This invention relates to a method for treating wells completed in subterranean formations to prevent the movement of unconsolidated sand particles from the formation into the well during recovery of formation fluid or away from the well during injection of an extraneous recovery fluid thereinto. The method is especially applicable to formations containing asphaltic or bituminous petroleum, such as tar sand deposits. In one embodiment, granular material such as sand or gravel is introduced into the formation adjacent to the well bore and saturated with bituminous or asphaltic petroleum. The bituminous petroleum naturally occurring in a tar sand material may be used, or bituminous petroleum may be pumped into the sand and gravel. Bituminous petroleum from tar sands is usually too viscous to be pumped in its natural state, so it must first be heated or diluted with a suitable solvent or incorporated into a bitumen-in-water emulsion prior to injection, with suitable subsequent treatment to evaporate the solvent or resolve the emulsion. Steam and air are injected in a controlled ratio to cause a low temperature, controlled oxidation to occur, creating a hydrocarbon cokelike material to form, which bonds the granular material together to form a permeable, rock-like substance which has sufficient permeability to permit flow of fluids therethrough but which has pore space of sufficiently small size to restrain movement of formation sand particles therethrough.
A method for consolidating sand around a well, involving injecting hot water or steam through well casing perforations in to create a cement-like area around the perforation of sufficient rigidity to prevent sand from flowing into and obstructing the well. The cement area has several wormholes that provide fluid passageways between the well and the formation, while still inhibiting sand inflow.
This process comprises injecting into the formations a liquid organic mixture containing at least one polymerizable chemical compound and a catalyst. The organic mixture reacts with a limited amount of injected oxidizing gas to produce a solid compound which consolidates the formations without substantially reducing their permeability. The process is characterized by the combined use of a polyethylenic hydrocarbon and of a catalyst which comprises at least one element of the group consisting of zirconium, cerium, lanthanum and lanthanides and at least one element selected from the group formed by vanadium, manganese, cobalt and zinc.
A method for controlling sand production by consolidating an incompetent formation is disclosed. In this method, elemental liquid sulfur is suspended in steam which is injected into the formation. The sulfur reacts with the in-place hydrocarbon to form a consolidating agent.
Wells drilled in poorly consolidated sand formations can be consolidated by heating a portion of the crude oil in situ in the bottom of the well so as to drive off the lighter ends leaving the heavy ends and asphaltenes at the bottom of the well. If additional pressure is then added at the top of the well, the heated fraction is forced into the surrounding cooler formations where it condenses and cools forming a semi-solid material tending to restrain sand from being produced upon further production of the well. The heated fluids will flow into any channels formed in the sand by said production. Continued application of pressure will cause flow channels to be formed in the cooling heavy portion by the light ends, ensuring permeability of the structure.
A method is provided for consolidating a geological formation comprising the injection of a liquid organic mixture into the formation then injection of a hot inert gas mixture through said liquid mixture, so as to transform this liquid mixture by a thermal polymerization reaction into a substance binding the non consolidated elements of the formation. The injected liquid organic mixture contains at least one polyethylenic hydrocarbon to which a catalyst may be added.
