Well Pressure Behavior of a Finite-Conductivity Fracture Intersecting a Finite Sealing-Fault Freddy H. Escobar; Freddy H. Escobar Universidad Surcolombiana Search for other works by this author on: This Site Google Scholar Djebbar Tiab; Djebbar Tiab University of Oklahoma Search for other works by this author on: This Site Google Scholar Sergio Berumen-Campos Sergio Berumen-Campos Pemex E & P Search for other works by this author on: This Site Google Scholar Paper presented at the SPE Asia Pacific Oil and Gas Conference and Exhibition, Jakarta, Indonesia, September 2003. Paper Number: SPE-80547-MS https://doi.org/10.2118/80547-MS Published: September 09 2003 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Get Permissions Search Site Citation Escobar, Freddy H., Tiab, Djebbar, and Sergio Berumen-Campos. "Well Pressure Behavior of a Finite-Conductivity Fracture Intersecting a Finite Sealing-Fault." Paper presented at the SPE Asia Pacific Oil and Gas Conference and Exhibition, Jakarta, Indonesia, September 2003. doi: https://doi.org/10.2118/80547-MS Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll ProceedingsSociety of Petroleum Engineers (SPE)SPE Asia Pacific Oil and Gas Conference and Exhibition Search Advanced Search AbstractHydraulic fracturing is important to the development of low permeability reservoirs. Recent advances in the technology of hydraulic fracturing, coupled with its economic success, have led to its application in high permeability reservoirs. Consequently, fracturing is now applied in all types of formations including highly faulted systems. The existence of a fault near a well may impede or contribute to the fracture extension process. Various models and techniques have been introduced in the literature for the interpretation of transient pressure behavior of vertically fractured wells. However, none of the current models and techniques has taken into account the case of a fracture intersecting a fault.This paper presents a theoretical model for analyzing the pressure behavior of a finite-conductivity vertical hydraulic fracture intersected by a sealing-finite fault, considering different angles of intersection and neglecting in all cases wellbore and fracture storage effects. The point at which fracture and fault conjoint has also been a matter of analysis in this study. The model was solved numerically using PEBI grids.For the case where the fracture-fault system form an angle of 90 or 75°, the pressure response is characterized by a maximum point or "hump" in the pressure derivative which takes place once the transient response of the fracture has vanished. This is because the fault delays the development of the pseudoradial flow regime. For smaller angles, a peak is not observed; however, there is a transition period that causes an apparent pseudoradial flow to develop earlier. This is because the hump tries to develop but the fault is not long enough for that to happen. When the fault is very long (LD > re), pseudoradial flow does not develop because the fault acts as a boundary. A horizontal line on the pressure derivative curve is observed which can be easily confused with that of the actual pseudoradial flow regime. Correlations to estimate both fault length and fracture-fault angles are presented. A simulated example is presented to illustrate the proposed step-by-step procedure for interpreting a post-fracture pressure test of well near a sealing-fault.IntroductionWell test analysis in hydraulically fractured wells has been a topic of interest to the oil industry since the early 1950's1–4. Since then, different approaches have been presented to study their pressure transient behavior. Numerical, physical semianalytic and analytic models have been proposed and analyzed3–10.The introduction of a sealing fault in the vicinity of the well makes the mathematical/numerical treatment of the fractured wells more difficult. Numerical techniques require the implementation of a gridding method that is different than the traditionally rectangular system to better capture the effects of the non-orthogonality problem introduced by the fault. In this study, PEBI grids, implemented in a commercial simulator were employed to solve the mathematical models11.Escobar12 first studied the pressure behavior of a vertical hydraulic fracture intersecting a fault. He used several fracture-fault angles and several fault lengths. As the angle of the fault is reduced from 90 to zero degrees and when fault and fracture conjoin at their tips, the characteristic signature, the "hump," is less evident or can be completely absent. The rotation of the fault from 90° to zero at the tip of the main fracture diminishes the influence of the fault on the formation of pseudoradial flow.Mathematical expressions for estimating the length of the fault and the fault-fracture angle were developed using the approach of the Tiab's Direct Synthesis Technique14–16. The procedure has a major effect in improving the analysis of a hydraulically fractured well pressure response since it allows us to understand the performance of hydraulical fractures intersected by a finite sealing-fault. Interpretation of pressure transient tests for finite-conductivity fractured wells by the Tiab's Direct Synthesis Technique is now extended to cover this new aspect. Keywords: horizontal line, drillstem testing, fracture, permeability, fracture conductivity, middle part, flow regime, dimensionless fracture conductivity, fault length, dimensionless pressure Subjects: Hydraulic Fracturing, Formation Evaluation & Management, Drillstem/well testing This content is only available via PDF. 2003. Society of Petroleum Engineers You can access this article if you purchase or spend a download.