The Paleozoic gas reservoirs in the Jingbian Gas Field, Ordos Basin, are characterized by strong heterogeneity. With the rapid development of this gas field, the gas reservoir formation pressure is gradually reduced and the production dynamic characteristics of different blocks are significantly distinct from each other. To provide a reference for the progressive development and production capacity compensation, typical blocks include two high-permeability blocks and one low-permeability block are selected to undergo a pilot test of gas well constant pressure production at different development stages of this field. The test data, collected from different wells with wellhead pressure of 13, 6 and 3 MPa respectively, is analyzed through the Arps equation, and the results reveal the production decline law of the lower Paleozoic gas reservoirs in the Jingbian Gas Field. (1) The production of high-permeability blocks under high and low pressure is in exponential decline, while the production decline rate tends to be flat-lined with the decreasing wellhead pressure. (2) The production of low-permeability blocks is in hyperbolic decline. (3) The production decline law of high- and low-permeability blocks have some common features, that is, under a certain gas production rate, the production decline rate is proportional to wellhead pressure, but is inversely proportional to dynamic producing reserve, drainage radius, and reservoir energy recharge speed.

Jingbian gas filed have two gas bearing reservoir,Neopaleozoic and Lower Palaeozoic Group,the Neopaleozoic gas bearing reservoir upgrowthes,but the reservoir physical property is poor,according to the technique and policy in nowadays,development economic results is relatively low. Utilizing consummate Lower Palaeozoic Group well pattern,uniting Neopaleozoic gas well logging interpretation and reservoir clascification criteria,Neopaleozoic gas well optimize empirical formula was builded,which was used to optimize gas well to forecast fluids rate,select highly fluids rate,better wellbore condition and poorly production of Lower Palaeozoic Group to check layer and patch perforation in Neopaleozoic reservoir,cut reformation cost,enhance gas well productivity,realize high efficiency and sustainable development of Jingbian gas filed.

The present paper gives a detailed description of interstratal,intrastratal and planar heterogeneity and its main influencing factors in the fluvial reservoirs of the 34 reservoirs in the 2nd member of the Shahejie Formation in the 2nd district of the Shengtuo Oil Field in the light of reservoir architectures and logging interpretation by using the entropy's method.The 34 reservoirs are turned out to be moderate to highly nonhomogeneous,and become progressively higher with the increase of water injection.The planar heterogeneity tends to be higher than the interstratal and intrastratal ones.The reservoir heterogeneity is believed to be controlled by reservoir architectures,and more complicated by diagenesis.The different heterogeneity tends to caused by deficient injection and production patterns.The heterogeneity index based on the entropy's method may be important to characterizing the heterogeneity of the fluvial reservoirs and predicting the distribution of residual oil.

在储层建筑结构划分、测井多参数处理结果的基础上,根据熵的原理,应用熵权法定量计算了胜坨油田二区沙河街二段3砂层组4小层(简称沙二段(34))河流相储层的非均质综合指数,按照不同的开发时期详尽分析了储层的层间、层内、平面非均质性特征,并阐述了储层非均质性的主要影响因素.结果表明:沙二段(34)储层层内、层间及平面非均质性中等-较强；随着注水开发的进行,非均质性有继续增强的趋势,平面非均质性较之层内和层间非均质性更强烈.同一小层及韵律层在不同开发时期的非均质程度有明显的差异.建筑结构控制储层非均质程度,成岩作用使非均质性复杂化,注采井网不完善加剧了非均质性的差异性.研究成果为剩余油的挖潜提供了重要依据.

针对靖边气田下古气藏开发中所暴露的主要矛盾和气井生产管理急待解决的地质问题,通过对钻井资料、地震资料、测井资料以及生产动态资料的综合分析与研究,进行构造精细解释、细分沉积相、精细刻画侵蚀古潜沟、致密相带分布分析、富水区分布范围划分和储层物性特征研究等工作,分小层建立高精度三维地质模型。在建立气田三维地质模型的基础上,细化各小层储量分布特征,分析储量动用程度,为气田后续加密部署提供合理井位建议。

靖边气田下古气藏为典型的海相碳酸盐岩储层,具有工区面积大,储层薄,储层致密区发育等特点。在该区块储层建模的过程中,存在着侵蚀沟槽发育、海相碳酸盐岩无精细相模型和无法判断储层沉积方向等问题。针对上述问题,创造性的提出了分层切割精细沟槽刻画技术、相控建模与储/地比模型约束技术和数据分析对比优化等技术,最终建立了符合气藏地质特征的三维精细地质模型,为气田开发调整方案的部署提供了地质基础。

Miall architectural structure analysis is applied to study the reservoir architecture structure of the subbed of Es234 of Shengtuo oil field. Thirteen types of lithofacies are distinguished through core observation. Based on the observation, correlation of connecting-well sections and recognizition of well logging curves, with the conception of stratification, six scales of bounding interfaces are defined. Based on the recognization of lithofacies and the classification of sequences, seven kinds of structures are identified, and they are channel sediments(CH), channel retention sediments(CHL), channel bar(CB), fall-siltseam(FS), natural levee(LV), crevassesplay (CS), Overbank fine sediments(OF). And finally, the planar and sectional assemblage models of architecture structure of 34 sand body are established. Channel filling(CH) and channel bar (CB)are the main architectural elements in the plane and three hierarchies are divided in the section.

Taking the No.34 layer in the second member of Shahejie Formation in Shengtuo Oilfield as an example,the stochastic modeling for spatial distribution of fluvial facies architecture was studied to investigate the remaining oil distribution rules.Seven coring holes were analyzed.Considering many factors such as lithology,sediment feature and electrical feature,nine lithofacies types,seven rank interfaces and seven architectural elements were established by lots of log data.A 3D distribution model for architectural element was developed with the sequential indicator simulation method.The model analysis revealed that the rate of channel charge and channel bar reached 63.1%.The natural levee accounted for 10.6%,and the crevasse splay,floodplain fine grain,channel lag deposit and interlayer accounted for 8.9%,8.1%,4.9% and 4.4%,respectively. Taking architectural element and remaining oil saturation model into a comprehensive element,the remaining oil was forecasted.Then,the same method was used for remaining oil distribution study of multi-architectural-elements combination.The remaining oil saturations of four blocks are above 50%.These areas would have rich remaining oil.

以胜坨油田二区沙二段34小层辫状河沉积砂体为例,建立其流动单元和建筑结构模型.通过2种模型对比研究可知,建筑结构和流动单元具有很好的对应关系,两者均是按照沉积体内部水动力条件变化所划分出来的储集体,具有相似储集条件的流动单元和建筑结构单元具有相同的平面和空间分布范围.将流动单元和建筑结构模型分别与剩余油饱和度模型进行叠合分析可知,储集物性较差的流动单元和建筑结构单元的大部分区域有剩余油分布,储集性能较好的流动单元和建筑结构单元的边缘部位及不同类型流动单元和建筑结构单元的交界部位也有剩余油分布.

To discuss the problem that the analysis of interior architectural structures of underground fluvial reservoirs is difficult, and the heterogeneity is serious. Based on cores, outcrop, drilling and well log data, this paper analyzes the fluvial characteristics of the 3 Sand Sets in the 2 member of Shahejie Formation(S32) in 2 District, Shengtuo Oilfield(TDSO), and recognizes all kinds of hierarchical bounding surfaces, lithofacies and architectural elements in the sandbody according to Miall's suggestion. Then the paper analyzes well logs of the architectural elements, and extracts characteristic parameters, to establish quantitative fuzzy digital model and develop a set of effective software to discriminate the types of architectural elements, and the results coincide very well with the interpretation of the geological specialist. Finally, geological models are established by using this software in Shengtuo Oilfield, and this method provides scientific foundation for enhancing oil recovery in mature oilfield.

Flow units and architecture models of the sedimentary sand bodies of braided river were established in Es2 34 of Shengtuo Oilfield. The comparison of these two models indicates that the good corresponding relationship exists between the architecture and flow units, both of which are the reservoirs divided by the change of hydrodynamic condition in the sedimentary body and have a fine correspondent relationship. With similar reservoir condition, the flow unit and architectural elements have same distribution in plane and space. The synthetically analysis on flow units, architecture models and remaining oil saturation showed that the remaining oil distributes mainly in the flow units or architectural elements with poor physical property, then the boundary of the flow units or architectural elements with goodphysical property, and the boundary of different flow units or architectural elements.

以胜坨油田坨七断块沙二段91层为例,通过对储层层内韵律性、层间差异性、层内层间隔夹层进行定量评价,揭示了91砂体储层层内、层间和平面非均质性特征,指出储层非均质性主要受到沉积相带、砂体展布和隔夹层分布的控制.研究了在储层非均质影响下剩余油的分布特征:在层内、层间非均质性影响下,剩余油主要分布在物性较差注采不完善的储层中;在平面非均质性控制下剩余油分布在平面上非主流线部位和渗透率较差的侧缘相带.