Well Completion and Simulation

Historically, managing and inhibiting corrosion, scaling and paraffin deposition downhole required surface chemical remediation. Numerous application scenarios involve truck treating, bulk tank placement and chemical injection.  A commonly used modification of this principle involves dropping solid chemical compounds down the backside of the wellbore and ultimately landing into the rathole (long cylindrical cavity inside the well casing, but below the tubing string) where the accumulated mass can rapidly dissolve.

While tubing anchors are extensively used to pull tension on production tubing to improve rod pump performance, several factors need to be considered regarding the placement of the anchor. This paper will discuss field examples of tubing anchor setting strategies, mechanisms that can lead to anchors getting stuck, and alternative anchor setting strategies.
 

Environmental concerns and increasing costs are creating a need for a polymer that will allow the use of a high salt, high hardness water in the making of a viscosified frac fluid. Any new polymer would also need to tick the boxes for cost, rheology, HS&E characteristics as well as breaking in the reservoir. Past development efforts have focused on improving organic-based polymers. A new approach was taken and a shift was made to the use of silica-based polymer.

Friction reducer is a hydraulic fracturing fluid additive meant to lower costs by decreasing the friction pressure in tubulars during pumping operations. High viscosity friction reducers (HVFRs) have become increasingly popular in well stimulation applications in lieu of conventional slick water fluid systems involving linear and cross-linked gels. However, various factors must be considered when assessing the effectiveness of using HVFRs under certain frac operation conditions.

This paper will present a methodology being applied which examines well heterogeneity, and designs the diversion strategy based on actual reservoir properties.  Estimations of minimum insitu stress at each cluster are combined with estimates of stress shadow effect both from previous stages and between treatment clusters, to determine at which pressure each cluster will accept fluid.  This data is then used to bin clusters into the ones which will be treated first, followed by a diverter slug, then second and potentially third.

The development of horizontal drilling combined with hydraulic fracturing has allowed operators to develop unconventional plays once considered uneconomical. As operators move toward drilling more complex sections in these plays, proper placement of a competent cement plug on the first attempt becomes increasingly challenging. The use of a bottom hole kickoff assembly (BHKA) minimizes risk and increases reliability for all cement plug operations; plugback, kickoff and/or abandonment.

Corrosion enhanced abrasive wear is a common cause of failure in sucker rod systems. The combination of high side loads caused by deviation and the presence of corrosive chemicals creates a very difficult environment for operators. The cyclical loading nature of sucker rod system adds to the problem, leading to premature failures in rods and tubing. Operators are turning to many technologies to increase mean time between failures (MTBF) in these challenging wells. Thermoplastic liners is one of the many options to extend run life in deviated wellbores.

Chlorine Dioxide (ClO2) has been used as a well damage removal and stimulation fluid since the late 1980’s. It was originally investigated as a means to remediate reservoirs of the permanently damaging effects of polymer, monomer, and polyacrylamide floods popular in the 1980’s across many conventional oilfields, including those in the Permian Basin of West Texas, U.S.A. Chlorine Dioxide is a strong oxidizer and highly effective biocide, very popular today for preparing frac waters and aiding in recycling produced waters, also to be used in fracturing.

During the life of Yeso horizontal oil producers, well intervention and remediation is an essential step to ensure the maximum inflow volumes are being obtained and recovered volumes are matching the established production decline curves. Utilizing a Jet Junk Basket BHA with stick pipe has enabled Concho to successfully clean out a wellbore without the added cost of energized fluids and minimize the risk from getting stuck due to lost circulation. Frac sand that migrates into the wellbore during production and scale precipitation can hinder the well’s drawdown.

This paper discusses Permian Basin examples of a modern epoxy resin system that is compatible with most water- and oil-based wellbore fluid systems. Its unique mechanical properties and resistance to contamination make it a good solution for issues too complex, costly, or difficult to resolve using traditional remediation methods and materials.