Unravelling the 'sweet spot' potential of fractured basement in Ketaling High by integrating complex seismic attribute and resistivity log evaluation.

2021 ◽  
Keyword(s):  
Evaluation Method ◽  
Response Analysis ◽  
Production Test ◽  
Well Test ◽  
Seismic Attribute ◽  
Well Location ◽  
Fracture Development ◽  
Fracture Intensity ◽  
Fracture Distribution ◽  
Resistivity Log

A proven Pre-Tertiary basement reservoir along NE-SW Ketaling high trend were already known throughout well test in several wells more than 15 years ago, but lack of interest in basement fractures gas on those past years and limited data provided, locked a potential gas accumulation in fractures. The most recently added data from 3D Seismic data and re-evaluation of log data, could seized those prospect. Combination of structural smoothing towards edge - detecting attributes are conducted, preceding ant track attribute generation as initial input for multi scale fault extraction. The following result is fracture distribution depicting area with intensive fracture location. Fracture intensity cube requires validation from well data. With no core data, slightly indication from drilling data, and only basic log available, resistivity log is a reliable option to be used. Log evaluation technique using response analysis of two resistivity by Rasmus (1982) is performed to identify fracture and fluid content in the basement reservoir, where the higher ratio between LLD/LLS indicate higher fracture intensity. Based on log evaluation method applied in K-1 well, the interval with massive fracture development is identified in metamorphic basement interval. The outcome coincide with the interval which later proven to produce gas higher than 1 MMscfd from production test result. Similarly, fracture intensity distribution from complex seismic attribute, ratified the conclusion from the respective method as well. To test the robustness of this method, identical workflow is assigned on other adjacent well penetrating basement interval, where no indication of hydrocarbon existence. Less intensive fracture interval is concluded occur on the respective well location, which responsible of no accumulation of hydrocarbon on the basement reservoir. The proposed workflow and method can be a solution for overlooked fracture basement reservoir optimization analysis due to limited available subsurface data condition.

The Performance Evaluation of Old Well after SRV in Ordos Basin Tight Oil Reservoir

2014 ◽  
Author(s):  
H.. Wang ◽  
X.. Liao ◽  
H.. Ye ◽  
X.. Zhao ◽  
C.. Liao ◽  
...  
Keyword(s):  
Evaluation Method ◽  
Ordos Basin ◽  
Fracture Network ◽  
Water Flooding ◽  
Tight Oil ◽  
Oil Reservoir ◽  
Well Test ◽  
Stimulated Reservoir Volume ◽  
Tight Oil Reservoir ◽  
Volume Fracturing

Abstract The technology of Stimulated reservoir volume (SRV) has been the key technology for unconventional reservoir development, it can create fracture network in formation and increase the contact area between fracture surface and matrix, thus realizing the three-dimensional stimulation and enhancing single well productivity and ultimate recovery. In China, the Ordos Basin contains large areas of tight oil reservoir with the porosity of 2~12 % and permeability of 0.01~1 mD. The most used development mode is conventional fracturing and water flooding, which is different from the natural depletion mode in oversea, but the development effect is still unfavorable. The idea of SRV is proposed in nearly two years in Changqing Oilfield. SRV measures are implemented in some old wells in tight oil formation. It is a significant problem that should be solved urgently about how to evaluate the volume fracturing effect. Based on the real cases of old wells with SRV measures, the microseismic monitoring is used to analyze the scale of formation stimulation and the complexity of fracture network after volume fracturing; the numerical well test and production data analysis (PDA) are selected to explain the well test data, to analyze the dynamic data, and to compare the changes of formation parameters, fluid parameters and plane streamlines before and after volume fracturing; then the interpretation results of well test with the dynamic of oil and water wells are combined to evaluate the stimulation results of old wells after SRV. This paper has presented a set of screening criteria and an evaluation method of fracturing effect for old well with SRV in tight oil reservoir. It will be helpful to the selection of candidate well and volume fracturing operation in Ordos Basin tight oil reservoir. It should be noted that the evaluation method mentioned in the paper can be expanded to volume stimulation effect evaluation in other unconventional reservoirs, such as tight gas, shale gas and so on.

Predicting Barik Formation Production from Seismic, Khazzan Field, North Oman

2015 ◽  
Author(s):  
T. Chris Stiteler ◽  
M. J. Philip
Keyword(s):  
Second Phase ◽  
Prediction Errors ◽  
Well Test ◽  
Depositional Facies ◽  
Geological Interpretation ◽  
Reservoir Models ◽  
Well Location ◽  
Depositional System ◽  
High Production ◽  
3D Seismic Data

Abstract Prediction of areas of good reservoir deliverability has been achieved by the integration of production data, petrophysical analysis, palaeocurrent analyses, core data and 3D seismic data. The key data in this comparative analysis are derived from a petrophysical workflow, which is calibrated to surveillance data and dynamic well test data. These data include porosity, porosity-thickness (PhiH), permeability, and permeability-thickness (KH). The results of this initial integration are compared with extractions from numerous seismically-generated attribute maps at each well location and used to define preferred seismic PhiH and KH maps. These can be utilised for well planning and further integrated with geocelluar reservoir models. Additional geological interpretation confirms that trends within the Barik depositional system can be recognised on seismic, defining areas which have the potential to have similar thickness, depositional facies and most likely, similar potential production within them. This has led to optimisation of the drilling schedule, allowing rescheduling of wells from areas that are now understood to be potentially poor to areas having higher potential, thus increasing efficiency. Additionally, this work indicates that wells having low production on test conform to areas where low production is predicted, but some wells in the predicted areas of moderate to high production show higher prediction errors than other wells within the same area. This methodology clarifies where differences between predicted and actual measurements occur, allowing the second phase of integration aimed at improving predictions and mitigating risks.

THE LA BELLA AND MINERVA GAS DISCOVERIES, OFFSHORE OTWAY BASIN

1995 ◽  
Vol 35 (1) ◽  
pp. 405 ◽  
Author(s):  
C.W. Luxton ◽  
S. T. Horan ◽  
D.L. Pickavance ◽  
M.S. Durham.
Keyword(s):  
Late Cretaceous ◽  
Oil And Gas ◽  
Hydrocarbon Exploration ◽  
Source Rocks ◽  
Production Test ◽  
Water Contact ◽  
Excellent Quality ◽  
Fault Block ◽  
Well Location ◽  
Gas Fields

In the past 100 years of hydrocarbon exploration in the Otway Basin more than 170 exploration wells have been drilled. Prior to 1993, success was limited to small onshore gas fields. In early 1993, the La Bella-1 and Minerva-1 wells discovered significant volumes of gas in Late Cretaceous sandstones within permits VIC/P30 and VIC/P31 in the offshore Otway Basin. They are the largest discoveries to date in the basin and have enabled new markets to be considered for Otway Basin gas. These discoveries were the culmination of a regional evaluation of the Otway Basin by BHP Petroleum which highlighted the prospectivity of VIC/P30 and VIC/P31. Key factors in this evaluation were:geochemical studies that indicated the presence of source rocks with the potential to generate both oil and gas;the development of a new reservoir/seal model; andimproved seismic data quality through reprocessing and new acquisition.La Bella-1 tested the southern fault block of a faulted anticlinal structure in the southeast corner of VIC/P30. Gas was discovered in two Late Cretaceous sandstone intervals of the Shipwreck Group (informal BHP Petroleum nomenclature). Reservoirs are of moderate to good quality and are sealed vertically, and by cross-fault seal, by Late Cretaceous claystones of the Sherbrook Group. The gas is believed to have been sourced from coals and shales of the Early Cretaceous Eumeralla Formation and the structure appears to be filled to spill as currently mapped. RFT samples recovered dry gas with 13 moI-% CO2 and minor amounts of condensate.Minerva-1 tested the northern fault block of a faulted anticline in the northwest corner of VIC/ P31. Gas was discovered in three excellent quality reservoir horizons within the Shipwreck Group. Late Cretaceous Shipwreck Group silty claystones provide vertical and cross-fault seal. The hydrocarbon source is similar to that for the La Bella accumulation and the structure appears to be filled to spill. A production test was carried out in the lower sand unit and flowed at a rig limited rate of 28.8 MMCFGD (0.81 Mm3/D) through a one-inch choke. The gas is composed mainly of methane, with minor amounts of condensate and 1.9 mol-% C02. Minerva-2A was drilled later in 1993 as an appraisal well to test the southern fault block of the structure to prove up sufficient reserves to pursue entry into developing gas markets. It encountered a similar reservoir unit of excellent quality, with a gas-water contact common with that of the northern block of the structure.The La Bella and Minerva gas discoveries have greatly enhanced the prospectivity of the offshore portion of the Otway Basin. The extension of known hydrocarbon accumulations from the onshore Port Campbell embayment to the La Bella-1 well location, 55 km offshore, demonstrates the potential of this portion of the basin.

Development of an Evaluation Method for Seismic Isolation Systems of Nuclear Power Facilities: Part 3 — Seismic Response of Crossover Piping for Seismic Isolation System

2014 ◽  
Author(s):  
Akihito Otani ◽  
Teruyoshi Otoyo ◽  
Hideo Hirai ◽  
Hirohide Iiizumi ◽  
Hiroshi Shimizu ◽  
...  
Keyword(s):  
Seismic Response ◽  
Nuclear Power ◽  
Seismic Isolation ◽  
Evaluation Method ◽  
Response Spectrum ◽  
Time History ◽  
Response Analysis ◽  
Isolation System ◽  
Isolation Systems ◽  
Seismic Isolation Systems

This paper, which is part of the series entitled “Development of an Evaluation Method for Seismic Isolation Systems of Nuclear Power Facilities”, shows the linear seismic response of crossover piping installed in a seismically isolated plant. The crossover piping, supported by both isolated and non-isolated buildings, deforms with large relative displacement between the two buildings and the seismic response of the crossover piping is caused by two different seismic excitations from the buildings. A flexible and robust structure is needed for the high-pressure crossover piping. In this study, shaking tests on a 1/10 scale piping model and FEM analyses were performed to investigate the seismic response of the crossover piping which was excited and deformed by two different seismic motions under isolated and non-isolated conditions. Specifically, as linear response analysis of the crossover piping, modal time-history analysis and response spectrum analysis with multiple excitations were carried out and the applicability of the analyses was confirmed. Moreover, the seismic response of actual crossover piping was estimated and the feasibility was evaluated.

Development of an Evaluation Method for Seismic Isolation Systems of Nuclear Power Facilities: Part 4 — Failure Behavior of Crossover Piping for Seismic Isolation System

2014 ◽  
Author(s):  
Teruyoshi Otoyo ◽  
Akihito Otani ◽  
Shunsuke Fukushima ◽  
Masakazu Jimbo ◽  
Tomofumi Yamamoto ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Seismic Isolation ◽  
Evaluation Method ◽  
Low Cycle Fatigue ◽  
Response Analysis ◽  
Failure Behavior ◽  
Isolation System ◽  
Isolation Systems ◽  
Seismic Isolation Systems ◽  
Failure Location

This paper provides a part of the series titled “Development of an Evaluation Method for Seismic Isolation Systems of Nuclear Power Facilities”. This part shows the failure behavior of crossover piping installed in a seismic isolated plant. The considered crossover piping is supported on one side by an isolated building and by a non-isolated building on the other side. During an earthquake, the piping structure is deformed due to the large relative displacements between the two buildings and at the same time excited by the different building seismic responses. Therefore, the high-pressure crossover piping structure requires both flexibility and strength. In this study, 1/10 scaled shaking tests and FEM analyses have been performed to investigate the failure behavior of the crossover piping, where both seismic motions and excitations have been taken into account. It was confirmed that the failure occurs at the piping elbow through low cycle fatigue. Moreover, the results of the elastic-plastic response analysis, which simulates an extreme level of excitation corresponding to more than three times the design level, are in good agreement with the test results. The simulation also succeeded in predicting the experimental failure location.

Comprehensive Well Test Interpretation Method, Process, and Multiple Solutions Analysis for Complicated Carbonate Reservoirs

2019 ◽  
Vol 141 (12) ◽  
Author(s):  
Renfeng Yang ◽  
Ruizhong Jiang ◽  
Shirish Patil ◽  
Shun Liu ◽  
Yihua Gao ◽  
...  
Keyword(s):  
Evaluation Method ◽  
Carbonate Reservoir ◽  
Carbonate Reservoirs ◽  
Production Performance ◽  
Physical Parameters ◽  
Test Interpretation ◽  
Well Test ◽  
Pressure Derivative ◽  
Fracture Characteristics ◽  
Parameter Evaluation

Abstract The main characteristic of the complicated carbonate reservoirs is notably strong heterogeneous, leading to a high uncertainty in formation parameter evaluation. The most reliable method for obtaining the dynamic parameters is well test interpretation. However, the well test curve shows similar characteristics for multi-layers reservoirs, dual-medium reservoirs, and carbonate reservoirs with lithology mixed sedimentation lithology. Sometimes the well test fitting result under the mentioned three kinds of models is satisfied, but the interpretation result is quite different. In order to reduce the parameter evaluation multiplicity, the synthetic identification and evaluation method for obtaining the physical parameters of the complicated carbonate reservoir was proposed, based on completion types, core analysis, lithology analysis, and well test results. The evaluation method distinguishes the different carbonate reservoir characteristics from similar well test responses by summarizing and classifying the completion method, reservoir fracture characteristics, and production logging test (PLT) results. The reliability of the proposed method is verified by an application of actual carbonate reservoir parameters evaluation. The proposed method can distinguish among multi-layers reservoirs, dual-medium, and complicated reservoirs with mixed sedimentation lithology whose main characteristic is that concavity existing in the pressure derivative curve. If the well test match results were satisfied enough which lead to the proposed method and process was ignored, the interpretation results and production performance prediction may deviate largely from the actual situation.

Applicability of Seismic Fatigue Evaluation by JSME Code Case, NC-CC-008

2019 ◽  
Author(s):  
Akihito Otani ◽  
Izumi Nakamura ◽  
Tomoyoshi Watakabe ◽  
Masaki Morishita ◽  
Tadahiro Shibutani ◽  
...  
Keyword(s):  
Evaluation Method ◽  
Shaking Table Test ◽  
Shaking Table ◽  
Evaluation Methodology ◽  
Response Analysis ◽  
Analysis Method ◽  
Seismic Evaluation ◽  
Fatigue Evaluation ◽  
Conservative Result ◽  
Current Rule

Abstract A Code Case, JSME S NC1, NC-CC-008, in the framework of JSME Nuclear Codes and Standards has been published. New seismic evaluation methodology for piping by utilizing advanced elastic-plastic response analysis method and strain-based fatigue criteria has been incorporated into the code case. It can achieve more rational seismic design than the current rule. This paper demonstrates validity and applicability of fatigue evaluation method proposed in the code case. Experimental results of a shaking table test for a piping model is used for comparing the evaluation by the current rule with one by the code case. As a result, it is confirmed that the code case can provide a rational and conservative result in the fatigue evaluation of piping. Moreover, cycle counting in the fatigue evaluation was examined for further progress of the code case.

scholarly journals Multi-scale fracture prediction and characterization method of a fractured carbonate reservoir

2020 ◽  
Author(s):  
Zhang Xiaoxia ◽  
Yu Jiajie ◽  
Li Nianyin ◽  
Wang Chao
Keyword(s):  
Large Scale ◽  
Evaluation Method ◽  
Positive Curvature ◽  
Carbonate Reservoir ◽  
Fracture Prediction ◽  
Distribution Data ◽  
Fracture Density ◽  
Multi Scale ◽  
Fractured Carbonate ◽  
Fracture Distribution

Abstract The WZ oilfield is characterized by a small production range, low recovery degree, strong reservoir heterogeneity, and complex fracture distribution. At present, there is no quantitative evaluation method for fractures of different scales. This causes problems that include an unclear understanding of reservoirs’ physical properties and remaining oil distribution and seepage characteristics. In this paper, multi-scale fracture prediction and a quantitative characterization method of a fractured carbonate reservoir are studied using three-dimensional seismic imaging logging and regional tectonic stress field distribution data. On the basis of analogs, variance cube, curvature, and the Pompano through-flowline system, large-scale crack recognition is carried out. Combined with the maximum positive curvature attribute, fracture density, and fracture direction interpreted by imaging logging, a small- and medium-sized fracture model is established. Finally, the multi-scale fracture prediction is carried out. This study has important theoretical significance for accurately describing and characterizing the multi-scale fracture distribution law and guiding the fine development of oilfields.

Constraining the distribution and relationship between overpressure, natural fracture density and temperature in the Cooper Basin, Australia

2016 ◽  
Vol 56 (1) ◽  
pp. 11 ◽  
Author(s):  
David Kulikowski ◽  
Dennis Cooke ◽  
Khalid Amrouch
Keyword(s):  
Uranium Content ◽  
Natural Fracture ◽  
Hydrocarbon Generation ◽  
Fracture Density ◽  
Fracture Detection ◽  
Field Scale ◽  
Seismic Attribute ◽  
Fracture Development ◽  
Generation Mechanisms ◽  
Cooper Basin

To effectively and safely extract hydrocarbon from low permeability and overpressured reservoirs in the Cooper Basin, a thorough understanding of the regional and field scale distribution of overpressure, temperature and fracture density is essential. Previous research omitted the effect of fluid expansion and hydrocarbon generation mechanisms for overpressure generation in the basin, albeit reservoir temperatures have sharply increased in the past five million years. The authors collate pressure (>8,000 samples) and temperature (>6,000 samples) data from 1,095 wells across the SA portion of the Cooper Basin and incorporate natural fracture densities from 28 interpreted borehole image logs to investigate the spatial variation, and potential relationship, between pressure, temperature and natural fracture density. Results show significantly lower geothermal gradients within the Patchawarra Trough, likely attributed to a lack of shallow volcanics, blanketing coals or low uranium content. Shallow volcanics are common in high-temperature areas such as the Moomba/Big Lake and Gidgealpa fields and deeper portions of the Nappamerri Trough, with overpressured wells (>0.45 psi/ft) appearing to cluster in these areas, particularly south of the Gidgealpa-Merrimelia-Innamincka Ridge. Fracture density shows no obvious relationship to pressure, inferring a dominant structural origin for natural fracture development. Although the authors cannot exclusively attribute fluid expansion and hydrocarbon expansion mechanisms to overpressure, they likely have a profound effect. Future work should investigate the feasibility of integrating pressure, vertical stress and sonic velocity to constrain the overpressure generation mechanism within the basin while incorporating field scale seismic attribute analysis for natural fracture detection and overpressure analysis.

A Novel Approach for a better exploitation of a 3D seismic on a development field 

2021 ◽  
Author(s):  
Nasrine Medjdouba ◽  
Zahia Benaissa ◽  
Sabiha Annou
Keyword(s):  
Reservoir Characterization ◽  
Seismic Analysis ◽  
Lower Triassic ◽  
Seismic Inversion ◽  
Reservoir Properties ◽  
Seismic Attribute ◽  
Amplitude Inversion ◽  
Well Location ◽  
Attribute Analysis ◽  
Novel Approach

<p>The main hydrocarbon-bearing reservoirover the study area is the lower Triassic Argilo-Gréseux reservoir. The Triassic sand is deposited as fluvial channels and overbank sands with a thickness ranging from 10 to 20 m, lying unconformably on the Paleozoic formations. Lateral and vertical distribution of the sand bodies is challenging which makes their mapping very difficult andnearly impossible with conventional seismic analysis. </p><p>In order to better define the optimum drilling targets, the seismic attribute analysis and reservoir characterization process were performed targeting suchthin reservoir level, analysis of available two seismic vintages of PSTM cubes as well as post and pre stack inversion results were carried out.The combination of various attributes analysis (RMS amplitude, Spectral decomposition, variance, etc.) along with seismic inversion results has helped to clearly identify the channelized feature and its delineation on various horizon slices and geobodies, the results were reviewed and calibrated with reservoir properties at well location and showed remarkable correlation.</p><p>Ten development wells have been successfully drilledbased on the seismic analysis study, confirming the efficiency of seismic attribute analysis to predicted channel body geometry.</p><p>Keywords: Channel, Attributes, Amplitude, Inversion, Fluvial reservoir.</p>

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