油气田测井技术综述

An overview of logging technology in oil and gas fields

地质测井是石油工业中一种连续监测系统,它是用于地质、天然气测井、钻井和超压研究的勘探评价井钻井过程中各种参数的连续监测系统。由于它是一种地层评价工具,各种参数的监测必须由地质学家进行,他们监视各种测井表上的数据并绘制图表。地质数据在钻井开发井时同样有用,因为它有助于通过气相色谱和荧光研究精确地确定气、油和油水接触。气相色谱法是地质工作的一部分,它也有助于确定天然气的组成特征和鉴别湿气和干气。地质测井的另一个主要应用是在钻井过程中进行超压研究,预测前方的孔隙压力,避免严重的井害。地质单元类型的选择取决于区域。然而,随着计算机技术的进步,地质复杂、认识不清地区的在线地质测井单元已经投入使用,在钻井过程中对地层评价起到了重要的作用。地质测井,实际上是一种可靠的地层评价工具,用于对地层中发生的油气进行定性测定。然而,在对套管和测试以及与勘探和开发井有关的其他细节作出重要决定时,所获得的数据必须由电缆测井加以补充。

Geologging, which is usually referred to in the oil industry as mud logging, is a continuous monitoring system of various parameters during drilling of exploratory-assessment wells aimed for geological, gas logging, drilling, and overpressure studies. Inasmuch as it is a formation evaluation tool,monitoring of the various parameters must be carried out by geologists, who keep round-the-clock watch and plot data on various log sheets. Geologging data are equally useful when drilling development wells, as it helps in pinpointing the gas-oil and oil-water contacts with the help of gas chromatography as well as fluorescence studies. The use of gas chromatography, which is a part of geologging, is also helpful in determining the compositional characteristics of natural gases and in identifying the wet and dry gases. The other principal application of geologging is in carrying out overpressure studies during the course of drilling and to predict pore pressure well ahead, to avoid serious well hazards, which could result in the loss of time,personnel, material, and money unless timely action is taken. Selection of the type of geologging unit depends on the area. However, with the advance in computer technology, on-line geologging units for areas where the geology is complicated and not clearly understood have come into use and played a major role in formation evaluation during the course of drilling. Geologging, is, in fact, a foolproof formation evaluation tool for carrying out the qualitative determination of oil and gas occurring in the formation. However, the data obtained have to be supplemented by wireline logs when making vital decisions with regard to casing and testing policies and other details related to both exploratory and development wells.