Software Showcase: Pressure Transient Analysis Programs

Abstract

The 1992 SPE PETROLEUM COMPUTER CONFERENCE introduced a new concept, the SOFTWARE SHOWCASE. This new program is intended to be similar to the "COMPARATIVE SOLUTIONS IN RESERVOIR SIMULATION" project that has been a popular feature of the SPE Symposium in Reservoir Simulation for a number of years. The Program Committee chose pressure transient analysis software as the SHOWCASE topic for the initial outing. A total of four (4) problem sets were developed from actual field data-sets from CONOCO and TEXACO. Ten vendors and service companies answered the call for papers and the results of their efforts are presented in this paper. We should point out that there is no "correct" or "unique" to the four sample problems based upon the information furnished to the participants. The overall intent of this paper is NOT to present either a direct or implied endorsement of any one software product but to spur spirited discussion in the are of well testing software and to provide a service to SPE members who might be involved in the evaluation of transient pressure analysis programs.

Khovanov homology and tight contact structures

“…to ensure that the spectral sequence from Kh to HF collapses at the E 2 stage. For any individual reasonably small knot this can be checked by a computer, for example using Baldwin's Kh program [Bal2] that computes the rank of reduced Khovanov homology with Z/2 coefficients. Checking the second condition, sl(K) = s − 1, is also routine for Kh Z/2thin knots (alternatively, one can use the Trans program [Bal2] to check ψ = 0).…”

“…For any individual reasonably small knot this can be checked by a computer, for example using Baldwin's Kh program [Bal2] that computes the rank of reduced Khovanov homology with Z/2 coefficients. Checking the second condition, sl(K) = s − 1, is also routine for Kh Z/2thin knots (alternatively, one can use the Trans program [Bal2] to check ψ = 0). Thus tightness of the contact structure on the branched double cover can be established by a computer calculation.…”

“…John Baldwin has pointed out that for a family of (non-quasi-alternating) transverse 3-braids K r = σ −r 1 σ 2 σ 2 1 σ 2 for r > 2 the transverse invariant ψ vanishes, but the contact structures on the branched double covers are tight, and have c(ξ) = 0. The vanishing of ψ can be established by the computer program [Bal2], while non-vanishing of the contact invariant follows from calculations in [HKM1] and [Bal1]. Obviously, Khovanov homology fails to detect tightness in this case (so this is really a non-example), but it is interesting to take a look at the corresponding contact structures.…”

“…Unlike [Bal1,HKM1], our proofs work for transverse braids of arbitary index, require no explicit calculations of the Heegaard Floer contact invariants, and are completely combinatorial (once Theorem 1.1 is in our hands). In fact, John Baldwin has recently written a computer program [Bal2] for determining whether ψ is non-zero for a given transverse braid. If the underlying link is quasi-alternating (or otherwise satisfies the collapsing condition of Theorem 1.1), we can establish tightness of the corresponding contact structure by a computer calculation.…”