Wastage Profile Study in Giant Offshore Oilfield, a Well Integrity approach to Optimize ICD Well Completion Design and Improve Corrosion Management for MRC wells.

Abstract

For the last 30 years, wells in the field have been suffering from medium to high corrosion rates in both near surface and downhole components. Remedial measures had been implemented in order to restore Well Integrity with different techniques. Corrective actions aside, a strong preventive approach is needed to better understand the root causes of such corrosion rates and scenarios where the integrity of specific wells has been seriously compromised due to corrosion problems.Taking a step further and considering the big implications of new projects such as Artificial Islands project, where the company will be drilling & completing over 300 Extended Reach Drilling (ERD) wells, Well Integrity input as a discipline becomes critical in order to ensure previous problems will not be repeated and all lessons learned throughout the years will be wisely taken into consideration when designing a new well to remain integral during its whole expected life.Understanding of the current corrosion mechanisms in the field was the key to find not only solutions, but also, to create an approach aimed to improve the future completion for Island wells in terms of design, materials and many other factors.An extensive multidisciplinary approach was carried out in order to successfully complete a full study in one of the pilot wells completed with Inflow Control Devices (ICDs), which will be analyzed in detail in this paper, covering the following areas:i. Well design and configuration ii. Well monitoring and performance review iii. Well diagnosis and failure investigation iv. Post-Failure modelling and well prediction v. Preventive/Corrective actions for future wells. Corrosion management and prevention of scale deposits were the two main challenges encountered during this project, which was launched and completed with the main objective of evaluate and optimize the ICD completion design in one Maximum Reservoir Contact (MRC) pilot well in the field, the findings and lessons learnt were used to upgrade the current well design and improve the development plan for the field.

The Effect of the Operation of Downhole Equipment on the Processes of Corrosive Wear (by the Example Inflow Control Devices of Nozzle Type)

“…Alvarez [ 14 ] revealed and proved the influence of the nozzle-type ICD on the corrosive wear of the pipe wall after (relative to the flow direction) the ICD was placed in it. The authors gave only general recommendations for minimizing or eliminating the effect of nozzle-type ICDs on the development of corrosion processes.…”

“…It is necessary to determine which group of factors has the greatest influence on the process of corrosion wear. Alvarez [ 14 ] showed that failure occurred only in certain sections of the pipe. At the same time, the remaining sections of the pipe, through which the flow passed with the same content of chemicals and mechanical impurities as through the inflow control devices, were not significantly affected by corrosion processes and subsequent destruction.…”

Flow simulation for a horizontal well with slotted screen and ICD completions based on the wellbore–annulus–reservoir model

“…Fluid flows from the oil reservoir into the wellbore through these completions, which result in additional pressure drop affects the production rate of horizontal wells. However, prediction models for horizontal well production rate based on slotted screen and ICD completions have been simplified, such that only the flow in the center tubing is considered while the flow in the annulus is disregarded (Alvarez, A. C. , et al, 2014;Javid, K. , 2018;Droppert, V. , 2020;Gurses, S. F., 2013;Goh, G. , 2016;Bol, L. , 2016;Shahkarami, A. , 2020;Eltazy, E., 2019;D Li, 2017). They all carried out the research on related models for ICD completion, but did not consider the effects of annulus flow.…”