Efficiency Of Oil Field Development Research Articles

Preparation and Performance Evaluation of Self-Degrading Temporary Plugging Agent for Well Workover of Fractured Reservoir

Abstract The temporary plugging technology is considered an important technology in the well workover process of oil and gas reservoirs. Gel is a frequently employed temporary plugging agent in oilfields; however, it has drawbacks, including poor cross-linking strength, unpredictable gelation duration, and considerable reservoir damage after application. To solve these issues, this study seeks to create a gel-based temporary plugging agent system that will improve the dependability and efficiency of oilfield development. In the study, acrylamide, hydrophobic monomers, initiators, crosslinkers, inorganic components, and scale inhibitors were used to formulate the temporary plugging agent. To close underground channels, the prepared plugging agent is injected into the underground and gels at high temperatures. In this study, the elastic modulus of the gel was investigated with a HAAKE rheometer, and the core flooding test was carried out to evaluate the plugging efficiency of the gel. Meanwhile, the visual code method was used to observe the formation time of the temporary plugging agent, and the self-degradation performance of the temporary plugging agent was studied. Hydrophobic monomers and inorganic materials significantly enhance the mechanical properties of the temporary plugging agent after forming the glue. The elastic modulus after crosslinking can reach about 450 Pa, and the maximum pressure of plugging can reach 2.4 MPa. The crosslinking time can be controlled within 30 minutes to 10 hours by adding the inhibitor. The crosslinking agent used in the system is ester organic matter, which can be hydrolyzed at high temperatures to achieve self-degradation performance, so that the degradation rate of the temporary plugging agent can reach 90% within 7 days after forming the glue. This temporary plugging agent has high strength, a controlled crosslinking time, and good self-degradation performance as compared to the typical gel-type temporary plugging agent. These qualities are crucial for reservoir protection and well workover.

A Productivity Prediction Method of Fracture-Vuggy Reservoirs Based on the PSO-BP Neural Network

Reservoir productivity prediction is a key component of oil and gas field development, and the rapid and accurate evaluation of reservoir productivity plays an important role in evaluating oil field development potential and improving oil field development efficiency. Fracture-vuggy reservoirs are characterized by strong heterogeneity, complex distribution, and irregular development, causing great difficulties in the efficient prediction of fracture-vuggy reservoirs’ productivity. Therefore, a PSO-BP fracture-vuggy reservoir productivity prediction model optimized by feature optimization was proposed in this paper. The Chatterjee correlation coefficient was used to select the appropriate combination of seismic attributes as the input of the prediction model, and we applied the PSO-BP model to predict oil wells’ production in a typical fracture-vuggy reservoir area of Tahe Oilfield, China, with the selected seismic attributes and compared the accuracy with that provided by the BP neural network, linear support vector machine, and multiple linear regression. The prediction results using the four models based on the test set showed that compared with the other three models, the MSE of the PSO-BP model increased by 23% to 62%, the RMSE increased by 12 to 38 percent, the MAE increased by 18 to 44 percent, the SSE increased by 23 to 62 percent, and the R-square value increased by 2 to 13 percent. This comparison proves that the PSO-BP neural network model proposed in this paper is suitable for the productivity prediction of fracture-vuggy reservoirs and has better performance, which is of guiding significance for the development and production of fracture-vuggy reservoirs.

Study on the rock physical mechanical properties evaluation of tight oil reservoir in Chang 7 member, Longdong area, Ordos Basin, China

The study aims to investigate the rock mechanical properties of the Chang 7 member tight oil reservoir in the Longdong region of the Ordos Basin, China, with the goal of enhancing the efficiency of oilfield development. Despite numerous contributions in the field of rock mechanics, challenges persist in reconciling experimental results with actual geological conditions and achieving comprehensive understanding of rock mechanical properties in tight oil reservoirs. To address this, a variety of experimental methods were employed to systematically assess the mechanical properties of the target reservoir. Rock density was measured using volumetric methods, tensile strength was evaluated through the Brazilian test, uniaxial and triaxial compression tests were conducted to assess rock mechanics properties, and dynamic elastic modulus and Poisson’s ratio were obtained via sonic velocity measurements. Furthermore, differential strain analysis and imaging log analysis were employed to determine the magnitude and direction of geostress. The results revealed that fine-grained sandstone exhibited higher rock density and relatively higher tensile strength, while muddy siltstone exhibited comparatively lower values in these aspects. Analysis of the influence of confining pressure on rock mechanics properties demonstrated a strong positive correlation between compressive strength and Young’s modulus with confining pressure, while Poisson’s ratio exhibited more irregular variations. Additionally, a mathematical relationship between dynamic and static rock mechanical parameters was established. Lastly, based on the characteristics of geostress, reliable foundations for optimizing hydraulic fracturing and wellbore layout were provided. This study has enriched and complemented the investigation of rock mechanical properties in tight reservoirs, offering vital parameters and theoretical support for the development of tight oil reservoirs. This bears significant importance in enhancing petroleum extraction efficiency and optimizing engineering design.

Improving the efficiency of oil field development based on the use of thermochemical treatment technology

The article is devoted to improving the technology of effect the oil reservoir and the bottomhole zone of production and injection wells. Based on laboratory experimental studies, a new technology that allows increasing oil displacement from a porous medium, as well as increasing well productivity has been developed. The composition of the proposed composition includes a strong oxidizing agent, low and trihydric alcohols, surfactants, etc. When the components of the composition interact, an exothermic reaction occurs, as a result of which a large amount of heat and gas are released in the bottomhole zone. Due to the released heat, the viscosity of heavy oil components, deposited in a porous medium and worsening the filtration characteristics of the formation, decreases. As a result of the impact of the composition, the permeability of the bottomhole zone, the productivity of production and injectivity of injection wells increase. Since the exothermic reaction takes place in the formation itself, this allows increasing the thermal effects.

Development of mathematical methods for processing tracer studies of wells

The use of tracer methods for studying oil wells makes it possible to determine the efficiency of oil field development. However, the reliability of the results of such studies largely depends on both the correctly selected indicators and the methods of interpretation. The currently developed theory of multiphase filtration and numerical analysis methods make it possible to use appropriate models to interpret the results of using various types of indicators. Of particular interest are mathematical models of processes occurring in oil-saturated rocks when using separable tracers.

Practice and understanding of potential tapping technology for ultra short radius horizontal wells

The oilfield has entered the ultra-high water cut period, the distribution of remaining oil is scattered, and it is difficult to tap the potential. On the plane, affected by sand body distribution and well pattern production objects, sand body perforation does not correspond to each other, forming residual oil with imperfect injection production relationship; The residual oil formed in the retention area at the edge of the fault due to the influence of fault shielding. Vertically, affected by the heterogeneity, interlayer and rhythm in the layer, the bottom of the thick oil layer is strongly washed, the middle is moderately strongly washed, and the top is weak and not washed. The production difference is large, and the remaining oil mainly exists at the top of the oil layer. The remaining oil with imperfect injection production relationship and special parts is tapped through ultra short radius horizontal wells to improve oilfield development efficiency.

Waterflooding optimization based on the CRM and solving the linear programming problem

Among the many technologies for increasing the efficiency of oil field development using waterflooding, the least economically expensive include hydrodynamic methods for increasing oil recovery, based on changing the directions of filtration flows. Thus, one of the key tasks of increasing the efficiency of waterflooding at a late stage of development is to reduce the volume of ineffective injection. The article discusses the problem of redistributing volumes of injected water between injection wells for a given total injection volume in order to increase oil production. An analytical relationship is proposed for assessing injection efficiency, based on known displacement characteristics and calculated well interference coefficients based on CRMP. The optimization problem is formulated as a linear programming problem. Using the example of a fragment of an oil deposit, the possibility of assessing the injectivity of injection wells is shown, which makes it possible to increase the predicted oil production by changing the direction of filtration flows in the formation. As a result of applying the developed algorithm, the predicted increase in cumulative oil production amounted to 19683 m³ (9.5%) over 15 years. Keywords: waterflooding optimization; capacitive-resistive model; CRM; linear programming; injection efficiency; interwell connectivity.

Geochemical properties of the upper devonian deposits (Semiluk, Mendym and Kynovian horizons) of the Volga-Ural province for improving the Romashkinskoye oil field development efficiency

This paper presents the results of geochemical and petrophysical studies of the Semiluk-Mendym (Domanik) and Kynovian deposits of the Frasnian age of the Devonian system at the Romashkinskoye giant oil field of the Republic of Tatarstan. The biomarker composition of the organic matter of the rocks is shown, its catagenetic maturity and facies conditions of its formation are assessed. In addition, the composition of saturated biomarkers (alkanes, steranes, and triterpanes) of Devonian oils were studied. The correlation «oil-organic matter of rocks» was carried out for oils of the Domanik and Kynovian horizons. It is shown that the differences in the biomarker composition of oils from the Domanik and Kynovian horizons are of practical importance in the field development process, since this allows optimizing the oil production process by evaluating the contributions of oil inflows from different reservoirs. Keywords: Domanik deposits; oil geochemical research; biomarkers; alkanes; terpanes.

Preparation, Characterization, and Performance of a Modified Polyacrylamide-Sericite Gel.

In this study, a modified chemical plugging agent is prepared with the aim to reduce the well moisture content and improve the efficiency of oilfield development. In comparison to other chemical plugging agents, the composite gels plugging agents have excellent blocking capacity and erosion resistance. In this study, optimal conditions for the preparation of plugging agents were explored. The results showed that the performance of polyacrylamide-sericite (PAM-sericite) gel improved at a polymerization temperature of 60 °C, a crosslinker concentration of 0.5%, an initiator concentration of 0.75%, an acrylamide concentration of 10.0%, and a sericite concentration of 10.0%. The characterization of PAM-sericite gel showed a certain fold-like shape with a smoother surface, indicating that the doped sericite makes the plugging agent more compact and firm. It was also found that the blocking ratio of the plugging agent can potentially reach 99.5% after the addition of sericite. Moreover, failure stress of the skeleton structure and the water swelling degree were increased by 63.5% and 51.2%, respectively. Additionally, long-term stability, temperature resistance, pressure resistance and pressure stability also showed improvement to varying degrees. It was concluded that this gel has better stability against different kinds of salt solutions and is not affected by particle size.

Обоснование зон с повышенной продуктивностью нефтяных залежей в карбонатных коллекторах (на примере Зимне-Ставкинско-Правобережного месторождения)

Introduction. The object of the study is the carbonate deposit of the Lower Triassic Neftekumsk Formation (Zimnyaya-Stavka field and Pushkarskoye field) in the Eastern Stavropol Territory. The purpose of the study is to increase the efficiency of oil field development based on the analysis of field and geological data, deciphering of satellite images and interpretation of structures of central type (SCT). Materials and methods of research. Regional studies of the fields of the Eastern Ciscaucasia, data on oil deposits and satellite images of various levels of generalization were used. New, non-traditional methods were employed, among which a field-lineament approach and a new method for selecting objects for the additional development of oil fields, based on deciphering of satellite images and interpretation of the structures of central type, taking into account data on the location of zones of increased productivity. Results and discussion. Research results and their discussion. As a result of the analysis and mapping of wells with the largest accumulated oil recovery from the main productive formations of the studied field, local centers of high-yield zones were identified. A scheme of oil and gas geological zoning of the central type structures and lineament nodes at the studied oil field was built, promising targets for infill drilling and geological and technical operations were identified to increase the degree of development of residual reserves, indicating specific areas for further development of this field. Conclusion. Based on the analysis of the geotectonic activity of the studied region, the influence of the geodynamic factor on the productivity of wells was established. The use of these approaches will improve the efficiency of forecasting carbonate reservoirs in order to identify promising and developed objects of additional exploration and development for infill drilling, geological and technical operations, and increase the degree of reserves development.

Discussion on key points of underground fracturing technology in oil field

Oilfield underground fracturing technology is an important oilfield development technology, through the injection of fracturing fluid to make the rock fracture expansion, in order to improve the productivity of oil reservoir. In this paper, the selection and design of fracturing fluid, the selection of fracturing tools and devices, the control of fracturing parameters, the control and evaluation of fracturing fractures, and the adjustment and optimization after fracturing are discussed. Through the analysis of these points, it can provide guidance and reference for oilfield engineers and technicians in actual operation to improve the fracturing effect and oilfield development efficiency.

Analysis of potential tapping and efficiency increasing measures of reservoir measures in late stage of oilfield development

In the process of oilfield development, with the continuous development of resource exploitation and oil transportation, the later exploitation is likely to reduce the potential energy of the oilfield, which has a serious impact on the oil exploitation. In order to make our oilfield development efficiency has been significantly improved, and effectively improve the comprehensive development and utilization efficiency of our oilfield, we must continue to use the oilfield potential enhancement technology. In the actual production process, we need to combine a variety of technologies, such as hydraulic transmission pressure fracture, water plugging, acidification and other technologies. Through the comprehensive utilization of these technologies, we can reduce the water content of comprehensive oil wells in the oilfield, effectively improve the production of the oilfield, bring greater economic benefits to the society, and promote the long-term, stable and healthy development of China’s oilfield.

Study on the Minimum Flowing Pressure Boundaries of Different Reservoirs in SZ Development Zone

Reasonable bottom-hole flow pressure is the guarantee for giving full play to oil well productivity and improving oilfield development efficiency. In the actual production process of the oilfield, when the bottom hole flow pressure is reduced to a certain extent, the liquid production of the oil well start to decrease, and there exist a maximum production point in the oil well. To study the minimum bottom-hole pressure limits of different water cut stages in SZ development zone, the inflow dynamic analysis model of oil well is put forward. By considering the influence factors of bottom hole flow pressure change, such as water cut, dissolved gas coefficient, saturation pressure and formation pressure change, the minimum allowable bottom hole flow pressure of SP oil layer is 1.5-2 MPa, and GTZ oil layer is 2-2.5 MPa. The proposed boundary model of bottom hole flow pressure provides theoretical guidance for reasonable flow pressure design and production allocation of oil wells.

Fine Geology Research in Late Stage of Oilfield Development Based on Computer 3d Geological Modeling Technology

According to the previous research and relevant work experience, the working efficiency of oilfield development is gradually reduced with the production time and it is difficult to guarantee the production results in the late stage of oilfield development. At this time, through the use of computer three-dimensional geological modeling technology, the detailed geological study of the oil field will be easier to accurately grasp the distribution of oil field resources, improve the work efficiency in the later stage of oil field development. This paper mainly studies the meaning, concept and the specific method of using 3d geological modeling technology of fine geology research in the late stage of oilfield development, hoping that the reading of this paper can provide some help and inspiration to the researchers in the field of oilfield development.

WELL PRODUCTION CAPABILITIES ASSESSMENT USING INDIRECT GEOLOGICAL AND GEOPHYSICAL INFORMATION

One of the main activities in improving the efficiency of oil field development is the improvement of waterflooding systems and the commissioning of additional production wells. When selecting foci for injection and commissioning of suspended and transit, it is important to know not only the expected degree of interaction between the injection and the producing wells surrounding it, but also the expected flow rates. The estimation of these parameters is made on the basis of direct research according to hydrodynamic, tracer, flow-measuring studies and geological field analysis. At the same time, in the conditions of hundreds of fields located on vast areas of hundreds of thousands of production and injection wells, it is not possible to implement these rather expensive research methods that need to be carried out regularly regardless of weather conditions and various organizational problems. In addition, these direct methods are not always possible for technical and technological reasons, and the results are often distorted by the influence of extraneous «noise» and do not correspond to the real picture of what is happening. One of the methods for predicting flow rates is to search for links between this parameter and data from geophysical studies and to use these links based on the analogy method. The dependence of the maximum optimal well flow rate on various geological and physical parameters for different groups of deposits in terrigenous reservoirs of the West Siberian oil and gas province influence is studied and multidimensional models are built. A potential well production-predicting algorithm is proposed basing on geophysical studies, based on the obtained models and the cross-correlation functions characterizing the degree of hydrodynamic interaction between production and injection wells values evaluating results. The algorithm allows the risks of making inefficient decisions reducing when the deposits’ development improving in terms of waterflooding systems reorganization and wells’ transfer to the existing fund from other horizons.

Estimation of displacement coefficient with due account for hydrophobization of reservoir using geophysical data of wells

AnnotationThe coefficient of oil displacement by water from productive reservoirs is one of the main parameters reflecting the efficiency of oil field development by maintaining reservoir pressure. This parameter is necessary for both calculation of reserves and composition of technological scheme and project for oil field development. The displacement coefficient is important information for localization of residual reserves of developed oil fields and for estimation of oil production dynamics and effectiveness of methods for intensification of oil field development and oil recovery. In reservoirs of Western Siberia, during the displacement of oil by water from voids of productive reservoirs, residual oil has two components: capillary trapped oil and adsorbed oil on the surface of clay aggregates as separate droplets and films. The work demonstrates that the fraction of capillary trapped oil can be estimated using the value of effective reservoir porosity, since it characterizes the correlation of the size of pores and interpore narrowings. The content of adsorbed hydrocarbons on the active surface of pores depends on the clayiness and activity of clay, and on wetting ability of oil as well. The clayiness of reservoir is proportional to its residual water content and tightly connected with initial oil content of the productive reservoir. The present work shows the possibility of taking into account the effect of hydrophobization of a reservoir on the residual oil content using the value of initial reservoir charge. Noteworthily, the effective porosity and initial reservoir charge with practically useful accuracy can by estimated using the data of conventional complex of geophysical surveys of wells.

Горизонтальные скважины и ГРП в повышении эффективности разработки нефтяных месторождений на примере НГДУ «Азнакаевскнефть»

Горизонтальные скважины и ГРП в повышении эффективности разработки нефтяных месторождений на примере НГДУ «Азнакаевскнефть»

日本発の技術開発のトレンドと事例

Sonic Scanner has been recently introduced to the market. This is the first 3D sonic logging tool developed in Japan. It measures sound slowness(1/velocity) of P and S wave along well axis, around well bore and away from well bore. There are many applications including drilling related applications. One example is “damaged zone” identification. Sonic Scanner is the latest example of logging tool developed in Japan, and there was a history to achieve such advanced tool development. It's been 70 years since the first electrical log was run in Japan, and it's been 50 years since logging service was brought into Japan. Schlumberger opened Engineering and Manufacturing center facility in Sagamihara 20 years ago, and started tool development. The reason Schlumberger opened such center in Japan was to capture Japanese leading technology and manufacturing quality and apply to oil field. One of the examples is color printer for oil field use, which was 20 years ahead of consumer market. The trend to capture leading edge“enabling” technologies to apply them to increase efficiency of oil field development will continue. To do that, we need to work with such technology providers that may be another strong industry in Japan or Academic community.