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Remote well monitoring is the ability to provide data obtained in or near the wellbore without requiring access and entry for intervention to the well. Downhole permanent monitoring has been a widely accepted technology since the early 1990s. There are advantages and disadvantages to all monitoring systems; however, improvements in reliability and the realization of the added value of information have made this technology commonplace in offshore and some land applications. Remote monitoring can be coupled with remote flow control applications in intelligent wells, or it can be run as a standalone system. Sensor systems may be electronic or optical based.
The 2021 SPE Annual Technical Conference and Exhibition (ATCE) will take place next month in Dubai from 21–23 September. Hosted by Dragon Oil, the conference offers a technical agenda that reflects the changing oil and gas industry and its effects on the full spectrum of disciplines. The industry's leadership role in adapting to the world's shifting markets and priorities will be highlighted throughout the event with top-level speakers and panelists. The technical sessions will focus on presentations of papers selected by the program committee to guide attendees in understanding and applying innovative and cost-effective technologies in all aspects of the industry throughout the life cycle of an asset. The power of data analytics has evolved throughout all disciplines and has led to a deeper understanding of drilling, completions, production and operations, and reservoirs.
In many operations worldwide, surface waters are injected into producing formations to enhance oil recovery. The types of surface waters used range from seawater (salt water) to lake water (brackish) to river water (fresh water). Surface water must be treated to remove undesirable components before injection. Treatment of surface water for injection requires a specially designed system made up of various components to remove or control any contaminants in the water. The system is engineered to perform the required treatment in the most cost-effective and environmentally sensitive manner. A typical system is shown in Figure 1. Commonly used methods for removal or control of these contaminants are discussed in this section. Surface waters normally contain suspended solids particles that, if injected into the producing formation, will plug the injection well. The type, concentration, and particle-size distribution of suspended solids in water will vary depending on the source of the surface water.
This chapter concerns the use of water injection to increase the production from oil reservoirs, and the technologies that have been developed over the past 50 years to evaluate, design, operate, and monitor such projects. Use of water to increase oil production is known as "secondary recovery" and typically follows "primary production," which uses the reservoir's natural energy (fluid and rock expansion, solution-gas drive, gravity drainage, and aquifer influx) to produce oil. The principal reason for waterflooding an oil reservoir is to increase the oil-production rate and, ultimately, the oil recovery. This is accomplished by "voidage replacement"--injection of water to increase the reservoir pressure to its initial level and maintain it near that pressure. The water displaces oil from the pore spaces, but the efficiency of such displacement depends on many factors (e.g., oil viscosity and rock characteristics).
The design of a waterflood has many phases. First, simple engineering evaluation techniques are used to determine whether the reservoir meets the minimum technical and economic criteria for a successful waterflood. If so, then more-detailed technical calculations are made. These include the full range of engineering and geoscience studies. The geologists must develop as complete an understanding as possible of the internal character of the pay intervals and of the continuity of nonpay intervals.
The United States remained Europe's top supplier of liquefied natural gas (LNG) in the first 3 months of 2021 as it continued to gain market share at the expense of Russia and Qatar, Europe's second- and third-largest sources of LNG, according to the EU Commission's latest European Gas Market Report. The US supplied 24% (4.2 Bcm) of the EU's overall LNG imports (17 Bcm in Q1 2021); Russia placed second at 21% (3.7 Bcm); and Qatar was third at 18% (3.1 Bcm), the EU Commission reported in early July. When compared to Q4 2020, the US picked up 2% market share from January to March this year, while Russia bested Qatar to become Europe's second-largest LNG supplier. Nigeria placed fourth, followed by Algeria and Trinidad and Tobago. A review of EU Commission reports dating back to 2019 reveals a steady quarter-to-quarter decline in Europe's LNG purchases while it also documents the growing rivalry between the US and Russia, Qatar's fall from dominance, and the emergence of the US as Europe's top LNG supplier starting Q4 2019.
Nearly 150 workers have been evacuated or are due for evacuation from Shell's Shearwater project in the North Sea since a COVID-19 outbreak emerged at the end of June, the company said on 20 July, as the industry called for an exemption from self-isolation rules for offshore workers. So far, 26 people at the Shearwater oil and gas hub have tested positive for COVID-19, with another 122 categorized as having been "close contacts" of those infected, Shell told S&P Global Platts. Most have already been flown to shore, with a small number isolating at the facility before returning to shore, Shell said, adding that the spread of infection was slowing, with only five cases detected in the last 7 days of the outbreak. Shearwater is the focus of concerns that rising UK infection rates could spread to the offshore oil and gas sector, which normally provides 1 million B/D of oil including the Brent and Forties benchmark grades and meets about half the country's gas needs. Offshore workforce numbers have recently recovered to well over 10,000, following a steep fall last year in response the pandemic, according to industry figures.
Produced water typically enters the water-treatment system from either a two or three phase separator, a free water knockout, a gun barrel, a heater treater, or other primary separation unit process. It probably includes small amounts of free or dissolved hydrocarbons and solids that must be removed before the water can be re-used, injected or discharged. The level of removal (particularly for hydrocarbons) and disposal options are typically specified by state, province, or national regulations. This article discusses techniques for the removal of free and dissolved hydrocarbons. See Removing solids from water for information on solids removal. Produced water contains small concentrations (100 to 2000 mg/L) of dispersed hydrocarbons in the form of oil droplets. In applying these concepts, one must keep in mind the dispersion of large oil droplets to smaller ones and the coalescence of small droplets into larger ones, which takes place if energy is added to the system. The amount of energy added per unit time and the way in which it is added will determine whether dispersion or coalescence will take place. Stokes' law, shown in Eq. 1, is valid for the buoyant rise velocity of an oil droplet in a water-continuous phase. Several immediate conclusions can be drawn from this equation.
Chevron, Shell, and TotalEnergies are supporting a 12-month research project, which is expected to achieve a world-first in demonstrating high-resolution satellite-based monitoring of anthropogenic methane (CH4) emissions at sea. Led by Canadian-based GHGSat, the new research project aims to assess the feasibility of space-based methane monitoring technology to measure emissions from offshore oil and gas platforms. GHGSat is testing a technique developed by NASA, amongst others, and proven in fields such as ocean height and ice-thickness measurement. With a vantage point 500 km above the Earth, and high revisit rates, the company believes satellites could hold the key to verifying emissions from rigs, easily and cost-effectively. The study will monitor 18 offshore sites in locations such as the North Sea and the Gulf of Mexico for over 12 months.
To estimate Rt under a variety of different logging conditions and in different formations, a simple three-parameter, step-profile invasion model is often used. This model consists of a flushed zone of resistivity Rxo and a sharp boundary at diameter di, with the uninvaded zone of resistivity Rt. Three independent, borehole-corrected resistivity measurements with appropriately chosen depths of investigation contain enough information from the formation to reliably solve for Rt using this model. Measurements with the following features should be chosen: small, correctable borehole effects; similar vertical resolutions; and well-distributed radial depths of investigation--one reading as deep as practical, one very shallow reading, and one intermediate reading. In conductive muds, the Dual Laterolog (DLL) Resistivity– Rxo combination tool provides simultaneous measurements suitable for evaluating Rt, Rxo, and di. It should be said that the value of Rt in a given bed is an interpreted parameter, and is almost never measured. As long as the formation is invaded, assumptions about the invasion profile must be made to estimate Rt. Figure 1 shows the electrode array used for deep and shallow laterolog measurements (LLd and LLs, respectively). Both logs share the same electrodes and have the same current-beam thickness, but different focusing currents give them different depths of investigation. The measure current (I0) is emitted from the central A0 electrode, returning to an "infinitely distant" electrode, usually at the surface.