Stimulating Low Permeability Carbonate Reservoirs by Applying Acid Fracturing with Open-Hole Multi-Stage Completions Combining Sliding Sleeves and Swellable Packers for Effective Fracture Placement

2016 ◽  
Author(s):  
Pablo Guizada ◽  
Ikhsan Nugraha ◽  
Ahmad Alrashed ◽  
Eduardo Soriano ◽  
Fernando Robles ◽  
...  
Keyword(s):  
Carbonate Reservoirs ◽  
Low Permeability ◽  
Acid Fracturing ◽  
Multi Stage ◽  
Open Hole

Modeling Acid Fracturing Treatments with Multi-Stage Alternating Injection of Pad and Acid Fluids

2021 ◽  
Author(s):  
Rencheng Dong ◽  
Mary F. Wheeler ◽  
Hang Su ◽  
Kang Ma
Keyword(s):  
Viscous Fingering ◽  
High Viscosity ◽  
Carbonate Reservoirs ◽  
Acid Etching ◽  
Fracture Geometry ◽  
Fracture Conductivity ◽  
Acid Fracturing ◽  
Fracture Surfaces ◽  
Low Viscosity ◽  
Multi Stage

Abstract Acid fracturing technique is widely applied to stimulate the productivity of carbonate reservoirs. The acid-fracture conductivity is created by non-uniform acid etching on fracture surfaces. Heterogeneous mineral distribution of carbonate reservoirs can lead to non-uniform acid etching during acid fracturing treatments. In addition, the non-uniform acid etching can be enhanced by the viscous fingering mechanism. For low-perm carbonate reservoirs, by multi-stage alternating injection of a low-viscosity acid and a high-viscosity polymer pad fluid during acid fracturing, the acid tends to form viscous fingers and etch fracture surfaces non-uniformly. To accurately predict the acid-fracture conductivity, this paper developed a 3D acid fracturing model to compute the rough acid fracture geometry induced by multi-stage alternating injection of pad and acid fluids. Based on the developed numerical simulator, we investigated the effects of viscous fingering, perforation design and stage period on the acid etching process. Compared with single-stage acid injection, multi-stage alternating injection of pad and acid fluids leads to narrower and longer acid-etched channels.

Overcoming Open Hole Multistage Acid Fracturing Challenges in Saudi Arabian Carbonate Reservoirs with Swellable Packers, Best Practices and Dynamic Evaluation

2016 ◽  
Author(s):  
Ataur R. Malik ◽  
Jairo A. Leal ◽  
Mohammed A. Asiri ◽  
Tolulope M. Ogundare ◽  
Eduardo Soriano ◽  
...  
Keyword(s):  
Best Practices ◽  
Saudi Arabian ◽  
Carbonate Reservoirs ◽  
Dynamic Evaluation ◽  
Acid Fracturing ◽  
Open Hole

Application of Mean Square Deviation Method to the Target Selection of Acid Fracturing for Fissure-Cavern Carbonate Reservoirs

2015 ◽  
Vol 1092-1093 ◽  
pp. 1356-1360
Author(s):  
Ya Hong Wu ◽  
Li Wang ◽  
Hao Qing Fang ◽  
Xi Shan Tian ◽  
Qiang Bo Mi ◽  
...  
Keyword(s):  
Neural Network ◽  
Bp Neural Network ◽  
Target Selection ◽  
Carbonate Reservoirs ◽  
Physical Parameters ◽  
Mean Square ◽  
Mean Square Deviation ◽  
Acid Fracturing ◽  
Open Hole ◽  
Deviation Method

The Ordovician fissure-cavern carbonate reservoirs of Tarim Basin have relatively large production thickness, long completion intervals and serious heterogeneity problems, former studies about physical parameters for fractured intervals of acid fracturing cannot be well presented through mean algorithm method. This paper uses mean square deviation method to acquire the values of the main influencing factors of acid fracturing, then optimizes the physical characteristics of the fractured intervals. The BP neural network simulation has been adopted to get the optimal BP neural network structure model. In Tarim, this study has simulated 20 wells before acid fracturing using the decision software which compiled by the optimum neural network construction. Comparative analysis has been made through application examples, the coincident rate of mean algorithm is 75%, compared with the 90% of mean square deviation method. Therefore, during the target selection for acid fracturing of heterogeneous carbonate reservoirs with long open hole intervals, it’s significant to use mean square deviation method to optimize physical parameters of reservoirs.

A Novel Coreflood Test to Evaluate EOR Potential of Wettability-Altering Surfactants in Oil-Wet Heterogeneous Carbonate Reservoirs

2021 ◽  
Author(s):  
Yue Shi ◽  
Kishore Mohanty ◽  
Manmath Panda
Keyword(s):  
Oil Recovery ◽  
Carbonate Reservoirs ◽  
Wettability Alteration ◽  
Low Permeability ◽  
High Permeability ◽  
Matrix Permeability ◽  
Rock Heterogeneity ◽  
The Matrix ◽  
Flow Through ◽  
Main Factors

Abstract Oil-wetness and heterogeneity (i.e., existence of low and high permeability regions) are two main factors that result in low oil recovery by waterflood in carbonate reservoirs. The injected water is likely to flow through high permeability regions and bypass the oil in low permeability matrix. In this study, systematic coreflood tests were carried out in both "homogeneous" cores and "heterogeneous" cores. The heterogeneous coreflood test was proposed to model the heterogeneity of carbonate reservoirs, bypassing in low-permeability matrix during waterfloods, and dynamic imbibition of surfactant into the low-permeability matrix. The results of homogeneous coreflood tests showed that both secondary-waterflood and secondary-surfactant flood can achieve high oil recovery (>50%) from relatively homogenous cores. A shut-in phase after the surfactant injection resulted in an additional oil recovery, which suggests enough time should be allowed while using surfactants for wettability alteration. The core with a higher extent of heterogeneity produced lower oil recovery to waterflood in the coreflood tests. Final oil recovery from the matrix depends on matrix permeability as well as the rock heterogeneity. The results of heterogeneous coreflood tests showed that a slow surfactant injection (dynamic imbibition) can significantly improve the oil recovery if the oil-wet reservoir is not well-swept.

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