scholarly journals Fluid pressure arrival-time tomography: Estimation and assessment in the presence of inequality constraints with an application to production at the Krechba field, Algeria

Geophysics ◽  
2010 ◽  
Vol 75 (6) ◽  
pp. O39-O55 ◽  
Author(s):  
Alessio Rucci ◽  
D. W. Vasco ◽  
Fabrizio Novali
Keyword(s):  
Surface Deformation ◽  
Transient Flow ◽  
Fluid Pressure ◽  
Inequality Constraints ◽  
Gas Production ◽  
Gas Field ◽  
Peak Displacement ◽  
Geomechanical Properties ◽  
Fluid Production ◽  
Using Data

Deformation in the overburden proves useful in deducing spatial and temporal changes in the volume of a producing reservoir. Based on these changes, we have estimated diffusive traveltimes associated with the transient flow due to production, and then, as the solution of a linear inverse problem, the effective permeability of the reservoir. An advantage of the approach based on traveltimes, as opposed to one based on the amplitude of surface deformation, is that it is much less sensitive to the exact geomechanical properties of the reservoir and overburden. Inequalities constrain the inversion, under the assumption that the fluid production only results in pore volume decreases within the reservoir. The formulation has been applied to satellite-based estimates of deformation in the material overlying a thin gas production zone at the Krechba field in Algeria. The peak displacement after three years of gas production is found to be approximately [Formula: see text], overlying the eastern margin of the anticlinal structure defining the gas field. Using data from 15 irregularly spaced images of range change, we have calculated the diffusive traveltimes associated with the startup of a gas production well. The inequality constraints were incorporated into the estimates of model parameter resolution and covariance, improving the resolution by roughly 30% to 40%.

scholarly journals Field-wide reservoir compressibility estimation through inversion of subsidence data above the Groningen gas field

2017 ◽  
Vol 96 (5) ◽  
pp. s117-s129 ◽  
Author(s):  
Rob M.H.E. van Eijs ◽  
Onno van der Wal
Keyword(s):  
Induced Seismicity ◽  
Surface Deformation ◽  
Gas Production ◽  
Potential Threat ◽  
Gas Field ◽  
Reservoir Compaction ◽  
The Difference ◽  
Seismological Model ◽  
Groningen Gas Field ◽  
Deformation Measurements

AbstractNot long after discovery of the Groningen field, gas-production-induced compaction and consequent land subsidence was recognised to be a potential threat to groundwater management in the province of Groningen, in addition to the fact that parts of the province lie below sea level. More recently, NAM's seismological model also pointed to a correlation between reservoir compaction and the observed induced seismicity above the field. In addition to the already existing requirement for accurate subsidence predictions, this demanded a more accurate description of the expected spatial and temporal development of compaction.Since the start of production in 1963, multiple levelling campaigns have gathered a unique set of deformation measurements used to calibrate geomechanical models. In this paper we present a methodology to model compaction and subsidence, combining results from rock mechanics experiments and surface deformation measurements. Besides the optical spirit-levelling data, InSAR data are also used for inversion to compaction and calibration of compaction models. Residual analysis, i.e. analysis of the difference between measurement and model output, provides confidence in the model results used for subsidence forecasting and as input to seismological models.

Natural and anthropogenic origin of subsidence of the Northern Adriatic coast (Italy) from satellite data and modelling

2020 ◽  
Author(s):  
Valeria Secreti ◽  
Elisa Trasatti ◽  
Marco Polcari ◽  
Matteo Albano ◽  
Letizia Anderlini ◽  
...  
Keyword(s):  
Time Series ◽  
Surface Deformation ◽  
Gas Production ◽  
Anthropogenic Factors ◽  
Organic Soils ◽  
Gas Extraction ◽  
Gas Field ◽  
Northern Adriatic ◽  
Hydrocarbon Reservoir ◽  
Gas Pumping

<p>Subsidence can be caused by multiple natural or anthropogenic factors. Natural factors account for compaction of recent sedimentary deposits, oxidation and shrinkage of organic soils. Anthropogenic factors include the pumping of groundwater for human use and the exploitation of hydrocarbon reservoir, both inland and off-shore. The area of Ravenna (Northern Italy) is affected by both anthropogenic and natural subsidence. Natural contribution is due to the compaction of the deposits of the Po plain, of approximately 2 mm/yr. This phenomenon has dramatically increased since the 1950s because of shallow groundwater pumping and deep gas production from several on-shore and off-shore reservoirs in the Upper Adriatic Sea basin.</p><p>In this work, we used SAR, GPS and levelling data to investigate the deformation detected at Lido Di Dante, located along the coastal area of Ravenna. This area is subject to gas pumping of the Angela-Angelina gas field, a gas reservoir exploited since 1973, with platform located very close to the coast, at approximately 2 km from the shoreline. We analysed SAR data from multiple missions from 1992 to 2018. In particular, the ESA’s archives were exploited considering ERS data (ascending and descending orbits, spanning 1992-2000), ENVISAT data (ascending and descending orbits, 2003-2010) and Sentinel-1 satellites (ascending and descending orbits, 2015-2018) and ASI’s images acquired by Cosmo-SkyMed (ascending orbit, 2011-2017). The GPS data are provided by Eni S.p.A. In particular, we consider the GPS ANGA, located offshore on the Angela-Angelina platform, and the GPS FIUN, located near Lido Di Dante. The levelling data are from Eni S.p.A. archives, span 1983-2017.</p><p>The subsidence detected by InSAR (Interferometric SAR) time series at Lido Di Dante from 1992 to 2018 is approximately 250 mm. The ERS time series show a change in the slope between 1997 and 1998, when the Angela-Angelina platform came into operation. There is a general correlation between gas extraction and surface deformation, indeed the subsidence increases when the gas production increases. Therefore, to better analyze the correlation between gas extraction and observed deformation, the exploited reservoir is modelled as a closing crack (dislocation tensile fault), whose contraction rate is constrained by data inversions. The results indicate that the subsidence in the area of Lido di Dante is the sum of natural contribution due to soil compaction and of hydrocarbon extraction activities during the periods of massive extraction.</p><p>In order to better discriminate the factors affecting subsidence we build a Finite Element Model, by means of the software Comsol Multiphysics. The geometry of reservoir has been deduced by literature, while the pressure inside the reservoir is modulated by the GPS signals at ANGA between 1998 and 2018. The results show that the contraction of reservoir due to gas pumping produces measurable deformation along the coastline. The vertical and horizontal cumulative displacements between 1998 and 2018 reach the maximum values of 28 cm and 15-20 cm, respectively.</p><p> </p>

Natural fractures in tight gas sandstones: a case study of the Upper Triassic Xujiahe Formation in Xinchang gas field, Western Sichuan Basin, China

2021 ◽  
pp. 1-18
Author(s):  
Yunzhao Zhang ◽  
Lianbo Zeng ◽  
Wenya Lyu ◽  
Dongsheng Sun ◽  
Shuangquan Chen ◽  
...  
Keyword(s):  
Production Capacity ◽  
Gas Production ◽  
Upper Triassic ◽  
Tight Gas ◽  
Natural Fractures ◽  
Carbon And Oxygen Isotopes ◽  
Gas Field ◽  
Xujiahe Formation ◽  
Western Sichuan ◽  
Tight Gas Reservoir

Abstract The Upper Triassic Xujiahe Formation is a typical tight gas reservoir in which natural fractures determine the migration, accumulation and production capacity of tight gas. In this study, we focused on the influences of natural fractures on the tight gas migration and production. We clarified characteristics and attributes (i.e. dips, apertures, filling degree and cross-cutting relationships) of the fractures based on image logging interpretations and core descriptions. Previous studies of electron spin resonance, carbon and oxygen isotopes, homogenization temperature of fluid inclusions analysis and basin simulation were considered. This study also analysed the fracture sequences, source of fracture fillings, diagenetic sequences and tight gas enrichment stages. We obtained insight into the relationship between fracture evolution and hydrocarbon charging, particularly the effect of the apertures and intensity of natural fractures on tight gas production. We reveal that the bedding fractures are short horizontal migration channels of tight gas. The tectonic fractures with middle, high and nearly vertical angles are beneficial to tight gas vertical migration. The apertures of fractures are controlled by the direction of maximum principal stress and fracture angle. The initial gas production of the vertical wells presents a positive correlation with the fracture abundance, and the intensity and aperture of fractures are the fundamental factors that determine the tight gas production. With these findings, this study is expected to guide the future exploration and development of tight gas with similar geological backgrounds.

scholarly journals Evaluation of natural gas production optimization in Kailashtila gas field in Bangladesh using decline curve analysis method

2015 ◽  
Vol 50 (1) ◽  
pp. 29-38 ◽  
Author(s):  
MS Shah ◽  
HMZ Hossain
Keyword(s):  
Production System ◽  
Gas Production ◽  
Curve Analysis ◽  
Production Optimization ◽  
Reservoir Pressure ◽  
Gas Field ◽  
Wellhead Pressure ◽  
Decline Curve Analysis ◽  
Decline Curve ◽  
Overall Performance

Decline curve analysis of well no KTL-04 from the Kailashtila gas field in northeastern Bangladesh has been examined to identify their natural gas production optimization. KTL-04 is one of the major gas producing well of Kailashtila gas field which producing 16.00 mmscfd. Conventional gas production methods depend on enormous computational efforts since production systems from reservoir to a gathering point. The overall performance of a gas production system is determined by flow rate which is involved with system or wellbore components, reservoir pressure, separator pressure and wellhead pressure. Nodal analysis technique is used to performed gas production optimization of the overall performance of the production system. F.A.S.T. Virtu Well™ analysis suggested that declining reservoir pressure 3346.8, 3299.5, 3285.6 and 3269.3 psi(a) while signifying wellhead pressure with no changing of tubing diameter and skin factor thus daily gas production capacity is optimized to 19.637, 24.198, 25.469, and 26.922 mmscfd, respectively.Bangladesh J. Sci. Ind. Res. 50(1), 29-38, 2015

A Dynamic Workflow of Well Health Issue Prediction – Sulfur Deposition

2021 ◽  
Author(s):  
Bashirul Haq
Keyword(s):  
Material Balance ◽  
Gas Production ◽  
Health Issue ◽  
Sulfur Deposition ◽  
Gas Reservoirs ◽  
Gas Field ◽  
Actual Performance ◽  
Sulphur Deposition ◽  
Balance Analysis ◽  
Sour Gas

Abstract Sour gas reservoirs are vital sources for natural gas production. Sulphur deposition in the reservoir reduces a considerable amount of gas production due to permeability reduction. Consequently, well health monitoring and early prediction of Sulphur deposition are crucial for effective gas production from a sour gas reservoir. Dynamic gas material balance analysis is a useful technique in calculating gas initially in place utilizing the flowing wellhead or bottom hole pressures and rates during the well's lifetime. The approach did not apply to monitor a producing gas's health well and detect Sulphur deposition. This work aims to (i) modify dynamic gas material balance equation by adding the Sulphur deposition term, (ii) build a model to predict and validate the issue utilizing the modified equation. A unique form of the flowing material balance is developed by including Sulphur residue term. The curve fitting tool and modified flowing gas material balance are applied to predict well-expected behaviour. The variation between expected and actual performance indicates the health issue of a well. Initial, individual components of the model are tested. Then the model is validated with the known values. The workflow is applied to active gas field and correctly detected the health issue. The novel workflow can accurately predict Sulphur evidence. Besides,the workflow can notify the production engineers to take corrective measures about the subject. Keywords: Sulfur deposition, Dynamic gas material balance analysis, Workflow

scholarly journals Drill core from seismically active sandstone gas reservoir yields clues to internal deformation mechanisms

Geology ◽  
2020 ◽  
Author(s):  
Berend A. Verberne ◽  
Suzanne J.T. Hangx ◽  
Ronald P.J. Pijnenburg ◽  
Maartje F. Hamers ◽  
Martyn R. Drury ◽  
...  
Keyword(s):  
Microstructural Analysis ◽  
Gas Production ◽  
Drill Core ◽  
Gas Reservoir ◽  
Gas Field ◽  
Reservoir Compaction ◽  
Key Factor ◽  
Forecasting System ◽  
Internal Deformation ◽  
Dauphiné Twinning

Europe’s largest gas field, the Groningen field (the Netherlands), is widely known for induced subsidence and seismicity caused by gas pressure depletion and associated compaction of the sandstone reservoir. Whether compaction is elastic or partly inelastic, as implied by recent experiments, is a key factor in forecasting system behavior and seismic hazard. We sought evidence for inelastic deformation through comparative microstructural analysis of unique drill core recovered from the seismogenic center of the field in 2015, 50 yr after gas production started, versus core recovered before production (1965). Quartz grain fracturing, crack healing, and stress-induced Dauphiné twinning are equally developed in the 2015 and 1965 cores, with the only measurable effect of gas production being enhanced microcracking of sparse K-feldspar grains in the 2015 core. Interpreting these grains as strain markers, we suggest that reservoir compaction involves elastic strain plus inelastic compression of weak clay films within grain contacts.

scholarly journals Research on Gas-liquid Mixed Transportation Technological Adaptability: A Case Study of the Western Sichuan Gas Field

2017 ◽  
Vol 10 (1) ◽  
pp. 37-47
Author(s):  
Qingsha Zhou ◽  
Kun Huang ◽  
Yongchun Zhou
Keyword(s):  
Flow Simulation ◽  
Field Tests ◽  
Economic Benefits ◽  
Gas Production ◽  
Simulation Software ◽  
Rapid Decline ◽  
Gas Field ◽  
Western Sichuan ◽  
Field Development ◽  
Well Production

Background: The western Sichuan gas field belongs to the low-permeability, tight gas reservoirs, which are characterized by rapid decline in initial production of single-well production, short periods of stable production, and long periods of late-stage, low-pressure, low-yield production. Objective: It is necessary to continue pursuing the optimization of transportation processes. Method: This paper describes research on mixed transportation based on simplified measurements with liquid-based technology and the simulation of multiphase processes using the PIPEPHASE multiphase flow simulation software to determine boundary values for the liquid carrying process. Conclusion: The simulation produced several different recommendations for the production and maximum multiphase distance along with difference in elevation. Field tests were then conducted to determine the suitability of mixed transportation in western Sichuan, so as to ensure smooth progress with fluid metering, optimize the gathering process in order to achieve stable and efficient gas production, and improve the economic benefits of gas field development.

Comprehensive Analysis of Production Loggings in Fuling Shale Gas Play in China

2021 ◽  
Author(s):  
Yaowen Liu ◽  
Wei Pang ◽  
Jincai Shen ◽  
Ying Mi
Keyword(s):  
Shale Gas ◽  
Mineral Content ◽  
Horizontal Wells ◽  
Organic Content ◽  
Gas Production ◽  
Liquid Loading ◽  
Comprehensive Overview ◽  
Gas Field ◽  
Well Trajectory ◽  
Positive Effect

Abstract Fuling shale gas field is one of the most successful shale gas play in China. Production logging is one of the vital technologies to evaluate the shale gas contribution in different stages and different clusters. Production logging has been conducted in over 40 wells and most of the operations are successful and good results have been observed. Some previous studies have unveiled one or several wells production logging results in Fuling shale gas play. But production logging results show huge difference between different wells. In order to get better understanding of the results, a comprehensive overview is carried out. The effect of lithology layers, TOC (total organic content), porosity, brittle mineral content, well trajectory is analyzed. Results show that the production logging result is consistent with the geology understanding, and fractures in the favorable layers make more gas contribution. Rate contribution shows positive correlation with TOC, the higher the TOC, the greater the rate contribution per stage. For wells with higher TOC, the rate contribution difference per stage is relatively smaller, but for wells with lower TOC, it shows huge rate contribution variation, fracture stages with TOC lower than 2% contribute very little, and there exist one or several dominant fractures which contributes most gas rate. Porosity and brittle minerals also show positive effect on rate contribution. The gas rate contribution per fracture stage increases with the increase of porosity and brittle minerals. The gas contribution of the front half lateral and that of latter half lateral are relatively close for the "upward" or horizontal wells. However, for the "downward" wells, the latter half lateral contribute much more gas than the front half lateral. It is believed that the liquid loading in the toe parts reduced the gas contribution in the front half lateral. The overview research is important to get a compressive understanding of production logging and different fractures’ contribution in shale gas production. It is also useful to guide the design of horizontal laterals and fractures scenarios design.

Correction for Geomagnetic Secular Variation Effects: A New Method (Case Study of the Altai Geodynamic Network)

2021 ◽  
Vol 62 (2) ◽  
pp. 255-262
Author(s):  
D.A. Kuleshov ◽  
P.G. Dyadkov ◽  
V.V. Plotkin
Keyword(s):  
Secular Variation ◽  
Surface Deformation ◽  
Liquid Core ◽  
New Method ◽  
Space Distribution ◽  
Main Magnetic Field ◽  
Positive Anomaly ◽  
Geomagnetic Secular Variation ◽  
Using Data ◽  
Curie Surface

Abstract ––The study focuses on detection of geomagnetic secular variation and the respective correction of tectonomagnetic data. A new technique is proposed for picking the secular variation component in the Earth’s main magnetic field recorded by precise measurements at 100 to 500 km sites on the surface. Long-period field variations presumably arise from fluid motions in the liquid core, at depths of 3000 km, whereas the sizes of observation networks are within 500 km. The sources of secular variation, irrespective of their configuration, are much deeper than those of tectonomagnetic anomalies located above the Curie surface depths of ~10 to 20 km. Therefore, the surfaces that represent the space distribution of secular variation must be smoother than the respective surfaces for tectonomagnetic anomalies. The problem is thus to separate the regional and local signals from the two types of sources located at different depths. The new method is tested using data of yearly geomagnetic measurements at more than 30 repeat stations of a ~120 km long geodynamic network in Gorny Altai spanning the period from 2004 through 2018. The secular variation pattern is reconstructed by quadratic interpolation. The precise data corrected for secular variation of the main field reveal previously hidden tectonomagnetic anomalies up to 12 nT. The 3 nT positive anomaly falls within the zone of surface deformation caused by the Mw = 7.3 Chuya earthquake of 27 September 2003.

scholarly journals Production-Induced Subsidence at the Los Humeros Geothermal Field Inferred from PS-InSAR

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Eszter Békési ◽  
Peter A. Fokker ◽  
Joana E. Martins ◽  
Jon Limberger ◽  
Damien Bonté ◽  
...  
Keyword(s):  
Synthetic Aperture Radar ◽  
Surface Deformation ◽  
Ground Deformation ◽  
Geothermal Field ◽  
Synthetic Aperture ◽  
Fluid Extraction ◽  
Volume Changes ◽  
Geomechanical Properties ◽  
Reservoir Compartmentalization ◽  
Aperture Radar

Surface deformation due to fluid extraction can be detected by satellite-based geodetic sensors, providing important insights on subsurface geomechanical properties. In this study, we use Differential Interferometric Synthetic Aperture Radar (DInSAR) observations to measure ground deformation due to fluid extraction at the Los Humeros Geothermal Field (Puebla, Mexico). Our main goal is to reveal the pressure distribution in the reservoir and to identify reservoir compartmentalization, which can be important aspects for optimizing the production of the field. The result of the PS-InSAR (Persistent Scatterer by Synthetic Aperture Radar Interferometry) analysis shows that the subsidence at the LHGF was up to 8 mm/year between April 2003 and March 2007, which is small relative to the produced volume of 5×106 m3/year. The subsidence pattern indicates that the geothermal field is controlled by sealing faults separating the reservoir into several blocks. To assess if this is the case, we relate surface movements with volume changes in the reservoir through analytical solutions for different types of nuclei of strain. We constrain our models with the movements of the PS points as target observations. Our models imply small volume changes in the reservoir, and the different nuclei of strain solutions differ only slightly. These findings suggest that the pressure within the reservoir is well supported and that reservoir recharge is taking place.

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