NOVELTY - An aqueous concentrate comprises polyvinyl alcohol resin having viscosity of 1-25 cps; and fluid loss ameliorating co-resin consisting of sulfonic acid-functionalized resins. A total resin content of the concentrate is 10-40 wt.% and the concentrate has viscosity of 10-15000 cps at 20degreesC.    USE - Used for hydraulic cement to provide slurry used to produce oil or gas (claimed).    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for:    (1) a resin blend as a fluid loss additive for hydraulic cement comprising polyvinyl alcohol resin having viscosity of 1-25 cps; and fluid loss ameliorating co-resin consisting of sulfonic acid-functionalized resins, wherein the polyvinyl alcohol resin is greater than or equal to 3 times the amount of sulfonic acid-functionalized co-resin by weight, and the resin blend imparts an American Petroleum Institute (API) fluid loss of less than 50 ml/30 minutes at 170degreesF and 1000 psi to a standard seawater cement slurry, when present at less than 1.5% bwoc (sic);    (2) a hydraulic cement slurry comprising water; cement; 0.25-5% bwoc of polyvinyl alcohol resin which has viscosity of 1-25 cps; 0.025-1% bwoc of a fluid loss ameliorating co-resin consisting of sulfonic acid functionalized resins; optionally, 0.01-0.4% bwoc of a retarder; and optionally, 0.05-0.4% bwoc of an extender;    (3) a cement formed from the dried slurry;    (4) a method of making a hydraulic cement slurry exhibiting reduced fluid loss including slurrying a hydraulic cement composition with water, and mixing a fluid loss additive with it, comprising preparing a cement slurry; providing an aqueous concentrate having 70-85 wt.% water, and 15-30 wt.% of a polymeric fluid loss composition which is substantially fully dissolved in the water; and combining the aqueous concentrate with the cement slurry;    (5) a method of producing oil or gas from subterranean wells, including slurrying hydraulic cement composition with water, mixing fluid loss additive with it to make a cement slurry exhibiting reduced fluid loss, and cementing a casing string in a wellbore by pumping the cement slurry down the wellbore and into the annulus between the casing string and an exposed borehole wall, comprising preparing the cement slurry;) providing fluid loss additive in the form of aqueous concentrate having total solids content of 10-30% and viscosity of less than 15000 cps; combining the fluid loss additive with the cement slurry; and cementing the casing string with the slurry;    (6) oil produced with the above method; and    (7) gas produced with the above method.    DESCRIPTION OF DRAWING(S) - The figure is a comparison of the fluid loss properties at elevated temperatures of blend composition and unblended resins.