Stochastic Life Cycle Approach to Assess Wellbore Integrity for CO2 Geological Storage

Abstract

Storage sites associated with depleted oil and gas reservoirs may contain many abandoned wellbores in addition to potentially unidentified wellbores. These wellbores have historically variable quality and quantity of cement that will have undergone ranging degrees of degradation. Wellbore performance in a single wellbore is dependent on the wellbore events (i.e. pressure and temperature changes) that occur within the life of the wellbore (Fourmaintraux et al., 2005; Gray et al., 2007). There is significant uncertainty surrounding the integrity of existing wellbores due to a lack of data. Successful implementation of carbon capture and storage (CCS) will depend on solving the small-scale leakage problem associated with localized flow along wellbores. Our knowledge of oil wellbore performance under different life stages of a well is still weak. Consequently, each wellbore is unique and general conclusions about well integrity are difficult to ascertain from analyzing only a single well. Each wellbore is considered as a risk and robust tools are needed to allow for the assessment of the performance for wellbores and investigate wellbore leakage mechanism. In this paper, a full lifecycle methodology is proposed to assess wellbore integrity as a measure of the risk of leakage. The methodology identifies the key elements to model the wellbore element and incorporates the use of a statistical approach to better understand the uncertainty in the risk estimation and interaction between various parameters controlling the model.

A numerical study on the feasibility of evaluating CO2injection wellbore integrity through casing deformation monitoring

“…The material properties for each component of the wellbore are listed in Table , and the deterministic values (DVs; values that remain unchanged in all simulation conditions) of the model for both surface casing and production casing are listed in Table . The formation temperature is calculated based on a geothermal gradient of 0.035°C/m found in previous studies . The mud hydrostatic pressure is calculated on a fresh water density of 1000 kg/m 3 .…”

“…The formation temperature is calculated based on a geothermal gradient of 0.035°C/m found in previous studies. 24 The mud hydrostatic pressure is calculated on a fresh water density of 1000 kg/m 3 . And the interface gap thermal conductance is based on the experimental and analytical results of a composite structural elements under simulated fire conditions 25 ( Table 3).…”

Study on sealing integrity of cement sheath in ultra deep well reservoir reconstruction

“…Using experimental devices, more in‐depth research has been conducted on the impact of changes in downhole construction conditions on the integrity of the cement sheath. They believe that the cement sheath should meet the short‐term and long‐term production tasks of the well and ensure its necessary strength requirements 10–14 . The convergence constraint method is applied to model the casing, cement sheath, and formation rocks as independent parts.…”

Development and application of on-line calibration device for water injection flowmeter

“…In the absence of an alternative flowmeter, a calibration requires at least two service visits to the site, and the water injection has to be stopped which will affect production. In the actual water injection process, the water injection flowmeter can not be calibrated twice a year that seriously affects the normal water injection metering and the fine water injection development [6][7][8][9]. Therefore, combined with the actual production situation, the paper studies the on-line calibration technology for the field water injection flowmeter that can meet the calibration technical requirements and operation management specifications.…”