Producing hydrocarbons from the lower Delaware formation in SE New Mexico and West Texas is often associated with high water production. In the Matthews Field in West Texas (Reeves County), an operator was encountering water production of over 600 BWPD (bbl of water per day) from wells that had been treated. The stimulation techniques and processes were modified in an attempt to improve the production results. Multiple stage treatments using coiled tubing (CT) with selective placement controls and reduced rates were performed to lower the fracture height growth. This method included using conventional fracturing fluids, specialized coiled tubing perforating and controlled fracturing placement, and a relative permeability modifier (RPM) capable of reducing the potential for water production by coating the formation rock. This paper will detail how these operations were performed. Introduction The operator has produced a steady production of oil from the Delaware pays in the Matthews Field (Fig. 1) for several years. The production decline in the field was rather flat, with an estimated reserve life of 25 to 30 years. Following the last completions, the average well produces approximately 300 BWPD along with hydrocarbons. Upon acquisition of this field some time ago, a disposal well readily available in the field was used. The produced water was injected into a nonproductive zone in this disposal well. Because the field is remote from the nearest disposal facility, transporting the water to an offsite facility would be expensive. Therefore, use of the disposal well was beneficial. Over time, the high production of water also added significant costs for lifting, additional facilities, etc. The operator obviously needed a method to reduce the water-oil ratio (WOR). The geological makeup of the Matthews Field and the methodology used to derive the applied treatment are covered in this paper. Included as well are (1) a general discussion of how RPMs work, and (2) details regarding the application in this particular case. The stimulation design and treatment is surveyed, including subsequent production results. In addition, an economic analysis of a drilled and completed well in this field is also provided. This paper illustrates how the RPM and other new technology can help decrease the WOR and increase the gas-oil ratio (GOR), thereby adding value for the operator. Geology The pay intervals of interest in this field are the Lower Delaware sands of Brushy Canyon and Cherry Canyon. Cherry Canyon is the more productive and is also noted for its high clay content and high water production. Its primary makeup is fine-grained sandstone with carbonate consolidation.[1] A variety of stimulation techniques has been used in this area, including fracturing with water and foamed fluids energized with either carbon dioxide or nitrogen. In this project, a conventional crosslinked fluid system was used. Stimulation treatments in the Brushy and Cherry sands are usually straightforward, but it is common for significant amounts of sand and water to flow back after treatments. A possible solution to this flowback problem entails pumping resin-coated sand, which has significant bonding capability. Use of this type of treatment in the subject well however was eliminated because of its high cost. Instead, a conductivity-enhancing additive was used to coat the proppant to help prevent sand flowback and fines migration. An RPM was also added to the treatment as a preflush to help combat water production.

No abstract

The cementing design process has been improved by using current technology to predict actual downhole conditions, allowing both the service provider and the well operator to manage fluid positions, critical circulating pressures and surface parameters while cementing casings in wells under stringent conditions. This paper explains how design data and real-time simulation of cementing jobs can be used to make detailed predictions of many well parameters and provide information allowing adjustments to be made during the cementing operation to alter the outcome or help improve the performance of the job. These tools can allow the operator and service provider tomore accurately predict cement tops,change casing programs,control flow-back rates and pressures,monitor equivalent circulating density (ECD) on specific zones, orenable personnel to create a better design for other wells in the field. The development of computer simulations to model surface and downhole conditions has been used for more than 26 years to improve and facilitate cementing operations under different and variable scenarios. By using this engineering computer program, many cementing failures can be prevented not only before the actual cementing operation is performed, but during the operation itself. Maintaining control and predicting problems is possible by taking into account all the monitored and calculated variables on a real-time mode and comparing the outputted prediction output with the pre-job design and the actual job in progress. Demonstrated by examples and case studies, the simulation process performs many steps needed to give precision to predictions in placement calculations. The computational process gathers information, and with multiple logical sequences, provides the most suitable solution for the scenario being studied. Multiple design program runs may be completed without jeopardizing the integrity of the well. While designing a plan, several parameters can be changed to predict the job performance or end results. Modifications or changes in various operational events for performance predictions may be used in making recommendations. Recommendations may be altered by changing such components as cementing materials, placement methods and even casing configurations to help ensure a better performance based on pre-job investigations. Introduction The zonal isolation behind casings achieved in the cementing processes is critical for the well's drilling and producing operations. Successfully performing a primary cement operation presents constant challenges and is best planned with up-to-date knowledge and engineering technology to achieve wellbore integrity and extended well life. The development of a computer simulation to model both surface and downhole conditions has been a valuable tool in use now for over 26 years. Its use has improved and facilitated cementing operations in complex and variable scenarios. The computer simulation program has constantly been scrutinized and modified through the years to improve its performance and the parameters it can handle based on observations and field engineering needs. By using this engineering computer simulation program, many cementing failures can be prevented not only before the cementing operation takes place, but during the actual operation itself. Maintaining control and predicting possible problems can be accomplished by analyzing all the monitored and calculated variables on a real-time mode and comparing these predictions with the pre-job design and the actual job itself. Ideally, in any computer-simulation process, many steps need to be evaluated to give precision to the predictions and calculations. The computational process gathers the information and, with multiple logical sequences, provides the most workable and suitable solution for the scenario being studied. Multiple design program evaluations and simulation runs may be completed at one's desk without jeopardizing the integrity of the well. While designing a plan, several parameters can be changed to predict the job performance or the calculated end results. Modifications or changes in various operational events are used in the development of recommendations. Recommendations may be altered by changing such components as cementing materials, placement methods or modes, and even casing configurations to help ensure a better performance.[1–6]

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractProducing hydrocarbons from the lower Delaware formation in SE New Mexico and West Texas is often associated with high water production. In the Matthews Field in West Texas (Reeves County), an operator was encountering water production of over 600 BWPD (bbl of water per day) from wells that had been treated. The stimulation techniques and processes were modified in an attempt to improve the production results. Multiple stage treatments using coiled tubing (CT) with selective placement controls and reduced rates were performed to lower the fracture height growth. This method included using conventional fracturing fluids, specialized coiled tubing perforating and controlled fracturing placement, and a relative permeability modifier (RPM) capable of reducing the potential for water production by coating the formation rock. This paper will detail how these operations were performed.