Remaining oil distribution characteristics in an oil reservoir with ultra-high water-cut

An accurate mapping and understanding of remaining oil distribution is very important for water control and stabilize oil production of mature oilfields in ultra-high water-cut stage.Currently,the Tuo-21 Fault Block of the Shengtuo Oilfield has entered the stage of ultra-high water cut(97.2%).Poor adaptability of the well pattern,ineffective water injection cycle and low efficiency of engineering measures(such as workover,re-perforation and utilization of high-capacity pumps)are the significant problems in the ultra-high water-cut reservoir.In order to accurately describe the oil and water flow characteristics,relative permeability curves at high water injection multiple(injected pore volume)and a semiquantitative method is applied to perform fine reservoir simulation of the Sand group 3e7 in the Block.An accurate reservoir model is built and history matching is performed.The distribution characteristics of remaining oil in lateral and vertical directions are quantitatively simulated and analyzed.The results show that the numerical simulation considering relative permeability at high injection multiple can reflect truly the remaining oil distribution characteristics after water flooding in an ultrahigh water-cut stage.The distribution of remaining oil saturation can be mapped more accurately and quantitatively by using the‘four-points and five-types’classification method,providing a basis for potential tapping of various remaining oil types of oil reservoirs in late-stage of development with high water-cut.

Displacement characteristics of CO_(2)flooding in extra-high water-cut reservoirs

Carbon dioxide(CO_(2))flooding is a widely applied recovery method during the tertiary recovery of oil and gas.A high water saturation condition in reservoirs could induce a‘water shielding’phenomenon after the injection of CO_(2).This would prevent contact between the injected gas and the residual oil,restricting the development of the miscible zone.A micro-visual experiment of dead-end models,used to observe the effect of a film of water on the miscibility process,indicates that CO_(2)can penetrate the water film and come into contact with the residual oil,although the mixing is significantly delayed.However,the dissolution loss of CO_(2)at high water-cut conditions is not negligible.The oil-water partition coefficient,defined as the ratio of CO_(2)solubility in an oil-brine/two-phase system,keeps constant for specific reservoir conditions and changes little with an injection gas.The NMR device shows that when CO_(2)flooding follows water flooding,the residual oil decreasesdnot only in medium and large pores but also in small and micro pores.At levels of higher water saturation,CO_(2)displacement is characterized initially by a low oil production rate and high water-cut.After the CO_(2)breakthrough,the water-cut decreases sharply and the oil production rate increases gradually.The response time of CO_(2)flooding at high watercut reservoirs is typically delayed and prolonged.These results were confirmed in a pilot test for CO_(2)flooding at the P1-1 well group of the Pucheng Oilfield.Observations from this pilot study also suggest that a larger injection gas pore volume available for CO_(2)injection is required to offset the dissolution loss in high water saturation conditions.

Development Strategies for Achieving High Production with Fewer Wells in Conventional Offshore Heavy Oil Fields in Bohai Bay,China

Development strategy for heavy-oil reservoirs is one of the important research interests in China National Offshore Oil Corp. （CNOOC） that plans a highly effective development for heavy oil fields in multilayered fluvial reservoirs because of their significant influence on marine oil and even on China＇s petroleum production. The characteristics analysis of multilayered fluvial reservoirs in the heavy oil fields in Bohai Bay indicates that large amounts ofoil were trapped in the channel, point bar and channel bar sands. The reserves distribution of 8 oilfields illustrates that the reserves trapped in the main sands, which is 20%-40% of all of the sand bodies, account for 70%-90% of total reserves of the heavy oil fields. The cumulative production from high productivity wells （50% of the total wells） was 75%-90% of the production of the overall oilfield, while only 3%-10% of the total production was from the low productivity wells （30% of the total wells）. And the high productivity wells were drilled in the sands with high reserves abundance. Based on the above information the development strategy was proposed, which includes reserves production planning, selection of well configuration, productivity design, and development modification at different stages.

Improved Approaches Coupling the Method on Discharge Allocation and“High Kv in Wellblock”for Simulating Multiaquifer Wells

The mathematic models to simulate the multiaquifer well using the discharge allocation based on explicit transmissivity-weighted or the implicit transmissivity and the hydraulic gradient(TJ method),can not describe the actual well,especially with vertical flow along the wellbore.In order to improve the accuracy of the results,two improved approaches are established,by coupling the ideas of"High Kv in Wellblock"into the aforementioned methods on discharge allocation to consider the vertical flow

APPLICATION OF HIGH-RESOLUTION MAGNETIC METHOD AND GRADIENT METHOD TO LOCATE ABANDONED BRINE-WELLS IN HUTCHINSON, KANSAS, U.S.A.

After successfully locating one abandoned brine well by an electromagnetic method during testing in 2001 and five abandoned brine wells by a high resolution magnetic method during 2002, a high resolution magnetic method was again proposed to search for wells in 2003 when a second sensor was employed to acquire data for calculating the pseudo vertical gradient of magnetic fields. Total area surveyed in 2003 was 1,024,000 ft 2, which was divided into grids with an average size of 10,000 ft 2 and distributed across eight different sites. Magnetic anomalies and their vertical gradients from known brine wells were first recorded as signatures to identify anomalies caused by possible buried brine wells. Of fifty one verified anomalies, thirty one anomalies were due to wells buried at depths from 0 to 8.5 ft: twenty one 6 to 9 inch abandoned brine wells, seven 1.5 to 3 inch probable water wells, one 16 inch dewatering well for a construction site at a depth of 3 ft, and two 4 inch wells on the ground surface. Approximate monopole shaped anomalies were observed from all these wells after data corrections. However, the range of amplitudes of magnetic anomalies from 7,000 to 28,000 nT from these abandoned brine wells was measured. This range of anomalies is mainly due to the thickness and depth of buried wells. Anomaly amplitudes from 1.5 to 3 inch wells are 4,000 to 8,000 nT and linearly correlate with the buried depth. One 3 inch well that caused an anomaly of 13,000 nT could be the inner pipe of a brine well. Gradient anomalies are roughly in a range of 100 to 200 nT/inch for 1.5 to 3 inch wells and 200 to 300 nT/inch for brine wells.As indicated by the potential field theory, gradient data possess higher horizontal resolution than the magnetic field itself. Gradient data provide valuable assistance in determining horizontal locations of anomaly sources for excavation. In practice, however, improvement in the horizontal resolution is limited by survey line spacing. If only one sensor is used in a survey, there is rapid decrease in the horizontal resolution when sensor height increases from 14 to 44 inches. This indicates that it is critical to keep the sensor as close to the ground as possible when hunting buried wells that are close to each other. It also suggests that the downward continuation is useful to increase the horizontal resolution in well hunting.

D-二聚体、超敏C反应蛋白联合Wells评分对早期静脉血栓栓塞症的诊断价值

目的D-二聚体、超敏C反应蛋白(hs-CRP)联合Wells评分对早期静脉血栓栓塞症(VTE)的诊断价值。方法选取2014年4月至2020年4月常州市第七人民医院收治的80例VTE患者作为观察组和80例非VTE患者作为对照组,比较两组患者的D-二聚体、hs-CRP水平和Wells评分,以及其与VTE发病的相关性。以受试者工作特征(ROC)曲线和曲线下面积(AUC)评估D-二聚体、hs-CRP、Wells评分单独及联合检测对早期VTE的诊断效能。结果观察组患者D-二聚体、hs-CRP水平和Wells评分均明显高于对照组,差异均有统计学意义(P<0.01)。观察组患者栓塞性疾病的可能性高于对照组,差异有统计学意义(P<0.05)。Spearman相关分析结果显示,D-二聚体、hs-CRP水平、Wells评分与VTE发生均呈正相关(r=0.422、0.502、0.392,P<0.05)。D-二聚体、hs-CRP、Wells评分联合诊断VTE的AUC为0.830(95%CI:0.766~0.894),灵敏度、特异度分别为75.00%、85.00%。结论D-二聚体、hs-CRP、Wells评分联合检测对早期VTE的诊断价值较高。

Methodology for production logging in oil-in-water flows under low flow rate and high water-cut conditions

This study aimed to obtain the production profiles of oil-in-water flow under low flow rate and high water-cut conditions in oil wells.A combination production profile logging composed of an arc-type conductance sensor(ATCS)and a cross-correlation flow meter(CFM)with a center body is proposed and experimentally evaluated.The ATCS is designed for water holdup measurement,whereas the CFM with a center body is proposed to obtain the mixture velocity.Then,a drift-flux model based on flow patterns is established to predict the individual-phase superficial velocity of oil-in-water flows.Results show that the ATCS possesses high resolution in water holdup measurement and that flow pattern information can be deduced from its signal through nonlinear time series analysis.The CFM can enhance the correlation of upstream and downstream signals and simplify the relationship between the cross-correlation velocity and mixture velocity.On the basis of the drift-flux model,individual-phase superficial velocities can be predicted with high accuracy for different flow patterns.

Progress and Development Direction of “Three-High” Oil and Gas Well Testing Technology

By reviewing the development of “three-high” oil and gas well testing technology of Sinopec in recent years, this paper systematically summarizes the application of “three-high” oil and gas well testing technology of Sinopec in engineering optimization design technology, and high temperature and high pressure testing technology, high pressure and high temperature transformation completion integration technology. Major progress has been made in seven aspects: plug removal and re-production technology of production wells in high acid gas fields;wellbore preparation technology of ultra-deep, high-pressure, and high-temperature oil and gas wells;surface metering technology;and supporting tool development technology. This paper comprehensively analyzes the challenges faced by the “three-high” oil and gas well production testing technology in four aspects: downhole tools, production testing technology, safe production testing, and the development of low-cost production test tools. Four development directions are put forward: 1) Improve ultra-deep oil and gas testing technology and strengthen integrated geological engineering research. 2) Deepen oil and gas well integrity evaluation technology to ensure the life cycle of oil and gas wells. 3) Carry out high-end, customized, and intelligent research on oil test tools to promote the low-cost and efficient development of ultra deep reservoirs. 4) Promote the fully automatic control of the surface metering process to realize the safe development of “three-high” reservoirs.

The Study of Tubing Vibration Mechanism in High Pressure Gas Well

Deep gas wells and gas fields have the characteristics of high pressure. The vibration of the tubing string during the production of gas wells causes the string to be subjected to severe stress and even dynamic fatigue failure. Therefore, this article is based on the dynamic finite element theory, aiming at the characteristics of large-size tubing strings in deep gas wells. The finite element mechanics model and mathematical model of the tubing string vibration of the packer of high-pressure gas wells were established, and the ANSYS software was re-developed. The finite element analysis program for the vibration dynamics of the unbuckled and buckled strings of gas wells was compiled with APDL, and the displacement of the longitudinal vibration of the tubing string of high-pressure gas wells was studied. According to different sizes of tubing strings currently used in deep gas wells and gas fields, simulation calculations are carried out, and the axial impact load and buckling damage laws of the tubing strings of the entire well section under different production rates are obtained. It provides a theoretical basis for the prediction of tubing string vibration law and measures to prevent tubing string vibration.

中国康养旅游高质量发展水平空间异质性及其驱动机制

辨析康养旅游高质量发展水平并剖析其空间异质性,对于稳步推进康养旅游高质量发展和加快健康中国建设至关重要。该文综合运用熵权TOPSIS、空间自相关、空间变差函数等方法探究2021年中国康养旅游高质量发展水平与空间分异格局,并利用地理加权回归模型分析其影响因素及驱动机制。研究表明:(1)中国康养旅游高质量发展水平呈现“南高北低”的不均衡空间分布格局,存在显著的空间正相关性,H-H集聚区主要为福建、江西、湖南、广西4省域,L-L集聚区以内蒙古、吉林、新疆3省域为主;高值区在东南—西北方向上表现出明显的梯度分布特征。(2)公路密度、康养旅游政策支持度、森林面积、城镇人均可支配收入是康养旅游高质量发展的主要影响因素且空间分异性显著,并形成以基础设施、康养需求、自然资源和经济基础为主的复合驱动机制。

超高温井固井水泥浆体系研究与应用

针对目前高温水泥浆抗高温外掺料以石英砂为主,水泥石200℃下高温强度衰退导致环空密封失效问题,研发了具有水化活性的富硅铝材料,其加量占水泥30%~70%时200℃×20.7 MPa×30 d下水泥石高温强度不衰退;将富硅铝材料作为水泥石高温强度稳定材料,优选配套外加剂,构建了富硅铝基超高温固井水泥浆体系,100~200℃下API失水量<50 mL,稠化时间150~500 min可调,水泥浆综合性能良好;水泥石200℃×20.7 MPa养护10、60、120、180 d抗压强度均>26 MPa,未见高温强度衰退。超声波强度曲线显示600 h内水泥石强度持续增长直至稳定发展,水泥石高温力学性能优异。SEM和XRD分析表明富硅铝材料参与水泥水化反应,消除体系中氢氧化钙,生成高温性能优良的铝氧四面体和硅氧四面体相互键接的空间三维网状结构,以及托勃莫来石、钙硅铝石等水化产物维持水泥石的高温强度稳定,水泥石结构致密。该水泥浆体系在干热岩固井中应用1个井次,固井质量优质,截至目前1000 d水泥环密封良好。

A New Method for Predicting Wall Sticking Occurrence Temperature of High Water Cut Crude Oil

In crude oil transportation, adhesion of oil on pipe wall can cause partial or total blockage of the pipe. This process is significantly affected by wall sticking occurrence temperature(WSOT). In this work, an efficient approach for estimating WSOT of high water-cut oil, which can agree well with the actual environment of multiphase transportation pipeline, is proposed. Based on the energy dissipation theory, it is possible to make comparison of average shear rates between the stirred vessel and the flow loop. The impacts of water content and shear rate on WSOT are investigated using the stirred vessel and the flow loop. Good agreement has been observed between the stirred vessel and the flow loop results with the maximum and the average absolute deviations equating to 3.30 °C and 2.18 °C, respectively. The development of gathering scheme can enjoy some benefits from this method.

Quantum Well Infrared Photodetectors:the Basic Design and New Research Directions

The basic design principles and parameters of GaAs/AlGaAs quantum well infrared photodetectors (QWIP) are reviewed.Furthermore new research directions,devices and applications suited for QWIPs are discussed.These include monolithic integration of QWIPs with GaAs based electronic and optoelectronic devices,high frequency and high speed QWIPs and applications,multicolor and multispectral detectors,and p-type QWIPs.

Potential risks of spectrum whitening deconvolution——compared with well-driven deconvolution

Deconvolution is widely used to increase the resolution of seismic data. To compare the resolution ability of conventional spectrum whitening deconvolution to thin layers with that of welldriven deconvolution, a complex sedimentary geological model was designed, and then the simulated seismic data were processed respectively by each of the two methods. The amplitude spectrum of seismic data was almost white after spectrum whitening, but the wavelet resolution was low. The amplitude spectrum after well-driven deconvolution deviated from white spectrum, but the wavelet resolution was high. Further analysis showed that if an actual reflectivity series could not well satisfy the hypothesis of white spectrum, spectrum whitening deconvolution had a potential risk of wavelet distortion, which might lead to a pitfall in high resolution seismic data interpretation. On the other hand, the wavelet after well- driven deconvolution had higher resolution both in the time and frequency domains. It is favorable for high resolution seismic interpretation and reservoir prediction.

“WELL”建筑标准在办公空间的运用

随着社会的发展,中国经济实力的日益增强,人们对办公环境的要求也越来越高。本文以美国国际 WELL 建筑研究所制定的WELL 健康建筑标准为基础,结合某办公空间改造项目为实例,探讨如何在办公场所的设计中应用这一套标准,哪些与健康密切相关的因素需要我们关注将是本文重点关注与讨论的内容,旨在为当代的人们营造一个全面的健康环境。

高含水油井关停后剩余油再富集速度研究

高含水断块油藏开发末期构造高部位油井在关井一段时间后,会产生剩余油再富集现象。目前关于剩余油再富集速度的研究中,对剩余油运移过程的影响因素考虑不够全面,影响计算精度。针对该问题,在对运移中剩余油再富集受力分析的基础上建立小油滴状和柱状剩余油再富集速度模型,通过正交试验确立2种剩余油再富集速度的主要敏感因素,并建立了2种剩余油再富集速度及再富集时间图版。研究结果表明:存在驱替压差时,储层渗透率为影响2种剩余油再富集速度的主控因素;当储层渗透率一定,驱替压差的增大和原油黏度的减小有利于2种剩余油再富集速度的增大;同一注采井距位置处的小油滴距离孔隙中滞留柱状剩余油越近,聚集过程中剩余油再富集时间越长,但数值上增加不多。该研究对高含水油藏剩余油再富集潜力区评价具有借鉴意义。

玛湖凹陷玛页1井风城组页岩油地质甜点优选

玛湖凹陷风城组属于具有物源多、岩性复杂、整体含油、甜点分散等特征的混积型碱湖沉积,为了对页岩油进行高效勘探和开发,需要对页岩油地质甜点优选。以高压压汞、岩石热解等实验结果为基础,对玛页1井风城组储集层及其页岩油可动性等进行评价,构建页岩油地质甜点优选模型,评价页岩油地质甜点垂向分布特征。结果表明:孔隙度、总有机碳含量、脆性矿物含量和游离烃含量与100倍总有机碳含量之差分别是评价风城组储集层储集性能、含油性、脆性和页岩油可动性的参数;利用4个参数构建页岩油地质甜点优选模型,玛页1井风城组一类、二类和三类页岩油地质甜点的页岩油甜点因子分别为大于0.2823、0.0111~0.2823和小于0.0111;玛页1井风城组一类页岩油地质甜点主要分布在风二段上部和风三段,岩性以泥岩和白云质泥岩为主。

THE SEMI-DISCREIXTE METHOD FOR SOLVING HIGH-DIMENSION WAVE EQUATION

The article gives a semi-discrete method for solving high-dimension wave equationBy the method, high-dimension wave equation is converted by, means of diseretizationinto I-D wave equation system which is well-posed. The convergence of the semidijcrete method is given. The numerical calculating resulis show that the speed of convergence is high.

海上油田污水回注井高效解堵技术研究与应用

针对污水回注井酸化效果不理想的问题,利用岩心流动实验、悬浮物含量及粒径测试、X射线衍射对堵塞情况进行了分析。在此基础上,利用填砂管流动和岩心溶蚀实验研发了一套兼具污油清洗与高溶蚀率的酸液体系。此外,结合储层特征优化了酸液置放工艺。结果表明,污油和固体悬浮物在近井地带形成的复合堵塞物是造成储层堵塞的主要原因;1%水基清洗剂洗油率达到86.44%,高溶蚀酸对固体悬浮物溶蚀率达到89.77%,二者复配体系能够快速瓦解油泥小球;化学微粒分流剂可对储层形成有效暂堵分流,且酸化后自动溶解。该技术矿场应用8井次,平均视吸水指数提高1.74倍。该技术适用于污水回注井解堵,并为提高海上污水回注井酸化效果提供理论和实践依据。