Sand Consolidation Testing in an API RP 19B Section IV Perforation Flow Laboratory

Abstract

Formation consolidation is a form of sand control that was used extensively in the past, but has been largely replaced by mechanical systems, such as gravel packs or expandable screens. This change has arisen because of a level of uncertainty regarding effective chemical placement and reliability. Challenging economics in the petroleum industry began to make alternative completion techniques more attractive for remediation applications, for developing and producing by-passed reserves behind blank pipe, and for completing marginal reservoirs. Low-cost completion alternatives are actively being sought for both injectors and producers. To understand the performance of various consolidation options, a series of tests was performed on samples of Castlegate sandstone, incorporating actual perforating operations in the lab to evaluate both treatment placement and performance under reservoir conditions. This paper provides details about the testing process that was used, as well as comparative results for various consolidation technologies, including curable and non-curable agents resulting in various degrees of cohesion between formation particulates. Post treatment evaluations included flow testing single and dual phase fluids under in-situ conditions, as well as post mortem evaluations of chemical placement and mechanical properties. Section IV perforation flow testing provided a realistic modeling technique to understand the effectiveness of a consolidating agent with respect to its placement or coating behavior, which in turn directly affects the resulting strength and retained permeability after chemical treatment. Results from the flow testing indicate that a critical strength is required to lock the treated sand in place and to overcome the drag force generated by flow. Depth of treatment penetration into the formation matrix is a function of treatment volume, pressure drop, and permeability. The amount of consolidating agent coating on the sand and the resulting strength depend on the concentration of the agent in the treatment solution. With efficient strength as a result of the consolidating agent treatment, only a small quantity of sand was observed to produce from the treated perforation, either with single or dual phase fluids, when compared to a much larger amount of sand produced from the perforation that lacked treatment, even when the perforation was subjected to a lower flow rate. Introduction Resin treatments are a form of sand consolidation used for sand control since the 1950s. Sand consolidation includes many appealing features, such as the elimination of complex completion equipment and pumping operations that are associated with conventional sand control completions using gravel pack or frac pack technologies. One of the primary concerns with sand consolidation has been the effective placement of the chemical treatments into the reservoir, especially when longer reservoir sections are exposed to the wellbore. Today, consolidation is used in a limited number of completions, typically when exploiting up hole by-passed reserves or in remediation applications where sand production becomes problematic only after water breakthrough in a wellbore. When wells are in the later stage of life and beginning to produce water, and thus produce an inflow of sand, they may become good candidates for sand consolidation treatment. It is always beneficial to physically simulate the merits of a new concept for well applications, when possible. Packed cylinders and Hassler core holders have been used to begin the process of evaluating consolidation system potential. In this case, a replicated wellbore with a perforation tunnel into semi-friable sandstone was used to perform a series of formation consolidation tests to evaluate the properties pertinent to what is considered a successful treatment. These properties include rock consolidation strength, depth of treatment, and post treatment permeability.

A Predictive Model for Sand Production in Poorly Consolidated Sands

“…Hence, it can be concluded that a consolidation treatment for a sample can be very effective at reducing the mass of sand produced and increasing the effective stress at which sand will fail. Same observations were made from experiments that studied the effectiveness of consolidation in preventing sand production (Haggerty, 2009). The financial benefit to operators using the consolidation treatment will vary depending on the tradeoff between the savings in sand disposal and the cost of the treatment.…”

Foaming Aqueous-Based Curable Treatment Fluids Enhances Placement and Consolidation Performance

“…Waterborne emulsion or microemulsion-type systems are becoming more standard in the coating industry as a means of eliminating the use of solvents and instead using water as the emulsion carrier (Haggerty et al 2009;Villesca et al 2010). A new concept was evaluated where a low concentration (less than 10% by weight) of small micron and submicron particles or droplets of consolidating material was dispersed in brine.…”

Particle Consolidation as a Means of Sand Control: Gulf of Mexico Applications

“…The hardened and bonded formation will have an increased UCS and cohesion force, which stops the particles from moving. The goal of these treatments is to increase the UCS of the perforations in the near-wellbore region while also increasing the cohesion forces of the grains with little reduction in permeability (Haggerty et al 2009). …”