Polymer-Free Fluids: A Case History of a Gas Reservoir Development Utilizing a High-Density, Viscous Gravel-Pack Fluid and Biopolymer-Free Reservoir Drilling Fluid

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractThis paper presents a case history of the completion procedures applied to a four-well gas reservoir development in the Norwegian sector of the North Sea where open-hole gravel packing was utilized as the sandface completion technique.The chosen technique to gravel pack the wells was based upon Alternate Path Technology, which incorporates shunt tubes with nozzles on the outside of the gravel pack screen. These shunts create an alternative flow path, allowing slurry to bypass premature bridging and fill any voids beyond the bridge. The use of shunt tubes gives the opportunity of achieving a complete gravel pack without the requirement of a filtercake-sealed wellbore. This introduces the possibility for the filter cake to be removed during the packing operation. As a result, a low-solids drilling fluid that deposits a chemically degradable filter cake can be utilized.The reservoir pressure in this field required relatively highdensity, reservoir drilling and gravel pack fluids (1.65 SG / 13.75 lb/gal). This paper describes the design and development work involved in formulating a mutually compatible, calcium bromide-based reservoir drilling fluid and a Viscoelastic Surfactant (VES) based gravel pack fluid and the subsequent successful application in a subsea field development.

Friction Pressure Performance of Commonly Used Viscous Gravel-Packing Fluids

“…Commonly used fluids are VESs as discussed in Daniel et al (2002), Campbell et al (2002), and Whaley et al (2007); polymer-based fluids such as xanthan discussed in Nguyen and LaFontaine (1990) and Underdown et al (1989); and HEC discussed in Underdown et al (1989) and Cole and Ali (1994). These fluids are non-Newtonian, exhibiting shear-thinning behavior.…”

“…This study discusses in detail the frictional pressure performance along with rheological properties of the three commonly used carrier fluids (Underdown et al 1989;Campbell et al 2002;Houchin et al 1988): VES, xanthan, and HEC. Field-scale yard tests were performed at ambient and elevated temperatures to acquire frictional-pressure data in various conduits including circular pipe (wash pipe), eccentric annuli (wash pipe/screen-base pipe), and rectangular tubes (shunt tubes).…”

Alternate Path Completions: A Critical Review and Lessons Learned From Case Histories with Recommended Practices for Deepwater Applications

“…• Conventional open hole gravel packs (using a wash pipe and in circulation mode), 15 • Conventional open hole gravel pack in circulation mode but without wash-pipe, 16 • Open hole gravel pack above frac pressure, 17 • Partial cake cleanup prior to gravel packing a water injector, • Open hole gravel pack with full losses in circulating position, 18 • Open hole gravel packs with filtercake cleanup chemistry incorporated into the gravel packing fluid, 19-23 • Open hole gravel pack in squeeze position, below 24 and above frac pressure with 17 and without 22 filtercake cleanup chemicals in the carrier fluid, • Open hole frac-pack, 25 • Open hole gravel packing of two sands separated by a long (530-ft) shale break, 23 • OHGP in wells drilled with OBM using water-based 18 and oil-based 26 …”

New Visco-Elastic Surfactant Formulations Extend Simultaneous Gravel-Packing and Cake-Cleanup Technique to Higher-Pressure and Higher-Temperature Horizontal Open-Hole Completions: Laboratory Development and a Field Case History From the North Sea.

“…17 During this testing, it was discovered that the fluid was significantly thinned after passing through the pumpng equipment (centrifugal and triplex pumps): the fluid would not suspend the gravel until after 5 to 8 minutes at 20°C (68°F). Subsequently, detailed laboratory testing conducted with an apparatus that could reproduce the results obtained in these yard tests helped us identify an additive that minimizes the concerns by substantially reducing "visco-elasticity recovery" time scales.…”

“…Four of these case histories are detailed in another paper, along with the lessons learned and the solutions identified during these completion operations. 17 In this paper, we present new surfactant formulations, which have unique chemistry that allows them to form viscoelastic solutions in high-density brines and remain stable at elevated temperatures, for higher-pressure, higher-temperature (HP-HT) gravel-packing applications. The paper is organized as follows.…”