FORM-A-PLUG II, 50 bblProducts Concentration,

lbm/bblQuantity, lbm

Freshwater

Soda ash 0.1 5

FORM-A-PLUG Retarder

12 600

FORM-A-PLUG II 100 5,000

FORM-A-PLUG Accelerator

50 2,500

CHALLENGEIncrease well integrity and reduce losses in a well with a gas kick and total downhole losses.

SOLUTIONPump a FORM-A-BLOK AS* acid-soluble lost circulation pill and a FORM-A-PLUG II* acid-soluble lost circulation plug to prevent losses and regain circulation.

RESULTSEstablished circulation and obtained a full return after eliminating losses and controlling the well by successfully pumping four tandem lost circulation pills and plugs.

Achieve well integrity following a gas kick and total downhole losses An operator in southwest Algeria drilled the 8½-in section of a vertical gas well with 1.06-sg oil-base mud to 5,203-ft [1,586-m] TVD. An additional 6.6 ft [2 m] was then added to the drill plan to confirm the formation lithology for a 7-in liner shoe. At this depth, a gas kick occurred and caused total downhole losses. Various grades of lost circulation pills with concentrations to 211 lbm/bbl [601.35 kg/m3] were pumped without returns, and the volume of lost mud totaled 6,424 bbl [1,027.7 m3].

Pump FORM-A-BLOK AS pill and FORM-A-PLUG II plug to solve lost circulation problem and gain reservoir protectionAfter pumping 140 t of various lost circulation materials without success, the operator contacted M-I SWACO and requested a new proposal to solve the downhole losses. M-I SWACO proposed pumping a tandem pill consisting of the FORM-A-BLOK AS pill and the FORM-A-PLUG II plug.

Three tandem pills each consisting of 50 bbl/50 bbl (8 m3/ 8 m3) were pumped, and the loss rate decreased gradually from total losses to partial losses at a rate of 94 bbl/h [15 m3/h]. A fourth tandem pill was then pumped ensuring that no crosslink reaction or fluid loss occurred while pumping through the BHA.

Regained full circulation and restored well stability After pumping the four pills, the losses were eliminated, circulation was established, well control was achieved with a 1.11 relative density, and operations resumed in the target reservoir. The BHA was then pulled out, and the wiper trip was performed successfully without any issues. A 7-in liner was then set and cemented.

CASE STUDY

Drilling Fluids

With FORM-A-BLOK AS pill and FORM-A-PLUG II plug positioned in the loss zone, the operator was able to confirm well integrity and eliminate fluid losses for well control.

*Mark of M-I L.L.C., a Schlumberger company.Other company, product, and service names are the properties of their respective owners. Copyright © 2017 M-I L.L.C. All rights reserved. 17-MI-251112

Enhanced Lost Circulation Solutions Provide Well Integrity and Eliminate Losses for Well Control FORM-A-BLOK AS pill and a base plug eliminate fluid losses, establish circulation, and enable full return, Algeria

miswaco.com

0 psi

Pa psi

Kick zone

Dry gas

95/8-in casing shoe at 4,482 ft [1,366 m]

TVD = 5,203 ft [1,586 m]

FORM-A-BLOK AS pill

FORM-A-PLUG II plug

Mud loss zone QZH at 5,200 ft [1,585 m]

Bit depth = 4,449 ft [1,356 m]

ReservoirsDMK at 4,475 ft [1,364 m]GEG at 4,560 ft [1,390 m]GOS at 4,859 ft [1,481 m]ATF at 5,052 ft [1,540 m]

Spacer

FORM-A-BLOK AS, 50 bblProducts Concentration,

lbm/bblQuantity, lbm

Freshwater

FORM-A-BLOK AS 32 1,600