This is the final paper in a series on the 3D multicomponent seismic experiment in Oman. In this experiment a 3D data set was acquired using three‐component geophones and with three source orientations. The data set will subsequently be referred to as the Natih 9C3D data set. We present, for the first time, evidence demonstrating that shear waves are sensitive to fluid type in fractured media. Two observations are examined from the Natih 9C3D data where regions of gas are characterized by slow shear‐wave velocities. One is that the shear‐wave splitting map of the Natih reservoir exhibits much larger splitting values over the gas cap on the reservoir. This increase in splitting results from a decrease in the slow shear‐wave velocity which senses both the fractures and the fracture‐filling fluid. Using a new effective‐medium model, it was possible to generate a splitting map for the reservoir that is corrected for this fluid effect. Secondly, an anomaly was encountered on the shear‐wave data directly above the reservoir. The thick Fiqa shale overburden exhibits a low shear‐wave velocity anomaly that is accompanied by higher shear reflectivity and lower frequency content. No such effects are evident in the conventional P‐wave data. This feature is interpreted as a gas chimney above the reservoir, a conclusion supported by both effective‐medium modelling and the geology. With this new effective‐medium model, we show that introduction of gas into vertically fractured rock appears to decrease the velocity of shear waves (S2), polarized perpendicular to the fracture orientation, whilst leaving the vertical compressional‐wave velocity largely unaffected. This conclusion has direct implications for seismic methods in exploration, appraisal and development of fractured reservoirs and suggests that here we should be utilizing S‐wave data, as well as the conventional P‐wave data, as a direct hydrocarbon indicator.

Permanent reservoir monitoring solutions, if of high enough sensitivity and low enough cost, can be used to tackle the many problems faced by seismic monitoring onshore and thereby increase the profitability of such IOR/EOR projects. Here we focus on thermal EOR monitoring using a SeisMovie® system provided by CGG, installed in one of the production pads in Peace River, and recording data since May 2014. The daily seismic data are integrated with other surveillance data to monitor steam conformance and provide options to adjust injection and production schedules to optimize recovery.

Fiber-optic distributed sensing is known in the oil and gas industry as an enabler for permanent temperature profiling along entire well paths. This application is limited to recovery processes with a pronounced thermal signature. Currently, we witness a confluence of novel fiber-optic technologies promising a much wider and more complete range of subsurface measurements. This opens new avenues in well and reservoir surveillance and highlights the opportunity for fiber-optic sensing to become a pervasive oilfield technology. In this paper we discuss field trials that combine Distributed Temperature Sensing (DTS), Distributed Strain Sensing (DSS) and Distributed Acoustic Sensing (DAS). These trials demonstrate the potential of fiber-optic sensing technology for well integrity monitoring, gas lift optimization, in-flow profiling and downhole seismic acquisition. Essential to realizing this potential is the development of cost-effective, easy-to-deploy fiber-optic cables optimized for these combinations of fiber-optic measurements. We also highlight the business integration challenge of handling, storing, and interpreting data volumes that reach levels of 1 TB/well/day. We conclude that while significant technology challenges remain, with a broad range of oilfield technology providers working on derisking fiber-optic sensing technologies, the industry is on the verge of a step change in well and reservoir monitoring capability.

The paper discusses a numerical model for radial transport in a toroidal plasma/gas mixture consisting of all charge states of deuterium, tritium and helium. Solutions of the steady-state momentum and particle balances indicate an enrichment of tritium gas near the reactor wall compared with deuterium. The helium enrichment ratio, although depending strongly on the ion transport model adopted, is always less than unity. Therefore, pumping helium from a cool plasma/gas blanket surrounding the entire plasma body is not attractive.

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