Located in Eastern Venezuela, San Joaquin Field, with a dailyproduction of about 800 mmcfgd, is the most important gasfield in Venezuela.Vertical wells have been drilled through twoshale/sandstone-layered formations where the gas payzonesare located. The extent of the drilling problems is reflected inthe 2003 average fluid losses, which were more than 2000barrels per well. If it is added the non-tangibles as theuncertainty of consequences in mud weight changes, we havethe perfect setting for new thoughts on well planning, beingManaged Pressure Drilling the logic next step, with the visiontowards reducing problems, time and cost.The two most important formations are Merecure, with1500 ft of thickness and 25 layers (pressure ranges between4000 psi and 700 psi) with shale intercalations that add anattention point for the field complexity. San Juan Formationhas its own considerations, with upper layers depleted andfractured, and a pressure differential of 2000 psi with lowerlayers that have high economical interest in the near future.The first challenge was to generate a geomechanic model,which used "breakout control" theories, for the developmentof the mud weight window to assure hole stability duringdrilling operations.Well control optimisation for high productivity layerswhere under balance conditions applied was a fundamentalconsideration due to environmental regulations, surfaceequipment design and ECD control.Well planning included "effective ROP increase"criterions, high durability drill bits, aggressive performancefor favourable drilling conditions and parameters control in atarget oriented philosophy. All of these relevant issues werethe synergistic points for engineering and operationsintegration.Actually, five wells have been drilled without lostcirculation reports, notable increase in ROP and a reduction intotal drill bits used. These have been important results and avery good start for the learning curve in this technologyimplementation.The MPD experience in San Joaquín Field is one of thefirst formally recorded in Venezuela and with these results itcan be said that this technology will be in this country for along time.
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