Stage Of Oilfield Development Research Articles

Collision adhesion law of oil Droplets-Bubbles with different particle sizes in free floating

The treatment of oily wastewater has become a serious problem in the late stage of oilfield development. At the same time, it is of great significance to the improvement of ecological environment. As the key process of oil-bearing wastewater treatment, the study on the binding and adhesion law of oil droplets and bubbles in flotation and its related mechanism can provide reference for its application. Using a double high-speed camera acquisition system, the floating process and collision adhesion law of oil droplets and bubbles in a vertical transparent circular tube were experimentally studied, and the collision adhesion process of oil droplets (0.721 ∼ 3.759 mm) and bubbles (0.797 ∼ 2.886 mm) in different diameters were analysed. It is concluded that the oil droplet and the bubble collide with each other, and then the bubble slides along the surface of the oil droplet, and a neck shape appears at the end of the contact site, and then the neck increases with the diffusion of the oil droplet to form an oil-bubble adhesion body. And the process of elastic drags and contraction separation of the mixture is also demonstrated. It is found that the combination of oil droplets and bubbles with different diameters will have two types of collision adhesion modes, which oil droplet type and oil film type, respectively. Therefore, the diameter ratio of oil droplets and bubbles is a key factor, and when the diameter ratio is greater than 0.75, the adhesion mode of the adhesive body changes from unstable oil droplet type to more stable oil film type.

Feasibility analysis of commingle production of multi-layer reservoirs in the high water cut stage of oilfield development

Multi-layer commingle production is a common development technique to improve the overall oil recovery of multi-layer reservoirs. However, this technique is mainly used at low water cut stage. Research on this technique at high water cut stage is comparatively few. Therefore, in order to improve productivity and recovery of wells, feasibility analysis of commingle production of multi-layer reservoirs in the high water cut stage is analyzed. To achieve a good commingle production result, the production layers must be optimized and inter-layer interference must be analyzed and reduced as much as possible. Factors, such as permeability, porosity, viscosity, capillary pressure, gravity, pressure difference, and water cut difference, have impact on commingle production. But it is difficult to consider all these factors. Therefore, according to the geological reservoir characteristics of X Oilfield, a model is established to simulate commingle production process, and the results are compared and analyzed. The interference degree is characterized by seepage resistance. The commingle production effect is evaluated by dimensionless oil increase coefficient, production index, and production index interference coefficient. The results show that the larger the difference of permeability ratio and water cut between multi-layers, the more severe the interlayer interference; dimensionless oil increase coefficients are all positive, it means that commingle production can achieve good oil increase effect even in the high water cut stage; the recommended technical limits for commingle production are that: permeability ratio is less than 5; commingle production timing is that water cut of low permeability layer is higher than 80%. This technique has been applied to X Oilfield, and the oil recovery increased about 2.8%, which confirmed this method feasibility.

An integrated methodological approach to substantiating the properties of high-viscosity oils using the example of the Karazhanbas oil field

Rationale: A characteristic feature of the modern stage of oil field development is the increase in the share of hard-to-recover oils, which mainly include heavy, highly viscous oils. This is due to changes in the structure of oil, an increase in the water cut of produced oil, geological and geophysical characteristics and conditions of oil occurrence that are unfavorable for extraction. The reserves of such oil significantly exceed the reserves of light and low-viscosity oil and, according to experts, they amount to at least 1 trillion tons. In industrialized countries they are considered not so much as a reserve for oil production, but as the main basis for its development in the coming years. The peculiarity of heavy oil is explained by its composition and PVT properties, which have a fairly serious impact on production.
 Target: Application of an integrated approach to substantiating the properties of high-viscosity oil and tools for mathematical modeling of the phase state of fluids in order to increase the reliability of reserve calculations and the efficiency of the oil field development.
 Materials and methods: The scientific work was based on the results of geochemical studies (fingerprinting and biomarker analysis), experimental data from rheological studies and the results of modeling the phase state of fluids.
 Results: It is proposed to use an integrated approach to data interpretation and compositional calculations, which make it possible to narrow the range of uncertainty and explain the huge variation in the values of physicochemical parameters across samples.
 Conclusion: An integrated approach to analyzing the results of PVT experiments, together with geological and field data and the results of geochemical studies, provides high-quality data that allows you to make strategic decisions on the oil field development, conduct accurate resource assessments and predict hydrocarbon production.

Estimation of the possibility of recovering residual reserves under the influence of polymer solutions at the final stage of oil field development

A two-phase four-component calculation model of filtration, which allows to estimate the possibility of extracting residual reserves when exposed to polymer solutions at the final stage of oil field development is suggested. On its basis, by reducing the degree of mineralization of the water entering the polymer solution to the degree of mineralization of formation water, by directing its flow to the parts of the collector that are well wetted by water, due to the closure of these parts, the possibility of ensuring the complete displacement of oil reserves and intensification of production was defined.

A novel physics-based resolution improvement method for neutron-density log

In the later stages of oilfield development, the accurate identification of thin reservoirs become increasingly crucial for oil and gas exploration. However, conventional logs have limited vertical resolution, making it challenging to identify thin reservoirs. This results in potential hydrocarbon layers getting overlooked during exploration. To address this issue, a novel resolution enhancement method for density and neutron porosity logs based on physical constraint optimization is proposed. The proposed method involves three main steps: (1) developing an objective function that relates the true formation density and porosity to the measurement based on the physics of nuclear, (2) setting density neutron cross-constraints using the volumetric model of logging interpretation, and (3) establishing the objective function matrix equations using sliding window technology and solving the matrix equations using the constrained least square method to obtain high-resolution density and neutron porosity logs. The proposed method is evaluated using both synthetic and field logs obtained from compensated density and compensated neutron tools. The results demonstrate an effective improvement in neutron porosity and density log resolution to 15 cm, which is significantly enhanced compared to the typical vertical resolution of 2 ft. This study offers a new perspective for enhancing the resolution of logs and contributes to the exploration and development of thin oil and gas resources. And the proposed method could be used in future exploration and production projects to identify potential hydrocarbon layers that might have been overlooked by conventional logs.

Study on Wastewater Demulsification Technology of Crude Oil in Xinjiang Oilfield

The Second Oil Production Plant of Xinjiang Oilfield produces a large amount of highly emulsified crude oil, which has a serious impact on the subsequent oil-water separation. At present, the concentration of demulsifier has increased to 2000 mg/L, but the demulsification effect is still poor. In this paper, the source and physical properties of highly emulsified crude oil are investigated firstly. The results show that highly emulsified crude oil is composed of three kinds of liquid: (1) conventional water flooding (WF); (2) chemical flooding (CF); (3) fracturing backflow fluid (FB). Among them, high zeta potential, low density difference, high viscosity, and small emulsion particles are responsible for the difficulty in the demulsification of the WF emulsion, while the high pH value is the reason why the CF emulsion is difficult to demulsify. Therefore, systematic experiments were implemented to investigate the optimal demulsification approach towards the three liquids above. As for the WF emulsion, it was necessary to raise the temperature to 70 °C and the concentration of the demulsifier to 200 mg/L. Moreover, it was only necessary to add 200 mg/L of demulsifier to break the CF emulsion after adjusting the pH value to 7, while no extra treatments were needed to break the FB emulsion. We hope this study can provide a new insight for the treatment of emulsions in the later stage of oilfield development.

Investigation of natural gas hydrate formation and slurry viscosity in non-emulsifying oil systems

At a later stage of oilfield development, there will be more free water in the pipeline, which may engender the phase inversion of water-in-oil emulsions, thereby augmenting the risk of hydrate plugging. In a novel 30 L high-pressure autoclave, the effects of wax content, water cut, temperature, initial pressure, and rotation speed on hydrate crystallization nucleation and slurry viscosity were examined. Results demonstrated that in systems with wax content greater than or equal to 2 wt%, at the onset of the swift hydrate growth stage, the aggregation of wax and hydrate will impair the gelling structure of wax-containing oil, inducing an abrupt fall in slurry viscosity. Consideration is given to the solubility fluctuation of the natural gas in oil, and an empirical prediction formula for gas consumption during hydrate formation in wax-containing systems is established. The presence of wax hinders the crystalline nucleation and growth of hydrates. Notwithstanding, the hydrate slurry viscosity of the wax-containing system is greater because the wax-hydrate aggregates have a more conspicuous effect on the slurry viscosity than the hydrate volume fraction. The water cut of 70% is a critical upper limit, above which the viscosity of hydrate slurry would increase dramatically. Higher rotation speed and initial pressure can significantly enhance the viscosity of hydrate slurries, but their effects on the hydrate nucleation induction time are more perplexing.

Study on tight reservoir law and prediction of favorable areas - Take Wangjiawan well block Wang 107 as an example

When the development of oil field continues, the production efficiency of the whole oil well will decline significantly. It is of importance to analyze the geological factors related to the reservoir storage law in order to re recognize the current status of the oil well and extract more resources from the oil well. This paper expounds that at the stage of oilfield development, the research on reservoir characteristics, reservoir sedimentary facies and reservoir characteristics and laws are discussed in depth and comprehensively, and the prediction of favorable areas of the oilfield is studied, which has brought corresponding references to oilfield staff. For the late stage of oilfield development, we should carry out fine geological research, determine the geological type, provide the best data base for improving the development plan of the reservoir, and carry out scientific analysis and research to improve the productivity of the late stage of reservoir development, so as to achieve the expected production efficiency.

The structure of the oil-bearing strata and possibility of extracting oil from them

It is important to study the structure of oil-bearing strata is. In many ways, the structure of the Earth’s layers affects the possibility of intensifying oil production. This is one of the urgent problems of the oil industry. Obviously, at various stages of oil field development, methods of intensifying oil production, depending on the structure of oil-bearing rocks and geological and physical characteristics have their own features, which are manifested when they are used in the field conditions. Determination of the oil recovery factor (ORF) causes great difficulty in the operational assessment of oil reserves. At the stage of initial assessment, this indicator is taken either by analogy, or approximately. In order to make this parameter more valid, the main factors influencing its formation were studied. The formula for calculating oil recovery factor takes into account three main coefficients: grids, displacement and waterflooding.

Study on Reservoir Dynamic Management Method in the Later Stage of Oilfield Development

Study on Reservoir Dynamic Management Method in the Later Stage of Oilfield Development

Innovative developments of sucker rod pumps to improve the performance of sand producing wells

At the last stage of oil field development, the use of sucker rod pumps is widespread. Due to the drop in formation pressure and other reasons, the inflow of fluid into the well is reduced. The efficiency of the pumps decreases, the pump cylinder is not completely filled. To eliminate these obstacles, a new submersible pump has been developed with a intake valve, which opens and closes with the movement of the balance head. In flooded and sandy wells, sand destroys the working parts of the pump, especially the gap between the plunger-cylinder pair, as a result reduced productivity of the pump. The new pump design allows solving the problem by emulsifying part of the product. The operation of the pump is mathematically justified.

Statistical modeling of oil reservoir life cycle

Based on statistical analysis, a method of stage-by-stage structuring and allocation of the boundaries of the stages of oil field development is proposed. The procedures for calculating the remaining recoverable reserves and the time to reach the maximum level of current oil production are given. Based on the values of accumulated oil production at the final stage of development, using the adaptive Kalman filter, forecasts of oil production are constructed in discrete time and estimates of the possibility of achieving design indicators with the existing development system are given. Keywords: Stage-to-stage structuring; Development stages; Forecast of recoverable reserves; Predicted oil production; Kalman filter.

Statistical modeling of oil reservoir life cycle

Based on statistical analysis, a method of stage-by-stage structuring and allocation of the boundaries of the stages of oil field development is proposed. The procedures for calculating the remaining recoverable reserves and the time to reach the maximum level of current oil production are given. Based on the values of accumulated oil production at the final stage of development, using the adaptive Kalman filter, forecasts of oil production are constructed in discrete time and estimates of the possibility of achieving design indicators with the existing development system are given. Keywords: Stage-to-stage structuring; Development stages; Forecast of recoverable reserves; Predicted oil production; Kalman filter.

Fine Geological Research in the Later Stage of Oilfield Development

Fine Geological Research in the Later Stage of Oilfield Development

Suggestions on Geological Potential Tapping and Efficiency Increasing in Later Stage of Oilfield Development

Suggestions on Geological Potential Tapping and Efficiency Increasing in Later Stage of Oilfield Development

Suggestions on Geological Potential Tapping and Efficiency Increase in the Later Stage of Oilfield Development

Suggestions on Geological Potential Tapping and Efficiency Increase in the Later Stage of Oilfield Development

Study and determination of regularities in variability of oil rheological properties to enhance oil recovery

The processes of oil production, collection and treatment are complicated by a complex of problems associated with the formation of stable oil emulsions, deposits of asphalt-resin substances and paraffinic hydrocarbons, inorganic salts. Moreover, the formed sediments often have a complex blend composition. Especially, at the late stage of oil field development, as a rule, procedures of gathering and processing of oil are complicated, in particular, by wall mud cake, low pressure, and also by an increase in the water cut of the product, with an increase in the volume of chemicals used during repair works and for production stimulation. Under these conditions, it becomes relevant to determine the regularities in changes of the rheological properties of oil to prevent complications in pumping equipment and flow strings, pipelines, equipment, and tank farm of oil gathering systems. The use of ultrasonic waves in electrophysical advanced recovery has a number of advantages, including simple and fast application, protection from wellbore damage, high profitability, low operating costs, significant compatibility with other enhanced oil recovery methods, and widespread application. This paper provides a technical and economic assessment of the effectiveness of electrophysical stimulation in the production field in Western Kazakhstan. The use of electrophysical stimulation technology in the production fields shows high technological efficiency. A decrease in the oil viscosity in a bottomhole zone of a production well during the use of ultrasound leads to an increase in the flood front during the water-driven operation of the reservoir. This matter was addressed in the present paper.

Seepage Behavior of Fractures in Paleogene Sandstone Reservoirs in Nanpu Sag, Bohai Bay Basin, Eastern China

Natural fractures play an important role in the seepage system of Paleogene sandstone reservoirs at Nanpu Sag. Characteristics and formation mechanisms of natural fractures and stress-sensitivity permeability are comprehensively investigated and their impact on water injection is discussed based on core and log data (FMI and diplog data) as well as stress-sensitivity permeability measurement. Results show that high-angle shear fractures, including NE-SW strike fractures and NW-SE strike fractures, are widely developed in the study area, which were primarily developed during the late Paleogene and late Neogene. The present maximum horizontal principal stress is orientated at N60°–80°E, approximately parallel to the NE-SW fractures, contributing greatly to the seepage system at the early oilfield development stage. Fractures in the study area can be divided into three phases and are characterized by obvious stress-sensitivity permeability, which is closely related to fracture aperture and throat size. Since the fracture occurrence enhances stress sensitivity of permeability, it is necessary to regulate well pattern based on dynamic behaviors of fractured reservoirs at different development stages.

APPROACHES AND TECHNOLOGIES TO REDUCE WATER CUT OF OIL AT THE LATER STAGE OF OIL FIELD DEVELOPMENT

Background The problem of developing residual oil reserves at a late stage of oil field development is known to a wide circle of specialists. Unfortunately, there are no significant positive results from the introduction of certain technologies that would make it possible to reverse the negative trend expressed in the progressive water cut of the produced products, a reduction in the existing well stock and a decrease in the profitability of oil production at such fields. Aims and Objectives Assessment of the technological efficiency of the technology introduction in order to reduce the water cut of the products. Results On the basis of theoretical, laboratory and field studies and observations, the concept of additional development of an oil reservoir depleted by previous development has been formulated.

Research on Partial Pressure of Oilfield Water Injection Pipeline Network System Based on Fuzzy Logic

Aiming at the middle and late stages of oilfield development, the retirement of water injection wells in old areas of the water injection system, the increase of water injection wells in new areas, and the incorporation of tertiary injection wells into the subsequent water flooding have caused great changes in the layout of the water injection pipeline network, causing the mixed injection of high and low pressure wells, a fuzzy logic method is proposed to divide the pressure of the water injection pipeline network, establishing a partial pressure reasoning model, setting the fuzzy domain and reasoning rules, and finally realize the division of high and low pressure areas of a large number of water injection wells. aking an oilfield water injection pipe network system as an example, the effectiveness of the method is proved through Matlab simulation and application research.