METHOD OF SEISMIC MONITORING OF DEVELOPMENT OF ULTRA-VISCOUS OIL DEPOSITS

摘要

FIELD: oil, gas and coke-chemical industries.SUBSTANCE: invention relates to oil industry, and more specifically to technologies providing rational and effective development of ultraviscous oil or bitumen by steam-gravity drainage using seismic monitoring. Disclosed is a method of seismic monitoring of development of shallow deposits of ultraviscous oil, which consists in the fact that a downhole observation system is formed to perform well seismic survey and a surveillance system is formed to perform seismic survey on linear profiles. Selecting at least three profiles and at least one profile for each group of unidirectional SAGD-wells, wherein linear profiles are oriented perpendicular to the direction of the horizontal part of the shafts passing through the dome area of the high-viscous oil trap. Moving non-explosive pulse source of longitudinal waves is exposed to daytime relief surface, four seismograms are recorded for each well, on which wave fields of surface arrangement of seven channels and submersible borehole seismometer are fixed. Basic seismic survey is performed on linear profiles passing through test wells by multiple overlapping technique. Each excitation point is processed with accumulation of source effects, followed by computer processing of base seismic survey materials along linear profiles by graph, characteristic for the common depth point method with its adaptation for shallow seismic survey with preservation of relative amplitude level, with selection of useful waves - straight, head and reflected waves. Further, along the reflected waves, a time profile and a model of interval velocities are constructed. Further, monitoring well seismic survey and monitoring seismic survey by linear profiles is performed. Further, computer-aided processing is performed and materials of monitoring well seismic survey are corrected for the effect of seasonal variations of elastic properties of the upper part of the section by comparing them with the data of the primary survey. Further, radial velocities of basic and monitoring filming are calculated. Models of interval velocities by linear profiles are loaded into a computer interpretation system, joint analysis of all obtained materials is carried out on a common cartographic basis. Spatial distribution of velocities is formed in the thickness enclosing productive stratum-collector, maps of difference parameters between basic and repeated surveys are calculated. Further, by estimating the difference parameters between the basic and the monitoring surveys, the beam speed is varied over the period of time between the basic and subsequent shooting, further, maps of difference parameters are compared with accumulated volume of steam injected into stratum-collector for entire period of production of ultraviscous oil and for time intervals between surveys. Results of previous calculations are analyzed, conclusions on directions of formation heating in zones between horizontal wells-injectors are made.EFFECT: increased accuracy and informativeness of the data.1 cl, 11 dwg