Use of Autonomous Inflow Control Device (AICD) within a Horizontal Gravel Pack Completion in a Depleted Reservoir Well

Abstract

Abstract Most oil production in Brazil comes from offshore fields, some of which are composed of poorly consolidated sedimentary rocks from the Miocene formation. Sand production from wells in these areas can be a significant problem, affecting the viability of field development. This sand builds up in the region near the well, resulting in damaged completion equipment and generating contaminated waste after separation. In addition to problems with sand production, some mature fields can present problems associated with the production of unwanted water and/or gas. The production of water or gas can have a negative effect on oil production because the water and gas have a lower viscosity than oil and thus can be produced easier. Also, the production of unwanted fluids can be channeled, thereby decreasing or even preventing the production of oil. Operators continuously strive to obtain cost efficiency in oil production, which encourages the development of new technologies to meet the increasing requirement of exploring unconventional fields. Several methods and technologies make development of fields with the conditions discussed viable. A combination of gravel pack placement techniques with conventional screens and an autonomous inflow control device (AICD) was first applied in an open horizontal well in the Campos basin for Petrobras in Brazil. A horizontal openhole gravel pack was performed in a well equipped with conventional screens and AICD screens to help control sand production and help control water production. Several tests were performed to help ensure well requirements would be achieved. In a controlled scenario, multiphase oil flow tests were conducted to determine the performance of the AICD. The test principle was to provide pressure drop across AICD vs. water cut % curves and delta pressure vs. flow rate curves. All tests were performed and some results will be described in this paper, but the main objective was to show the successful operation performed because of the challenging scenario proposed. Apart from being the first installation in a horizontal well for this operator, the completion schematic using two different types of screens and the low fracture gradient present in this field created a complex environment for pumping the gravel pack. The wellbore was designed with AICDs from the toe to half of the horizontal section of the open hole; the other half was completed with conventional premium screens. Swellable packers were installed between the AICDs and conventional screens. The swellable packers installed provide two different primary functions. The first is to segregate two different zones of the heterogeneous reservoir; the second is to force the flow to cross the screens per zone to allow the function of the AICD to be studied. To testify the reservoir engineer's theory of the water reaching the toe, water and oil tracers were installed along the horizontal section and samples were collected during the life of the well. There were 72 pieces of oil tracer and 72 pieces of water tracer applied to each carrier. The application began from the center of the carrier section and was evenly distributed on both sides of the center line (oil tracer on one side, water tracer on the other). This allowed the engineers to access real data about the reservoir and the water cut through the wellbore length. This gravel pack design was the first to be reported for this type of sand control completion. The gravel pack treatment used the alpha wave/beta wave placement technique; however, it was not applied in its entirety when using screens with an AICD. The AICD has the ability to generate an additional pressure drop in high-mobility fluid, such as water. The friction pressure during the beta wave was a concern that had to be addressed because the slurry had to be dehydrated through the screen and the AICD created a choke on that flow path. Consequently, premature sandout can occur. The operational results show that it is technically possible to pump a gravel pack in horizontal wells completed with conventional and AICD screens. The significant investment involved with a deepwater environment with horizontal wells requires the most advanced techniques and best operational procedures available to help enable long-term, reliable production that is economically viable. The use of a gravel pack with a state-of-art screen provides the best solution for this offshore well in a sand and water-production field.