Reservoir’s varying permeability and pressure required various stimulation techniques

The Nejo field in northeast Mexico produces gas condensate and light crude from the Oligocene Frio Marino (OFM) formation. The reservoir is characterized by laminated sandstones with a wide range of permeabilities and pore pressures, .01–10 mD and .37– .9 psi/ft, respectively. As such, most wells in Mexico’s Nejo field require hydraulic fracturing treatments to achieve commercial production rates.

Iberoamericana de Hidrocarburos S.A. de C.V. (IHSA) applied different hydraulic fracturing techniques depending on each well’s conditions. In overpressured layers with permeabilities higher than .1 mD, IHSA used conventional crosslinked gel treatments. In low-pressure layers, it applied energized fluids. And, in tight gas reservoirs with permeabilities below .1 mD, the operator typically used a hybrid fracturing technique consisting of slickwater and crosslinked gel fluid systems.

Schlumberger proposed channel fracturing technique to increase production

To optimize production from wells usually stimulated with crosslinked gel, Schlumberger proposed applying HiWAY flow-channel fracturing service. The HiWAY service engineers stable pathways within the fracture, enabling hydrocarbons to flow through flow channels instead of the proppant pack. Because of the potential to achieve infinite fracture conductivity, and increase recovery, IHSA decided to conduct a five-well field trial in two formations.

The stimulation team combined the HiWAY service’s fracturing fluids and proprietary fibers on site with specialized mixing equipment. Then, the fracturing fluid system and proppant were pumped downhole in pulses—creating a stable proppant arrangement in the formation.

HiWAY well outperformed previous-best offset well

After the treatment, IHSA and Schlumberger conducted a rigorous comparison between the HiWAY wells and validated offset wells. The teams took bottomhole flow pressure measurements for each fracturing job, and calculated the corresponding productivity index (PI) and normalized PI. The flow capacity of the formation was quantified by the production of the permeability and the interval thickness. IHSA also periodically measured cumulative production.

The pilot wells showed between 86–132% higher sustained production rates. In fact, one of the wells (Nejo-A) produced 8% more oil and 22% more gas than the best offset well. Four wells stimulated with the HiWAY service showed, on average, 62% higher normalized initial PI than offset wells. In addition, fracturing fluid recovery increased 12–20% over the conventional crosslinked gel hydraulic fracturing treatments. IHSA applied the service to four more wells. Now, IHSA regularly uses the HiWAY service to complete new wells throughout Nejo field.