塔里木盆地顺北区块二叠系井漏复杂的分析及对策

顺北区块钻井项目施工中,二叠系的井漏复杂情况较多,漏失量大,易发生再次或多次漏失,严重时导致井壁垮塌掉块卡钻,致使井下复杂情况高发,给钻井工程带来损失,影响了该区块的勘探开发速度。二叠系火成岩发育,地层裂缝发育,地层破裂,钻井时井下复杂主要表现为漏失。针对此问题开展了顺北地区二叠系井漏复杂分析,结合顺北区块施工项目的实际情况以及二叠系地层特点,分析了该区块的二叠系钻进难点,总结了随钻堵漏技术具体的施工措施和不同漏速下的堵漏方案.经过实践验证,该综合防漏堵漏对策能有效减少井漏复杂,提高堵漏效率。     

Optimal pumping from skimming wells from the Yamuna River flood plain in north India

This report examines the problem involving the pumping of groundwater from a group of 90 existing wells along the banks of the Yamuna River, northwest of Delhi (India), underlain with geologically occurring saline water. It is known that unregulated pumping will lead to upconing of saline water and therefore it is necessary to determine optimal rates and associated well locations (from an existing group of candidate wells that supply drinking water to the city of Delhi) that will minimize the total salinity. The nonlinear, non-convex problem is solved by embedding the calibrated groundwater model within a simulation-optimisation (S/O) framework. Optimisation is accomplished by using simulated annealing (SA), a search algorithm. The computational burden is primarily managed by replacing the numerical model with a surrogate simulator-artificial neural network (ANN). The model is applied to the real system to determine the optimal pumping schedule. The results of the operational model suggest that the skimming wells must be operated from optimal locations such that they are staggered in space and time to obtain the least saline water.     

Diagnosis of trace Pb in domestic wells,Upper Gloucester Catchment,Maine, USA

Dissolved Pb in 32 wells associated with corroding submersible pumps is examined within a rural water district after almost 20 years (1984–2002). Groundwater Pb ranged from 0.4–24.9 μg L⁻¹ after 24 h pump flushing. Preliminary geochemistry and representative borehole lithology examinations were extrapolated by Markov chain modeling. The first-order geostatistical realizations of glacial sediments coupled with the Monte Carlo Metropolis-Hasting method suggest that elevated trace Pb persists in sand and gravel units, and continues at least to 40 m depth in the catchment. The ²⁰⁷Pb/²⁰⁶Pb and ²⁰⁸Pb/²⁰⁶Pb isotope compositions of groundwater Pb were decisive in discriminating the importance of leached Pb from submersible pump materials among geogenic sources.     

水源热泵抽灌井布局及其运行过程中地下温度变化

本文以某水源热泵空调系统为例,建立了抽灌场地及周边地下水动力场与温度场的耦合数学模型,运用数值法求得系统运行过程中地下水的温度变化,分析了场地"热短路"效应和不同含水层中温度场的影响范围,以定量化的手段科学评价了场地抽灌井的布局及其可行性。分析结果表明,由于抽灌井之间的"热短路"程度较轻,场地的抽灌井布局可保证系统的高效运行。     

Real-time reservoir management: A multiscale adaptive optimization and control approach

We propose a decision-making approach for optimizing the profitability of hydrocarbon reservoirs. The proposed approach addresses the overwhelming complexity of the overall optimization problem by suggesting an oilfield operations hierarchy that entails different time scales. We discuss system identification, optimization, and control that are appropriate at various levels of the hierarchy and capitalize on the abilities of permanently instrumented and remotely actuated fields. Optimization is performed in real-time and is based on feedback. We provide details on real-time identification of hybrid models and their use at the scheduling and supervisory control levels. Case studies using field-calibrated simulation data demonstrate the applicability and value of the proposed approach. Directions for future development are given.     

水泥浆失重对高压油气井固井质量的影响分析及工艺对策

高压油气井由于存在高压地层,在整个钻井工程中都引起了高度重视。有些高压油气井可能还存在低压易漏层。在固井候凝过程中,水泥浆会产生失重,进而降低了井筒内的液柱压力,如果液柱压力低于失重井段的地层压力,地层流体将会向环空侵入,造成窜槽,甚至会引发井控事故;如果液柱压力高于地层（破裂）压力将引起地层漏失,进而污染油气层,造成水泥浆低返。因此,处理好固井过程中井筒内动态压力和地层压力的关系以及制定相关的应急措施是高压油气井固井成败的关键。分析了水泥浆失重对高压油气井固井质量的影响因素,提出了高压油气井油气水侵的预防措施和固井中相关风险的应急措施和机制。     

辽河油田欢喜岭沙河街组沙四段精细地层划分与对比

文章在通过综合研究辽河油田欢喜岭X区地震、测井、岩性等资料基础上,采用"井震结合"的方法对区内能够钻到沙四段的113口井的岩性、电性进行分析,对欢喜岭区内的沙河街组沙四段进行了精细化分与对比,并将沙四段地层划分为Te(特岩)、DuⅠ(杜Ⅰ)、DuⅡ(杜Ⅱ)、DuⅢ(杜Ⅲ)4套小层。沙四段的精细地层划分与对比,为研究砂体展布、沉积微相等提供了地质基础数据,对油田的开发具有一定的指导意义。     

Using the extended finite element method for simulation of transient well leakage in multilayer aquifers

The extended finite element (XFEM) is applied to the problem of transient leakage from abandoned or free-flowing artesian wells in perforated aquifer-aquitard systems. To more accurately capture the singularities in potentiometric head at the wells, the standard linear finite element basis is locally augmented with asymptotic analytical solutions which enable more accurate calculations of leakage rates between aquifers. Highly accurate flux estimates are obtained without the need for higher mesh resolution near wells. Simulations are carried out to test both the accuracy and convergence properties of the XFEM implementation, and the XFEM results are compared to those of a high-resolution standard finite element model. It is seen that for the type of singularity-driven problem posed here, the standard FEM is unable to resolve leakage rates without very fine discretization, but that the XFEM performs robustly with fewer degrees of freedom. The impact of aquifer geometric heterogeneity on leakage rates is assessed and seen to be an important factor in determining total leakage. It is demonstrated that the XFEM may be a valuable tool in many water resources applications where small-scale effects can impact global system behavior.     

Analytical solution for two-phase flow in a wellbore using the drift-flux model

This paper presents analytical solutions for steady-state, compressible two-phase flow through a wellbore under isothermal conditions using the drift flux conceptual model. Although only applicable to highly idealized systems, the analytical solutions are useful for verifying numerical simulation capabilities that can handle much more complicated systems, and can be used in their own right for gaining insight about two-phase flow processes in wells. The analytical solutions are obtained by solving the mixture momentum equation of steady-state, two-phase flow with an assumption that the two phases are immiscible. These analytical solutions describe the steady-state behavior of two-phase flow in the wellbore, including profiles of phase saturation, phase velocities, and pressure gradients, as affected by the total mass flow rate, phase mass fraction, and drift velocity (i.e., the slip between two phases). Close matching between the analytical solutions and numerical solutions for a hypothetical CO₂ leakage problem as well as to field data from a CO₂ production well indicates that the analytical solution is capable of capturing the major features of steady-state two-phase flow through an open wellbore, and that the related assumptions and simplifications are justified for many actual systems. In addition, we demonstrate the utility of the analytical solution to evaluate how the bottomhole pressure in a well in which CO₂ is leaking upward responds to the mass flow rate of CO₂-water mixture.     

高密市激电测深定井方法探讨

在高密的找水工作中,采用激电测深法进行定井,推断含水层的位置和富水性,在物探确定的异常部位实施钻探,找水效果显著。根据高密市找水定井实例,简要介绍激电测深定井法在找水定井过程中应注意的事项,为今后运用该方法进行找水定井工作提供借鉴。