New Type Curves For The Analysis Of Pressure Transient Data Of Horizontal Wells In Non-Newtonian Fluid Reservoirs

ABSTRACT

This novel work is based on the study of Vongvuthipornchai and Raghavan, 1987. In this work a new 3-Dimensional non-linear partial differential equation describing the transient flow of nonNewtonian fluid in porous media is developed for a hypothetical no-flow boundary cuboid reservoir. The basic assumptions in the mathematical modeling of the differential equations are; permeability anisotropy with directional permeabilities ݇௫, ݇௬ ܽ݊݀ ݇௭ , an isothermal, single phase, slightly compressible fluid with steady state viscosity was assumed, the horizontal well was place in the ydirection perpendicular to the direction of maximum permeability݇௫. The effects of gravity were neglected and the reservoir fluid was considered to be a non-Newtonian pseudo plastic fluid that obeys the power law model.

The derived equation was discretized using finite difference approach; the system of linear equations obtained from the discretization was solved with the aid of a MATLAB 7.5.0R code to obtain pressure data. Type curves involving the log-log plot ofܲ௪஽ ܸݏ ݐ ݀݊ܽ ஽ݐ ஽כܲ ௪஽Ԣܸݏ ݐ ஽were made for cases when there is permeability isotropy and anisotropy of different power law flow index ݊ ranging from 0.1 to 1 for horizontal well length of 600ft, 1000ft and 1200ft. The developed type curves were validated by considering a Newtonian case and using Tiab Direct synthesis (TDS) technique to analyze the radial flow regime for the determination of average permeability as well as the procedure presented in Vongvuthipornchai and Raghavan, 1987 to analyze the early linear flow for determining ݇௫ and the Pseudo steady state flow regime was used to determine the drainage area. Subsequently, examples where given to determine mobility and ݇௫ for a non-Newtonian fluid of ݊ = 0.1 with methods presented in the work of works of Igbokoyi and Tiab, 2007 and Vongvuthipornchai and Raghavan, 1987.

The Validation of this works shows that the result obtained from the case when a Newtonian fluid was assumed were very close to the actual property been determined. Similarly, the results obtained from the example when ݊ = 0.1 gave close values of݇௫ and reasonable value of mobility. This novel work will thus lay a back ground for further works in the analysis of pressure transient data of horizontal well in non-Newtonian or heavy oil reservoirs.