Proposal
Most of the reservoirs located in the Campos Basin, deepwater and ultra-deepwater offshore Brazil are described as unconsolidated sandstone that require sand control on both producers and water injection wells. Horizontal Open Hole Gravel Pack completions are the preferred method of development. Due to the recent discoveries of heavy oil reservoirs, there is a necessity of longer horizontal open hole sections. Low fracture gradients may limit the length of gravel pack in the open hole section because of the pressure increase during the Beta wave proppant deposition phase.
This system allows the gravel pack assembly to be installed and the gravel pack to be pumped during the alpha and beta wave deposition phases without the limitation of high pressures that could fracture the well. The benefits of the Single Trip Horizontal Gravel Pack and Selective Stimulation System (SHGPSS) using the differential valve include the ability to complete longer horizontal intervals, valuable rig-time savings and, efficient mechanical diversion of the stimulation fluid.
This paper outlines the first application of the SHGPSS system using a differential valve to successfully complete a horizontal well in the Campos Basin, offshore Brazil. The need for a differential valve is primarily in horizontal gravel packing operations when normal circulating rates and pressures around the openhole would exceed formation break down pressure. The valve is intended to be easily spaced out and run in the washpipe. At a predetermined differential pressure the valve opens and the return flow path distance around the bottom of the tailpipe is shortened, thus reducing backpressure preventing filter cake damage without slowing the pump rate.
Economic considerations along with completion efficiencies are especially important on deepwater, subsea completions. The utilization of differential valves allows completion of extended-reach open hole wells and/or low fracture gradient reservoirs insuring alpha and beta wave proppant deposition phases yielding efficient completions with improved coverage.
