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Candidate screening for matrix acidizing has gained attention in recent years due to the importance in driving towards acidizing success rate and efficiency improvement. This paper presents a comprehensive workflow featuring a simple step-by-step method utilizing mainly production and basic reservoir data. The objective of the workflow was to ensure the right candidates were selected, standardized checklist of information being reviewed and time saving to shortlist wells with formation damage issues. Basic production data such as liquid rate (oil and water rates), water cut, gaslift rate and sandcount along with basic reservoir data such as permeability and height were powerful parameters that drive the workflow. Formation Damage Indicator (FDI) and Heterogeneity Index (HI) concepts were introduced to provide the initial screening of the wells. Other subsequent parameters were evaluated according to specific cut-off values. These cut-off values have made the workflow standardized and practical to speed-up the screening of candidates. Once the wells have passed through the workflow, the shortlisted candidates were matured by performing nodal analysis, studying on the detailed formation damage type and skin evaluation, formulating the remedial solution and quantifying the potential gain. This workflow was tested throughout selected fields in the Malaysia region operated by PETRONAS Carigali, which proved to be efficient in identifying the acidizing candidates. The ultimate aim of the work was to automate the selection of wells with productivity issues using real-time data. The workflow was then brought into an Integrated Operations (IO) environment using the same step-by-step method whereby the required data used for the screening process were pulled from corporate database. The IO environment retrieves data from master and asset databases to perform calculations using various parameters with its cut-off values. Using this method, candidate screening processes were shortened from two weeks to one day. In total, 750 strings were analyzed using this workflow, which resulted in 101 strings shortlisted as stimulation candidates. Twenty-eight strings have been executed from year 2017 until 2018 with a total 6500 bopd gain. Success rate has improved from 55% to 73%. The additional benefit of the workflow was also the ability to group wells with lifting issues, water production problems and sand production issues. The unique digitalized workflow is now a one-click exercise, which enables engineers to increase their operational efficiency resulting in huge cost and time saving opportunities. |
