Drilling and completing geothermal wells in the Salton Sea Geothermal Area represents a unique challenge. Acidic, corrosive produced fluids, combined with high
temperatures and the requirement for a long service life often necessitate high cost, corrosion resistant casing materials. Unfortunately, these materials can be susceptible to wear. Therefore, casing protection becomes vital in providing a long service life. Wear must be minimized, because the resulting damage can be impossible to repair. Rotating drill pipe protectors have been run to protect casing for years, but with shallow casing set points and long bit runs, maintaining protection of the casing results in these protectors being run into open hole. This often causes damage to the protectors, resulting in debris in the hole and subsequent loss of casing protection. On one well in the Salton Sea area, an operator had experienced difficulties in running rotating protectors in open hole. The large volume of debris from damaged rotating
protectors caused a well sidetrack. Non-Rotating Protectors (NRPs) were investigated as an option. As a result, a high-temperature, high-strength version of a Non-Rotating Protector (NRP) that is commonly used in oil and gas cased hole applications, was developed and tested. These tests were run alongside other casing protection methods to evaluate both their durability and their suitability for protecting casing in geothermal wells. In a 2,314 m vertical geothermal well with 1,372 m of 2507 super-duplex stainless steel casing, non-rotating protectors were run immediately above the BHA to evaluate suitability in open hole conditions. They were run 549m into open hole for more than 130 rotating hours at temperatures ranging from 120°C to 190°C. The protectors showed minimal wear and no signs of significant damage. As a result, a program was developed to provide effective casing protection while maintaining an optimized drilling program. The program included the use of computer simulations that predict contact forces and casing wear.