Abstract: A method of determining GOR comprising subjecting a fluid to spectroscopic analysis at a first wavelength sensitive to gas and a second wavelength sensitive to oil, determining a response matrix for the contribution of gas at the first and second wavelengths and the contribution of oil at the first and second wavelengths, determining a signal response vector and the two wavelengths, calculating a mass fraction vector from the response matrix and the signal response vector and using the mass fraction vector to determine GOR.

Abstract: A new process of fracture stimulating a carbonate reservoir in a subterranean formation to stimulate the production of hydrocarbon fluids from the formation is described. During the process, the composition and reactivity of the fracture stimulation fluid that is injected into the formation surrounding a wellbore is varied from a lower reactive fluid to a higher reactive fluid. The process is designed to stimulate the fracture starting from the tip of the fracture and progressing along the fracture back to the wellbore. The reactivity of the fracture stimulation fluid is increased to maintain optimum stimulation conditions for the formation of conductive flow channels along the faces of the fracture. An optimum fracture stimulation efficiency number, Ff, is used (generally integrated into a fracture simulator computer program) to regulate the fluid composition by reactivity and flow rate, based on formation and fluid parameters.

Abstract: A wavefield separation method and apparatus for 3D VSP data, which handles arbitrary 3D source and receiver geometries, and common shot 3C data oriented to North, East and Vertical geographical coordinates and makes use of anisotropic medium properties at the downhole receivers. When given a range of propagation angles, slowness and polarization vectors are computed for each plane wave and a linear system is solved at each frequency to yield the scalar plane-wave amplitudes. A novel regularization scheme is used that obviates the need for eigen analysis of the steering matrix. Sums within subsets of these scalar plane waves are constructed to provide up and down qP (P), qS (Sv) and Sh wavefields. Vector residuals can be computed for parameter testing, quality control and imaging purposes.

Abstract: A sleeve for an acoustic logging tool has a structure with a window section having fewer bars than a conventional sleeve separated by a slotted region with thin circumferential slots which are stress-relieved at the ends (“dumb-bell” shaped). Steel receiver mounts are provided for hydrophone pressure sensors and this, together with the axially oriented hydrophones makes the tool less susceptible to interfering vibration.

Abstract: A well treatment fluid composition that comprises a carrier fluid and an amphoteric surfactant, and optionally a viscosifying agent and proppant, is well suited for use in fracturing coal beds to stimulate methane production. The composition preferably is a foam that comprises a gas such as nitrogen or air. Preferably, the surfactant has the formula R—NH2—(CH2)n—C(O)OX wherein R is a saturated or unsaturated alkyl group having from 6-20 carbon atoms, n is from 2-6, and X is hydrogen or a salt forming cation.

Abstract: A method for assessing the fracture pressure closure is proposed. This method includes first injecting a fluid into the formation at a first generally constant rate Q to create a fracture, and then, dropping the pumping rate to significantly smaller feed rate q so that the volume of the fracture becomes constant, in other words. As the fracture volume becomes constant at equilibrium, the well is shut-in. The wellbore pressure is monitored and the closure pressure is determined from the analysis of the wellbore pressure using a time-function of the dimensionless “shut-in” time, defined as the ratio of time since shutting to pumping time. This method provides a way of estimating the friction component of the monitored wellbore pressure due to the fracture tortuosity and friction. It is applicable to the art of fracturing subterranean formations and more particularly to the process of designing and analyzing stimulation treatments.

Abstract: Viscoelastic surfactant based aqueous fluid systems useful as thickening agents in various applications, e.g. to suspend particles produced during the excavation of geologic formations. The surfactants are zwitterionic/amphoteric surfactants such as dihydroxyl alkyl glycinate, alkyl ampho acetate or propionate, alkyl betaine, alkyl amidopropyl betaine and alkylimino mono- or di-propionates derived from certain waxes, fats and oils. The thickening agent is used in conjunction with an inorganic water-soluble salt or organic additive such as phthalic acid, salicylic acid or their salts.

Abstract: A valve apparatus that has a longitudinal axis therethrough comprises a valve seat member, a valve closure member, a fluid flow path, and a screening member. The valve seat member comprises a hollow bore and a first frustoconical contact surface. The valve closure member comprises a body and a second frustoconical contact surface that is adapted to seal against the first frustoconical contact surface. The valve closure member is movable along the longitudinal axis of the valve apparatus. The fluid flow path extends through the bore of the valve seat member and between the valve seat member and the valve closure member. This fluid flow path is closed when the second frustoconical contact surface is sealed against the first frustoconical contact surface. The screening member is attached to at least one of the valve closure member or the valve seat member, and screens particles from fluid passing through the fluid flow path when the valve closure member approaches the valve seat member.

Abstract: A surfactant composition for use in well treatment, particularly for removing oil-based mud deposits from a well prior to cementing, comprises an alkylpolyglucoside in a solution of a mutual solvent for water and hydrocarbon. The composition can be used to formulate a chemical wash by dissolving the composition at a concentration of about 1%-10% (e.g. 5%) by weight in water or brine.

Abstract: The combination of the cement contamination laboratory measurements and the field log measurement allows to perform the evaluation of cement placement and quality related to the designed percentage cement displacement coverage and set-up times in the casing annulus. Since the logging time after the cement job is completed is known, a comparison between the acoustic impedance or compressive strength measured using the USI log and the acoustic impedance or the compressive strength measured in the laboratory, a level of mud contamination can be derived at every point across the wellbore. From the laboratory correlations, cement strength prediction with time can be established. This new product will give the operator an accurate tool to recommend performing remedial cementing with a higher success rate.

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: This Invention relates to a novel reversible thickener, i.e., a fluid whose viscosity can be carefully modulated—from very low viscosity to sufficient viscosity to act as a barrier to further flow; particularly preferred embodiments are directed to fluids and methods for stimulating hydrocarbon low viscosity to sufficient viscosity to act as a barrier to further flow; particularly preferred—bearing formations—i.e., to increase the production of oil/gas from the formation. In particular, the Present Invention is directed to a family of fluids (and methods incorporating those fluids) intended to be pumped through a wellbore and into the hydrocarbon-bearing formation.

Abstract: Methods are provided for increasing the production of hydrocarbons from shaly formations that contain adsorbed condensed hydrocarbon gases by treating such formations with dewatering compositions comprising surfactants that cause the surfaces of the formation to be or to remain oil-wet. The methods may be used in stimulation (acidizing or acid fracturing or hydraulic fracturing), remediation or workover, and in enhancing flow from natural fractures or from unstimulated formations.

Abstract: Cementing compositions which are particularly suitable for squeeze cementing operations, comprise an aqueous phase, and a micro-cement, the aqueous phase including an aqueous suspension comprising a vinyl acetate type polymer obtained by chemically cross-linking a polyvinyl compound, a nanolatex and an anionic surfactant with a cloud point of more than 80° C.

Abstract: The present invention provides a cementing composition for an oil well or the like with porosity of less than 50%, and with a solid phase constituted by 35% to 65% (by volume) hollow microspheres, 20% to 45% Class G Portland cement, and 5% to 25% of Class G Portland micro-cement. The invention is used to cement conductor pipes in arctic zones or in deep water holes.

Abstract: Methods for determining the best value for at least one slowness-related parameter that has been determined in a number of ways is disclosed. Sonic logging data input in the methods are processed to determine multiple values of at least one slowness-related parameter using slowness/time coherence (STC) processing methods. The error of each determined parameter is determined and the determined errors used in selecting a representative parameter value from the multiple determined slowness-related parameter values.

Abstract: The present invention provides cementing compositions for oil wells or the like comprising an hydraulic binder and reinforcing particles constituted by a flexible material of low compressibility, and with an average grain size of less than 500 &mgr;m. The compositions of the invention are of particular advantage when cementing zones which are subjected to extreme dynamic stresses, such as perforation zones and the junctions of a multi-branch lateral well. They are also highly suitable for producing plugs.

Abstract: Coiled tubing (120) is used to drill into a subsurface formation and provide a conduit back to the surface to allow sensors (200) to be deployed and measurements made for monitoring of the formation. A method of monitoring subsurface formation properties between injection and production wells comprises using coiled tubing (120) to drill sensor holes at predetermined positions between the injection and production wells and fixing the coiled tubing permanently in the hole such that a sensor (200) can be deployed in the tubing to provide measurements of the formation.

Abstract: A method of cementing a well permitting a reduction in the degree of diameter reduction of casing or liners required, and not requiring excessively large initial conductor casing, is described. The method is characterized by provision of an enlarged wellbore and a novel liner structure which is adapted for expansion of a reduced diameter section thereof downhole, providing, before expansion of the section, unimpeded flow of fluid from the enlarged wellbore during cementing and close fit of the expanded section with the casing or preceding liner, after cementing is completed and expansion of the section. A novel well liner structure and novel well liner expansion means are disclosed.