DTS based hydraulic fracture identification and production profile interpretation method for horizontal shale gas wells

Research Progress of Applying Distributed Fiber Optic Measurement Technology in Hydraulic Fracturing and Production Monitoring

“…The anti-Stokes light can be used as a reference value for removing signal noise. As shown in Equation ( 2), the ratio of Stokes-light and anti-Stokes-light intensity is calculated to obtain the measured value of temperature [6,10,11].…”

“…The output profiles of shale-gas reservoirs were interpreted to identify effective artificial fractures based on the positive correlation between flow rate and temperature drop, in addition to analyzing the three most important factors affecting temperature variation: fracture halflength, gas-flow rate and the permeability of the modified zone. The fracture half-length was used as the inversion target parameter and applied in a shale-gas well with good results [33]; subsequently, Luo et al, using the SA algorithm to explain the output profile, not only overcame the defect that the L-M algorithm might fall into the local optimum and not obtain the global optimum solution, but also avoided the problem of randomly distributed and uncontrollable inversion errors caused by the random inversion calculation of the MCMC algorithm. The reliability of their model was verified by using the PLT results in the field.…”

“…These can not only detect downhole temperature, vibration, strain, and seismic waves without interfering with the well, but also obtain distributed data information along the length of the borehole, which is widely used in fracture monitoring, production logging and VSP. With the advantages of its low cost, long-time monitoring, high resolution and sensitivity, and high temperature and pressure resistance, distributed fiber optic measurement technology has become one of the important development trends of hydraulic fracturing and production monitoring technology [6][7][8].…”

Investigation and Application of Perforation Optimization Method on Shale Gas Horizontal Well with Numerical Simulation of Multicluster Fracturing under Dense-Segment Pattern

“…Hydraulic fracturing has been regarded as a major technique helping stimulate the oil and gas reservoirs. − During a hydraulic fracturing process, sand-carrying fluid is pumped into the well bore to propagate induced fractures in the formation. − Multistage fracturing and horizontal drilling are the major techniques applied in the stimulation of unconventional reservoirs such as tight sand and shale, which are hard to develop with economic benefits by normal ways due to the ultralow permeability and low porosity. − The engineering pattern of stage-by-stage simultaneous fracturing with multiple perforation clusters has been seen as a critical stimulation method and has been proven functioning better than that with one cluster per stage in enhancing the flow abilities of oil and gas in unconventional reservoirs. , However, there is evidence indicating an attendant problem that the profile of the inflow rates of multiple perforation clusters turns out to be nonuniform due to the poor fracture propagation uniformity, which causes the low utilization ratio of perforations and massively blocks the production potential of one fractured horizontal well. − Miller et al’s study indicates that only about 20% of the clusters contribute to the 80% of the total production by acquiring and interpreting the production logs from more than 100 horizontal shale wells in multiple basins. Coincidentally, Cipolla et al drew a similar conclusion with that above by reviewing production logs for over 100 horizontal shale-gas wells, in which less than 30% of the perforation clusters produces the most of the gas and 40% or more of the clusters are nonproductive.…”

Study on the Influence Law of Temperature Profile of Vertical Wells in Gas Reservoirs

“…The distributed optical fiber-based downhole temperature measurement technology (DTS) is gradually being applied to the downhole dynamic monitoring of oil and gas wells [1,2]; DTS technology can identify artificial fractures [3], determine the fluid type [4], assess the effects of fracturing reconstruction [5], and quantitatively interpret the production profile, fracture flow contribution, and fracture parameters of fracturing horizontal wells [6][7][8], particularly for horizontal wells.…”