Abstract
In the past, sand retention testing (SRT) research for steam-assisted gravity drainage (SAGD) injector was a parametric study, or general solution, rather than a case-specific solution for a particular problem in terms of testing parameters. Testing parameters were assigned based on hypothetical assumptions due to a lack of necessary field data to perform such a study. Field data are often confidential and nearly impossible to obtain for a hazardous scenario like a thermal injector flowback. The literature is rich with multiple proposed slotted liner (SL) design criteria for SAGD production wells. The SRT designed for SAGD producer takes into consideration some measurable factors to specify suitable aperture size. In contrast, SRT for the SAGD injector seems to rely on industry experience or rules of thumb. A systematic methodology, consisting of three steps, was developed for SL design using the SRT setup for SAGD injector wells. The first step involves estimating the laboratory testing variables or operational parameters based on case-specific data and reservoir simulations to assess the consequences of steam flowback. A 2D Computer Modelling Group (CMG) thermal simulator was coupled with gas flow correlation and used to predict the outcomes of SAGD injector flowback. The second step involves developing a new SRT setup dedicated to SAGD injector flowback laboratory testing. Intensive testing was performed to troubleshoot the problems associated with a high-velocity gas flow. The third and final step involves conducting six tests to verify the developed setup's performance. The consideration of thermodynamic equilibrium improved testing by avoiding inconsistent assumptions used in the previous studies. Neither low steam quality (SQ) nor high SQ flowback scenarios used in the past are found to fully represent SAGD injector flowback. SAGD injector depth and other operational parameters are linked to flowback differential pressure. In other words, one set of testing parameters cannot be representative for all SAGD injector, which makes developing design criteria a challenge. The preliminary results of SRT for SAGD injector indicate the possibility of using small aperture size slots of 0.010 inch that do not cause significant permeability reduction at laboratory scale, unlike the case for SAGD producer SRT. This may justify why the industry tends to prefer small aperture size slotted liner for SAGD injector completion. Eventually, this research should be considered as a first step only in SRT for SAGD injector flowback, and necessary methodology enhancements and facility upgrades should be investigated in future work.
NSTL