By OGJ editors
HOUSTON, Apr. 13 -- Calvalley Petroleum Inc., Calgary, tested a horizontal appraisal well that confirms a continuous reservoir over the 7-km-long structure of the Hiswah oil discovery on Block 9 in Yemen.
The Hiswah-4 well, drilled vertically to 1,276 m, was to evaluate the oil-bearing Saar formation and gather reservoir data including two separate 9-m cores.
Independent petrophysical analysis determined that Hiswah-4 intersected 60 m of gross 35° gravity oil and 20 m of gross gas pay over an 80-m gross interval, with 16% porosity. Cores cut from the Saar oil column show good oil staining within microfractured, high-energy carbonate grainstones that are comparable to the Hiswah-3 reservoir.
Production tests, conducted over the open hole with an electric submersible pump, established flow rates of up to 1,200 b/d of oil and 400 Mcfd of gas. The test was terminated due to a pump failure, but oil continued to flow without artificial lift at rates up to 1,098 b/d before the well was successfully controlled by injecting 1,100 bbl of kill fluid into the wellbore.
The test resumed with new downhole and surface equipment. Only 20% of the kill fluid was recovered, and the well flowed at a reduced sustained flow rate of 380 b/d of oil and 600 Mcfd of gas and no water.
Preliminary evaluation indicates that the reduced flow rate may be due to wellbore damage at the time the kill fluid was injected and the downhole equipment removed after the initial test.
Hiswah-4 is the second of several horizontal appraisal wells planned for the Hiswah oil pool. The rig is being moved to the Hiswah-5 well, 700 m northwest of Hiswah-4. Calvalley operates the block.
