| Author's Name: YU Yichang1,2, GUO Rui2, LI Fengfeng2, LIN Minjie2, SHEN Boheng2,
SHEN Yi3, HAN Haiying2, SONG Shiqi1 |
| Based on the data of seismic, well logging, core, cast thin sections and conventional physical properties, taking
the middle-lower section of Mishrif Formation in the Middle East X Oilfield as an example, the identification of sequence
stratigraphic orders and the controlling effects of sequence stratigraphic orders on sedimentary evolution are studied. The
results show that: (1) The Mishrif Formation is divided into 5 third-order sequences (SQ1-SQ5) and 10 fourth-order se⁃
quences (PSS1-PSS10). The MB2—MC1 single layers in the middle-lower section of Mishrif Formation correspond to
SQ2-SQ3, including 4 fourth-order sequences (PSS3-PSS6), in which multiple fifth-order and sixth-order sequences are
developed. (2) Carbonate open platform-weakly rimmed platform of a sub-basin is developed in the study area, and the
reservoirs mainly exist in platform margin shoals and open platform shoals. The shoal facies can be further subdivided into
rudist shoal, rudist-containing bioclastic shoal, bioclastic-arene shoal, bioclastic-spherical shoal and bioclastic shoal ac⁃
cording to bioclastic types. (3) The sixth-order sequence controls the sedimentary sequence of a single shoal body, the
fifth-order controls the combination characteristics of multiple shoal bodies, the fourth-order sequence determines the
evolution characteristics of sedimentary microfacies, and the third-order sequence determines the evolution characteristics
of sedimentary systems. (4) In the early stage of PSS3 and PSS4 of SQ2 sequence, the two fourth-order sequences are in a
platform front slope environment, with the development of lens-shaped collapsed coarse-grained sediments. In the later
stage of PSS3 and PSS4, a sedimentary sequence of the platform margin intershoal → medium energy shoal is developed.
The PSS5 and PSS6 of the SQ3 sequence develop a sedimentary sequence of platform margin intershoal → medium energy
shoal → high energy shoal. After the completion of SQ3 sedimentation, a special incision filling sedimentation is formed. |
