Vol 4, No 2 (2022)
- Year: 2022
- Articles: 10
- URL: https://vestnik-ngo.kz/2707-4226/issue/view/4609
- DOI: https://doi.org/10.54859/kjogi.202242
Full Issue
Articles
Experience of planning and support of 3D seismic exploration on the example of a deposit in the South Torgay basin
Abstract
The modern development of seismic fieldwork technologies and data processing and interpretation techniques make it possible to obtain high-quality material not only for studying structural features, but also for in-depth analysis of rock anisotropy: a detailed understanding of the spatial heterogeneity of lithological and petrophysical properties, predicting the nature of fluid saturation, analyzing finely disjunctive tectonics, fracture density and propagation geometry.
Quality control at all stages of the field seismic survey and processing is also important. It is necessary to understand that quality control consists in direct participation in the work process from the beginning of seismic survey planning to obtaining the final result and interpretation.
This article discusses the importance of full technical support for seismic exploration from planning and design of field work for solving the geological problems, to choosing the optimal processing graph, the results of which have a significant effect on structural and dynamic interpretation. On the example of the South Torgay Basin field, the detailed design of seismic surveys, the use of the latest fieldwork and data processing technologies made it possible to obtain more complete geological and geophysical information. As a result of the work carried out, in 2021, all wells drilled on the basis of the new seismic survey obtained an industrial inflow of hydrocarbons.
3-10
Use of neural networks for dynamic interpretation of seismic data
Abstract
Neural networks and machine learning have long been used by almost everyone in their daily lives, perhaps not always consciously. When an algorithm of social networks identifies the faces of people in a photo or a voice assistant helps us search for some information, machine learning techniques underpin all of these activities.
In recent years neural networks are finding more and more applications in the fields of oil and gas exploration and production. This article aims to illustrate an example of the application of neural networks in the analysis of seismic data for an active oilfield by predicting 3D cube of petrophysical properties to further detail the geological model and search for additional hydrocarbon accumulations.
One of the key conditions for successful prediction of petrophysical properties using neural networks is a wide sample of well data for effective training of a non-linear operator. In our case, since it is a producing field, there were more than 100 wells available, which fully meets the requirements of the algorithm. Another important condition for application of this technique is having high-quality well ties for the used wells, this step of the workflow will also be described within the article.
A distinct feature of neural network analysis, in contrast to classical inversion, is that it does not use a seismic wavelet. The neural network automatically determines such an operator that best describes the correlation between several seismic traces in the wellbore area and the log curve. This feature reduces the analysis time and produces express results if the above mentioned conditions are met, which makes the neural network technique an effective tool for dynamic analysis of seismic data.
27-34
Formation and preservation of reservoirs at great depth
Abstract
The article comprises of the conditions for the formation of reservoirs that retain their properties at great depths, as well as the geological features that are necessary for their safety during subsidence. Since the factors that ensure preservation are very diverse, their digitization is quite difficult; rather, we should say on considering many factors, the combination of which, and not necessarily all at once, is sufficient to forecast the existence of hydrocarbon deposits (and therefore, first of all, reservoirs) at depths that have become technologically accessible, that is, to expand the range geological forecast, which is technologically achieved.
11-26
Application of geomechanics in the construction of horizontal wells at the fields of Embamunaigas JSC
Abstract
Horizontal drilling is currently being actively developed in the near and far abroad to increase oil production, and Embamunaigas JSC is a prime example of this type of drilling in Kazakhstan. At the same time, horizontal drilling is a fairly complex and costly process, just like the construction of deep exploration wells, which requires a comprehensive approach to planning and execution of work.
Geomechanical modelling plays a crucial role in selecting process parameters for drilling, determining optimum well design and other characteristics required to ensure wellbore integrity and overall well construction success.
The mechanical properties model takes into account rock strength characteristics, horizontal stress directions of the geological environment and many other aspects that help make drilling safer, reduce the risk of complications and maintain borehole integrity.
This study describes the process of creating geomechanical models for the construction of complex horizontal wells in the fields of Embamunaigas JSC based on the geomechanical core studies carried out at the S. Nurzhanov field and an analysis of the hydraulic fracturing database for the fields of Embamunaigas JSC. As a result, a safe drilling mud density range (“safe drilling window”) was determined and recommendations were given for the optimisation of drilling parameters and well design.
35-46
Application of proxy models for oil reservoirs performance prediction
Abstract
The evolution of oil and gas reservoirs development parameters prediction has received new opportunities due to the development of digital technologies and computing power. The idea and first experiments in the use of artificial neural networks for various kinds of applied problems as classification of workover actions, automatic interpretation of geophysical well logging and core analyses results can be considered as an important milestone for the oil industry. The application of machine learning for reservoir development parameters prediction is currently a pressing and unresolved issue. Disputes arising in attempts to industrialize this technology are associated with so-called “black box” – a situation when the constructed model cannot explain physical laws and it is almost impossible to track intermediate results in the process of calculating non-linear dependencies. Given the problems described above, the current best practice is to combine machine learning models and physically meaningful analytical models as described in this paper.
47-56
Study of the applicability of foam for steam conformance control to conditions of the Karazhanbas field
Abstract
Thermal enhanced oil recovery methods are a traditional approach in the primary and secondary development of heavy oil fields. Despite the effectiveness of such methods, there are breakthroughs of working fluid into production wells due to the presence of high permeability channels, resulting in a sharp increase in the watercut and an increase in the bottom hole temperature.
The article presents a literature review of the world experience in application of various steam conformance control methods. Based on the literature review, the applicability of foam systems at the Karazhanbas field was studied; core flood experiments were carried out to determine resistance factor and displacement efficiency. Obtained results confirm the formation of foam in reservoir conditions by increase in injection resistance during its filtration through core sample and visually at the outlet, the increase in displacement efficiency was 17,41%. The scientific novelty of the work lies in the study of the applicability of steam conformance control technology based on foam, which has not been previously studied and tested at any field in Kazakhstan.
57-69
Progress of polymer microspheres for profile control in oil field
Abstract
For the past decades, long-term water flooding processes have to water channeling in mature reservoirs, which is a severe problem in oilfields. The development of better plugging ability and cost-effective polymer microspheres is a key aspect for the control of excess water production. Research on polymer microspheres applicable in a heterogeneous reservoir to plug high permeable channels has been growing significantly as revealed by numerous published scientific papers. This review intends to discuss different types of the polymer microspheres and oil displacement efficiency. The related difficulties and future prospects of polymer microspheres are also covered. The review provides a basis to develop polymer microspheres for future applications in oilfields. It will assist the researchers to further develop polymer microspheres to improve the oil recovery from mature reservoirs under economic conditions to meet the requirements of future oilfields.
70-85
Injecting water into a gas cap: evolution of the oil refinery development system in offshore field
Abstract
The article comprises of the results of research work on a solution for injecting water into a gas cap in the field located on the shelf of the Caspian Sea. A practically significant approach has been identified, a concept was developed, as well as the necessary conditions for pumping water into the gas cap. An analysis of the impact of water injection into the gas cap on the wells of ringing was carried out. The water injection efficiency monitoring program has been developed.
86-94
Comparison of various approaches in numerical modeling of well stimulation methods
Abstract
This paper a numerical simulation of methods of intensification of flow to the well by using various approaches. To simulate the hydrochloric acid impact, an approach was applied based on changing the well productivity factor, as well as an approach that consisted of using a chemical reaction in a hydrodynamic model. The criteria for qualitative forecasting of technological development indicators was the actual data on one of the wells of the analogous field of the object. As a result of calculations on the example of a actual field in the conditions of extended horizontal wells, increments of additional oil production were obtained with applying various approaches of modeling the process of hydrochloric acid treatment. It was revealed that in the conditions of extended horizontal wells, the use of negative values of skin factors increases oil production by several times in comparison with the approach of compositional modeling with the occurrence of chemical reactions. Sensitivity analysis to the volume and concentration of the injected acid was carried out by using specialized software. It was concluded that as a result of the chemical reaction in compositional modeling, the effect of hydrochloric acid treatment significantly depends on the composition of the rock, the reaction rate, the concentration and volume of the injected acid. Multi-stage hydraulic fracturing was modeled by using a planar fracture system tool and discrete fracture system model. A slight discrepancy between the results of calculating the hydrodynamic model between these methods for modeling multi-stage hydraulic fracturing was identified.
95-100
The results of single well chemical tracer tests to assess the effectiveness of surfactant-polymer exposure at the Kholmogorskoye field
Abstract
Methods of enhanced oil recovery in general and surfactant-polymer flooding in particular are considered as tertiary methods for the development of mature oil fields in Western Siberia, with the potential to increase oil recovery to 60-70% of the initial geological reserves.
To select an effective mixture of surfactants and polymer for surfactant–polymer flooding, laboratory tests were carried out in which the thermal stability, phase behaviour, interfacial tension and rheology of the formulations were tested. Filtration experiments were also carried out to optimize the volumes of injected fringes and the concentrations of reagents in them. At the final stage, single well chemical tracer tests (SWCTT) were carried out to assess the effectiveness of surfactant-polymer flooding on two wells of the Kholmogorskoye field. In order to investigate different technical and economic models of surfactant-polymer exposure, SWCTT tests were conducted with the same surfactant, but with a different design. The results of the SWCTT tests showed that the residual oil saturation in the affected area after injection of the surfactant-polymer solution decreased by about 11% compared to water flooding, which is about a third of the residual oil after flooding. The tested surfactant showed acceptable efficiency under suboptimal temperature conditions, which is favorable for the use of the selected surfactant-polymer composition for neighboring deposits and formations with different reservoir temperatures, but similar water composition.
In general, the results of the conducted field tests correlate with the results of the main laboratory experiments for the selected surfactant.
101-111