A Semianalytical Approach to Estimate the Locations of Malfunctioning Horizontal Wellbore through Bottom-Hole Pressure and Its Application in Hudson Oilfield

Abstract

Some wellbore segments have little or no contribution to total production rates because of reservoir heterogeneity, completion methods, and nonuniform formation damage along the horizontal wellbore. This work presents a semianalytical approach to determine the effective producing length (EPL) and production distribution of horizontal well, and further estimate the locations of malfunctioning horizontal wellbore and the segments of water or gas coning through the history matching of bottomhole-pressure (BHP) data. In this approach, horizontal wellbore was divided into multiple producing segments and each producing segment (PS) can be considered as a cylindrical source. New pressure-transient solutions are further developed for a horizontal well with multiple segments of arbitrary length, production, skin factor, and spacing. This work obtaines the type curves and further investigates the effect of crucial parameters (e.g. EPL, spacing between PS, number, production and skin factor of each PS) on pressure-transient behaviors. Results show that there are distinct differences among type curves with different parameters above. A horizontal line with the value of 0.5/N can be noticed in the pressure-derivative curve during the second radial-flow regime when inteferences between PS are minor. If the second radial-flow was misinterpreted as pseudoradial-flow, the interpreted permeability will be N times smaller than the accurate result. Therefore, it is significant to identify the horizontal line correctly especially for low-permeability reservoir (hard to reach the second radial-flow) and offshore oil fields (because of the short testing time). Finally, a history matching procedure is developed to determine the parameters above, and has been applied into two horizontal wells of Hudson oilfield in Tarim Basin. Case studies highlight the physical consistency of the solution, and demonstrate its practicability to estimate the EPL and diagnose the locations of malfunctioning horizontal wellbore. The approach proposed in this work can be used to evaluate formation and well performance along horizontal wellbore so that engineers could make decisions on field strategies to improve well performance.

An Improved Rate-Transient Analysis Model of Multi-Fractured Horizontal Wells with Non-Uniform Hydraulic Fracture Properties

“…Pressure-transient analysis (PTA) and RTA have been acknowledged as effective approaches to understand the reservoir/well performance and estimate its parameters by using transient bottomhole-pressure (BHP) data or long-term production data [22][23][24][25][26][27]. However, due to technical and economic difficulties of well-testing operations in tight reservoirs, RTA based on daily production data is more attractive [23].…”

Rate Decline Analysis for Horizontal Wells with Multiple Sections

“…Other PTA models are proposed in different works [32][33][34][35][36]. He et al [37] proposed a method for estimating malfunctioning horizontal wellbore through bottom hole pressure data. Qin et al [38] developed novel approach to evaluate nonuniform production distribution of multifractured horizontal wellbore based on PTA.…”

Diagnosis of Water-Influx Locations of Horizontal Well Subject to Bottom-Water Drive through Well-Testing Analysis

“…Pressure transient analysis (PTA) has been extensively used for evaluating production performance of horizontal wells [5,[37][38][39][40][41][42][43][44][45]. Kamal et al [44] pointed out that even if the horizontal well is entirely open or perforated, some of the segments are nonproducing.…”

“…Kamal et al [44] pointed out that even if the horizontal well is entirely open or perforated, some of the segments are nonproducing. He et al [45] and Qin et al [46] established a PTA model to estimate the effective producing length and identify locations of underperforming horizontal segments. Detailed description about PTA of MSM can be found in He et al [45].…”

“…He et al [45] and Qin et al [46] established a PTA model to estimate the effective producing length and identify locations of underperforming horizontal segments. Detailed description about PTA of MSM can be found in He et al [45]. Additionally, this phenomenon of nonuniform production distribution also exists in multifractured horizontal wells [47][48][49][50][51][52].…”