Compressive seismic data acquisition in a desert area of western China: A case study

2020 ◽  
Vol 39 (5) ◽  
pp. 340-344
Author(s):  
Guoxu Shu ◽  
Taikun Shi ◽  
Liang Huang ◽  
Zhenghui Gao ◽  
Gonghe Lv ◽  
...  
Keyword(s):  
Seismic Data ◽  
Western China ◽  
Seismic Exploration ◽  
Data Reconstruction ◽  
Desert Area ◽  
Data Set ◽  
Imaging Quality ◽  
Seismic Data Acquisition ◽  
Legacy Data

The seismic exploration industry continuously demands better imaging quality and consequently requires denser spatial sampling, which increases acquisition cost and time. To alleviate this burden, compressive sensing (CS) theory has been introduced in the design of acquisition geometry, as it requires fewer shot and receiver locations than traditional methods. In 2017, we conducted a field experiment in a desert area in western China. This was the first such test in China to utilize CS theory in a field test. The survey had 1760 shot records with irregular shot and receiver locations designed with guidance from CS theory. By way of data reconstruction, a seismic data set with higher sampling density (7.5 × 7.5 m bin size) was acquired, and the imaging quality was improved significantly compared to existing legacy data (15 × 15 m bin size). These results indicate that a CS-designed acquisition may reduce cost while enhancing imaging quality.

Trends in onshore seismic data acquisition: a case study on cable-free nodal systems

2016 ◽  
Vol 56 (2) ◽  
pp. 601
Author(s):  
Nabeel Yassi
Keyword(s):  
Data Quality ◽  
Data Acquisition ◽  
Seismic Data ◽  
Seismic Exploration ◽  
Quality Data ◽  
Seismic Surveys ◽  
The Past ◽  
Seismic Data Acquisition ◽  
2D And 3D

The desire to conduct onshore seismic surveys without cables has been an elusive dream since the dawn of seismic exploration. Since the late 1970s, seismic surveys were conducted with cabled multi-channels acquisition systems. As the number of channels steadily grew, a fundamental restriction appeared with hundreds of kilometres of line cables dragged on the ground. Seismic surveys within rugged terrain—across rivers, steep cliffs, urban areas, and culturally and environmentally sensitive zones—were both challenging and expansive exercises. Modern technology has made different cable-free solutions practical. High-resolution analogue to digital converters are now affordable, as are GPS radios for timing and location. Microprocessors and memory are readily available for autonomous recording systems, along with a battery the size and weight of a field nodal now promising to power an acquisition unit for as long as required for normal seismic crew operations. Many successful 2D and 3D seismic data acquisition using cable-free autonomous nodal systems were attempted in the past few years; however, there remain a number of concerns with these systems. The first concern queries whether the units are working according to manufacturer specifications during the data acquisition window. The second is the limited or no real-time data quality control that inspires sceptics to use the term blind acquisition to nodal operations. The third is the traditional question of geophone array versus point receiver acquisition. Although a string of the geophone can be connected to autonomous nodes, the preference is to deploy a single or internal geophone with the nodes to maintain the proposed flexibility of cable-free recording systems. This case study elaborates on the benefits of the cable-free seismic surveys, with specific examples of 2D and 3D exploration programs conducted in Australia in the past few years. Optimisation of field crew size, field crew resources, cost implications, and footprint to the environment, wildlife and domestic livestock will be discussed. In addition, the study focuses on the data quality/data assurance and the processes implanted during data acquisition to maintain equivalent industry standards to cable recording. Emphases will also include data analysis and test results of the geophone array versus the cable-free point receiver recording.

scholarly journals Investigation of geophysical challenges in land seismic data acquisition in Nigeria: case study of parts of the Niger Delta region

2021 ◽  
Vol 11 (2) ◽  
pp. 587-599
Author(s):  
C. N. Onwubuariri ◽  
L. S. Al-Naimi ◽  
B. I. Ijeh ◽  
T. I. Mgbeojedo ◽  
M. U. Igboekwe ◽  
...  
Keyword(s):  
Seismic Data ◽  
Niger Delta ◽  
Weather Conditions ◽  
Seismic Exploration ◽  
Noise Interference ◽  
Niger Delta Region ◽  
Cloudy Weather ◽  
Seismic Acquisition ◽  
Seismic Data Acquisition

AbstractGeophysical analysis was carried out to evaluate the challenges encountered in land seismic exploration within the study area. This analysis cuts across various stages in land seismic acquisition. These stages include the following: the availability of the prospect map as originally planned by the prospect owners—the client, the desk study and planning of this map by the seismology section (planning seismologist) for acquisition convenience and the field implementation of the acquisition which the survey, drill and recording (preloading, shooting, swath move, line check, LAUX crew and recording platform) sections carried out. The challenges observed included environmental challenges, noise interference, weather conditions (statics or electrostatics interference), line break, faulty equipment, wrong detailing, cake or expired explosives, poor or compromised supervision, security and permit challenges. These challenges are peculiar to Nigeria due to inadequate implementation of policies that guide human settlements and activities. Nigeria is within the climate region where most at times it is very impossible to control natural events like cloudy weather, rainfall, thundering and lightening. As such, the problem of static charges interfering with acquired seismic data becomes inevitable, mostly during the rainy season. Almost total dependency on imported technology and lack of readily available experienced manpower also contribute to these challenges, most especially when it has to do with proper inspection of equipment and materials required for the acquisition and supervision processes. Approaches to follow to minimize the observed challenges were equally highlighted.

Applications of Artificial Neural Networks for Seismic Facies Classification

2021 ◽  
Vol 73 (02) ◽  
pp. 68-69
Author(s):  
Chris Carpenter
Keyword(s):  
Neural Network ◽  
Seismic Data ◽  
Reservoir Characterization ◽  
Probabilistic Neural Network ◽  
Oil Field ◽  
Seismic Facies ◽  
Data Set ◽  
Full Field ◽  
Facies Classification

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 200577, “Applications of Artificial Neural Networks for Seismic Facies Classification: A Case Study From the Mid-Cretaceous Reservoir in a Supergiant Oil Field,” by Ali Al-Ali, Karl Stephen, SPE, and Asghar Shams, Heriot-Watt University, prepared for the 2020 SPE Europec featured at the 82nd EAGE Conference and Exhibition, originally scheduled to be held in Amsterdam, 1-3 December. The paper has not been peer reviewed. Facies classification using data from sources such as wells and outcrops cannot capture all reservoir characterization in the interwell region. Therefore, as an alternative approach, seismic facies classification schemes are applied to reduce the uncertainties in the reservoir model. In this study, a machine-learning neural network was introduced to predict the lithology required for building a full-field Earth model for carbonate reservoirs in southern Iraq. The work and the methodology provide a significant improvement in facies classification and reveal the capability of a probabilistic neural network technique. Introduction The use of machine learning in seismic facies classification has increased gradually during the past decade in the interpretation of 3D and 4D seismic volumes and reservoir characterization work flows. The complete paper provides a literature review regarding this topic. Previously, seismic reservoir characterization has revealed the heterogeneity of the Mishrif reservoir and its distribution in terms of the pore system and the structural model. However, the main objective of this work is to classify and predict the heterogeneous facies of the carbonate Mishrif reservoir in a giant oil field using a multilayer feed-forward network (MLFN) and a probabilistic neural network (PNN) in nonlinear facies classification techniques. A related objective was to find any domain-specific causal relationships among input and output variables. These two methods have been applied to classify and predict the presence of different facies in Mishrif reservoir rock types. Case Study Reservoir and Data Set Description. The West Qurna field is a giant, multibillion-barrel oil field in the southern Mesopotamian Basin with multiple carbonate and clastic reservoirs. The overall structure of the field is a north/south trending anticline steep on the western flank and gentle on the eastern flank. Many producing reservoirs developed in this oil field; however, the Mid- Cretaceous Mishrif reservoir is the main producing reservoir. The reservoir consists of thick carbonate strata (roughly 250 m) deposited on a shallow water platform adjacent to more-distal, deeper-water nonreservoir carbonate facies developing into three stratigraphic sequence units in the second order. Mishrif facies are characterized by a porosity greater than 20% and large permeability contrast from grainstones to microporosity (10-1000 md). The first full-field 3D seismic data set was achieved over 500 km2 during 2012 and 2013 in order to plan the development of all field reservoirs. A de-tailed description of the reservoir has been determined from well logs and core and seismic data. This study is mainly based on facies log (22 wells) and high-resolution 3D seismic volume to generate seismic attributes as the input data for the training of the neural network model. The model is used to evaluate lithofacies in wells without core data but with appropriate facies logs. Also, testing was carried out in parallel with the core data to verify the results of facies classification.

Applying integrated seismic technology to complex foothill areas of foreland basins in China

2019 ◽  
Vol 38 (8) ◽  
pp. 597-603
Author(s):  
Yong Fang ◽  
Wenshan Luo ◽  
Xiaoxia Luo ◽  
Xukui Feng ◽  
Bo Zhao ◽  
...  
Keyword(s):  
Seismic Data ◽  
Model Building ◽  
New Technologies ◽  
High Density ◽  
Hydrocarbon Exploration ◽  
Western China ◽  
Seismic Exploration ◽  
Foreland Basins ◽  
Near Surface ◽  
True Surface

Due to complicated near-surface conditions, including large elevation changes and complex geologic structures, accurate imaging of subsurface structures for hydrocarbon exploration in the foreland basins of western China has been challenging for many years. After decades of research and fieldwork, we developed an effective seismic exploration workflow that uses the latest technologies from acquisition to imaging. They include 3D high-density and wide-azimuth (WAZ) acquisition, 3D true-surface tilted transverse isotropy (TTI) anisotropic prestack depth migration, and dual-detachment structural modeling and interpretation. To further reduce uncertainty in velocity model building and improve imaging quality, our geologists, geophysicists, and reservoir engineers worked closely through the exploration cycle (seismic acquisition, processing, and interpretation). This exploration model has been used successfully in hydrocarbon exploration of many complex foothill areas in western China. Three-dimensional WAZ high-density seismic surveys have been conducted over 40,000 km2 of the foreland basins, greatly improving the field seismic data quality. After application of 3D true-surface TTI anisotropic depth model building and imaging with integrated structural interpretation, new discoveries of hydrocarbon reservoirs have increased. The application of new technologies not only increased drilling success but also reduced depth well-tie errors between seismic data and wells.

A statistical methodology for deriving reservoir properties from seismic data

Geophysics ◽  
1995 ◽  
Vol 60 (5) ◽  
pp. 1437-1450 ◽  
Author(s):  
Frédérique Fournier ◽  
Jean‐François Derain
Keyword(s):  
Seismic Data ◽  
Large Scale ◽  
Seismic Attributes ◽  
Seismic Facies ◽  
Reservoir Properties ◽  
Data Set ◽  
Analysis Technique ◽  
Seismic Facies Analysis ◽  
Statistical Relationships

The use of seismic data to better constrain the reservoir model between wells has become an important goal for seismic interpretation. We propose a methodology for deriving soft geologic information from seismic data and discuss its application through a case study in offshore Congo. The methodology combines seismic facies analysis and statistical calibration techniques applied to seismic attributes characterizing the traces at the reservoir level. We built statistical relationships between seismic attributes and reservoir properties from a calibration population consisting of wells and their adjacent traces. The correlation studies are based on the canonical correlation analysis technique, while the statistical model comes from a multivariate regression between the canonical seismic variables and the reservoir properties, whenever they are predictable. In the case study, we predicted estimates and associated uncertainties on the lithofacies thicknesses cumulated over the reservoir interval from the seismic information. We carried out a seismic facies identification and compared the geological prediction results in the cases of a calibration on the whole data set and a calibration done independently on the traces (and wells) related to each seismic facies. The later approach produces a significant improvement in the geological estimation from the seismic information, mainly because the large scale geological variations (and associated seismic ones) over the field can be accounted for.

Diffractivity — Another attribute for the interpretation of seismic data in hard rock environment, a case study

2016 ◽  
Vol 4 (4) ◽  
pp. B23-B32 ◽  
Author(s):  
Mohammad Javad Khoshnavaz ◽  
Andrej Bóna ◽  
Muhammad Shahadat Hossain ◽  
Milovan Urosevic ◽  
Kit Chambers
Keyword(s):  
Seismic Data ◽  
Hard Rock ◽  
Shear Zones ◽  
Primary Objective ◽  
Seismic Exploration ◽  
Image Point ◽  
Small Scale ◽  
Imaging Method ◽  
Data Set ◽  
Diffraction Imaging

The primary objective of seismic exploration in a hard rock environment is the detection of heterogeneities such as fracture zones, small-scale geobodies, intrusions, and steeply dipping structures that are often associated with mineral deposits. Prospecting in such environments using seismic-reflection methods is more challenging than in sedimentary settings due to lack of continuous reflector beds and predominance of steeply dipping hard rock formations. The heterogeneities and “fractal” aspect of hard rock geologic environment produce considerable scattering of the seismic energy in the form of diffracted waves. These scatterers can be traced back to irregular and often “sharp-shaped” mineral bodies, magmatic intrusions, faults, and complex and heterogeneous shear zones. Due to the natural lack of reflectors and abundant number of diffractors, there are only a few case studies of diffraction imaging in hard rock environments. There are almost no theoretical models or field examples of diffraction imaging in prestack domain. We have filled this gap by applying a 3D prestack diffraction imaging method to image point diffractors. We calculated the diffractivity by computing the semblance of seismic data along diffraction traveltime curves in the prestack domain. The performance of the method is evaluated on a synthetic case and a field seismic data set collected over the Kevitsa mineral deposit in northern Finland. The high-resolution results obtained by the application of prestack diffraction imaging suggest that diffractivity is a robust attribute that can be used in addition to other seismic attributes for the interpretation of seismic data in hard rock environment.

Design and application of a towed land‐streamer system for cost‐effective 2-D and pseudo-3-D shallow seismic data acquisition

Geophysics ◽  
2001 ◽  
Vol 66 (2) ◽  
pp. 482-500 ◽  
Author(s):  
M. van der Veen ◽  
R. Spitzer ◽  
A. G. Green ◽  
P. Wild
Keyword(s):  
Data Acquisition ◽  
Cross Sections ◽  
Seismic Data ◽  
Simulated Data ◽  
Cost Effective ◽  
Original Data ◽  
Data Set ◽  
Rubber Sheet ◽  
Shallow Seismic ◽  
Seismic Data Acquisition

To reduce the field effort required for 2-D and 3-D shallow seismic surveying, we have developed a towed land‐streamer system. It was constructed with self‐orienting gimbal‐mounted geophones housed in heavy (1 kg) cylindrical casings, sturdy seismic cables with reinforced kevlar sheathing, robust waterproof connectors, and a reinforced rubber sheet that helped prevent cable snagging, maintained geophone alignment, and provided additional hold‐down weight for the geophones. Each cable had takeouts for 12 geophones at 1 m or 2 m intervals. By eliminating the need for manual geophone planting and cable laying, acquisition of 2-D profiles with this system proved to be 50–100% faster with 30–40% fewer personnel than conventional procedures. Costs of the land‐streamer system and total weight to be pulled could be minimized by employing nonuniform receiver configurations. Short receiver intervals (e.g., 1 m) at near offsets were necessary for identifying and mapping shallow (<50 m) reflections, whereas larger receiver intervals (e.g., 2 m) at far offsets were sufficient for imaging deeper (>50 m) reflections and estimating velocity‐depth functions. Our land‐streamer system has been tested successfully on a variety of recording surfaces (e.g., meadow, asphalt road, and compact gravel track). The heavy weight of the geophone casings and rubber sheet ensured good geophone‐to‐ground coupling. On the asphalt surface, a greater proportion of high‐frequency (above 300–350 Hz) energy was recorded by the land streamer than by standard baseplate‐mounted geophones. The land‐streamer system is a practical and efficient means for surveying in urbanized areas. Acquisition and processing of 3-D shallow seismic data with the land‐streamer system was simulated by appropriately decimating and reprocessing an existing 3-D shallow seismic data set. Average subsurface coverage of the original data was ∼50 fold, whereas that of the simulated data was ∼5 fold. The effort required to collect the simulated pseudo-3-D data set would have been approximately 7% of that needed for the original field campaign. Application of important data‐dependent processing procedures (e.g., refraction static corrections and velocity analyses) to the simulated data set produced surprisingly good results. Because receiver spacing along simulated cross‐lines (6 m) was double that along in‐lines (3 m), a pattern of high and low amplitudes was observed on cross‐sections and time slices at early traveltimes (⩽50 ms). At greater traveltimes, all major reflections could be identified and mapped on the land‐streamer data set. With this cost‐effective approach to pseudo-3-D seismic data acquisition, it is expected that shallow 3-D seismic reflection surveying will become attractive for a broader range of engineering and environmental applications.

scholarly journals Supplemental Material: Intrarift fault fabric, segmentation, and basin evolution of the Lake Malawi (Nyasa) Rift, East Africa

2020 ◽  
Author(s):  
C.A. Scholz ◽  
et al.
Keyword(s):  
Seismic Data ◽  
Data Interpretation ◽  
Background Information ◽  
Gis Analysis ◽  
Structural Restoration ◽  
Main Paper ◽  
Local Relief ◽  
Seismic Data Acquisition ◽  
Legacy Data ◽  
Segment Data

Provides additional background to methodologies used for analyses presented in main paper. Presents background information on SEGMeNT Project; summary of seismic data acquisition parameters; SEGMeNT data processing and legacy data reprocessing details; seismic data interpretation and integration methods; GIS analysis of local relief in the rift; expanded summary of structural restoration methods; summary of volcanic load estimates and methods; summary of the lineament analyses; and discussion of the age of the Malawi Rift.

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