Multicomponent Seismic Technology Research Articles

Advantages of joint interpretation of P-P and P-SV seismic data in geothermal exploration

Conventional P-P seismic images of geothermal reservoirs are often of poor quality because P-P data tend to have a low signal-to-noise ratio across geothermal prospects. Fracture identification, fluid prediction, and imaging inside subsurface areas influenced by superheated fluids are some of the challenges facing the geothermal industry. We showed that multicomponent seismic technology is effective for addressing all of these challenges across geothermal reservoirs, even when P-P data are of low quality. Although multicomponent seismic technology has advantages in geothermal exploration, there are not many published examples of multicomponent seismic data being used to characterize geothermal reservoirs. We evaluated data examples that illustrate advantages of multicomponent seismic technology for imaging within and below zones having superheated fluids, estimating fracture attributes, analyzing reservoir trapping structures, differentiating lithologies, and predicting spatial distributions of pore fluids. All examples we tested are from the Wister geothermal field in Southern California.

Interpretation of fractures and joint inversion using multicomponent seismic data — Marcellus Shale example

Evaluating and exploiting unconventional complex oil and gas reservoirs such as the Marcellus Shale gas reservoirs within the Appalachian Basin in Pennsylvania, USA, have gained considerable interest in recent years. Technologies such as conventional 3D seismic, horizontal drilling, and hydraulic fracturing have been at the forefront of the effort to exploit these resources. Recently, multicomponent seismic technologies have been integrated into some resource evaluation and reservoir characterization activities of low-permeability rock systems. We evaluated how multicomponent seismic technology provides value to reservoir characterization in shale gas exploration. We improved fault interpretations and natural fracture identifications by means of [Formula: see text] and [Formula: see text] integrated interpretation. In addition, using P-P-/P-SV-joint inversion, we extracted key parameters, such as [Formula: see text] ratio and density, that improve stratigraphic interpretation and rock-property descriptions of shale gas reservoirs.

Interpretation of multicomponent seismic data across Wister geothermal field, Imperial Valley, California

Multicomponent seismic technology has been implemented across Wister geothermal field in southern California to evaluate the potential for further development of geothermal resources. The seismic survey was positioned atop the San Andreas fault system that extends southward from the Salton Sea. An interpretation of Wister Field geology was made using both P-P and P-SV seismic data. Two formation horizons, Canebrake/Olla/Diablo and Deguynos, were interpreted. Seismic time-structure maps were generated for each horizon. The objective of the study was to determine whether productive geothermal resources could be detected and mapped more reliably with multicomponent seismic data than with single-component P-P data. Complex faults associated with the regional San Andreas Fault system were interpreted across the [Formula: see text] 3D image space. The structural maps created are thought to be some of the most accurate depictions of subsurface structure publicly available in this area of the Imperial Valley. Particular attention was given to documenting faults that cut across deep strata. Both P-P and P-SV seismic showed evidence of such deep faults. Rock properties were analyzed from well logs. Log data showed that clastic rocks at this site exhibited measurable differences in [Formula: see text] velocity ratios for different rock types. Specifically, sand-prone intervals were associated with relatively low [Formula: see text] velocity ratios, and shale-dominated intervals had higher [Formula: see text] ratios. Using this rock physics behavior, [Formula: see text] values derived from seismic traveltime thicknesses were useful for recognizing lithological distributions and identifying favorable reservoir facies. Seismic data across Wister Field, like seismic data across many geothermal fields, have a low signal-to-noise character. We demonstrate that a unified and integrated interpretation of P and S data, even when seismic data quality is not as good as interpreters wish, can still yield valuable information for resource exploitation.

Integrated time-lapse monitoring of a Morrow reservoir using multi-component seismic and flow simulation, Postle Field, Oklahoma

Nataly A. Zerpa and Thomas L. Davis determine whether time-lapse multi-component seismic technology is applicable for not only identifying but monitoring the reservoir at Postle Field, Oklahoma under miscible CO2 water-alternating-gas (WAG) flooding for enhanced oil recovery (EOR).

Data Processing of Marine Multicomponent Seismic-A Case Study of 4-Component 2D OBC data, Offshore Norway-

Multicomponent seismic technology has been improved significantly with higher fidelity acquisition systems and more advanced data analysis methods. Especially in marine seismic, 4-Component Ocean Bottom Cable (OBC) is practically applied for reservoir characterization and exploration at the water depth of more than 1000m. Converted wave processing and interpretation is a fairly new topic and there is a lack of data and expertise around the world. Until now, the most common converted wave data has been essentially 1-D, VSP and OBS (Ocean Bottom Seismometer) records. Recently there is an increasing use of multi-component OBC 2-D and 3-D surveys. They are especially applied to evaluate reservoirs, because it has been revealed that P-S converted waves can give valuable additional lithological information. They also give clear reflections where the P-wave reflections are poor due to a very small acoustic impedance contrast. It is worthwhile that we introduce the actual processing of the 4-C line to discuss on P-S converted wave processing and later to develop new tools and techniques in this rapidly evolving field. Since marine multicomponent seismic survey has not been carried out yet in Japan, we use a 4-Component OBC (4C OBC) 2-D line, acquired by PGS Norway in 1998. The data was purchased by JNOC/TRC in 2002, as a part of the methane hydrate research program, to evaluate the use of P-S converted wave data in determining the properties of the hydrate layer and the BSR. The 4C line was acquired along the track of a previous conventional streamer line which showed a BSR. The location is in the Norwegian Sea, just up-dip of a major sedimentary slide, known as the 'Storegga Slide'. The results of the first investigation of the 4C data were published by Andreassen et al (2001). They presented a very significant difference between the P-wave and the PS converted wave sections in the hydrate layer and around the BSR. In fact, the BSR was not visible on the PS-wave section. The result shows that a lot of additional information is contained in the converted waves. We reprocessed the 4C data and discussed the specific problems.

Multicomponent seismic technology for imaging deep gas prospects

Multicomponent seismic technology for imaging deep gas prospects

Multicomponent seismic technology for imaging deep gas prospects

Across the Gulf of Mexico, operators are targeting deeper and deeper drilling objectives. For deep targets to be evaluated, seismic data require relatively long source-receiver offsets. Most shallow-water operators in the gulf consider 30 000 ft (9 km) to be the deepest target depth that will be drilled for the next several years. For geology at depths of 9 km to be imaged, seismic reflection data must be acquired with offsets of at least 9 km. We suggest in this paper that modern 4-C OBC data can provide good quality P-SV data to such depths and should be integrated into prospect evaluations. Long-offset surveys are difficult to achieve using towed-cable seismic technology in areas congested with production facilities, typical for many shallow-water blocks across the northern Gulf of Mexico shelf. Ocean-bottom-cable (OBC) and ocean-bottom-sensor (OBS) technologies are logical options for long-offset data acquisition in congested production ar-eas because ocean-floor sensors are immobile once deployed and can be positioned quite close to platforms, well heads, or other obstructions that interfere with towed-cable operations. An example illustrating the deployment of ocean-floor sensors through a congested platform complex in part of the area of study is illustrated in Figure 1. A 10-km diameter circle is positioned atop this map of production facilities to illustrate the difficulty of towing a 10-km cable across the area in any azimuth direction. In contrast, OBC lines AA, BB, and CC (actual profiles used in this study) pass within a few meters of several production platforms. Figure 1. 4-C OBC data acquisition across congested areas. An additional appeal of OBC seismic technology is that 4-C data can be acquired, allowing targeted reservoir intervals to be imaged with P-SV wavefields, as well as P-P wavefields. Once 4-C seafloor receivers are deployed, source boats can maneuver along a receiver line to …

A 9-C, 2-D land seismic experiment for lithology estimation of a Permian clastic reservoir

The past 15 years have seen several successful applications of multicomponent seismic technology in hydrocarbon exploration. Many successes have been reported in the marine environment, where statics and surface wave noise are less serious than on land. Nevertheless, research into land multicomponent methods continues with many encouraging results.