Geological structure update using fault seal analysis at the early stage of Chayandinskoye gas condensate field development

Author(s):  
V.A. Markelov ◽  
R.A. Khusainov ◽  
V.Yu. Silov ◽  
E.V. Chepkasova

The paper shows a sophisticated approach of fault sealing analysis for Chayandinskoye gas condensate field. The gas-oil system of the field is complicated by large number of the geological faults, which leads to its block structure. Preliminary calculations using the field simulation models showed that the faults conductivity might significantly affect technical and economic features of the field. Conducted interference well tests allowed to estimate fault conductivity before the juxtaposed field blocks development. The studies were carried out in gas-saturated porous medium with low formation-pressure conductivity in wells located at distance exceeding 3000 m. Hydrodynamic connectivity between three areas was analyzed. As a result, the field geological structure was locally updated: the initially considered sealing fault identified by the seismic survey data was reconsidered as a partially conductive and additional sealing boundary between two wells was recognized, which wasn’t identified earlier due to its low amplitude. Proposed approach allows to estimate the hydrodynamic blocks connectivity at the early stages of the field development thus to improve simulation models forecasts and project decision making.

2020 ◽  
Vol 43 (3) ◽  
pp. 350-363
Author(s):  
L. A. Rapatskaya

The study aims to analyze the relationship between the redetermination of the complexity of the geological structure of the Verkhnechonsky oil and gas condensate field and the schedule adjustment of the field development plans. The paper uses the data on the exploration and production wells obtained from the pilot operation of JSC Verkhnechonskneftegaz, the geophysical work results, and the research materials publicly available in the press. The geological structure of the Verhnechonskoye oil and gas condensate field is unique in its complexity. This is due to the following factors: a combination of tectonic disturbances accompanied by the intrusion of traps; high mineralization of the reservoir water; sharp variability of the filtration and reservoir properties of the producing horizons by area and section due to the unevenness of the lithological composition of the reservoirs, their salinization and complete pinch-out. The development system of any field should take into account the peculiarities of the field’s tectonic and lithological-facies structure, and meet specific technical and economic requirements for drilling and operating wells. The complexity of the field structure requires a thorough selection of a development system that inevitably changes as the features of the field structure are studied, e.g. vertical drilling suggested at the initial stage of the filed development was shortly after replaced with inclined-horizontal drilling with the calculation of two options. Within the pilot operation project of the Verkhnechonsky field, JSC Verkhnechonskneftegaz has developed two variants of uniform grids of directional and horizontal wells with pattern flooding for the most explored deposits of the Verkhnechonsky horizon of blocks I and II. Because of the intensive processes of the reservoirs’ secondary salinization, the flooding method required a study of the reservoir water composition. However, the proposed drilling plan using a downhole engine and gamma-ray logging could not ensure the wellbores ducting through the most productive sections of the horizon, therefore, the flow rates of some directional and horizontal wells were not high enough. To increase the drilling efficiency, the specialists of the Drilling Department (JSC Verhnechonskneftegaz), together with the Department of Geology and Field Development (Schlumberger Ltd.), proposed a new methodology that increases the drilling efficiency by using a rotary-controlled system, logging-while-drilling, and geosteering. Thus, the development system of the Verkhnechonsky oils and gas condensate field was changing in the process of specifying the field’s geological structure, anisotropy reservoir properties, and the thickness of the producing horizons in size and cut, their salinization and pinch-out, and the composition of the reservoir waters.


2018 ◽  
Vol 9 (3) ◽  
pp. 587-627 ◽  
Author(s):  
K. Zh. Seminsky ◽  
V. A. Sankov ◽  
V. V. Ogibenin ◽  
Yu. P. Burzunova ◽  
A. I. Miroshnichenko ◽  
...  

The article presents the results of the tectonophysical approach to the analysis of stress fields and the structure of gas–condensate deposits with the complex platform cover. The discussed case is the Kovykta license area (LA) in Eastern Siberia, Russia. In the upper part of the cross section, the network of fault zones was identified from the relief lineaments and structural data. The dynamic conditions for faulting (compression, extension, and strike-slip) were reconstructed by the paragenetic analysis. The state of crustal stresses in the study area was studied by tectonophysical modeling using gelatin as an optically active material. The applied method was successful in distinguishing between the zones of faults in the platform cover, which differ in the degree of their activity in the specified stress fields. The lower part of the cross section in the NE segment of the Kovykta LA is considered as an example of the tectonophysical interpretation of the electrical and seismic survey data in order to identify the fault zones and reconstruct the corresponding stress fields. Based on the synthesis of the analyzed data, it is revealed that the deposits like the Kovykta gas condensate field (GCF) show the zone-block structure of the platform cover formed under the influence of several stress fields closely associated with the stages of tectogenesis in the adjacent mobile belts. The next objective is to enhance the tectonophysical approach in order to develop a hierarchical model of the GCF zone-block structure, which details need to be known for improving the prediction of sites with the complicated stress-strain state of rocks and mitigating the risks associated with drilling exploration and production wells.


Author(s):  
R.R. Haliulin ◽  
◽  
S.N. Zakirov ◽  
A.H. Kha ◽  
N.E. Vedernikov ◽  
...  

2019 ◽  
Vol 21 (4) ◽  
Author(s):  
Nishant Kumar ◽  
Bettina Suhr ◽  
Stefan Marschnig ◽  
Peter Dietmaier ◽  
Christof Marte ◽  
...  

Abstract Ballasted tracks are the commonly used railway track systems with constant demands for reducing maintenance cost and improved performance. Elastic layers are increasingly used for improving ballasted tracks. In order to better understand the effects of elastic layers, physical understanding at the ballast particle level is crucial. Here, discrete element method (DEM) is used to investigate the effects of elastic layers – under sleeper pad ($$\text {USP}$$USP) at the sleeper/ballast interface and under ballast mat ($$\text {UBM}$$UBM) at the ballast/bottom interface – on micro-mechanical behavior of railway ballast. In the DEM model, the Conical Damage Model (CDM) is used for contact modelling. This model was calibrated in Suhr et al. (Granul Matter 20(4):70, 2018) for the simulation of two different types of ballast. The CDM model accounts for particle edge breakage, which is an important phenomenon especially at the early stage of a tamping cycle, and thus essential, when investigating the impact of elastic layers in the ballast bed. DEM results confirm that during cyclic loading, $$\text {USP}$$USP reduces the edge breakage at the sleeper/ballast interface. On the other hand, $$\text {UBM}$$UBM shows higher particle movement throughout the ballast bed. Both the edge breakage and particle movement in the ballast bed are found to influence the sleeper settlement. Micro-mechanical investigations show that the force chain in deeper regions of the ballast bed is less affected by $$\text {USP}$$USP for the two types of ballast. Conversely, dense lateral forces near to the box bottom were seen with $$\text {UBM}$$UBM. The findings are in good (qualitative) agreement with the experimental observations. Thus, DEM simulations can aid to better understand the micro-macro phenomena for railway ballast. This can help to improve the track components and track design based on simulation models taking into account the physical behavior of ballast. Graphical Abstract


2021 ◽  
Author(s):  
Vil Syrtlanov ◽  
Yury Golovatskiy ◽  
Ivan Ishimov

Abstract In this paper the simplified way is proposed for predicting the dynamics of liquid production and estimating the parameters of the oil reservoir using diagnostic curves, which are a generalization of analytical approaches, partially compared with the results of calculations on 3D simulation models and with actual well production data.


2021 ◽  
Author(s):  
Pavel Dmitrievich Gladkov ◽  
Anastasiia Vladimirovna Zheltikova

Abstract As is known, fractured reservoirs compared to conventional reservoirs have such features as complex pore volume structure, high heterogeneity of the porosity and permeability properties etc. Apart from this, the productivity of a specific well is defined above all by the number of natural fractures penetrated by the wellbore and their properties. Development of fractured reservoirs is associated with a number of issues, one of which is related to uneven and accelerated water flooding due to water breakthrough through fractures to the wellbores, for this reason it becomes difficult to forecast the well performance. Under conditions of lack of information on the reservoir structure and aquifer activity, the 3D digital models of the field generated using the hydrodynamic simulators may feature insufficient predictive capability. However, forecasting of breakthroughs is important in terms of generating reliable HC and water production profiles and decision-making on reservoir management and field facilities for produced water treatment. Identification of possible sources of water flooding and planning of individual parameters of production well operation for the purpose of extending the water-free operation period play significant role in the development of these reservoirs. The purpose of this study is to describe the results of the hydrochemical monitoring to forecast the water flooding of the wells that penetrated a fractured reservoir on the example of a gas condensate field in Bolivia. The study contains data on the field development status and associated difficulties and uncertainties. The initial data were results of monthly analyses of the produced water and the water-gas ratio dynamics that were analyzed and compared to the data on the analogue fields. The data analysis demonstrated that first signs of water flooding for the wells of the field under study may be diagnosed through the monitoring of the produced water mineralization - the water-gas ratio (WGR) increase is preceded by the mineralization increase that may be observed approximately a month earlier. However, the data on the analogue fields shows that this period may be longer – from few months to two years. Thus, the hydrochemical method within integrated monitoring of development of a field with a fractured reservoir could be one of the efficient methods to timely adjust the well operation parameters and may extend the water-free period of its operation.


2021 ◽  
Author(s):  
Subba Ramarao Rachapudi Venkata ◽  
Nagaraju Reddicharla ◽  
Shamma Saeed Alshehhi ◽  
Indra Utama ◽  
Saber Mubarak Al Nuimi ◽  
...  

Abstract Matured hydrocarbon fields are continuously deteriorating and selection of well interventions turn into critical task with an objective of achieving higher business value. Time consuming simulation models and classical decision-making approach making it difficult to rapidly identify the best underperforming, potential rig and rig-less candidates. Therefore, the objective of this paper is to demonstrate the automated solution with data driven machine learning (ML) & AI assisted workflows to prioritize the intervention opportunities that can deliver higher sustainable oil rate and profitability. The solution consists of establishing a customized database using inputs from various sources including production & completion data, flat files and simulation models. Automation of Data gathering along with technical and economical calculations were implemented to overcome the repetitive and less added value tasks. Second layer of solution includes configuration of tailor-made workflows to conduct the analysis of well performance, logs, output from simulation models (static reservoir model, well models) along with historical events. Further these workflows were combination of current best practices of an integrated assessment of subsurface opportunities through analytical computations along with machine learning driven techniques for ranking the well intervention opportunities with consideration of complexity in implementation. The automated process outcome is a comprehensive list of future well intervention candidates like well conversion to gas lift, water shutoff, stimulation and nitrogen kick-off opportunities. The opportunity ranking is completed with AI assisted supported scoring system that takes input from technical, financial and implementation risk scores. In addition, intuitive dashboards are built and tailored with the involvement of management and engineering departments to track the opportunity maturation process. The advisory system has been implemented and tested in a giant mature field with over 300 wells. The solution identified more techno-economical feasible opportunities within hours instead of weeks or months with reduced risk of failure resulting into an improved economic success rate. The first set of opportunities under implementation and expected a gain of 2.5MM$ with in first one year and expected to have reoccurring gains in subsequent years. The ranked opportunities are incorporated into the business plan, RMP plans and drilling & workover schedule in accordance to field development targets. This advisory system helps in maximizing the profitability and minimizing CAPEX and OPEX. This further maximizes utilization of production optimization models by 30%. Currently the system was implemented in one of ADNOC Onshore field and expected to be scaled to other fields based on consistent value creation. A hybrid approach of physics and machine learning based solution led to the development of automated workflows to identify and rank the inactive strings, well conversion to gas lift candidates & underperforming candidates resulting into successful cost optimization and production gain.


Author(s):  
Sudhakar Y. Reddy

Abstract This paper describes HIDER, a methodology that enables detailed simulation models to be used during the early stages of system design. HIDER uses a machine learning approach to form abstract models from the detailed models. The abstract models are used for multiple-objective optimization to obtain sets of non-dominated designs. The tradeoffs between design and performance attributes in the non-dominated sets are used to interactively refine the design space. A prototype design tool has been developed to assist the designer in easily forming abstract models, flexibly defining optimization problems, and interactively exploring and refining the design space. To demonstrate the practical applicability of this approach, the paper presents results from the application of HIDER to the system-level design of a wheel loader. In this demonstration, complex simulation models for cycle time evaluation and stability analysis are used together for early-stage exploration of design space.


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