Investigating the Effect of Hydraulic Fracturing in the Pressure Transient Response for Multilateral Wells in Dry Gas Reservoirs

Ahmed, M. Elmuzafar (KFUPM) | Abdalla, Mohamed (KFUPM)

OnePetro 

Abstract

Using pressure transient testing is very useful to identify reservoir properties, such as permeability, and reservoir size. However, it can also be used as an evaluation tool to test the success of the fracturing process as well as identifying the fracture properties such as conductivity and size. This paper presents an investigation of the fracture properties and their effect on pressure and pressure derivative signature in multilateral wells at dry gas reservoir as well as the effect of the number of laterals, length of laterals and reservoir anisotropy.

The base case scenario was built using ECLIPSE simulator. More than 20 scenarios were used to generate the data and use the early production region as the drawdown feed data. different scenarios were investigated to analyze the pressure derivative signature and hence study how hydraulic fracture stages will appear in the curve and how can we utilize that to characterize our fracture. The effect of the lateral length and the number of laterals were studied then the fracture effect introduced to the base case starting from 1 stage fracturing up to 8 stage fracturing. Furthermore, the reservoir anisotropy and the fracture conductivity was explored.

The results of this study can be used as qualitative method to judge the success of the fracturing job by comparing the response before and after the fracturing. It was noticed that increasing the number of lateral and the length of lateral shifted the pressure derivative curve down. However, increasing the fracture stages while keeping the number of lateral constant affected only the early region.

Well testing techniques can be extended to study the complex geometry of multilateral well especially when hydraulic fractures are induced. It will be a great benefit to the industry to test their work with a quick method without the need to use downhole monitors.

Introduction

Recently the multilateral drilling and hydraulic fracturing has gained a considerable momentum, because they maximize the exposure area and hence increase the hydrocarbon production. Many researchers have investigated the performance of single and multilateral wells considering the reservoir anisotropy (smith et al. 1995; Retnanto et al. 1996; Clifford et al. 1996; Yildiz and Ozkan 1997)