The early stages of a coalbed methane (CBM) project development often require more extensive use of currently available technologies than can be economically justified when approached from a conventional oil and gas drilling focus. As a result, key evaluation tools and technologies are either omitted or not considered before significant decisions are made regarding viability of a CBM play. Understanding that the various lifecycle phases will each affect different objectives and decision points is important. Following site acquisition and estimating basic drilling costs, at least five lifecycle phases can be identified: (1) Regional Resource Reconnaissance, (2) Local Asset Evaluation, (3) Early Development, (4) Mature Development; and (5) Declining Production.A systematic review of current and recently developed enabling technologies is presented in the context of their potential use and applicability. Environmental risk and other constraints that can impact development vary globally, as do economics and production forecasting. New and emerging chemical technologies, as well as hydraulic fracturing refinements, play key roles in various lifecycle phases and decision making to identify successful CBM development projects as early as possible. The paper presents strategies that can reduce development phase failure risk and help predict or rank production potential. Economic constraints usually become more restrictive as the lifecycle moves to Phase 4 and beyond, but key information needed to enter Phase 4 is often overlooked. Examples of this scenario are presented from a global perspective.Globally, new and existing technologies combined with dynamic gas and electricity markets are changing the nature of CBM development opportunities. More accurate and timely go/no-go information needs to be used in the decision making process. Converting development opportunities to development successes involves integrating planning and evaluation methods, using targeted development technologies in the proper phase, and managing risk. TX 75083-3836, U.S.A., fax 01-972-952-9435.

This paper was prepared for presentation at the 1999 SPE Rocky Mountain Regional Meeting held in Gillette, Wyoming, 15–18 May 1999.

In wells with relatively high levels of iron, the use of polyacrylamide friction reducers (FR) used for hydraulic fracturing can result in poor performance due to negative chemical interactions. Hazra, et.al. (URTeC 2487 July 2020) documented a problem with the chemical reaction of FR and iron (ferrous and ferric) during hydraulic fracturing. This chemical reaction can create an accumulation of a semi-solid mass referred to as "gummy bears" due to their rubbery texture (figure 1). These gummy bears can form in surface and subsurface equipment and inhibit well production. In addition to the formation of gummy bears, the performance of FR is significantly impaired when reacting with iron (figure 2). Pyrite (FeS2) is a common mineral found in source rock. Ferrous iron (Fe2+) can be released by oxidative dissolution of pyrite minerals. In reservoirs with high concentrations of pyrite, iron can be released by dissolving reservoir rock during acid spearheading. Acid spearheading is a common industry practice during hydraulic fracturing operations. The process involves pumping a small quantity of acid pre-frac to dissolve rock material around the wellbore, cleaning up perforations, and reducing near wellbore entry friction. The focus of the acid spearhead is to lower breakdown pressures and improve injectivity during hydraulic fracturing. The problem that Hazra (2020) described was on a Woodford Shale project in Oklahoma. The Woodford is known to contain significant quantities of pyrite (observed at around 2%). One solution proposed was to eliminate the use of acid during the hydraulic fracturing operation. The potential downside was higher near wellbore frictions that would need to be addressed by higher hydraulic horsepower (HHP) and FR volumes. Figure 1 Effect of Fe2+ and Fe3+ on friction reduction properties of polyacrylamide friction reducer Figure courtesy of Downhole Chemical Solutions Figure 2 Gummy Bears Photo courtesy of Downhole Chemical Solutions The process of explosive perforating can create high near wellbore friction due to the perforation tunnel crushing that occurs during the perforation process. The acid spearhead is pumped to clean up this crushed zone and improve perforation tunnel performance. A new system of perforating was described by Albert (SPE 199274-MS 2019) that incorporated propellant and explosives perforating to eliminate the perforation tunnel crushed zone and reduce near wellbore friction. This paper will describe a Barnett Shale project that utilized this new composite perforating method to eliminate the use of acid.

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractWells completed by the openhole cavity technique in the Fruitland formation of the fairway zone in the San Juan basin have demonstrated gas production rates nearly ten times greater than production rates from wells completed by fracturing in the same area, but expensive trial and error selection of wells to cavity complete outside the fairway and in other basins must be made. Data from numerous wells were obtained from four companies active in the basin. Five parameters namely in-situ stress, bottom-hole pressure, ash content, volatile matter, and depth to the top of the Fruitland coalseams were statistically ranked by their importance to the success of cavity completion techniques, and these five parameters were contoured using the "Surfer" software. From the resulting contours, boundaries of fairway zones similar to that of the San Juan basin can now be defined in unexplored basins. This study is the first to assimilate enough minimum in-situ stress data in the San Juan basin to statistically correlate with production rates. The statistical analysis shows minimum in-situ stress to be the most important parameter of the five studied for successful cavity completions. A threshold minimum in-situ stress between 2080-2359 psi is required if other parameters of the study are satisfactory. The study is important for coalbed methane development around the world where coalseams as successful as the San Juan fairway are sought for the application of cavity completions.

The early stages of a coalbed methane (CBM) project development often require more extensive use of currently available technologies than can be economically justified when approached from a conventional oil and gas drilling focus. As a result, key evaluation tools and technologies are either omitted or not considered before significant decisions are made regarding viability of a CBM play. Understanding that the various lifecycle phases will each affect different objectives and decision points is important. Following site acquisition and estimating basic drilling costs, at least five lifecycle phases can be identified: (1) Regional Resource Reconnaissance, (2) Local Asset Evaluation, (3) Early Development, (4) Mature Development; and (5) Declining Production.A systematic review of current and recently developed enabling technologies is presented in the context of their potential use and applicability. Environmental risk and other constraints that can impact development vary globally, as do economics and production forecasting. New and emerging chemical technologies, as well as hydraulic fracturing refinements, play key roles in various lifecycle phases and decision making to identify successful CBM development projects as early as possible. The paper presents strategies that can reduce development phase failure risk and help predict or rank production potential. Economic constraints usually become more restrictive as the lifecycle moves to Phase 4 and beyond, but key information needed to enter Phase 4 is often overlooked. Examples of this scenario are presented from a global perspective.Globally, new and existing technologies combined with dynamic gas and electricity markets are changing the nature of CBM development opportunities. More accurate and timely go/no-go information needs to be used in the decision making process. Converting development opportunities to development successes involves integrating planning and evaluation methods, using targeted development technologies in the proper phase, and managing risk. TX 75083-3836, U.S.A., fax 01-972-952-9435.