RPSEA-Backed Fracture Technique Ready For Field Trials
(Tech Connections Column, October 2012, American Oil and Gas Reporter)
The Research Partnership to Secure Energy for America manages a U.S. Department of Energy
research and development program for upstream oil and gas technologies. One project completed in
the small producer subprogram has been vetted in laboratory trials as being ready for field
demonstration. RPSEA has selected a follow-on project to accomplish the field trials, pending final award.
The original investigation team is assembled to conduct the field demonstration project. Led by DaniMer Scientific LLC, the team includes CSI Technologies LLC,
EnerPol, Texas A&M University, and Ampak. PTTC has agreed to participate in recruiting additional smaller producers for a project steering committee, and to support
technology transfer efforts.
The initial project, “Creating Fractures Past Damage More Effectively with Less,” was completed in July. Many of the promising results are included in SPE paper
152189, “Eco-Friendly Creation of Propped Hydraulic Fractures,” and are summarized here. The new excitement, however, is in the field trials planned for the
anticipated award. In that process, the proposers will need industry participants for a voluntary project steering committee to guide the effort, and for wells of
opportunity to actually conduct small propped fracture jobs using the new technology.
Near-well-bore damage can occur in new or aging wells, limiting initial production or increasing decline, respectively. This process aims to remediate the effects of
near-well-bore damage to production capacity more cheaply, effectively, and environmentally friendly than competing treatments.
The process uses a polymer introduced into the well bore as solid pellets containing proppant. The polymer degrades in the aqueous environment to form a viscous,
proppant-containing gel fluid. The well is pumped to above fracturing pressure before the polymer degrades further, and the proppant/gel mix is injected into the
induced fractures surrounding the well bore, penetrating on the order of tens of feet. The polymer continues to degrade to a clear aqueous fluid, leaving the proppant
in the fractured, near-well-bore region.
In carbonate reservoirs, the degraded polymer has an added advantage because it is a water-soluble organic acid and further creates fracture conductivity, even
without proppant.
The key technology is the degradable polymer, which transports the proppant and then depolymerizes into water-soluble organic acids. These flow out of the
formation, leaving the formation and the proppant pack without gel blockage. Technical criteria must be met to assure the polymer hydrolyzes into gel at an
appropriate rate at formation temperatures, and then meets final degradation time frames in the formation. The polymer also must be environmentally benign,
amenable to standard fracturing processes, and safe enough so as not to require special handling for worker safety.
A suitable suite of polymers for application in the 130-250 degree Fahrenheit range has been developed in the initial laboratory phase. Manufacturing methods for the
polymers and proppant-polymer field-usable materials have been developed. The research also identified methods for estimating productivity enhancements and
payback times to assess the applicability of the method for a particular well treatment.
The Houston Area Research Center has identified this novel fracturing technology as a new, environmentally friendly production enhancement process with multiple
benefits over conventional hydraulic fracturing treatments.
The objective of the new field project is to conduct several well tests of fracturing technology to confirm its applicability, and to analyze placement and production
improvement results to validate the method’s field utility. Field design protocol and simulation software will be developed and used to evaluate test wells from
candidates operated by producers volunteering for the project.
Once the candidate wells are chosen, pre-job testing will be performed on the wells, and pumping and placement procedures will be determined. The polymer
materials will be manufactured, based on the well criteria. The team will perform simulation, and bench- and pilot-scale quality control testing, using the materials
manufactured specifically for the job. Data gathered during and after the treatments will be recorded, analyzed and compiled into a report summarizing the work done
on the project.
Successful completion of the proposed project will result in a new type of production improvement that is ideally suited to small producers. The potential benefits
include reduced horse-power and simpler execution, making the process accessible to even small pumping companies.
The developers expect the process to reduce the amount of water required and to
eliminate damage caused by traditional frac fluid gellants. The process may be applied to
wells that require fracture treatments with fewer than 50,000 pounds of proppant and that
have substantial tubular configurations that would allow for adequate volume of material
placement. The technology could be applicable to 40 percent of U.S. hydraulic fracturing
treatments.
Anyone interested in offering a test well or who would participate in the steering
committee may contact me at w law son@pttc.org. You will be playing an essential role in
developing new technology for revitalizing damaged wells.