梓潼凹陷须四段致密砂砾岩储层高产控制因素分析

Factors Affecting High Yield of Tight Sand-conglomerate Reservoirs in Xujiahe 4 Member, Zitong Depression, Sichuan Basin

梓潼凹陷须家河组四段砂砾岩储层致密,非均质性强,单井产能差异大,部分气井生产压力和产量递减快,但是也不乏W4井和WC1井这样的高产稳产井。分析须家河组四段致密砂砾岩储层的高产稳产主控因素,可为指明该区须家河组勘探方向提供依据。从岩性、裂缝、测试方法和钻井过程等多因素考虑,在分析失利井原因的基础上,认为砂砾岩储层物性优劣和裂缝发育程度是影响高产稳产的主要因素。因此,寻找相对高孔砂砾岩和裂缝发育段是梓潼凹陷须家河组四段致密储层高产稳产的关键。

In Zitong Depression, Sichuan Basin, the reservoirs of Xujiahe 4 Member are composed of tight sand and conglomerate,and characterized by strong heterogeneity. Moreover, there is big difference among single-well deliverability, a number of gas wells also appear quick production-pressure drop and yield decline except some with high and stable yield such as W4 and WC1 wells.Analyzing the main factors affecting this high and stable yield is conducive to looking for an exploration and development way of Xujiahe Formation in this study area. After finding out why some wells are in failure from aspects of lithology, fracture, testing methods,and drilling procedure, it is deemed that the main affecting factors are petrophysical property and fracture development degree of the sand and conglomerate. So, it's very critical to seek some sand and conglomerate segments with higher porosity and developed fractures in Xujiahe 4 Member, Zitong Depression.