An Economic Solution To Revive Sanded Wells: First Rigless Through Tubing Gravel Pack in Malaysia

Abstract

TX 75083-3836, U.S.A., fax +1-972-952-9435. AbstractSand production is a major problem in the oil and gas industry. Loss of production, sand disposal issues, the need for routine cleanouts, damage to well jewelry, and stuck well accessories are the most common reasons for setbacks caused by sand production. The sand control methods yield the most desirable results when are implemented early in the life of a well before sand production becomes a problem because of the onset of water production or before formation damage occurs as a result of formation disturbances or subsidence. For the wells that start sand production at a later stage, workover with conventional gravel packing is one way to alleviate the problem, but such a costly undertaking is not always economically justifiable.The candidate field is located at offshore Terengganu in Malaysia and has been in production since 1982. The reservoir consists of several layers, including the unconsolidated (J-sand) layer. Well A, for which the initial producing intervals were isolated, was recompleted in the J-sand layer by March 2005 and started producing 250 BOPD. Unfortunately, the well could only produce for 3 months before it was shut-in due to severe sand production. The well had been shut in for 4 years and even after a series of coiled tubing operations to perform sand cleanout, it was not possible to flow the well for a single day.Because of the marginal reserves available and the high cost of mobilizing a workover rig to perform a conventional gravelpack completion, the operator chose to recomplete the well using a rigless technique that allowed the gravel pack to be placed through the existing completion tubing.To ensure the best possible perforation packing efficiency and annulus pack quality, the "vent screen and isolation packer" through-tubing gravel pack (TTGP) technique was used. After the TTGP operation, production stabilized at about 180 BOPD. This method can be considered for the wells that are shut-in because of severe sand production and the wells that are producing at restricted production rates due to sanding problems.