Title: In Amenas XLOT Procedures for Tg-374

1 Objective

Perform an extended leak-off test (XLOT) in the Silurian as a part of the hydraulic fracturing work at In Amenas.

Determine the minimum horizontal stress.

2 Safety

Perform pre-job meeting with all involved personnel. Review LCM pill chemicals and pit status for mixing the LCM pill.

3 Technical Information

Mud system will be 1.09 Baradrill WBM during the test. Use Casing test data to determine the fluid compressibility of the

WBM. The XLOT (cycles 1 and 2) shall be reported in Open Wells. All

data from the test, surface and downhole, shall be sent by mail to Hassi Messaoud office. ASCII or other readable formats are accepted.

4 Preparation

BASP Take representative mud test prior to XLOT

Weatherford Mudlogger to prepare for dumping 1 sec pressure data to ASCII

file (time, depth, standpipe/choke pressure). All logging systems synchronized or lag times recorded

(mudlogger, cementer).

Schlumberger Cement

Prepare cement unit computer to log the following data at 1 sec intervals to file: time, pump rate, pumped volume, and pressure.

Record bleed-back volume manually as fast as possible. Install adjustable choke/valve on the bleed back line. A total back

flow time of 5-10 min is targeted, but this is difficult to guarantee. The choke setting has to be fixed during each back flow, so you may mark 3-4 settings on the choke with different pressure drop to be prepared. If you see that back flow is too rapid (1-3 min) you can choke the valve more before the next cycle and opposite if back flow is taking too long. If you do not find the appropriate setting in the first two cycles, consider to run a cycle no 3 otherwise identical to cycle 2.

One way to do a first bleed-back choke setting is to adjust bleed-back choke / valve on cement unit bleed off line until a backpressure of 850PSI is seen on the pump gauge with a pump rate of 0.6 bpm. This choke opening will be used throughout the XLOT.

Verify function of pressure gauges on cement unit. Important: Prepare an arrangement to measure the bleed back

volume. Record the level increase in the tank with as short intervals as possible. One way to do this is using the metering system in the displacement tanks divided in ¼ bbl.

Well Status The 9 5/8” casing shoe is set at 2135 m MD/TVD Well is filled with 1.09 SG Baradrill WBM 12 ¼” TD section 2138 m MD/TVD. 9 5/8” casing tested to 3500 psi 8 ½” hole at 2140 m MD/TVD. (2 m of new formation) Well confirmed stable after flow check. Any gas has been

circulated out.

5 Test Preparation

RIH with drill out 8 ½” BHA and precautionary wash last stand, tag and record top of cement in the 9 5/8” casing. Perform trip drill.

Tag float collar. Drill out half 9 5/8” casing shoe and displace / convert mud

system 1.09 SG Baradrill.

Drill shoe and 2 meters of new formation. Circulate out gas and cuttings; it is very critical that mud is homogenous before XLOT

Spot 30bbls LCM with bottom of pill 300m above casing shoe (Pill No. 2 in Detailed Drilling Procedures)

Pull back into casing shoe and rack back stand Make up circulating sub. Install Dowell chicksan line on rig floor.

Flush lines and evacuate air prior to MU circulating head Line up to pump down both drill pipe and annulus. Pressure test both lines to 4000 Psi. NO PRESSURE DROP WILL BE

ACCEPTED. Space out string and Close BOP (pipe rams). NOTE: Flush lines and evacuate air. Air in the system can ruin

the test. Zero pressure gauge (cement unit recording rigfloor pressure) Pressure up well to 100 psi using cement pump. Re-zero volume

counter. Do not bleed-off pressure. Synchronize mud logging and cement unit logging systems. If not

able to synchronize systems, record the time difference between the two

6 XLOT Cycle 1

Pump with constant rate (0.25 -0.8 bbl/min) down choke lines and drill pipe

Keep pumping with same constant rate a further 6.3 bbls into the formation after formation breakdown

Max surface pressure 3500 psia Stop pump and shut-in well for 15 min recrding shut-in pressure

every minute Open low torque valve and bleed back manually to reference

pressure on the cement unit through pre-set low torque while recording time, pressure and bleed back volume. Do not adjust the low-torque valve during bleed back

After the flow back valve is closed, observe the pressure for at least 4 minutes. If pressure increases, wait until the pressure starts to level off and then bleed off the pressure before next cycle

Write down return volume Refill displacement tank

7 XLOT Cycle 2

Pressure well to reference pressure of 100 psia using cement pump

Re-set ‘volume pumped to zero

Pump with constant rate (0.25 -0.8 bbl/min) down choke lines and drill pipe

Keep pumping with same constant rate a further 6.3bbls into the formation after fracture reopens

Max surface pressure 3500 psia Stop pumping, open bleed-off valve and immediately start bleed

back to reference pressure 100 psion the cement unit through pre-set low-torque valve while recording time, pressure and bleed back volume. Do not adjust the low-torque valve during bleed back

After the bleed-off valve is closed, observe the pressure for at least 4 minutes. If pressure increases, wait until the pressure starts to level off and then bleed off the pressure

Bleed off remaining pressure. Write down return volume Open BOP. Observe well 15 minutes Resume drilling operations.

8 Other

The overall responsible person to coordinate the operation is: DRILLING SUPERVISOR.

The equipment must be checked while at rig site. The cement unit must be tested and all gauges calibrated before

the Job (During Drill out cement and circulate if possible). Test Schlumberger cement unit with all equipment.