thereof which will also enhance gel viscosity it will be understood that in view of the teaching of the present invention in particular having regard to fig2 a person skilled in the art will find the selection of the appropriate quantity of acid of a desired strength to be an obvious matter of choice involving no undue experimentation or the like in this regard it must be understood that the design criteria for any particular fracturing job will vary and it is not sufficient merely to always obtain the maximum or any given viscosity moreover since the chemical environment in a formation will be unique the fracturing fluid for it must be adjusted according using the application of well accepted principles of engineering and the present invention the partially acidified phosphate ester is then mixed in the hydrocarbon fluid to be gelled with a trivalent cation preferably iron ferric supplied as ferric citrate ph about 2 5 the phosphate alkyl esters and cations form a mesh like network in the hydrocarbon fluid resulting in a gel the hypothesized reaction is as follows it will be understood that such a network will transform the essentially two dimensional phosphate alkyl ester to a three dimensional very viscous gel the gelling rate is moreover greatly enhanced in the presence of a surfactant the sulphate groups formed in.