This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 202419, “Performance Review of Chemical Sand Consolidation and Agglomeration for Maximum Potential as Downhole Sand Control: An Operator’s Experience,” by Nur Atiqah Hassan, SPE, Wei Jian Yeap, SPE, and Ratan Singh, Petronas, et al., prepared for the 2020 SPE Asia Pacific Oil and Gas Conference and Exhibition, originally scheduled to be held in Perth, Australia, 20–22 October. The paper has not been peer reviewed.
Chemical sand consolidation (SCON) and sand agglomeration have been identified as effective chemical treatments to control sand production downhole. Both treatments involve injection of chemicals into the near-wellbore area of the reservoir with the aim of improving the strength of the formation and thus reducing the tendency for sand production. The complete paper presents lessons learned and best practices from several chemical SCON and sand-agglomeration treatments performed in mature fields in Malaysia.
SCON and Sand Agglomeration History and Performance
Petronas has deployed approximately 20 SCON and three sand-agglomeration treatments over nine different offshore fields since 2009. Of 20 planned SCON jobs, four were suspended for a variety of reasons such as budget constraints or operational complexity. Of the 16 SCON jobs executed, a success rate of approximately 75% was achieved. The number of sand agglomeration jobs executed is significantly lower; only three were completed, with one failure case.
In terms of effective production, SCON has better overall performance than sand agglomeration. The average effective production period for SCON is approximately 2.9 years, while the average effective production period for sand agglomeration is approximately 2.5 years.
Criteria for Candidate Selection Completion Type. - In considering the historical success rate of SCON and sand-agglomeration jobs according to completion type, most viable candidates were completed with perforated cased hole, contributing to approximately 87% of all chemical SCON and sand-agglomeration jobs. Despite the challenges caused by chemical placement in openhole completions, all of these jobs have been successful because of stringent planning. Overall, the success rate for chemical SCON and agglomeration under cased-hole completion is approximately 73%.
Perforation Interval Length. - For effective chemical placement, the perforation interval length is limited to 20 ft according to internal guidelines, especially for cases using bullheading as the placement method.
For perforation interval lengths greater than 120 ft, the failure rate can be as high as 10%. According to historical trends, no failure was encountered for chemical SCON and sand-agglomeration jobs with perforation intervals of less than 40 ft. The historical analysis indicates, therefore, that the benchmark criteria of perforation interval length could be extended to 40 ft from the current 20 ft.
Placement Method. - Most chemical treatment jobs executed were completed using bullheading, contributing to approximately 80% of all chemical SCON and sand-agglomeration jobs. No failure cases were recorded for treatments that used coiled tubing because of the controlled chemical placement. Perforation intervals of almost 100 ft using bullheading placement methods have succeeded. One contributing factor for successful treatment in long intervals using bullheading is the use of diversion techniques. Nitrogen is commonly used as part of a diversion method along with chemical application.