Estimation of Non-Uniform Production Rate Distribution of Multi-Fractured Horizontal Well Through Pressure Transient Analysis: Model and Case Study

Abstract

The severe decline of oil production has been observed in many multi-fractured horizontal wells (MFHW) within only one or two years. It is thus essential to determine production rate distribution of MFHW for improving oil production. However, available pressure-transient analysis (PTA) models of MFHW hardly consider the effect of non-uniform production rate distribution of both horizontal sections and hydraulic fractures on pressure-transient response, which may lead to erroneous results. This paper aims at presenting an innovative approach to estimate non-uniform production rate distribution along horizontal wellbore in a relatively economical way. A novel model was proposed to better characterize flow in hydraulic fractures and horizontal wellbore. In order to better characterize pressure drops in hydraulic fractures, we first modeled fluid flow in fractures with finite conductivity by two parts, variable-mass-linear flow for fluid far from wellbore and radial flow for fluid near wellbore. Meanwhile, horizontal wellbore with finite conductivity was divided into multiple horizontal sections, and each section is considered as a cylindrical source. As a result, a semi-analytical solution was developed. We further compared it with numerical model to verify the accuracy. A new flow regime (the second radial flow) is discovered and behaves as a flat on pressure derivative curves. It would lead to erroneous results if the new regime is regarded as pseudo-radial flow. Case study indicated that the production rate distribution obtained by the model proposed in this paper match well with production logging test (PLT), which validated the accuracy of the proposed approach and explored the feasible application in well performance evaluation of MFHW. In addition, operators could make reasonable decisions to improve well performance based on the evaluation results.

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

“…In fact, PLT results have demonstrated that the production profile is non-uniform [12,48,49] as shown in Figure 1. Although He et al and Qin et al [49][50][51] have presented PTA models of to analyze the effects of non-uniform production on pressure transient characteristics, the well testing interpretation is limited since is hard to reflect the information for a large region with testing data due to the low permeability in tight formations and short testing time. Qin et al discussed the rate transient response of a multi-segment horizontal well with non-uniform production distribution along horizontal wellbores [52].…”

Rate Decline Analysis for Horizontal Wells with Multiple Sections

“…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. During past years, although plenty of work has been developed for PTA of horizontal wells and multifractured horizontal wells with multiple sections [39][40][41][42][43], rate decline analysis of HWMS is still rarely documented.…”

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

“…Aibazarov et al [20] described how to determine the downhole fluid flow path and further to optimize water shut-off operations by using integrating data from spectral noise logging tools and multisensor production logging. Over the past few years, many researchers pinpointed water entry intervals through production logging [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36]. On the other hand, another monitoring system can provide vital data (e.g., pressure and temperature) for waterinflux detection.…”