The Stimulation Technology Research and Application in the Heavy Oil CarbonateReservoir of the Fracture and Cavity

摘要

The Ordovician carbonate reservoir in Taliram Basin isrntypical of fractured and caved reservoirs with thick oil layer,rnhigh temperature, deep zone and extra heterogeneity togetherrnwith high density, high viscosity and high freezing point et al asrncommon characteristics of crude oil. More than 80% wells havernto be stimulated before economically producing. Based on thernlaboratory researches and plentiful field practices, the followingrnstimulation modes are formed: the multiplayer acid-fracturingrnfor long open-hole interval or layered acid-fracturing, height-controlrnacid-fracturing against bottom water coining, arncombination of hydraulic fracturing and acid fracturing. On thernbasis of drill so&g, logging data, well-recorded data and somerngeophysical data such as change rate of logging amplitude,rncohere body and Jason reversion et al., model for well selectingrnand layer appraising is developed. We develop high-viscorngelling acid, retarded acid based on surfactant, low frictionrnresistance emulsified acid as well as insitu stiffening acid, withrnbetter retardancy, low leakage and low friction as the result, withrnwhich the damage near the wellbore is effectively solved andrndeeply penetrated acid-etched fracture is obtained. Furthermore,rnthe 3D acid fracturing optimization design techniques forrnfractured and caved reservoir brought forward in this paper havernaccurately calculated the treatment data and fracture geometry,rnthus the effectiveness of acid fracturing is increased a lot. Up tornthe end of 2003, more than 220 times of application of acid-fracturingrnin Ordovician Carbonate Reservoir of Tahe Oilfieldrnlocated in the northeast of Taliram Basin of China have indicated that 98.8% were effective, with average single-wellrnincremental yield of 60t/d and the period of validity over 250rndays, therefore, Tahe oilfield has increased the production aboutrn311.8×10 4 t altogether.