苏南地区上古气井低产低效主控因素分析

MAIN INFLUENCING FACTORS OF LOW YIELD AND LOW EFFICIENCY FOR UPPER PALEOZOIC GAS WELLS, SOUTHERN SULIGE GASFIELD

上古生界主力含气层段的二叠系石盒子组盒8段和山西组山1段,具有较好的开发潜力,但上古投产井生产动态特征资料显示,该区气井总体产量较低,稳产能力较差。针对这一生产现状,主要从沉积、成岩角度,剖析了上古气藏低产低效的主控因素,认为距离物源远,砂岩埋藏深且粒度细,单砂体段多层薄,软组分含量较高,压实作用及胶结作用强烈,储层物性差以及普遍产水等都是导致低产低效的主要因素,提出积极实施水平井及加强排水采气是提高气藏开发效率的有效手段。

As the main gas-bearing intervals in the Upper Paleozoic, both Permian Shihezi8 and Shanxi 1 members have a better development prospect. However, it is shown from some data on dynamic performance of producing wells that, their production is always low and their stable productivity is poor. So, the main factors to affect not only low yield but also low efficiency of the Upper Paleozoic gas reservoir were analyzed in terms of sedimentation and diagenesis. The main factors include that(1)the reservoirs are far away from material origin;(2)sandstone reservoirs are characterized by deep burial depth and fine grain size;(3)there are several single sandstone intervals with thin thickness;(4)there are a lot of soft composition;(5)either compaction or cementation is strong;(6)the petrophysical properties are very poor;and(7)water is often produced from the wells. So, we present two effective tools of adopting horizontal-well drilling and strengthening water drainage and gas production in order to increase development efficiency.