Integrating Horizontal Wellbores When Building a Geological Model of an Offshore Field

2021 ◽  
Author(s):  
Oksana Vasilievna Kokareva ◽  
Yana Andreevna Miryasova ◽  
Tamara Aleksandrovna Alekseeva
Keyword(s):  
Thin Layers ◽  
Geological Model ◽  
Reservoir Properties ◽  
Neutron Porosity ◽  
Model Geometry ◽  
Dip Angle ◽  
Interpretation Algorithm ◽  
Density Image ◽  
Horizontal Wellbores ◽  
Offshore Field

Abstract With the advent of the equipment for full well logging suite in the horizontal wells, it became possible to evaluate the reservoir's quantitative parameters. However, the original curves are mainly used for this purpose, which leads to significant errors, in particular due to the significant influence of nearby reservoirs on the tools readings in the penetrated deposits. There is a need to discuss the current issues of interpretation in directional, horizontal and multi-lateral wells with the experts. 3DP module in the downhole software platform* allows to evaluate the overall influence of geometric effects, as well as to adjust logging curves for the influence of several reservoirs on the logging tools responses, which are not still taken into account by conventional methods when processing. The modeled density image is especially useful for confirming the model geometry, updating the local dip angle, and identifying areas, where additional features, such as thin layers, are to be added. The accounting for density and neutron porosity for layers in the petrophysical analysis increases the efficiency of calculating clay volume and porosity, which affects the saturation. The authors also proposed a methodology for assessing share of sand component based on RHOB image. Further accounting of NTG, for the correct assessment of the reservoir properties in a heterogeneous reservoir, followed by the data accounting in the geological model. The results obtained in the course of the work allowed to apply the spatial interpretation of horizontal well in geological modeling, as well as to improve the interpretation algorithm.

Geological model and optimal well placement substantiation at the western part Tyumen suite layers of Khanty-Mansiysk Autonomous Okrug — Ugra

2021 ◽  
pp. 8-24
Author(s):  
S. R. Bembel ◽  
R. V. Avershin ◽  
R. M. Bembel ◽  
V. I. Kislukhin
Keyword(s):  
Seismic Survey ◽  
Geological Model ◽  
Reservoir Properties ◽  
Well Placement ◽  
Oil Reserves ◽  
Multi Stage ◽  
Reservoir Conditions ◽  
Hydrodynamic Calculations ◽  
Field Information ◽  
Clay Barriers

The middle Jurassic Tyumen sediments have been involved in the development of oil facilities in the territory of the Khanty-Mansiysk Autonomous Okrug — Ugra for the last decade. The Jk2-5 formation is represented by complex interlayering of poorly permeable sandy-aleurite lenses and clay barriers with low reservoir properties. Recoverable oil reserves of the Jk2-5 formation on the Krasnoleninsky arch amounts to several hundred million tons. According to the collector permeability, the reserves of the object are classified as hard-to-recover. There are no effective technologies to involve such reserves in the development now. Standard methods of drilling and operation of inclined wells doesn't allow achieving acceptable oil production rates under these reservoir conditions. Based on the analysis of seismic survey data, correlation of well sections, field information, a geological model of a productive reservoir on the Krasnoleninsky arch was created. The multi-step hydrodynamic calculations made it possible to clarify the parameters of the profile of horizontal wells, the number and configuration of operations for multi-stage hydraulic fracturing. Based on the results of the research, recommendations were developed to well placement, drilling and well operation for specific field areas in order to increase the oil resource development efficiency.

scholarly journals Data assimilation and uncertainty assessment in 3D geological modeling

2017 ◽  
Author(s):  
Daniel Schweizer ◽  
Philipp Blum ◽  
Christoph Butscher
Keyword(s):  
Data Assimilation ◽  
Information Entropy ◽  
Model Uncertainty ◽  
Model Space ◽  
Distance Measures ◽  
Geological Model ◽  
Multiple Model ◽  
Geological Data ◽  
3D Geological Modeling ◽  
Model Geometry

Abstract. The quality of a 3D geological model strongly depends on the type of integrated geological data, their interpretation and associated uncertainties. In order to improve an existing geological model and effectively plan further site investigation, it is of paramount importance to identify existing uncertainties within the model space. Information entropy, a voxel based measure, provides a method for assessing structural uncertainties, comparing multiple model interpretations and tracking changes across consecutively built models. The aim of this study is to evaluate the effect of data assimilation on model uncertainty, model geometry and overall structural understanding. Several geological 3D models of increasing complexity, incorporating different input data categories, were built for the study site Staufen (Germany). We applied the concept of information entropy in order to visualize and quantify changes in uncertainty between these models. Furthermore, we propose two measures, the Jaccard and the City-Block distance, to directly compare dissimilarities between the models. The study shows that different types of geological data have disparate effects on model uncertainty and model geometry. The presented approach using both information entropy and distance measures can be a major help in the optimization of 3D geological models.

scholarly journals Modern geodynamics and its influence on the secondary filtration properties of the collectors of the northeast part of the Sakhalin shelf

2017 ◽  
pp. 16-23
Author(s):  
V. A. Zaitsev ◽  
V. Yu. Kerimov ◽  
S. G. Ryabukhina ◽  
A. V. Bondarev
Keyword(s):  
3D Model ◽  
Hydrodynamic Modeling ◽  
Geological Model ◽  
Okhotsk Sea ◽  
Tectonic Structure ◽  
Reservoir Properties ◽  
Horizontal Migration ◽  
Porosity And Permeability ◽  
Filtration Properties ◽  
Geodynamic Activity

The complex tectonic structure of the Okhotsk Sea shelf and high geodynamic activity makes it necessary to use of geomechanical modeling for the prediction of the secondary reservoir properties of collectors. 3D model of fractured porosity and permeability for Kirinskoye, Ayashsky and East-Odoptinsky license areas was built. The results of modeling revealed filtration channels where can occur both vertical and horizontal migration of hydrocarbons. It is found that the secondary permeability significantly is different of the upper and lower stratigraphic horizons and the okobykayskaya clay stratum is the surface, which is a regional tire. All calculations were performed on a 3D grid geological model, which allows using the data for hydrodynamic modeling.

scholarly journals Uncertainty assessment in 3-D geological models of increasing complexity

Solid Earth ◽  
2017 ◽  
Vol 8 (2) ◽  
pp. 515-530 ◽  
Author(s):  
Daniel Schweizer ◽  
Philipp Blum ◽  
Christoph Butscher
Keyword(s):  
Information Entropy ◽  
Model Uncertainty ◽  
Model Space ◽  
Distance Measures ◽  
Geological Model ◽  
Multiple Model ◽  
Geological Data ◽  
Geological Models ◽  
Different Types ◽  
Model Geometry

Abstract. The quality of a 3-D geological model strongly depends on the type of integrated geological data, their interpretation and associated uncertainties. In order to improve an existing geological model and effectively plan further site investigation, it is of paramount importance to identify existing uncertainties within the model space. Information entropy, a voxel-based measure, provides a method for assessing structural uncertainties, comparing multiple model interpretations and tracking changes across consecutively built models. The aim of this study is to evaluate the effect of data integration (i.e., update of an existing model through successive addition of different types of geological data) on model uncertainty, model geometry and overall structural understanding. Several geological 3-D models of increasing complexity, incorporating different input data categories, were built for the study site Staufen (Germany). We applied the concept of information entropy in order to visualize and quantify changes in uncertainty between these models. Furthermore, we propose two measures, the Jaccard and the city-block distance, to directly compare dissimilarities between the models. The study shows that different types of geological data have disparate effects on model uncertainty and model geometry. The presented approach using both information entropy and distance measures can be a major help in the optimization of 3-D geological models.

Feasibility Analysis of Fractured-Horizontal Well Development in HuaQing Ultra-Low Permeability Reservoir

2013 ◽  
Vol 772 ◽  
pp. 755-760
Author(s):  
Shao Yuan Mo ◽  
Shun Li He ◽  
Shuai Wang ◽  
Hai Yong Zhang ◽  
Li Jing Chang ◽  
...  
Keyword(s):  
Horizontal Well ◽  
Oil Field ◽  
Low Permeability ◽  
Geological Model ◽  
Reservoir Properties ◽  
Fracture Spacing ◽  
Low Permeability Reservoir ◽  
Horizontal Length ◽  
Fractured Horizontal Well ◽  
Half Length

Fractured-horizontal well can effectively reduce the percolation resistance near wellbore, improve the fluid mobility and enhance the production. However, in Chang 6 ultra-low permeability reservoir, BaiBao block, HuaQing oilfield, the efficiency of fractured-horizontal well is highly poor due to the production swiftly down and water cut sharply up. For studying the unsatisfying oil development by fractured-horizontal well in HuaQing oil field, the evaluation of reservoir properties and the option of stratum for fractured-horizontal well application have been performed based on the practical geological model of BaiBao block in HuaQing oil field. The numerical simulation is used to study the effect of reservoir permeability, Thickness and Aeolotropism on the production and to optimize the horizontal length, fracture spacing, half length and conductivity. The conclusion shows that Chang 63 stratum is qualified for fractured-horizontal well application. Through the practical geological model, the optimizations of horizontal length range, fracture spacing, half length and conductivity are 800m to 1200m, 77m, 150m, and 15μm2cm, respectively. The results can be conducted for fractured-horizontal well application in HuaQing oil field.

Sequence stratigraphic analysis and integrated 3D geological modeling of M1 block, Wenmingzhai oilfield, Dongpu depression, China

2013 ◽  
Vol 5 (3) ◽  
Author(s):  
Xue Li ◽  
Jinliang Zhang ◽  
Yong Yuan ◽  
Cunlei Li ◽  
Ningning Meng
Keyword(s):  
High Resolution ◽  
Stratigraphic Correlation ◽  
Geological Model ◽  
Geological Modeling ◽  
Reservoir Properties ◽  
3D Geological Modeling ◽  
Sequence Stratigraphic ◽  
Work Related ◽  
3D Geological Model ◽  
Geological Research

AbstractThe M1 block is a typically complex fault-block oilfield, whose recovery has reached 30.5% through the twenty years waterflooding development. Remaining oil scatters very widely and the production between layers is in a high degree. However, many problems have been exposed at the same time which hinder improvement of the recovery rate and sustainable development of the reservoir. Hence, it is important to carry out basic geological research and form a comprehensive understanding of reservoir properties. However, few such studies have been conducted in China. In this study, work related to basic geological research was conducted based on high-resolution sequence stratigraphy, seismic interpretation technology and 3D visual geological modeling, and significant results were achieved. Three sequence orders and three types of interfacies in the stratigraphic architecture of M1 block were identified through seismic sections, logging curve characteristics and entropy spectrum analysis. Thirty-two short-term sequence cycles (fifth order), eight mid-term sequence cycles (fourth order) and two long-term sequence cycles (third order) were identified, followed by the establishment of a high-resolution isochronous stratigraphic correlation framework. Finally, a regional 3D geological model was established on the basis of these preliminary studies. The integrated 3D geological model is a valuable tool for reflecting geological bodies accurately, and it can accurately represent and describe reservoir heterogeneity.

scholarly journals A Practical Method to Calculate and Model the Petrophysical Properties of Reservoir Rock Using Petrel Software: A case Study from Iraq

2020 ◽  
pp. 2640-2650
Author(s):  
Sarah Taboor Wali ◽  
Hussain Ali Baqer
Keyword(s):  
Water Saturation ◽  
Three Dimensional ◽  
Carbonate Reservoir ◽  
Reservoir Rock ◽  
Sequential Gaussian Simulation ◽  
Geological Model ◽  
Petrophysical Properties ◽  
Reservoir Properties ◽  
Software Models ◽  
Average Water

Nasiriyah oilfield is located in the southern part of Iraq. It represents one of the promising oilfields. Mishrif Formation is considered as the main oil-bearing carbonate reservoir in Nasiriyah oilfield, containing heavy oil (API 25o(. The study aimed to calculate and model the petrophysical properties and build a three dimensional geological model for Mishrif Formation, thus estimating the oil reserve accurately and detecting the optimum locations for hydrocarbon production. Fourteen vertical oil wells were adopted for constructing the structural and petrophysical models. The available well logs data, including density, neutron, sonic, gamma ray, self-potential, caliper and resistivity logs were used to calculate the petrophysical properties. The interpretations and environmental corrections of these logs were performed by applying Techlog 2015 software. According to the petrophysical properties analysis, Mishrif Formation was divided into five units (Mishrif Top, MA, shale bed, MB1 and MB2).    A three-dimensional geological model, which represents an entrance for the simulation process to predict reservoir behavior under different hydrocarbon recovery scenarios, was carried out by employing Petrel 2016 software. Models for reservoir characteristics (porosity, permeability, net to gross NTG and water saturation) were created using the algorithm of Sequential Gaussian Simulation (SGS), while the variogram analysis was utilized as an aid to distribute petrophysical properties among the wells.      The process showed that the main reservoir unit of Mishrif Formation is MB1 with a high average porosity of 20.88% and a low average water saturation of 16.9%. MB2 unit has good reservoir properties characterized by a high average water saturation of 96.25%, while MA was interpreted as a water-bearing unit. The impermeable shale bed unit is intercalated between MA and MB1 units with a thickness of 5-18 m, whereas Mishrif top was interpreted as a cap unit. The study outcomes demonstrated that the distribution accuracy of the petrophysical properties has a significant impact on the constructed geological model which provided a better understanding of the study area’s geological construction. Thus, the estimated reserve h was calculated to be about 7945 MSTB. This can support future reservoir development plans and performance predictions. 

Advanced Formation Evaluation Approaches in Complex Low-Resistivity Thin Shale Sand Laminations: Success Case Histories from Western Ukraine

2021 ◽  
Author(s):  
Chiara Cavalleri ◽  
Yernur Akashev ◽  
Samira Ahmad ◽  
Sviatoslav Yuras ◽  
Vasyl Karpyn ◽  
...  
Keyword(s):  
High Resolution ◽  
Matrix Effects ◽  
Thin Layers ◽  
Advanced Technology ◽  
Free Fluid ◽  
Fold Belt ◽  
Reservoir Properties ◽  
Local Conditions ◽  
Low Resistivity ◽  
Anisotropic Layers

Abstract Several gas fields from the Carpathian Foredeep basin are characterized by high heterogeneity of rock quality. It is critical to understand the characteristics of pore architecture and mineralogy to quantify the rock's storage capacity and productivity. Field "A" is characterized by thin low-resistivity shale-sand laminations, which poses technical challenges to conventional evaluation methods. Until recently, only conventional local logging suites were deployed, and cutoffs-based interpretation was applied. Core analysis was not done. The Ukrainian segment of the Carpathian fold belt and foredeep is located in the westernmost part of the country, bordering Poland, Slovakia, and Romania. A few fields are situated in the foreland basin but most of the production comes from the fold belt, where complex structural traps are in a series of nappe units. Many of the fields were found based on an understanding of the surface geology alone. The presence of anisotropic layers with a predominance of very thin beds and intercalation of shale, siltstone, and sands with low resistivity contrast between water and gas significantly affects the definition of the reservoir properties and potential. Recently, the use of modern logs was mandated to obtain reliable information. In this study, we analyze and discuss the applicability and results of using advanced technology and tailored logs interpretation methods adapted for the local conditions. These methods were applied in different cases in 2019-2021 and enabled building the first robust petrophysical model for these types of reservoirs. Tri-axial resistivity measurements combined with high resolution density and neutron porosity logs optimally defined the porosity and saturations within the thin bedded sequences. Water volumes and textural parameters were computed from dielectric dispersion measurements. Pores system's heterogeneity and grain sorting, free fluid content and downhole testing optimization was performed using high-resolution nuclear magnetic resonance logs. The ability to measure formation pressure in the thin layers help understanding connectivity and deliverability of the reservoirs. The integration of these log measurements enabled unlocking the true properties of the anisotropic layers and quantify the hydrocarbons in place. High-definition borehole imager and dipole sonic logs complemented the petrophysical logs analysis and assisted the geomechanics and geophysics modeling. The addition of pulsed neutron spectroscopy logging further reduced the evaluation uncertainties providing an independent assessment of gas presence and proper control on mineralogy and matrix effects on the log responses to further refine the computation of total and effective porosity, and volumes within the thin sands. Finally, accurate reservoir summations were calculated and used together with producibility estimates and rock mechanical properties to guide the completion and production strategy. This paper presents examples of fit-to-purpose evaluation programs being deployed in such complex scenarios. In addition, it describes key information used to define a future field development management strategy and to optimize the petrophysical analysis. A comprehensive evaluation program and logs analysis can also be used as data calibration for other offset wells and nearby fields with similar properties and evaluation challenges.

Characterisation of the Dogger and Trias deep ressources in Orléans Métropolis, Centre-Val de Loire region, France : 3D geomodel and first geothermal potential assessment

2021 ◽  
Author(s):  
Virginie Hamm ◽  
Laure Capar ◽  
Perrine Mas ◽  
Philippe Calcagno ◽  
Séverine Caritg-Monnot
Keyword(s):  
Seismic Data ◽  
Geothermal Energy ◽  
District Heating ◽  
Geological Model ◽  
Paris Basin ◽  
Reservoir Properties ◽  
Geothermal Resources ◽  
Geothermal Well ◽  
Geothermal Potential ◽  
Heating Networks

<p>In Ile-de-France region, in the center of Paris Basin, geothermal energy contributes to a large extent to the supply of heating networks with about 50 of the 70 deep geothermal installations dedicated to district heating in France. Those installations mainly exploit the Dogger limestones between 1500-2000 m deep, which are present throughout the Paris Basin. In the case of Centre Val-de Loire region, south of Paris Basin, deep geothermal energy is very little developed, only one geothermal well is currently in operation and targeting the Triassic aquifer at Chateauroux on the southern edge of the basin. A former doublet had also targeted the Trias at Melleray (Orléans metropolis) in the 1980’s but was shut down after one year due to reinjection problem.</p><p>In 2019, Orléans metropolis, in collaboration with BRGM, has launched a program in order to investigate its deep geothermal resources like the Dogger and Trias aquifers between 900 m and 1500 m deep. This action is in line with Orléans métropolis Territorial Climate Air Energy Plan (PCAET) and master plan for the heating networks adopted which foresee 65 000 additional dwellings to be connected using geothermal energy based heating networks.</p><p>In order to reduce the risks of failure of deep geothermal drilling, one of the prerequisites is a better knowledge of the subsurface. This requires the development of an accurate 3D subsurface geomodel as well as the most reliable possible hydrodynamic and thermal parameters to assess the geothermal potential. The purpose of this work was to produce a 3D geological model of the Dogger and Triassic units, on the scale of Orléans Metropolis, based on hydrocarbon and geothermal well data as well as interpretation of 2D seismic data. Seismic data acquired in the 1960s and the 1980s were processed and interpreted. A particular attention was paid to the Sennely fault and its geometry. It crosses the study area and was interpreted as a relay fault segmented in three parts. The horizon picking points were then converted from two-way time to depth and integrated in the GeoModeller software for the development of the 3D geomodel. It was then used for first hydrothermal simulations in order to assess the theorical potential of the Dogger and Trias aquifers at Orléans metropolis.</p><p>The 3D geomodel and first geothermal potential assessment have allowed defining areas of interest for geothermal development into the Dogger or Trias. However an initial exploratory drilling well or additional exploration techniques will be necessary to confirm/specify the reservoir properties (useful thickness, porosity, permeability) and the connectivity of the reservoir(s) and the flow rates that can actually be exploited, which cannot be predicted by the current geological model.</p>

Velocity dispersion: A tool for characterizing reservoir rocks

Geophysics ◽  
1997 ◽  
Vol 62 (2) ◽  
pp. 477-486 ◽  
Author(s):  
Raymon L. Brown ◽  
Dirk Seifer
Keyword(s):  
Elastic Scattering ◽  
Seismic Data ◽  
Test Site ◽  
Thin Layers ◽  
Velocity Measurements ◽  
Reservoir Properties ◽  
Reservoir Rocks ◽  
Intrinsic Attenuation ◽  
Intrinsic Anisotropy ◽  
Sonic Logs

Apparent discrepancies between velocity measurements made with different frequencies in a formation at the Gypsy test site are explained in terms of elastic scattering and intrinsic attenuation. The elastic scattering component of the dispersion (38%) in a marine interval above the Gypsy sandstone is estimated via simple models constructed from well log information. Any dispersion above the predicted value for elastic scattering in this interval is assigned to intrinsic attenuation (62%). Using the vertical measurements in the well, the marine interval directly above the Gypsy sandstone has an estimated intrinsic [Formula: see text] and an effective Q because of the scattering of [Formula: see text]. The total Q of the combined mechanisms is 32. The dispersion of the vertical measurements through the heterogeneous sands and shales of the Gypsy formation can be explained using an intrinsic [Formula: see text] and neglecting the effects of scattering. The horizontal observations require a more detailed modeling effort to unravel the relative roles of path and volume effects, elastic scattering, attenuation, and intrinsic anisotropy. Thin layers barely resolvable on the sonic logs play a significant role in modifying the cross‐well response. Potentially, the dispersion can be a key to mapping reservoir properties using crosswell and surface seismic data.

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