Origin and distribution of formation water in tight sandstone reservoirs in the northeastern Ordos Basin

Chen Zhaobing; Yang Youyun; Shao Jinhui; Zhu Yushuang; Chen Xinjing; Shi Lei; Meng Di

doi:10.11743/ogg20190210

Views : 0 下载量: 229 CSCD: 12

PDF
Export
Share
Collection
Album

Origin and distribution of formation water in tight sandstone reservoirs in the northeastern Ordos Basin
Vol. 40, Issue 2, Pages: 313-325(2019)
Online First：28 April 2019，

Published：2019
DOI： 10.11743/ogg20190210
稿件说明：

移动端阅览

DOI：

Chen Zhaobing, Yang Youyun, Shao Jinhui, et al. Origin and distribution of formation water in tight sandstone reservoirs in the northeastern Ordos Basin[J]. 2019, 40(2): 313-325. DOI： 10.11743/ogg20190210.

摘要

通过地震、钻井、测井及生产动态等资料，结合压汞、气水相渗、物性和水化学等测试分析，对鄂尔多斯盆地东北部神木气田地层水的化学特征、成因、空间分布特征及控制因素进行了研究。研究区处于气水过渡区，地层水属于“Ⅴ”型CaCl

型，以低矿化度的“酸点水”和高矿化度的常规地层水为主。纵向上，各层之间沉积、岩相差异及距气源远近不同是造成地层水纵向差异分布的主要因素。本溪组与太原组层内稳定分布的多套致密灰岩阻碍了烃类进入储层，造成原始气藏充注程度不高，地层水相对富集；石千峰组远离气源中心，烃类供给不足，气驱水不彻底；山西组属“自生自储”成藏组合，充注程度高，产水量少。平面上，受晚白垩世末期盆地“西倾”构造运动影响，盆地东北部整体抬升并发生气水二次调整，导致含气层位增多，连续气柱高度上升；同时气藏压力下降，盆地边缘地层水顺层侵入，各层均不同程度产水，形成“多层含气、普遍低产、气水同产”的格局，表现为自西向东地层水的规模及产水量逐渐增大，矿化度逐渐升高。研究结果为鄂尔多斯盆地边缘气水空间分布及成因理论提供了一定科学依据。

Abstract

The chemical features

genesis

spatial distribution characteristics and controlling factors of the formation water in Shenmu gas field

northeastern Ordos Basin

were studied by the analysis of seismic

drilling and logging

as well as performance data combined with test analysis of mercury injection

gas-water relative permeability

physical and hydrochemical properties.Since the studied area is located in the transitional area from water to gas

the formation water herein is of "V-shaped" CaCl

type

with low salinity"acid water" and high salinity conventional formation water being dominant.Vertically

the differential distribution of formation water are mainly caused by the differences of deposition

lithofacies and distance from gas source for various formations.Multiple tight limestones distributed in the Benxi and Taiyuan Formations have blocked the entry of hydrocarbons into reservoirs

leading to a low degree of gas charging for the original reservoirs and relatively high enrichment of formation water.The Shiqianfeng Formation

located far away from gas source

is in short of hydrocarbon supply with incomplete gas displacement of water.The Shanxi Formation is a self-sourced indi-genous play

which has a high degree of gas charging and low quantity of water produced.Horizontally

influenced by the "west-dipping" structural movement of the basin in the Late Cretaceous

the northeastern Ordos Basin uplifted as a whole along with the secondary adjustment of water/gas contact

producing more gas-bearing horizons and continuously increa-sing the height of gas columns; meanwhile

the pressure in the gas reservoir decreased

and the formation water at the basin margin invaded into bed laterally

leading to the pattern of "multiple gas layers

low gas yield and water-gas co-production"

characterized by the ever-increasing formation water scale and water production from west to east with a gradual increase of salinity.The results provide some basis for prediction of the spatial distribution and genesis of gas and water at the margin of the Ordos Basin.