高含硫气藏开发中防硫堵和防腐蚀措施探讨

高含硫气藏开发过程中,硫的大量沉积会引起地层、井筒和集输管线堵塞,导致气井产能急剧下降,甚至停产。同时由于产出气体H_2S和CO_2含量高,腐蚀性较高,容易产生电化学失重腐蚀、氢脆和硫化物应力腐蚀三种类型的腐蚀。这两个开发难题严重影响和制约高含硫气藏的开发生产。     

潜江凹陷老新地区油气成藏机理与勘探潜力

在综合应用地质、地震、试油和化验分析资料基础上,根据油气成藏动力学理论对油气成藏条件和油气成藏机理进行综合分析,认为,老新地区具备形成岩性油藏和构造-岩性油藏的良好条件。油气是在高地层温度、地层压力场和势能场等主要动力作用下形成和在沉积型、构造型和复合型油气输导体系中运移。油气于荆河镇组沉积中后期聚集成藏,其空间分布具有互补性。直路口断层下降盘是隐蔽油藏勘探的最有利区。     

裂缝性油气藏勘探技术与应用

裂缝不仅是决定低渗透储层产能的关键因素,而且也直接控制着裂缝性油气藏的形成与分布。裂缝性储层识别与评价一直是油气藏勘探的重点和难点,而地质资料分析只是作为裂缝分布的一种定性测算,测井中的裂缝鉴定虽能达到定量水平,但只是小范围的、局部的。地震资料虽是大范围的,但其对地层的分辨率较低。因此,综合应用各种资料描述和预测裂缝分布是裂缝性油气藏勘探的基本思路。     

页岩气水平井组拉链压裂过程中地应力的分布规律

页岩储层具有低孔隙度、超低渗透率的特征,往往需要通过水力压裂才能使气井具备一定的生产能力。拉链压裂是近年来针对页岩气藏缝网压裂的一项新兴工艺,为了认清压裂过程中裂缝应力干扰后地应力场的分布规律并给页岩压裂设计提供参考,首先假设地层为均质、各向同性弹性体,然后通过位移不连续法,建立起地层应力场分布数学模型,并利用线性叠加原理,得到人工裂缝周围水平应力场的分布情况。研究发现：①裂缝周围的地应力随着与裂缝距离的远近有不同程度的增加;②裂缝尖端处存在应力集中现象,且在裂缝尖端附近产生的拉应力使得水平应力有所减小;③裂缝对水平最小主应力的影响程度大于对最大主应力的影响;④随着裂缝条数的增加,诱导应力的叠加干扰对水平主应力的影响不断增强,且水平应力差异性逐渐减小;⑤在裂缝交错排列的区域内,应力干扰较强,应力场分布较复杂。上述研究成果对页岩气水平井组拉链压裂的优化设计具有指导意义。     

Predicting the Morphodynamic Response of Silt-Laden Rivers to Water and Sediment Release from Reservoirs: Lower Yellow River, China

The high sediment load of the Yellow River results in rapid infilling of its reservoirs when sediment is not regularly flushed. Simultaneously, the downstream reaches of the Yellow River experience extremely high siltation rates, which are reduced when sediment is retained in its reservoirs. To minimize siltation in the reservoirs and the downstream river bed, water and sediment are released from the reservoir in a controlled way through flushing experiments. In this paper, we analyze the effect of such a flushing event on the downstream river bed through data analysis and numerical modeling. Sedimentation may be minimized by relating the amount of sediment released from the reservoir to the sediment available for release through operational monitoring and by releasing relatively clear water after turbid water. Despite this flushing of sediment, the reservoir will eventually fill up, and more sediment released again into the lower Yellow River. The change in discharge magnitude and frequency brought about by the reservoir will then probably result in increased siltation rates in the lower Yellow River compared to the predam situation.     

Time-Domain Hydrodynamic Forces on Rigid Dams with Reservoir Bottom Absorption of Energy

In this investigation, a two-dimensional time-domain closed-form mathematical model for the hydrodynamic forces on the upstream vertical face of a given rigid dam subjected to a specified horizontal ground motion accelerogram was developed. The model includes the absorption of energy at the elastic reservoir bottom, characterized by the impedance ratio of the sub-bottom materials with respect to water (α). The formulated boundary-value problem is solved in Laplace’s domain and subsequently transformed back to the time domain. Response spectra for the hydrodynamic base shear force and overturning moment are constructed for extreme values of the parameter α. It is found that, frequently, including the solid-foundation elasticity in the reservoir model attenuates the resultant hydrodynamic forces on a rigid barrier, as compared to the results for the case of a rigid reservoir foundation. In this case, the elasticity of the sub-bottom materials constitutes an effective energy dissipating mechanism (radiation damping). By contrast, for sub-bottom materials with less-than-water impedance, amplification of the effective earthquake forces is obtained, as compared to the results for the case of a rigid reservoir foundation.     

有界分形油藏的压力动态分析

从广义对流扩散方程出发，首先给出了其在拉氏空间中的通解，然后给出了等压或不渗透外边界条件下，考虑井筒存储和表皮效应的拉氏空间中的解；计算并讨论了孔隙度和渗透率谱指数θφ，θｋ和井筒存储系数Ｃｄ及表皮因子ｓ′对无因次井底压力的影响，并求得了不渗透边界影响到达井底后双对数曲线上出现的直线段斜率为１。     

Modeling a Plunging Underflow

A coupled three-dimensional hydrodynamics and two-dimensional underflow model is adapted to provide simulation of plunging inflows in reservoirs. The new approach accounts for the effect of the barotropic term prior to the plunge point of the inflow. Simulations of plunging flows in constant width and constant slope channels are conducted and the resulting plunge depths are in agreement with prior empirical models. Simulation of a previously measured underflow in Wellington Reservoir (Australia) demonstrates the model application to a plunging inflow in a natural water body and good agreement between field and model results.     

缅甸某区块始新统沉积相对储层的控制作用分析

研究区位于缅甸伊洛瓦底盆地中部,是油气勘探的有利地区。通过对研究区始新统不同沉积相带储层特征研究,认为水下分流河道为最有利的储层发育微相;分流河道、辫状河道、河口坝次之;天然堤、决口扇砂体的储层性质相对较差,反映了沉积相对储层的发育特征有一定的控制作用。     

基于图像的珍珠表面细微破损检测技术

研究珍珠表面破损检测问题,提高检测的准确性。针对珍珠表面十分光滑,细微的破损时常发生,传统的图像检测或者肉眼检测很难保证珍珠表面细微破损被准确检测出来。造成检测的准确率不高的问题,为了解决这一问题,提出采用计算机视觉图像的珍珠表面细微破损检测方法。通过去除图像中的噪声和一些干扰测量的部分。采用非规则破损表面的测量方法,通过精密测量珍珠图像映射圆表面的像素缺失度,完成珍珠表面细微破损检测。实验证明,上述方案切实可行,可以达到较高的精度,取得了令人满意的效果。