Pressure-Transient Behavior of Multisegment Horizontal Wells With Nonuniform Production: Theory and Case Study

Field data indicate production profile along horizontal wells is nonuniform. This paper develops an analytical model of multisegment horizontal wells (MSHWs) to estimate rate distribution along horizontal wellbore, interpret the effective producing length (EPL), and identify underperforming horizontal sections using bottom-hole pressure (BHP) data. Pressure solutions enable to model an MSHW with nonuniform distribution of length, spacing, rate, and skin factor. The solution is verified with the analytical solution in commercial software. Type curves are generated to analyze the pressure-transient behavior. The second radial-flow (SRF) occurs for the MSHWs, and the duration of SRF depends on interference between segments. The pressure-derivative curve during SRF equals to 0.5/N-p (N-p denotes the number of mainly producing segments (PS)) under weak interference between segments. The calculated average permeability may be N-p times lower than accurate value when the SRF is misinterpreted as pseudoradial-flow regime. The point (0, 0, h/2) are selected as the reference point, and symmetrical cases will generate different results, enabling us to distinguish them. Finally, field application indicates the potential practical application to identify the underperforming horizontal segments.