In the meantime, new development projects and established fields are facing novel challenges that require innovative subsea solutions. At Shell’s Parque das Conchas development in Brazil, a pioneering combination of subsea gas/liquid separation and ESP lift is being used to efficiently produce widely varying wellstreams from three separate fields. Meanwhile, Statoil is trying to extend the productive lives of its mature Åsgard and Gullfaks fields offshore Norway through the use of subsea gas compression, making already profitable fields more valuable.
While not spectacular, the global upstream market is posting a substantive recovery from the downturn that hit during late 2008 and persisted through 2009. Last year, despite weak US and European economies, drilling and production activity registered solid gains. That trend continues, as operators take advantage of increased cash flows generated by relatively high oil prices.
Columns
Alas, physicists in Hong Kong have determined that time travel is impossible. Their study concluded that even a single photon was simply too slow-footed to ever outrun the speed of light, meaning that, unless something new comes along, we are all stuck in the here and now.
Click … click … click. The roller coaster clatters to the top just before it plunges, making you scream out loud and feel a tight knot in your stomach. That’s what I remember from riding the Texas Cyclone roller coaster in Houston’s Astroworld about 40 years ago. I haven’t ridden any roller coasters since, but the feeling is not much different from riding up and down the oil and gas economic roller coaster.
Dr. William J. Pike
Those of you who worked in the wild and wooly offshore arena in the boom days of the late ’70s and early ’80s will recall that our lost-time-incident (LTI) rates were almost astronomical. We were desperate for hands. Guys that worked in a convenience store one day were on the rig floor the next and, possibly, on the brake in just a couple of years. Whole crews had less than a year’s experience on some onshore rigs. To complicate matters, we were just beginning to drill high-pressure gas formations. It is no wonder, then, that at times I flew over as many as three burned-up jackups in a row while changing out of Cameron, Louisiana. It is no wonder also that our casualty (not fatality) rate per capita offshore at times exceeded that of our troops in Vietnam.
Three decades ago, the inner workings of complex petroleum reservoirs were a deep mystery—one that billions of dollars and the dream of the next big discovery rested upon. Since that time, Dr. Ali Dogru, Saudi Aramco chief technologist, has helped unlock the mystery of the petroleum underworld and brought dozens of declining fields back to life.
The revelation of Venezuelan President Hugo Chavez’s cancer in June raised the question: Will he be able to run for reelection next year? However, after undergoing surgery to remove a baseball-sized tumor from his pelvic area and two rounds of chemotherapy in Cuba, Chavez was as busy as ever in late August—crediting Jesus and Castro for his recovery, nationalizing Venezuela’s gold industry, and vowing to continue supporting Libya’s Muammar al-Qaddafi even as rebels stormed the gates of Qaddafi’s compound in Tripoli.
The Dutch North Sea is a mature area, with many conventional fields developed over the past 50 years and other discoveries left temporarily stranded. Shallow gas accumulations on the shelf were recognized in the early 1970s but were never developed because of low reservoir pressures and unconsolidated sand issues.
Life on Earth is ubiquitous and adaptable. From the top of a bone-dry mountain in Antarctica to the bottom of a 7-mile-deep trench in the ocean to the lip of an erupting volcano, you will find microbes, comfortably basking in unspeakably harsh environments, happy as unicellular clams.
News & Resources
The world supply of crude oil received a bump last month to 88.7 million bpd, with Canadian production making up for declines in the UK fields. Production outside of OPEC is expected to average 53 million bpd for the year. OPEC averaged just over 30 million bpd after the midsummer mark. Demand continues to be weak, reflecting slow economic growth worldwide. Rotary rigs in the US continued their upward trajectory, reaching 1,900 total rigs running at the end of July, while internationally the rig count climbed by 90 onshore, to 1,187, excluding Iraq, Iran and the Sudan, where data is sparse. Oil prices, which had sagged since last April, have continued to recover as the summer wanes.
Sri Lanka’s External Affairs Minister GL Peiris announced that the country is in talks with Gazprom Managing Director Valery Gulev regarding an exploration venture in the Mannar basin. “Peiris discussed with the visiting delegation issues connected with Russian cooperation in such fields as oil exploration in the Mannar basin and the Cauvery basin, the procurement of liquid natural gas, and technical expertise in respect of refineries,” said the ministry. The Mannar basin lies south of the Cauvery basin, west of Sri Lanka, and is believed to hold more than 1 billion bbl. Cairn Energy began its three-well campaign in the Mannar basin earlier this year marking the first time drilling has taken place in the country in 25 years.
Industry At A Glance
International Offshore Rigs
International Rotary Rig Count
International Rotary Drilling Rigs Graph
US Gas Prices ($/MCF) & Production (BCFD)
International Geophysical Activity
U.S. Geophysical Activity
Selected World Oil Prices Graph ($/bbl)
U.S. Oil Production
US Rotary Drilling Rigs
Rotary Rigs Running in US
Workover Rig Count
World Oil and NGL Production
Supplement
Growing activity levels are increasing service and equipment demand across a broad scope of applications.
