The application of high-resolution 3D seismic acquisition techniques for carbonate reservoir characterization in China

Feng, Xi‐Qiao; Wang, Yanfeng; Wang, Xuejun; Wang, Naijian; Guocheng, Gao; Zhu, Xinjian

doi:10.1190/1.3686914

Cited by 13 publications

(6 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Successful data processing in this area often focuses on preserving the true amplitudes in the whole processing workflow, for example, amplitude compensation, noise attenuation, resolution enhancement, and prestack migration. Significantly, the basic criterion for preserving amplitude is that the AVO characteristics between synthetic and obtained gathers should be similar Zhang et al 2011a,b;Feng et al 2012;Wang et al 2012). Meanwhile, the prestack seismic inversion should be applied by controlling the quality of four major approaches, including angled partial stack data preparation, wavelet estimation, low-frequency model (LFM) building, and inversion parameter control (Zhang et al 2011a,b).…”

Section: Resultsmentioning

confidence: 99%

Fluid mapping in deeply buried Ordovician paleokarst reservoirs in the Tarim Basin, western China

et al. 2015

View full text Add to dashboard Cite

The storage spaces within deeply buried Ordovician paleokarst reservoirs in the Tarim Basin are mostly secondary and characterized by strong heterogeneity and some degree of anisotropy. The types of fluids that fill the spaces within these reservoirs are of great importance for hydrocarbon exploration and exploitation. However, fluid identification from seismic data is often controversial in this area because the seismic velocity for this particular reservoir could be significantly influenced by many factors, including pore shapes, porosity, fluid types, and mineral contents. In this study, we employ the differential effective medium-Gassmann rock physics model to interpret and discuss the characteristics of conventional karstic carbonate reservoirs in the Tarim Basin that are filled with different fluids (oil, gas, and water) using logging data and thus objectively build corresponding fluid identification criteria. These criteria are subsequently evaluated by amplitude versus offset (AVO) forward analysis based on typical logging data and further applied to ascertain the reservoir fluid types in two different areas in the Tarim Basin based on prestack inversion results. For conventional carbonate reservoirs, gas can be distinguished from heavy oil and water, but heavy oil and water are broadly similar on seismic data. For condensate carbonate reservoirs, water can be differentiated from light oil (i.e., condensates) and gas, but light oil and gas demonstrate substantial similarities in terms of their seismic responses. The predicted fluid results are in good agreement with the results of drilling and oil testing. In particular, modeling the seismically resolvable reservoirs in the carbonate strata in the Tarim Basin, which have needle-and sphere-shaped storage spaces (pore aspect ratio > 0.3) and clay content that is lower than 5%, indicates that fluid properties could be properly evaluated if the porosity is larger than 5% for conventional carbonate reservoirs and >7% for condensate carbonate reservoirs.

show abstract

Section: Resultsmentioning

confidence: 99%

Fluid mapping in deeply buried Ordovician paleokarst reservoirs in the Tarim Basin, western China

et al. 2015

View full text Add to dashboard Cite

show abstract

“…The small radius amplitude curvature anomalies appear as bright spot anomalies on the seismic section. Those vertical karst anomalies within the Ellenburger have an almost identical appearance to infilled karst col-lapse features widely seen in the Tarim Basin, China (Chen et al, 2010;Liu et al, 2011;Feng et al, 2012). Those vertical karst anomalies within the Ellenburger have an almost identical appearance to infilled karst col-lapse features widely seen in the Tarim Basin, China (Chen et al, 2010;Liu et al, 2011;Feng et al, 2012).…”

Section: Amplitude Curvaturementioning

confidence: 93%

Attribute expression of fault-controlled karst — Fort Worth Basin, Texas: A tutorial

Zhang

Zhou

et al. 2014

Interpretation

View full text Add to dashboard Cite

Much of seismic interpretation is based on pattern recognition, such that experienced interpreters are able to extract subtle geologic features that a new interpreter may easily overlook. Seismic pattern recognition is based on the identification of changes in (1) amplitude, (2) phase, (3) frequency, (4) dip, (5) continuity, and (6) reflector configuration. Seismic attributes, which providing quantitative measures that can be subsequently used in risk analysis and data mining, partially automate the pattern recognition problem by extracting key statistical, geometric, or kinematic components of the 3D seismic volume. Early attribute analysis began with recognition of bright spots and quickly moved into the mapping of folds, faults, and channels. Although a novice interpreter may quickly recognize faults and channels on attribute time slices, karst terrains provide more complex patterns. We sought to instruct the attribute expression of a karst terrain in the western part of the Fort Worth Basin, Texas, United States of America. Karst provides a specific expression on almost every attribute. Specifically, karst in the Fort Worth Basin Ellenburger Group exhibits strong dip, negative curvature, low coherence, and a shift to lower frequencies. Geomorphologically, the inferred karst geometries seen in our study areas indicate strong structural control, whereby large-scale karst collapse is associated with faults and where karst lineaments are aligned perpendicularly to faults associated with reflector rotation anomalies.

show abstract

“…Although the cost of fullazimuth and high-density seismic acquisition is very expensive, wide-range and high-density seismic data acquisition is particularly necessary for complex carbonate reservoirs dominated by secondary pore space (Feng et al, 2012). Figure 2 shows the imaging-precision comparison for different acquisition systems.…”

Section: Key Issuesmentioning

confidence: 98%

Carbonate reservoirs dominated by secondary storage space: Key issues and technical strategy

et al. 2015

View full text Add to dashboard Cite

Carbonate reservoirs of the Tarim Basin in China are buried deeply, with strong later diagenesis, and seldom are controlled by geologic facies. The effective storage spaces are mainly dissolution caves and fractures with few primary pores. Fluid distribution in the reservoir is extremely complicated. All these characteristics make it a world-class challenge for oil and gas exploration and production. Conventional poststack methods ignore the complexity of the reservoir medium with low accuracy of prediction results, by which the location of the dissolution cave is determined roughly. Only faults and fracture zones can be described to a certain degree instead of quantifying the fracture detection. Aiming at the key problems of the complex carbonate reservoirs in the Tarim Basin, a series of techniques has been developed to improve the successful rate of reservoir prediction, including the following aspects: the wide-azimuth and high-density data-acquisition technique to improve the quality of the original seismic data; a series of migration techniques including prestack reverse time migration; and amplitude-preserved Q migration to improve the quality of seismic gathers and the imaging precision with the matching precision of AVO gathers. The target reservoir data dominant frequency increased by more than 15% and by nearly 20 Hz. In addition, the effective DEM-Gassmann rock-physics model is proposed for velocity prediction, by which relative error of estimated shearwave velocity reaches to less than 5%. Furthermore, an advanced inversion algorithm is introduced to improve the accuracy of extracted elastic information. By using new prestack inversion and frequency-dependent AVO inversion, the tie rate of the dissolution-cave reservoir and fluid prediction increased by more than 15%. Furthermore, the fracture-prediction tie rate can be enhanced by 20% through limited-azimuth anisotropic inversion, on the basis of which the quantitative identification of fracture fluid for actual seismic data can be realized.

show abstract

The application of high-resolution 3D seismic acquisition techniques for carbonate reservoir characterization in China

Abstract: This paper describes major challenges to seismic acquisition in China's Tarim Basin (Figure 1) and how high-resolution 3D seismic surveys can improve reservoir imaging in this area.

Cited by 13 publications

References 2 publications

Fluid mapping in deeply buried Ordovician paleokarst reservoirs in the Tarim Basin, western China

Fluid mapping in deeply buried Ordovician paleokarst reservoirs in the Tarim Basin, western China

Attribute expression of fault-controlled karst — Fort Worth Basin, Texas: A tutorial

Carbonate reservoirs dominated by secondary storage space: Key issues and technical strategy

Contact Info

Product

Resources

About