Abstract: An apparatus (10) for lifting and moving an object that is underwater. The apparatus including a first (12) and a second (14) chamber, both chambers containing a first (16) and a second (18) fluid. There is a conduit (20, 21) in fluid communication with the first and second chambers, the first and second fluids moveable between the first and second chambers.

Abstract: The method includes a step of introducing into the reservoir, via a well, a mixture comprising a scale inhibitor, a first scale precursor and a second scale precursor. The first and second scale precursors can react together to form scale. The first scale precursor may be an ammonium salt. The method can further comprise a step of stopping the introduction into the reservoir of the mixture and shutting in the well for 2-24 hours, and a step of introducing into the reservoir a further mixture comprising a scale inhibitor, a first and second scale precursor which can react together to form scale. The steps of stopping and resuming the introduction of mixtures may be repeated at least once. The components of the mixtures may be provided as concentrated solutions and diluted in a stream of water prior to being introduced into the reservoir. The method provides an effective way of generating a barrier to fluid flow in a reservoir. The method may be a method of abandoning an entire well in a reservoir.

Abstract: A method of a bandoning a well in a reservoir. The method including the step of forming a scale in the reservoir by introducing into the reservoir a first solution comprising a first scale precursor and a second solution comprising a second scale precursor and a scale inhibitor. The first solution and second solution are able to react together to form the scale. The method further includes the step of at least partially filling the well with cement.

Abstract: A method of installing marine equipment, the method including providing a marine apparatus comprising the marine equipment and a buoyancy device including at least a first and a second tank. The first tank containing air and the second tank containing a buoyant liquid having a specific gravity of less than 0.8 g/cm3. The method including providing a template on the seabed and guiding the marine apparatus down onto the template. Also a buoyancy device comprising at least a first and a second tank, the first tank containing a first fluid and the second tank containing a second fluid.

Abstract: A method of insulating pipeline bundles used in recovering hydrocarbons from wells is disclosed. A polymeric substance, such as an orthophosphate ester, is injected into the annulus between a carrier pipe and the hydrocarbon conveying tubulars. A ferric salt, such as ferric sulphate, may be added as a gelling agent. The mixture results in a gel having a dynamic viscosity of greater than (1000) PaS. The gel insulates the inner hydrocarbon-conveying tubulars from the surrounding seawater thus helping to maintain the relatively high temperature therewithin. This in turn reduces the likelihood for chemicals, such as hydrates, to be precipitated out of the oil phase.

Abstract: A process for recovering materials from a subterranean formation, for example in enhanced oil recovery, comprises: (A) (a) (i) selecting a first polymeric material having a repeat unit of formula (A) wherein A and B are the same or different, are selected from optionally-substituted aromatic and heteroaromatic groups and at least one comprises a relatively polar atom or group and R1 and R2 independently comprise relatively non-polar atoms or groups; or (ii) selecting a first polymeric material prepared or preparable by providing a compound of general formula (B) wherein A, B, R1 and R2 are as described above, in an aqueous solvent and causing the groups C?C in said compound to react with one another to form said first polymeric material; (b) selecting a second polymeric material which includes a functional group which is able to react in the presence of said first polymeric material to form a third polymeric material; (c) causing the formation of said third polymeric material by a reaction involving said firs

Abstract: Alkali metal carboxylate salt brines, such as cesium formate brine, are used in oil and gas drilling procedures. Contamination with chloride ions can be controlled by treatment with a silver salt solution, and removing silver chloride formed. High density brines can be obtained, suitable for re-use.