Abstract: An aqueous oilfield treatment fluid containing a chelating agent and an HF source is described. This fluid is effective at dissolving siliceous materials such as clays and keeping the dissolved materials in solution. In particular it is effective at preventing re-precipitation of initially-dissolved silicon as silica and therefore reduces damage to sandstones with which it is contacted. Methods are given for using this fluid for sandstone matrix stimulation, removal of clay-containing drilling fluid components and filter cakes from wellbores, sandstone acid fracturing, and gravel pack and proppant pack cleaning.

Abstract: Disclosed are methods of modeling stimulation treatments, such as designing matrix treatments for subterranean formations penetrated by a wellbore, to enhance hydrocarbon recovery. The modeling methods describe the growth rate and the structure of the dissolution pattern formed due to the injection of a treatment fluid in a porous medium, based on calculating the length scales for dominant transport mechanism(s) and reaction mechanism(s) in the direction of flow lX and the direction transverse to flow lT. Methods of the invention may further include introducing a treatment fluid into the formation, and treating the formation.

Abstract: An aqueous oilfield treatment fluid containing a chelating agent and an HF source is described. This fluid is effective at dissolving siliceous materials such as clays and keeping the dissolved materials in solution. In particular it is effective at preventing re-precipitation of initially-dissolved silicon as silica and therefore reduces damage to sandstones with which it is contacted. Methods are given for using this fluid for sandstone matrix stimulation, removal of clay-containing drilling fluid components and filter cakes from wellbores, sandstone acid fracturing, and gravel pack and proppant pack cleaning.

Abstract: A method for designing acid treatments provides for the selection of optimal treatment for well stimulation wherein reservoir characteristics are obtained to further select the reaction kinetic data on the minerals of interests, the treatment to the reservoir is scaled up using a mathematical model and real time damage are computed based on bottomhole pressure and injection rate and compared to that predicted by the mathematical model to adjust the treatment. The model generated facilitates optimization of matrix treatments by providing a rapid quantitative evaluation of various treatment strategies for a formation. Stimulation with non-traditional fluid recipes containing mixtures of inorganic and organic acids, and chelating agents can be readily computed. The computed values can then be used in an economic model to justify the additional costs associated with the use of the non-traditional fluids.

Abstract: A new averaged/continuum model is presented for simulation of wormhole formation during matrix stimulation of carbonates.