同生断层及其伴生褶曲的组合式样

石油钻探遇断层而失败的情形时有发生,其中多数是由于对同生断层及其伴生褶曲认识的错误所引起。为减少勘探失误,本文讨论了同生断层及其伴生褶曲空间组合的一些规律。（1）同生断层可分为盆地边界同生断层和内部同生断层两大类。边界同生断层的断面产状基本形态有勺形、椅形、阶形和坎形四种。（2）边界同生断层是追踪盆前的一组或两组基底断裂发育而成的。单向追踪的边界同生断层平面伸展较平直;双向追踪的边界同生断层平面伸展呈锯齿形。（3）内部同生断层及其伴生褶曲在剖面上的组合式样有正牵引和同向y字形派生断层、逆牵引和反向y字形派生断层。这两类四种形变可单一出现,也可在同一剖面中共存。（4）内部同生断层系的平面组合基本式样有帚状和雁列两种。构成地堑式的两条同生断层断距都较大时就会有挤压背斜出现（构成w形构造）。（5）中国东部裂谷系盆地中的所谓“滚动背斜”都不具备标准的“滚动”特征;它只产生在特定的层位上;对它与其称“滚动背斜”,不如称“逆牵引背斜”为宜。

COMBINATION STYLES OF CONTEMPORANEOUSFAULT AND ASSOCIATED FOLDS

: During petroleum exploration , drilling failures are often met with when fault are encountered. Most failures are caused by the misunderstanding of the contemporaneous fault and the associated fold. In order to minimize the failures, some distribution rules of the contemporaneous faults and their associated folds are discussed in this paper. (1)The contemporaneous can be divided into two classes, i. e., basin boundary contemporaneous fault and inner contemporaneous fault. Attitude of fault plane for basin boundary one shows as four basic types, i. e. , spoon shaped, listric shaped, step shaped and scrap shaped. (2)The boundary contemporaneous fault are developped through the tracing of the one or two sets of basement fault: formed in pre-basin-forming periods, when the boundary fault traced a single direction, then its extension is straight, while when the boundary contemporaneous fault traced two directions, then it will show the zig-zag shape. (3)In a section, the combination styles of the inner contemporaneous faults and their associated fold may show as normal drag fault and synthetic Y-shaped derivative fault, or as reversed - drag fault and antisynthetic Y-shaped derivative fault. All of these fault deformations of the two classes or four kinds may occur alone or may coexist in one section. (4 )The plane combination styles of inner contemporaneous faults may show as the broom-type and the en echelon one. Compression anticline might appear (composing the w-type structure), when the displacement of the two graben-forming contemporaneous faults are greater. (5)Those are called "rollover anticlines" in eastern China rift basins do not possess the standard "rollover" features , because of they are developped only in special layer. Therefore , it is better to be named as "reversed-drag anticline" than to call it as "rollover anticline".