CH-1620 Saudi Arabia

The Challenge:
In drilling the 16″ hole of LUKSAR’s appraisal well, frompartial to total losses were expected in the notorious Wara (dolomite and sand), Khafji(loose sand) and the Shu’aiba highly porous carbonatesformation (Limestone and/or Dolomite). Shu’aiba isfractured due to existing faults or due to its super high permeability. From previous experience in the region (North Rub Al-Khali),most of the time in attempt to regain circulation, lost circulation materials and cement plugs are useless.Other drilling challenges are tight hole and sloughing shale in the Biyadh/Buwaib formations between 6,600 ft7,800 ft and at the Dhruma formation at ±11,500 ft.

The Action :
The 16″ hole was drilled from 4,950 ft using a KCI Polymer mud with mud weight of 66 pcf (8.8.ppg) to 74 pcf (9.9 ppg). Top of the troublesome Shu’aiba formation was expected to be at 6498 ft. Started adding FRACSEAL into the active mud when drilling at 6,000 ft (±500 ft above losszone). Mud weight was controlled using calcium carbonate. Since FRACSEAL was added, the concentration was maintained at 7-8 ppb throughout drilling until the section TD at 12,120 ft.

The Result :
The 16″ hole was drillied with minimal losses. No other drilling challenges expected were found or detected such as sloughing shale, tight hole, bit balling and stuck pipe across the dolomite stringers. At earlier time, thissection (±7,100 ft) was completed with two casing sizes (16″ & 12- 14″). Due to the problematic formations were well protected, LUKSARwas able to eliminate one casing size on this well and had a cost savings of USD4MM – in terms of reduced rig days, cement and drilling fluids volume and casing.

CH-1618 Indonesia

The Challenge:
Offshore east java has a problem with rancak formation. it’s primarly shale with limestone stringers, shales normally washout and leave in-gauge limestone stringers.

The Action :
15 ppb of FRACSEAL fine was mixed in hi vis sweep by pumping every stand drilled.

The Result :
Shales were stabilized in this high deviated well. FRACSEAL fine 15 ppb also improve ROP, hole cleaning efficiency and prevent any losses before its started. Torque and drag was sifnificantly reduce and was much lower than seen other wells that were less diviated and then trip out was very smooth.

CH-1612 Fracseal Saudi

The Challenge :
Hole problems anticipated in the 12¼” hole sections are partial/severe losses and sloughing shale. Partial/Severe loss is potential in WARA (5374′) and SAFANIYA (5740′) formations, while the interval of KHAFJI between 6,134 ft -6,670 ft is an unconsolidated sand section. Shale along the entire 12¼” hole section is fluid sensitive. Shale sloughing and/or swelling can arise at any time along this section. Interval for losses between 5,374 ft – 5,915 ft (541 ft footage).

The Action :
The 12¼” hole was drilled using OBM of 81 PCF (10.8+ ppg). Initially 3 ppb FRACSEAL was maintained in the active OBM. Drilling at 5100 ft (200 ft above predicted 1st loss zone to encounter) FRACSEAL concentration was increased from 3 ppb to 10 ppb. While drilling the expected interval for losses between 5,374 ft – 5,915 ft, added 2 sacks per hour of FRACSEAL to replenish portion screen out with drilled cuttings. FRACSEAL of 9 ppb was retained in active OBM from 6,670 ft till 8,068 ft (9⅝”csg point).

The Result :
Not even one predicted hole problems encountered. It was a smooth drilling operation. The hole was slick and in good shape. Wara, Safaniya were protected, Khafji was stabilized from possibly partial losses and differential sticking. Caving and sloughing shale was not observed throughout drilling.

CH-1611 Fracseal Kenanga

The Challenge :
To control Severe/ Total losses expected in the Pendopo and Lower Pendopo formations from 4,000 ft to 5,615 ft. The Lower Pendopo is a highly porous and fractured limestone formation, one of infamous interval for Severe and Total losses.

The Action :
Drilling 12¼” hole, the active circulating system was pre-treated with 6.0-8.0 ppb FRACSEAL® starting from 4,000 ft until casing point @5,615 ft. In case of severe losses, the hole was swept with pills containing 60-70 ppb total combination of FRACSEAL® and CaCO3 Fine.

The Result :
Wireline Caliper logs data showed achieving excellent hole size (gauged hole) and shape starting from 4,000 ft to casing point at 5,615 ft. The 9⅝” casing was smoothly run and cemented. Overall 12¼” hole section was an improved drilling efficiency, wireline logs and also reducing Non Productive Time.

CH-1609 Fracseal ONJW

The Challenge :
The well need to be sidetracked from 945/8″ csg. window using a 8 1/2″ bit. Two problematic sections have to be penetrated. Parigi (dolomite & sand) and Pre-Parigi (limestone) are two thick formations for sloughing shale, losses, tight hole, bit balling and stuck pipe across limestone stringers associated with these two formations. At the nearest (previous) well had to pump more than 20 cement plugs to combat loss of circulation in these notorious sections.

The Action :
The 8½” hole was drilled from 9⅝” casing window at 2,583 ft. FRACSEAL was maintained at 648 ppb in the 9.1 ppg Low pH Desco active mud. Drilling at 2960 ft had initial loss at 10-20 bph. FRACSEAL concentration was increased to 7.5 ppb and seepage losses reduced and hole was static and stable until drilling at 3,400 ft. Sometimes sudden high losses were detected, then displaced hole with FRACSEAL pill containing 30 ppb FRACSEAL and 10 ppb CaCO3 Medium while keeping 6H8 ppb in the active mud.

The Result :
None cement plugs needed for stopping losses in this well. Had a relative smooth drilling of the long section of 8½” hole up to to 7″ liner point at 8,450 Y (MD). The 7″ liner was run and set without any problem.

CH-1608 OMV Norge

The Challenge :
Wishing has a water sensitive shale in the 8½” section prone for mud losses, hole instability, and need to be drilled using oil based mud, resulted in a costly drilling operation. A highly deviated and horizontal sections in this field become even more difficult to drill.

The Action :
After the 9-5/8″ casing was set at 947,5 m, a horizontal 8½” hole was drilled. From 955 m the active mud was treated with FRACSEAL. Had smooth drilling and static hole until 1060 m, then a static loss (S/L) at 6 m3/hr (±38 bph) was observed. While maintaining FRACSEAL 6-8 ppb in the system drilling was continued penetrating further loss interval. At 1120 m had losses at 12 m3/hr (76 bph), 6 m3 (±38 bbl) STOPLOSS pill @ 37 ppb was pumped and followed by a hesitation squeeze. The incorporation of FRACSEAL in the active OBM was through direct additions or sweeping pills containing 15-20 ppb FRACSEAL.

The Result :
This section was drilled with minimized problems. Maintaining FRACSEAL in the active system gives tremendous effect to drilling efficiency. Hole remained relatively stable throughout horizontal drilling operation. It becomes product and treatment of choice for drilling the same section in this field, especially for high-angle and horizontal trajectory.

CH-1607 Onshore Romania

The Challenge :
The onshore Tintea field in Romania is notorious when it comes to drilling shale intervals of Pontian and Meotian formations. Hole instability in these stressed shales poses a major problem and has resulted in several stuck pipe and lost BHAs over the years. Selection of drilling fluid, either water based mud or synthetic oil based mud, does not help to resolve the situation as similar problems have been encountered using either mud system.

The Action :
Recently, a drilling mud additive, used successfully for promoting hole stability in wells drilled in the North Sea was proposed to be used in the Tintea field. This additive which is primarily a borehole stabilizing and lost circulation material consisting of micronized organic cellulose fibers also helps to stabilize the stressed shale formations where micro-fractures exist by effectively bridging them off..

The Result :
Hole remained stable without any excessive drag, over-pull, or stuck tendencies. Following this successful field trial, it is now the product of choice whenever hole stability issues are encountered in Tintea field. It was used in two subsequent wells to the trial well and delivered the same result. The Company’s drilling fluids specialists working closely with the Service Providers have perfected the combination of using these fibers together with calcium carbonate in the appropriate concentration and have delivered wells within time and budget.

CH-1601 Austria

The Challenge :
The Vienna Basin has a history of lost circulation ranging from continuous seepage to severe losses. Complete losses, pack offs and stuck problems had caused lost of many BHA’s. The magnitude of overpressures in combination with the expected losses is the greatest challenge in planning this well. The 9⅝” casing cannot be set deeper than ± 3,600 m.

The Action :
The 12¼” hole was drilled from 2,954 m using a WBM (Glycol Polymer) of 1.57 SG. Severe losses were encountered up to 30 m3/hr. Active mud was pretreated with 5 ppb FRACSEAL. STOPLOSS pills were also deployed for controlling high losses. Through a circulating sub, pumped 2 m³ Hi Viscosity mud as lead spacer, followed by 6 m³ of 50 ppb STOPLOSS then 3 m³ of Hi Viscosity mud as tail spacer.

The Result :
Most losses were reduced by 90%. Shale stone (Gas Shale) was stabilised without any sloughing. The hole was drilled successfully without having to run the contingent 11¾” liner programmed to be set at 3,600 m. The cost saving for the elimination of this liner is approximately EUR 2.0 million (including the hole enlargement costs prior to running the liner). Drilling operation was performed successfully and the 9⅝” casing was run and cemented at 4,496 m, which considered to be one of the deepest 9⅝” casing point in Austria. The well was TD at 6,020 M using only 3 casing strings (previously had to use 4 or 5 casings). The final hole size (8 ½”) was drilled without having to reduce the mud weight.