GRE

Concentric Stinger Yard Trial

The GRE Concentric Stinger yard trial was successfully performed by MB Petroleum’s NTPS department on August 20th, 2006 at the Rusayl Oilfield Center (ROC). The yard trial demonstrated the ability of the GRE Concentric Stinger to transport two chemicals without mixing with each other except in lost circulation zone; once these two chemicals meet each other in the lost circulation zone, they set up instantly thus curing lost circulation. The trial was attended by 15 drilling engineers, production chemists and production technologists from PDO.

GRE Concentric Stinger is a tool indigenously designed by NTPS. This tool is constructed out of Glass Reinforced Epoxy (GRE) which has sufficient burst and collapse strength. At the same time this is easily drillable. The inner and outer GRE pipes are connected by flow paths so that two chemicals pumped through inner and outer pipes cannot

mix inside the tool. The chemicals system is based on sodium silicate and HSR Class G Oil well cement. When these two components meet each other they set immediately. Ultra Sonic Cement Analyzer has been used to determine compressive strength as 500 psi (3,450 kPa) which allows drilling without side tracking.

While drilling UeR formation in the surface hole, total losses are encountered; when surface pipe is cemented, because of losses cement job is poor and is unable to prevent corrosion of the surface pipe and also in case of thermal wells renders the well unfit. If GRE Concentric Stinger along with proposed chemical system is able to cure losses, it will be an economic solution to construct fit for purpose oil and gas wells.

CTR has been signed up with PDO for curing Umm-er-Radhuma (UeR) formation losses on five South Oman wells.

The first field trial was successfully performed on Nimr-630 (Rig-53) on February 4th, 2007. Second field trial was successfully performed on Nimr-634 (Rig-1) on March 8th, 2007. The first trial cured partial losses. The second one cured total losses.