元坝气田雷口坡组古溶沟展布及其对气藏的控制

Distribution of ancient ditches in Leikoupo Formation and its control over gas accumulations in Yuanba Gas Field

范志伟

Fan Zhiwei

中国石化 勘探南方分公司, 成都 610041

SINOPEC Southern Exploration Branch, Chengdu, Sichuan 610041, China

在详细论述元坝气田雷口坡组古溶沟形成条件、识别方法及展布特征的基础上，重点剖析了古溶沟对储层、圈闭、流体及油气富集区的影响，提出有利的勘探目标区。剥蚀作用、早期断裂及湿热气候控制了古溶沟的形成；溶沟区具有残留地层薄、上覆地层增厚及潜流带发育等特征，地震剖面上可见“下凹”及“双向上超”等现象。工区内发育4个主要溶沟区，单条溶沟宽度一般在2~3 km，切割深度为30~60 m；岩溶残丘地层保存较全，储集空间发育，为有利目标区。

Based on the analyses of generation condition, identification method and distribution feature of the ancient ditches in the Leikoupo Formation in the Yuanba Gas Field, the influences of ancient ditches on reservoir, trap, flow and hydrocarbon enrichment were discussed, and several favorable exploration targets were pointed out. Erosion, early fracture and hot and humid climate controlled the generation of ancient ditches. The ditch area was featured by thin residue formation, thickening overlying formation and underflow development. "Concave" and "bidirectional onlap" were identified on seismic sections. There are four main ditch areas in the study area, usually 2-3 km wide for a single ditch, and the cutting depth is 30-60 m. Karst residual hills, which were well-preserved and favorable for reservoir, are potential targets for exploration.

https://doi.org/10.11781/sysydz201405562