Polyurethane for Sand Control
November 25, 2010 § 1 Komentar
Sand production is one of the biggest problems in oil and gas production. Sand can damage the surface and down hole facilities. Sand production simply occurs in unconsolidated formation. To overcome this constraint, mechanical and chemical method has been much developed. In this research chemical method based on polyurethane, and organosilane is used to solve sand production replacing recent polymer.
Polyurethane is synthesized by reacting polyol and diisocyanate. Polyol can be produced from castor oil those are cheap and environmental friendly. Organosilane will act as a coupling agent, which can bind with organic and inorganic materials. Hence it will enhance organosilane to bind strongly with sand grains.
In this study, polyurethane maintains stability of organosilane towards temperature and pressure expansion. Combination of organosilane and polyurethane will be injected into artificial cores to evaluate its mechanical properties with and without resin treatment. Those artificial cores resemble rock in a reservoir by utilizing data from the real field. It is synthesized to represent the real core in an oil and gas field. That core has 2:1 sand and cement ratio. Core test is conducted by using a triaxial stress instrument. Temperature will be raised until 80ºC to investigate stability of resin.
Lab test varies three adhesive material for chemical sand consolidation those are commercial epoxy, furfuryl alcohol and synthesis polymer based on polyurethane (PU)-organosilane. Result indicates that new resin system based on PU-organosilane create stronger sand grains binding thus less sand is produced without reducing too much permeability and porosity compared to others.
Februari 24, 2010 § 2 Komentar
this is published as requirement for indonesian petroleum association. the wohle part is not stated here
Poorly consolidated and unconsolidated reservoir has created its own problem. People knows sand production as a big trouble as effect of poorly consolidated and unconsolidated reservoir. Sand production causes erodes tanks and pipe lines, increase maintenance cost, lost oil production. Many researches and papers has been published concerning on this topic. Based on the observation we conclude that sand problem could be solved by injecting the polymer to cement or to consolidate the sand grains. Hence it was not carried out together with oil production. Adhesive characteristics owned by the polymers are the key for the work.
After evaluating previous work, epoxy resin and furan resin are mostly used. Both enhance good attempt to achieve better result among others. Nevertheless it is never stated the comparation between both resin on a one work. Each research showed their own strength utilizing their own polymer. So that readers are less chance to compare the best.
What we have done are to select all alternative polymers which can be used to overcome sand production. Readers will be able to evaluate the best resin by their own. Furan resin and epoxy resin used on our work, as the best resin so far, will be compared directly. Furan resin are thermally stable and experience self condensation with existing acid catalyst. Polymer produced are strong and brittle but low adhesion compared to epoxy resin. Meanwhile epoxy resin will create polymer with great stiffness and strongly bind caused by crosslink structure.
This work had few steps. Firstly, it is important to remove the formation fluid from the reservoir before injecting resin, well known as preflush system. Mud acid or alcohol mostly acts its role for this objective. Alcohol preflush to remove clay mineral around the rock sand. The agent used for preflush system must be suitable with the resin. After that, resin solution is injected to the reservoir and completed with overflush. All steps must be completed as an unity tocreate the best result.
After consolidating the sand rock, the next step for this work is to enhance the permeability. It will be approached by adjusting the concentration for resin used in the system. By examining any range of concentration we evaluate the best one those fullfiled all parameter wanted, to consolidate sand rock and to enhance the permeability.