to operate as described above referring to fig2 an alternative embodiment of the retrievable frac packer 10 of fig1 a 1c is shown first check valve 42 of fig1 is replaced by a sliding sleeve valve 242 for run in sliding sleeve valve 242 seals in both directions and allows retrievable frac packer 210 to be run in as a bridge plug once in position hydraulic pressure may be applied for example at the same time frac operations are conducted above the retrievable frac packer 210 sliding sleeve 250 into an open position 252 and allowing sliding sleeve valve 242 to function in the same manner as first check valve 42 of fig1 referring now to fig3 a and 3b retrievable frac packer 310 is shown in the set position upper compression member 320 has been moved downward relative to the annular body 312 of retrievable frac packer 310 compressible seal 316 is in sealing contact with the inner wall 318 of the well casing 314 latch 330 is set by the interlocking of ratchet arm 332 with ratchet base 334 preventing loss of compression force against compressible seal 316 slip 328 is also forced outward into mechanical engagement with the inner wall 318 of well casing 314 resulting from the downward movement of lower compression member 324 relative to the annular body 312 of retrievable frac packer 310 as shown in fig3 a the initial setting of retrievable frac packer 310 allows frac operations to proceed first check valve 342 and compressible seal 316 prevent fluid flow downhole of the retrievable frac packer 310 during frac operations after the degradable ball 348 has dissolved second check valve 346 u201c.