|Theme||Visible||Selectable||Appearance||Zoom Range (now: 0)|
Oil or gas wells produce a mixture of hydrocarbon gas, condensate, or oil; water with dissolved minerals, usually including a large amount of salt; other gases, including nitrogen, carbon dioxide (CO2), and possibly hydrogen sulfide (H2S); and solids, including sand from the reservoir, dirt, scale, and corrosion products from the tubing. For the hydrocarbons (gas or liquid) to be sold, they must be separated from the water and solids, measured, sold, and transported by pipeline, truck, rail, or ocean tanker to the user. Gas is usually restricted to pipeline transportation but can also be shipped in pressure vessels on ships, trucks, or railroad cars as compressed natural gas or converted to a liquid and sent as a liquefied natural gas (LNG). This chapter discusses the field processing required before oil and gas can be sold. The goal is to produce oil that meets the purchaser's specifications that define the maximum allowable water, salt, or other impurities. Similarly, the gas must be processed to meet purchaser's water vapor and hydrocarbon dewpoint specifications to limit condensation during transportation. The produced water must meet regulatory requirements for disposal in the ocean if the wells are offshore, reservoir requirements for injection into an underground reservoir to avoid plugging the reservoir, and technical requirements for other uses, such as feed to steam boilers in thermal-flood operations, or in special cases, for irrigation. The equipment between the wells and the pipeline, or other transportation system, is called an oilfield facility. An oilfield facility is different from a refinery or chemical plant in a number of ways.
Chemical treatment with demulsifiers is used to counteract the natural surfactants present, and wetting agents or other chemicals sometimes are used to carry the suspended solids into the water layer. The presence of a band of emulsion in centrifuged samples indicates that further chemical treatment might be needed.
Chevron has moved up plans to early 2022 to drill a fifth production well at Israel's Leviathan gas and condensate field in the Eastern Mediterranean, driven to boost production after demand for the field's gas rose reportedly by an unanticipated 6% in the first half of 2021. Field operator Chevron holds a 39.66% stake in Leviathan following its acquisition a year ago of Noble Drilling. Chevron's partners are Israeli E&P partnership Delek Drilling (a subsidiary of Delek Group) which owns the majority 45.34% share and the Israeli limited partnership, Ratio Oil and Gas (15%). The deepwater field 125 km west of Haifa has estimated reserves of 649 Bcm of natural gas and 41 million bbl of condensate which Delek said represents two-thirds of total gas resources discovered in Israeli waters so far. Production initiated in late December 2019 supplies Israel's domestic market and is exported to Egypt and to Jordan.
Introduction Tubing is the normal flow conduit used to transport produced fluids to the surface or fluids to the formation. Its use in wells is normally considered a good operating practice. The use of tubing permits better well control because circulating fluids can kill the well; thus, workovers are simplified and their results enhanced. Flow efficiency typically is improved with the use of tubing. Furthermore, tubing is required for most artificial lift installations. Tubing with the use of a packer allows isolation of the casing from well fluids and deters corrosion damage of the casing. Multicompletions require tubing to permit individual zone production and operation. Governmental rules and regulations often require tubing in every well. Permission may be obtained for omission of tubing in special cases (tubingless completions). These special completions typically are flowing wells with relatively small casing. Tubing strings are generally in outside diameter (OD) sizes of 2 3/8 to 4 1/2 in. The proper selection, design, and installation of tubing string are critical parts of any well completion. See the chapter on inflow and outflow in this section of the handbook for more information. Tubing strings must be sized correctly to enable the fluids to flow efficiently or to permit installation of effective artificial lift equipment. A tubing string that is too small causes large friction losses and limits production. It also may severely restrict the type and size of artificial lift equipment. A tubing string that is too large may cause heading and unstable flow, which results in loading up of the well and can complicate workovers. The planned tubing must easily fit inside the installed casing.
The well flowline, or simply flowline, is the first "pipeline" system connected to the wellhead. The flowline carries total produced fluids (e.g., oil, gas, and production water) from the well to the first piece of production equipment--typically a production separator. The flowline may carry the well-production fluids to a common production battery, a gathering pipeline system, process facility, or other. Interconnecting piping includes the piping between the various pieces of production/treating equipment such as production separators, line heaters, oil heaters, pump units, storage tanks, and gas dehydrators. The piping systems may also include headers, fuel systems, other utility piping, and pressure-relief/flare systems.
Specifications for sales gas describe the required physical properties of the gas such that it can be transported under high pressure through long distance pipelines at ground temperature without forming liquids, which could cause corrosion, hydrates, or liquid slugs into downstream equipment. Limits on the content of certain nonhydrocarbon compounds are also specified.
It has often amounted to little more than background noise. Now, engineers with one of the largest shale producers in the US consider the water-hammer signal to represent a potential trove of insight into stimulation performance. ConocoPhillips has spent almost 3 years developing a new approach to water-hammer analysis and recently shared the first public details of that work in a technical paper (SPE 204154). Perhaps the core takeaway is that, within a few minutes of post-stage data, a picture of reservoir and stimulation quality is available. The challenge lies in how to bring that picture into proper focus. The water hammer is a pressure pulse that moves through the wellbore at the speed of sound in fluid, or around 5,000 ft/s, which is more than fourfold the speed of sound in air.
The second of Nord Stream 2's twin pipelines is scheduled for completion in August, with the first line having been finished and prepped for filling earlier this month. Some analysts are looking forward to what effect the eventual commissioning of the beleaguered project will have on European energy security. The answer, say analysts who understand that the European gas market has evolved in the last decade to diminish the importance of Russian pipeline gas in the energy mix, is "not that much." Politically, though, Nord Stream 2 has been nothing less than a high-stakes poker game among nations to achieve geopolitical goals. Operated by Russia's Gazprom, the $11 billion Nord Stream 2 doubles the capacity of the original Nord Stream export line, which went into service in 2011.
TC Energy said this week that it has terminated plans to complete the transborder Keystone XL Pipeline which has faced legal battles and permitting challenges for more than a decade. The Calgary-based pipeline operator halted construction on the project on 20 January, the day that US President Joe Biden took office and in one of his first acts as chief executive revoked the pipeline's permits. TC Energy's CEO, François Poirier, issued a statement that said the company values the experience it gained, and relationships made with various stakeholders while pursuing the ill-fated project. "Through the process, we developed meaningful indigenous equity opportunities and a first-of-its-kind, industry-leading plan to operate the pipeline with net-zero emissions throughout its life cycle. We will continue to identify opportunities to apply this level of ingenuity across our business going forward, including our current evaluation of the potential to power existing US assets with renewable energy," Poirier said in the statement.