Impact assessment of interlayers on geological storage of carbon dioxide in Songliao Basin

Abstract

Reservoirs in the Songliao Basin are characterized by strong heterogeneity, which increases the difficulty of exact reservoir prediction. The clay interlayer developed in the reservoir is an important factor affecting the heterogeneity of the reservoir. Using the reservoir numerical simulation technology, an attempt has been made to investigate the storage efficiency during CO2 sequestration in Songliao Basin considering different types of interlayer in underground formations. Results indicate that type I interlayer, with a large thickness embedded between the two sand bodies has function of shunting and blocking to alleviate the impacts on cap rock. The type II interlayer has a small thickness and locates inside a single sand body, with poor physical properties and continuity, which has the same blocking effect on CO2 distribution and moderating influence on the cap rock. The physical properties of type III interlayer are same as the type II interlayer, but it has uneven distribution and poor continuity. In addition, three schemes of perforated zone were designed and their effects on CO2 storage efficiency and stability were studied. For a single reservoir, the scheme I is to perforate a whole reservoir, which is more conducive to maintain the reservoir’s stability. For multiple sets of “single-reservoir”, the scheme II can be preferentially selected to perforate the reservoir section below the interlayer when the injection volume is small. However, the scheme III can be used to perforate the interlayer and the reservoir below that when the injection volume is large. The study is beneficial to provide guidance and advice for selecting a suitable CO2 geological storage and reduce the risk of CO2 leakage.

Risk assessment on the CCUS project using risk breakdown structure methodology: A case study on Jilin oilfield CO2‐EOR Hei‐79 block

“…Normal faults occur in the caprock of Hei-79 and no geological faults have been discovered. 14,47 (3) Natural factors. The Songliao Basin experiences weak tectonic fault activity and the frequency of strong earthquakes in this area is relatively small.…”

“…Fracturing has resulted in layer fracturing and fault activation. 14 (5) Human activities. Human activities occur 3 km away from the site boundary.…”

“…Illegal drilling and oil theft occurs due to its economic value. 14 (6) External social factors. The project enjoys good public support.…”

“…The Hei-79 block is a low-permeability oil reservoir with a sufficient gas source and a reservoir formation pressure exceeding that of CO 2 flooding. 14 The minimum miscible pressure can be developed in the Hei-79 block for CO 2 miscible flooding. The Hei-79 block is in central Songnen Plain, an alluvial low plain with a flat and open terrain and a ground elevation of between 145 m-150 m. The CO 2 test area consists mainly of dry fields and grasslands.…”

Geological sequestration of CO2 in a water-bearing reservoir in hydrate-forming conditions

“…It was found that a relatively slow injection rate of the mixture gives better response in terms of the amount of hydrate formed. Zhang et al [23] recently studied the effect of interlayered geological system on CO 2 storage with the objective to help in selection of suitable storage site.…”