Foam Cleanout Operations for Open Hole Completions in Coal Bed Methane Wells Located in San Juan Basin

摘要

During the years oil and service companies have beenrnexperiencing problems with completions in open holerncoal bed methane wells in the San Juan Basin located inrnNorthern New Mexico and Southern Colorado (Figure 1).rnUsing cavitation technique, large amounts of coal finesrnare disturbed and fall into the wellbore. These fines havernto be effectively transported to the surface. Significantrnamount of time was needed to remove them usingrnair/mist circulating fluid. Conventional cuttings transportrntechniques cannot be used in these wells due to lowrnreservoir pressure and formations that are highlyrnsensitive to chemicals.rnDecision was reached to implement stable foam as arncirculating medium to remove coal fines out of wellbore.rnIn order to establish compatibility of foam with formationrnfluid, extensive laboratory tests of surfactants andrnchemical additives were implemented. The desired air,rnwater and surfactant rates were determined and fieldrntests were conducted. A number of field test showed thatrnthe foam as a circulating medium improved transport ofrncoal fines out of hole, eliminated loss of circulation, andrnsignificantly reduced time needed to clean out the well.rnThe wells that were cleaned using foam that led to 40 %rnreductions in cost and times spend on location. Thisrnpaper provides operational characteristics and designrnguidelines for foam cleanouts that can be used byrnoperators for improved fines transport out of cavitatedrnwells.