Search

Terrain correction is to eliminate the effect of terrain relief around measurement points on observation results in gravitational and geoelectrical prospecting. Because the microscopic mechanism of spontaneous potential anomalies formed by terrains is rather complex, it is difficult to obtain an analytic formula, whereas a more intuitive method can be adopted instead to find out the fitting formula between these two variables. According to the study, in spontaneous potential gradient calculation, spontaneous potential anomalies caused by topography can be divided into two types: one is that anomalies have a mirror-image relation with terrain relief, which accounts for the majority of cases; the other one is that anomalies have an inverted mirror-image relation with terrain relief. The relation between a majority of anomalies and terrain relief could be linear, quadratic or exponential, among which linear relation is the primary. As for which fitting relation should be adopted specifically, it can be decided by selecting a typical terrain and spontaneous potential curve first and judging through the law of variations; and trial calculation method can be adopted as well to choose the appropriate fitting formula by comparing the correction effects. The Ordos Basin was selected to be the research site in this paper and the terrain correction method which is applicable to spontaneous potential gradient calculation was put forward. Through the comparison of the correction results of three kinds of fitting formulas, it was concluded that the linear fitting formula can better describe the relationship between relative height and spontaneous potential correction amount in the surveyed area. Terrain correction can effectively eliminate the correlation between relative height and spontaneous potential. The corrected spontaneous potential curves can reflect subsurface geological structure better, and the anomalies showed by the spontaneous potential contour map can be more prominent. Terrain relief can influence the appearance of anomalies in spontaneous potential gradient calculation, especially when the area of rugged terrain is comparable to the area of target geological bodies, which may make it difficult to distinguish these two anomalies. Thus the study on terrain correction has great importance in practice.

The upper spontaneous potential produced by oil and gas accumulation is of a stable potential field, and its intensity is directly proportional to the content of the source and inversely proportional to the radius apart from the source. Theoretical research and practical results show that anomalies of spontaneous potential can indicate oil-bearing sandstone bodies and locate the areas of oil and gas accumulation. In oil areas which have fewer reservoir beds, the petroleum reservoir thickness can be predicted by determining the linear relationship between potential intensity and apparent equivalent thickness. In the Weixing (卫星) oilfield, which is devoid of sufficient reservoir beds, its apparent equivalent thickness can be predicted by the linear equation h= -0.19x+0.74. On the basis of geological research, we use the spontaneous potential method to predict the equivalent thickness, helping in the selection of the most appropriate drill sites to enhance the probability of successful well boring so as to serve the next round development of the oilfield.

We report here the different components of erythrocyte membrane skeleton proteins between acute monocytic leukemic (AMoL) patients and normal people. The bands in the 2 region of ghost membrane from AMoL patients exhibited significant differences on SDS gel electrophoresis. Band 2.2 was found to be missing and a “new” band with molecular weight (MW) 161 000 appeared. Also band 4.9 was missing, and the amounts of spectrin, actin, and band 4.8 of AMoL patients were decreased markedly. No such alterations can be seen in normal individuals, even in acute myeloid leukemic (AML) and chronic myeloid leukemic (CML) patients