Screenless Frac-Pack Completions: Case Studies From Jidong Field, China
Authors: Bybee Karen 
Published: February 2015

This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper SPE 108909, "Screenless Frac-Pack Completions - Case Studies From Jidong Field, China," by Chang Xue Jun, SPE and Chen Ren Bao, PetroChina Jidong Oilfield, and Wirdansyah Lubis, Deng Hui, and Philip Nguyen, SPE, Halliburton, originally prepared for the 2007 SPE Asia Pacific Oil and Gas Conference and Exhibition, Jakarta, 30 October-1 November. The paper has not been peer reviewed.

With careful planning, a screenless frac-pack treatment provides an effective method for controlling flowback of proppant and formation sand to maintain well production without work-overs caused by solid-particulate production. Properly coating with optimal liquid-resin-system (LRS) concentration and curing, LRS-coated proppant will transform into a high-strength, permeable mass to withstand high drawdown and the effect of stress/strain cycles during well operations. Screenless frac pack is an economical- and viable-completion method for wells with marginal reserves.

Introduction

The case studies discussed in the full-length paper are oil wells operated by PetroChina in the Jidong oil field. These wells generally have high-permeability unconsolidated sand and high water saturation. Over the past several years, the operator has applied high-rate water-pack completions to control production of formation sand and fines in these wells. Since being drilled, each of these wells has been completed at least twice using a high-rate water-pack method. The objective of this completion technique was to create a tight proppant pack in the annulus between perforated casing and the sand screen, with the attempt to squeeze as much proppant as possible out into the formation to control migration of formation sand and fines, bypassing near-wellbore damage, and to obtain a low skin factor. The production results, however, indicated that this completion method was not as successful as planned.

Even after being completed with premium screens, these wells continued to produce formation sand, resulting in decreased production and plugging of electrical submersible pumps, requiring frequent workovers and downtime. The screens often became plugged with formation sand and fines. Sand production prevented the operator from increasing well production to desired levels.

The operator also tried flexible-proppant technology in one well, as a field trial, by mixing deformable particulates as part of the proppant to help lock the proppant in place. However, proppant and formation sand continued to be produced as a result of insufficient cohesion provided by the deformable particulates and their inability to withstand high surges of production fluids.

In addition to the disappointing performance of these completions, the frequency of workovers required to clean out proppant and formation sand in these wells averaged once every 2 to 3 months. As a result, the operator considered field trials of screenless frac-pack completions using a tip-screenout design and a newly developed curable resin for controlling flowback of proppant and formation sand. These completions were performed in two campaigns during the second quarter of 2006 and the first quarter of 2007, respectively.