Rialto Energy Ltd., Perth, completed drillstem tests at Gazelle field on Block Ci-202 offshore Ivory Coast and estimated reservoir deliverability at 33 MMscfd with 4-1/2-in. production tubing.
Maximum rates with the 3.5-in. test string were 19.5 MMscfd and an unstabilized 760 b/d of 40° gravity oil from separate sands in the Upper Cenomanian UC-1 reservoir. Downhole equipment limits constrained the gas flow.
Rialto said the Gazelle-P3 ST2 appraisal and well test data obtained will facilitate optimal and timely development and that the offsetting Condor gas discovery demonstrates the block’s remaining high impact exploration potential.
The main DST focused on the UC-1C gas reservoir at 2,632.9-2,666.6 m measured depth rotary table, successfully averaging 17.5 MMscfd for 10 hr on a 44/64-in. choke with 1,470 psia flowing wellhead pressure.
Before the oil test, cement bond logs indicated that the zones may not be hydraulically isolated in the wellbore. The UC-1A oil reservoir perforated at 2,678.0-2,713.2 m MDRT achieved an unstabilized flow rate of 760 b/d before gas originating from the overlying gas reservoir via behind-casing channeling prevented further oil flow.
Gazelle-P3 ST1 penetrated the UC-1 reservoirs 800 m from the existing IVCO-14 discovery well and also appraised the Gazelle LC-2 primary gas reservoir. It also successfully penetrated a downdip portion of the high impact, 750 bcf Condor prospect. The ST2 well was then drilled to further appraise and test the UC-1 reservoirs closer to the IVCO-14 well.
The ST1 and ST2 wells are drilled to total depths of 3,685 m RT and 2,979 m RT, respectively. The wells will be suspended for future use.
The rig will spud the Gazelle-P4 well, designed to appraise the UC-2 and UC-4 oil reservoirs, the UC-3, UC-5, and LC-1 gas reservoirs, and obtain another penetration of the LC-2 reservoir.
A Condor appraisal well is one of several high impact candidates earmarked for drilling in 2013.