Post-Stimulation Results and Analysis of Highly Successful Multi-Stage Acid Fracturing Campaign Performed in Tight Gas Carbonate Formations in Saudi Arabia

2010 ◽  
Author(s):  
C.A. Franco ◽  
J.R. Solares ◽  
N.S. Al-Shammari ◽  
M.M. Al-Harbi ◽  
E.A. Alabbad ◽  
...  
Keyword(s):  
Saudi Arabia ◽  
Tight Gas ◽  
Acid Fracturing ◽  
Multi Stage ◽  
Carbonate Formations

scholarly journals Case study of acid fracturing of Ordovician geothermal reservoir in Taiyun area

2021 ◽  
Vol 300 ◽  
pp. 01002
Author(s):  
Xingwu Feng ◽  
Ruohan Hu ◽  
Degang Xing ◽  
Qingzhong Yu ◽  
Jiawei Chen ◽  
...  
Keyword(s):  
Experimental Tests ◽  
Hot Water ◽  
Geothermal Reservoir ◽  
Water Production ◽  
Fracture Width ◽  
Acid Fracturing ◽  
Fracture Length ◽  
Multi Stage ◽  
Resistance Reduction ◽  
Carbonate Formations

The thermal reservoir in Taiyun area mainly consists of Ordovician and Cambrian carbonate formations. The target interval of example well contains more than 95% carbonate, being thick, argilliferous and have well-developed natural fissures and rich hot water. However, sometimes stimulation is necessary to achieve the designed water production rate. In this paper, multistage alternating injection acid fracturing technology is selected according to lithologic characteristics of geothermal reservoir. A gel acid, which is a composite of 20%HCl+0.8%SHY1+2% corrosion inhibitor+1.5% iron ion stabilizer+1% cleanup additive, is optimized and developed by experimental tests. Its viscosity can reach 27 mPa·s. Then, pumping schedule of multi-stage alternate injection acid fracturing is optimized by numerical simulator of acid fracturing design. It is shown from job pressure of field sample well that resistance reduction ability of gel acid needs to be further improved. Moreover, from the analysis results of pressure decline after acid fracturing, the fluid efficiency is 42.32%, net pressure is 3.3 MPa, and the dynamic fracture length is 107m, the maximum fracture width is 8.6mm by fitting treatment pressure. The water production increase factor reaches 1.2 after acid fracturing treatment. Therefore, the acid fracturing treatment is successful.

Permeability prediction of multi-stage tight gas sandstones based on Bayesian regularization neural network

2021 ◽  
Vol 133 ◽  
pp. 105320
Author(s):  
Yanqiu Zhou ◽  
Xiaoqing Zhao ◽  
Chengzhou Jiang ◽  
Shichen Liu ◽  
Zongyan Han ◽  
...  
Keyword(s):  
Neural Network ◽  
Bayesian Regularization ◽  
Tight Gas ◽  
Permeability Prediction ◽  
Multi Stage ◽  
Bayesian Regularization Neural Network ◽  
Tight Gas Sandstones

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.

Sign in / Sign up

Export Citation Format

Share Document