Oil Layer Thickness Research Articles

Optimization of horizontal well pattern in low permeability layered reservoir

The southern part of Jin45 fault block is a low permeability layered reservoir with thin oil layer thickness. And the development of horizontal well pattern has good economic benefit in Jin45 fault block. The oil layer distribution of reservoir is quite different. The distribution of main layer is stable, but the distribution of non-main layer is unstable. In this study, through reservoir engineering method and numerical simulation method, the horizontal well pattern direction, well pattern form, well spacing and horizontal well length are optimized to determine the horizontal well pattern of main layer. On this basis, according to the principle of “parallel deployment of horizontal wells and sharing injection-production well pattern”, the horizontal well pattern of non-main layer is preliminarily designed to ensure the development effect and economic benefit to the greatest extent.

Oil Spill Thickness Determination from L-band Synthetic Aperture Radar

ABSTRACTEfficient and effective oil spill response requires accurate information regarding slick location, extent, and thickness to direct remediation activities. Of these three, the most challenging to determine is thickness. Ideally, the needed information would be provided by remote sensing instruments, particularly those operating from space. In this study we consider the capability of L-band synthetic aperture radar (SAR) for identifying oil layer thickness for slicks in open water given the range of oil properties and environmental conditions typical in this setting. The goal is to determine layer thickness with precision equivalent to that of the Bonn Agreement Oil Appearance Code. Here we report preliminary results of an ongoing study to determine whether either relative or absolute slick thickness can be determined from L-band SAR. The study has an experimental component, which uses low noise airborne SAR data acquired over slicks to evaluate the capability to determine relative thickness, i.e., to differentiate sheen from zones of varying thicker oil within a slick. The component of the study to evaluate whether absolute thickness can be determined from SAR uses backscatter simulations within a physics-based model of electromagnetic scattering from slicked and unslicked ocean surfaces accounting for oil properties, meteorological conditions, and sea state. As part of the theoretical component of the study, we evaluate the backscatter sensitivity to oil characteristics to determine which properties most influenced the SAR measurements. These results are used to determine whether the oil-to-water ratio or the oil thickness can be quantified with reasonable accuracy based upon SAR backscatter intensities alone or whether it requires calibration to go from relative to absolute thickness. The ratio of the backscatter contrast between clean and slicked ocean surfaces is shown to be sensitive to variations within slicks that well correlate with the oil layer thickness. Determination of absolute thickness is much more challenging given the variation of oil properties as the oil weathers on the sea surface.

The Application of Fuzzy Comprehensive Evaluation Method in Evaluating Remaining Oil Potential of Oil Layer

In this paper, remaining oil saturation, microfacies type, oil layer thickness, structure, permeability variation coefficient, injection-production relationship, injection-production perfection degree, effective perforation thickness, connected thickness, water injection distance, water injection well pattern, water cut of oil well and production measures, these thirteen static and production dynamic indicators constitute the evaluation factor set of remaining oil potential, hierarchy and statistical analysis of weight coefficients are carried out for each factor, taking block A as an example, the multi-level fuzzy comprehensive evaluation method is used to quantitatively evaluate the remaining oil potential of complex heterogeneous reservoir, so as to achieve the purpose of regional governance in accordance with size of remaining oil potential.

Study on the applicability of sand control fracturing technology in Lamadian oilfield

At present, the proportion of water drive fractured wells is as high as 85.8%, and the proportion of repeated wells is as high as 47.7%. In view of this reality, the potential tapping objects are gradually transferred to isolated sand body, river channel edge and top of thick oil layer. Due to the limited fracture length ratio of conventional fracturing, the potential tapping effect is poor. Therefore, the sand body fracturing method is adopted for this section, that is, increasing the fracturing scale and improving the production degree of oil layer by increasing the fracture length ratio. According to the statistics of the effect of sand control fracturing well, combined with the sand body development characteristics, connectivity characteristics and injection production relationship, the influencing factors of sand control fracturing effect are analyzed, and the applicability of sand control fracturing technology in Lamadian oilfield is clarified.

Investigation on Washing Condition of Reservoir in Region A

At present, A oilfield is in the extremely high water-cut period, and it is the key to realize the distribution of residual oil potential. Through the data analysis of the sealed coring well, this is one of the most intuitive and reliable methods for residual oil distribution. The changes and growth of water wash thickness of various oil layers can be understood and analyzed, and the evolution process of oil formation status can be clearly seen with the deepening of oilfield water injection development and the infilling and adjustment of well pattern. The results show that the area is in the condition of medium water washing and still has great potential. The washing degree of one kind of oil layer is high, mainly medium and strong washing. The weak and unwashed oil layers are mainly concentrated in the second and third oil layers, which are the target of the next adjustment and exploration. According to the distribution of residual oil in the second and third oil layers, the next step is to optimize the adjustment of injectionproduction well pattern and the modification of cooperation measures. For improving the level of weak and unwashed reservoirs, it is of guiding significance for the subsequent development of reservoirs in the ultra-high water-cut period.

A Prediction Model for Water Absorption Profile Based on IDW-DTW-RNN Method

At present, many low-permeability oil fields are entering the later stages of development, and there will be problems of difficulty in water injection and poor water injection effects. Obtaining water absorption profiles and their changes can more effectively help formulate layered water injection strategies. Generally, the isotope water absorption profile method is often used to obtain the water absorption profile. This method is accurate, but the test cost is higher and the actual oil field measurement data is less. Based on the measured water absorption profile data, this paper selects 8 factors including effective thickness of oil layer, effective permeability, measure coefficient, crude oil viscosity, crude oil volume coefficient, injection-production pressure difference, well spacing, and connection coefficient between oil and water wells as the main influencing factors of the profile prediction model. Taking water injection wells data with 8 factors as input, a water injection profile prediction neural network model based on inverse distance weighting method and dynamic time warping, namely called IDW-DTW-RNN, is trained in this study. This model is applied in oil field, and the accuracy is obviously improved compared with the conventional method, which is in line with the actual development situation. It provides a scientific basis for the adjustment and optimization of the later injection-production structure of the oilfield.

Oil-gas-water system study in fine reservoir description researches—taking Yulou oil-bearing sets in the West depression in Liaohe Basin in China as an example

Taking a steam flooding experimental area in the West depression in Liaohe Basin in China as an example, the development characteristics of reservoir oil-gas-water system is studied using methods of geological statistics and comparative analysis based on the comprehensive of core, well logging, analytical test, and development performance data. The aimed stratum has good oil-bearing properties, and the oil content level of cores is mainly oil sand and oil-bearing sandstone. The lower limit of effective reservoir has a porosity of 28% and a permeability of 30 mD. In the aimed stratum, the oil viscosity increases gradually with the increase of oil density, and the correlation between the wax content and density of oil is not obvious. With the increase of oil viscosity, the resin and asphaltene contents increase. And with the increase of oil density, the resin and asphaltene contents gradually increase as well. The oil density is relatively big, and most of the 14 samples have a density greater than 0.97 g/cm3. The oil viscosity is mostly greater than 5000 mpa s. The wax content is relatively low (mostly less than 2.5%) with the maximum of 4%. The contents of resin and asphaltene are both greater than 38%, which are relatively high. The formation water is NaHCO3 type which is slightly alkaline. The oil-water contacts of different reservoirs in Yulou oil-bearing sets I are between depth of 1020 m and 1060 m. The distribution of oil layers is jointly controlled by the sediments and structures factors. For the thickness of single oil layer, the maximum is more than 5 m, while the minimum is only one to 2 m. The edge and bottom water plays a very important role in the development of oilfields. In designing and executing various EOR methods in the process of thermal recovery, the influence of reservoir oil-gas-water system should be fully taken into account.

Reservoir prediction and application of multi-attribute fusion

Under the existing well pattern density conditions, there are still uncertainties in the understanding of reservoir distribution in XX Oilfield. The main reasons are that the different sedimentary environments and complex and changeable sedimentary models lead to uncertainties in reservoir prediction under the guidance of sedimentary models; Second, the sedimentary mechanism of different types of sand bodies is different, and there are multiple solutions in cross-well prediction. Therefore, other means must be used for auxiliary analysis in reservoir prediction, so as to improve the accuracy of sand cross-well prediction. This paper focuses on the basic method of reservoir prediction based on seismic multi-attribute fusion, which can further improve the accuracy of cross-well prediction in the cross-well prediction of thick oil layers In addition, the sand body distribution characteristics corrected by multi-attribute fusion slice are applied to measure well selection and layer selection, and comprehensive analysis of remaining oil is carried out by integrating various disciplines, and relatively high-quality potential tapping horizons are determined, which further improves the coincidence rate of potential tapping by measures.

Application of well-seismic reservoir prediction technology in oilfield

This study mainly takes the thick oil layer in Lamadian Oilfield as an example. This oil layer is mainly developed in the area dominated by fluvial sediments, and the reservoir sand body space changes frequently. If we only rely on the traditional single well logging data, it is difficult to directly and effectively predict the changes of the whole sedimentary sand body, and the spatial configuration relationship between river boundary and other sedimentary microfacies can not be effectively predicted. In order to effectively improve the understanding of cross-well sand bodies, it is necessary to effectively combine well seismic with reservoir prediction technology, give full play to the advantage of high resolution of well seismic in the longitudinal direction, and predict its specific adaptability and application according to different situations, so as to better improve the prediction accuracy of reservoir sand bodies and provide important information data for the rational adjustment of cross-well encryption and the formulation of effective measures to tap potential. Based on this, this article deeply analyzes the application value of well-seismic combined reservoir prediction technology in oil fields.

Buckling and Drying Kinetics of Particle-Stabilized Water Droplets Fully or Partially Immersed in an Oil Layer.

We have investigated the effect of buckling of particle-stabilized water droplets on the drying kinetics. Particle-stabilized water droplets in an oil phase were prepared and the shrinking modes of the droplets during drying were controlled by the wettability of the particles. We obtained water droplets with and without buckling and used them in drying experiments. The drying times were comparable when the droplets were fully immersed in a thick oil layer. However, when the thickness of the oil layer was smaller than the droplet diameter, the buckled droplets showed faster drying. Observation of the reflection images around the droplets suggested that the buckled droplets preferentially shrank in the height direction, while the droplets without buckling isotropically shrank. Mathematical models that assumed diffusion of dissolved water molecules in the oil layer showed good agreement with the experimental data. The effective water-oil interfacial area was constant in the buckled droplets, whereas it shrank in the droplets without buckling. This would be a reason for the faster drying of the partially immersed buckled droplets. Particulate shells on liquid droplets could be used to enhance droplet drying.

Raw and acetylated Sugarcane Bagasse (Saccharum officinarum) and Rubber wood (Hevea brasiliensis) in oil spill sorption at Pantai Kuala Perlis

In this research, raw and modified (acetylated) sugarcane bagasse (SGB) (Saccharum officinarum) and rubber wood (RB) (Hevea brasiliensis) were used as sorbents in oil sorption to absorb the used oil in the seawater sample at Pantai Kuala Perlis. The research is done using different time which are 5, 10 and 15 minutes with different thickness of oil layer which are 10 and 20 ml, using 2 g of sorbents. In the percentage of oil removal and oil sorption capacity, 15 minutes was chosen as optimum adsorption time and 10 ml as optimum oil thickness. In term of effect of adsorption time, for overall results, the longer the adsorption time, the higher the sorption capacity and percentage removal of oil. Meanwhile, in term of effect of oil layer thickness, the lower the thickness of oil layer, the higher the sorption capacity and percentage removal. For Fourier Transform Infrared Spectroscopy (FTIR), the spectroscopic data shown that both modified SGB and RB had O-H, CH3 and C=O functional group at the range of 3000-3500, 2500-3000 and 1500-2000 cm-1 respectively. These shown that modified RGB and RB had successfully synthesized. For salinity test, there were no significance different between the initial salinity and after-adsorption salinity of the seawater sample.

The effectiveness to cleanup oil spills from the water environment of the combined sorbent on the basic of PUF and chitin

This study provides information about evaluating the parameters (density, buoyancy, sorption capacity) of a combined oil sorbent based on polyurethane foam filled with chitin (PPU10M). In comparison with the original chitin, the developed sorbent has better buoyancy, and commensurate with the pure polyurethane foam (PUF). The effect of the contact time, the type of the water, the thickness of the oil layer and the adsorbent dosage are studied. The results show that the optimal contact time of the sorption process is 60 minutes. In which, the oil capacity of the sorbent PPU10M in artificial seawater reaches 13.6 g/g and in artificial river water 13.2 g/g. The sorbent dose depends on the thickness of the oil layer on the water surface. For a thin oil layer, the use of 1g of adsorbent reaches higher oil capacity but the oil removal percentage lower in comparison to the dose of 2g sorbent. For an oil layer thickness equal to or greater than the height of the sorbent cube, the efficiency of oil removal is observed better when using 2g of sorbents. Thus, it is considered that the use of 2g sorbents is optimal. A generalization of the research results indicates the prospects of the developed combined sorbent based on chitin and polyurethane for oil spill treatment.

Slippery liquid‐infused porous surfaces: The effect of oil on the water repellence of hydrophobic and superhydrophobic soils

AbstractSoil wettability is important for understanding a wide range of earth system processes, from agricultural productivity to debris flows and sediment fan formation. However, there is limited research considering how soil–water interactions, where the soil grains are naturally hydrophobic, might change in the presence of oil from natural hydrocarbon leakage or oil spills. Here we show how slippery liquid‐infused porous surfaces (SLIPS) apply to hydrophobic soils, by physical modelling of surfaces of different grain sizes and examining their interactions with water before and after impregnation with silicone oil. Using contact and sliding angle measurements and laser scanning fluorescence confocal microscopy, we demonstrate that soil SLIPS can be created with thick oil layers and thin conformal oil layers on median grain sizes of 231 μm and 32 μm, respectively. Until now, SLIPS have only been observed in human‐made materials and biological surfaces. The mechanisms reported here demonstrate that SLIPS can occur in natural granular materials, providing a new mechanism for water‐shedding in soil and sediment systems. Furthermore, the water‐shedding properties may be long lasting as conformal oil layers are stabilized by capillary forces. These results have important implications for understanding soil physics and mechanics where oil is present in a soil, and for agricultural hydrophobicity on shallow slopes.Highlights We model oil contamination on a hydrophobic model soil as a mechanism for creating SLIPS. Soil SLIPS have implications for water‐shedding, oil spill remediation and earth processes. Our model soils exhibit extreme water‐shedding, illustrated by low water droplet sliding angles. This is the first physical modelling observation of SLIPS arising from hydrophobic soil.

Impact of wind on in-situ burning behavior of spilled oil on open water

Spilled oil may cause serious environmental pollution and ecological destruction. Thus, an efficient oil spill response is essential to reduce and minimize the impacts seen from an oil spill. In-situ burning (ISB) has been proven to be one of the most convenient and efficient treatment methods for oil spills on sea. When in-situ burning operation is carried out on sea, the wind is usually available. Spilled oil pool fire flame will be blown to tilt with an angle from the vertical direction and the flame length will be stretched. This effect of flame on downstream will be significantly enhanced. It may even cause the burning of spilled oil out of control or hazard the operators near site. Therefore, it is meaningful to study the burning behavior of oil pool fire on open water under wind.A small-scale oil pool fire on open water experiment system was designed, which could simulate the boundary conditions of sea surface ISB. A series of experiments were carried out to study the effects of oil pool diameter, oil layer thickness and wind speed on fire flame length and flame tilt angle. Flame characteristics and temperature of burning system were recorded. This study observes burning behavior to evolve from short pool fire to long declining phase which transient through boilover stage. Dimensionless flame length in pool fire stage increases with wind speed. As expected the flame tilt is strongly influenced by wind speed, tilt angle increase with wind speed. The observed experimental behavior is captured as improvement in the flame length and flame tilt angle models.This study helped better understanding fire behavior in evolving environmental conditions, and the most importantly developed model would help guide better assessment of fire mitigation strategies.

Detection of Wavy Sea Surface Oil-Derivative Contamination with Forward Specular High-Frequency Scattering

Abstract A spectrum of low-frequency (20–30 Hz) amplitude fluctuations of the ultrasonic (10 MHz) signal specularly scattered from water surfaces covered with monomolecular and thicker crude oil origin films of well-defined, oceanographically relevant viscoelastic properties was examined in laboratory and at-sea conditions. The relationship between the surface water wave (30 Hz) damping coefficient and the oil layer thickness was established, and compared to the one predicted by the classical Stokes theory. The depression of the spectral energy density of wind-driven waves by surface films was inferred from the ratio of acoustic signal fluctuations spectra with/without films, and compared to that resulting from the Marangoni damping theory applicable to monolayers of particular surface viscoelasticity. The agreement between the theory and experimental data was satisfactory. As shown in at-sea experiments performed with a free-floating, buoy-like acoustic system, and an artificial oil slick spread over the Baltic Sea surface, the film’s rheological surface properties can be recovered from acoustic surface probing, as well as oil spill edge detection. Simultaneous statistical analyses of the scattered signal amplitude distribution parameters turned out to be unequivocally related to the oil substance fraction weight, oil layer thickness, and the form of oil contamination.

Genetic analysis of remaining oil in thin and poor layers in Lamadian oilfield

Understanding the distribution of remaining oil and its genesis is the basic work of geological research. Lamadian oilfield has entered the late development stage of ultra-high water cut, the thick oil layer of water drive is decreasing gradually, and the thin and poor oil layer is becoming an important target of adjustment and tapping potential below 1.0m. In order to further improve the development effect of thin and poor reservoir, it is necessary to analyze the saturation field of the numerical model based on interpretation result, core analysis result of sealed coring well and water drive model. The remaining oil characteristics of thin and poor reservoir are studied by means of statistics, genetic analysis, dynamic analysis and static analysis.

Effects of suspended particulate matter, surface oil layer thickness and surfactants on the formation and transport of oil-sediment aggregates (OSA)

This study illustrated the significant effects of oil surface layer thickness, the presence of suspended particulate matter (i.e. sediment resuspension) and surfactants (chemical oil dispersants and a bio-surfactant) on the formation and transport of oil-sediment aggregates (OSA). Oil spill thickness on surface waters influenced the weathering rates of residual oil. Thin oil slicks on the water surface were more readily dispersed by physical processes. This study provided evidence for the dispersion of thin oil slicks by the bursting of air bubbles. The OSA formation within the water column by interaction of oil with suspended particulate materials promoted the sedimentation of oil. The addition of a chemical dispersant (i.e., GM-2) and biosurfactant (i.e., rhamnolipid) to a surface oil slick increased the dissolved and aggregated oil concentrations in the aqueous phase and subsequent oil biodegradation rates. These findings provide a deeper understanding on the processes influencing vertical distribution and environmental persistence of a crude oil spilled on the ocean surface both in the presence and absence of surfactant additions.

Optimization of development mode of asphalt profile control based on numerical simulation and study of its mechanism

Asphalt profile control is an effective method, which can further improve oil recovery of reservoir polymer flooded, it has a lot of advantages including high strength profile control, seal strata formation efficiency, low cost and no pollution, but there has not a perfect evaluation system for its development mode. The effect of different concentration, injection rate, radius of profile control, the timing of profile and segment combination way on the oil displacement effect of the asphalt profile control were researched using numerical simulation method on actual typical well area in Daqing oilfield, and the mechanism of asphalt profile control was studied in detail. According to the results of laboratory test, the largest Enhanced Oil Recovery (EOR) of asphalt was obtained at injection concentration 4000 mg/L, and the best combination was “high–low–high” concentration slug mode. According to the results of numerical simulation, the best concentration, injection rate, radius of profile control and injection timing were 4000 mg/L, 0.15 PV/a (Pore Volume [PV], m3), 1/2 of well spacing and 96% water cut in single slug of asphalt injection system, when the injection condition was multiple slug, the “high–low–high” slug combination mode was the best injection mode. These results could provide effective development basis for asphalt profile control after polymer flooding in thick oil layers.

Application of binary compound water control technology in the development of horizontal wells in offshore oil fields

Offshore A oil field is a typical bottom water reservoir with thin thickness of oil layer and large thickness ratio of water layer and oil layer. Due to its strong bottom water energy, serious non-homogenous and the impact of the bottom ridge, most of the horizontal well production segment is seriously water out.Based on interaction relationship between horizontal segment trajectory and oil and-water interface, the distribution and contrast of permeability along horizontal segment and the comprehensive analysis of production performance, this paper combines the characteristics of the residual oil distribution of typical wells and the mechanism of dual compound oil addition, and from the perspective of combining theory with the field creatively put forward the dual composite water control mode of first injecting gel segment plug and then injecting foam. then completed the design of dual compound water control mode and dosage of the typical well. After processing water control measures, the production data shows that the water content decreased significantly after opening the well, from 95.1% before water control to 80%, which was 15% lower. Also the oil production rate has a significant increase from 2.3t/d before water control to maximum to 9t/d after implementing control measures and cumulative oil increase is 550t with effective period of 135 days. The effect of oil and precipitation is obvious.

ТЕХНИЧЕСКИЕ РЕШЕНИЯ ПО ОЦЕНКЕ ОБВОДНЕННОСТИПРОДУКЦИИНЕФТЕДОБЫВАЮЩИХ СКВАЖИН

Актуальность исследования определена необходимостью стандартизации способов и методик по определению обводненности продукции нефтедобывающих скважин. Цель: оценить причины и условия возникновения систематической погрешности при определении состава скважинной продукции, минимизировать ошибки в измерениях обводненности путем создания новых технологий. Объектом исследования являются нефтедобывающие скважины и процессы, протекающие при движении пластовой продукции от забоя скважины до штатного пробоотборника на выкидной линии устьевой арматуры. Методы исследования основаны на отборе устьевых проб продукции скважин до и после гомогенизации жидкости в выкидной линии скважины. По технологии отбора объемных скважинных проб жидкости оценивалась толщина слоя нефти над водной фазой с помощью разработанного устройства, в котором фиксированный объем нефти переводится в делительную воронку путем снижения давления и добавления в нефть органического растворителя. Установлено, что в высокообводненных скважинах наблюдается гравитационное разделение скважинной жидкости на прослои с различным содержанием нефти и воды. Следствием этого становится поступление в пробоотборную тару жидкости, не соответствующей составу скважинной продукции. Рассмотрены возможные решения существующей проблемы пробоотбора: скважинный поток необходимо гомогенизировать перед штатным пробоотборником или отбирать объемные пробы в течение длительного периода времени. Относительная погрешность измерения доли нефти и воды в объемных пробах с помощью разработанного устройства не превышает 0,1 % для высокообводненных скважин. Рассмотрен альтернативный способ оценки обводненности скважинной продукции, основанный на применении двух датчиков давления в колонне лифтовых труб над электроцентробежным насосом, соответствующий требованиям репрезентативности оцениваемых дискретных проб скважинной жидкости.