Acquiring Accurate Reservoir Data During TCP To Maximize Oil Production and Increase ESP Run Life

Day 3 Wed, November 14, 2018

Theuveny

2018

Today many exploration, appraisal and development welltest operations are performed in new frontiers. These include extreme environmental conditions and reservoirs bearing complex reservoir fluids, such as heavy oil, or fluids with a high concentration of H2S, CO2, high wax and asphaltenes content, which have rarely been tested in the past. Many failures and operational issues have hindered the interpretability of data, significantly increased the total costs of such well tests or led to severe HSE incidents. Currently, such operations are often designed and executed on a case-by-case basis, and there are no practical recommendations available that would summarise the well testing experience in such environments to guide the operating companies through the process of efficiently planning welltest operations. Consequently, operations are often planned on a "copy-paste" basis, with potentially disastrous consequences. This paper describes in detail the challenges associated with safety, flow assurance, safe handling and disposal of produced fluids, and data quality during current welltest operations with complex reservoir fluids or challenging environmental conditions. Complex reservoir fluids, including highly corrosive fluids, introduce unique challenges that need to be addressed at the design stage of the test, each requiring an appropriate design of surface well test spread and DST string, as well as the overall job operation and equipment planning to incorporate "what-if" scenarios. To address these issues, we summarize the best well-testing practices, and for each of the cases outlined illustrate proven welltesting techniques. Examples show that it is nearly impossible to perform the well test and handle complex reservoir fluids at surface using a traditional approach and standard well test equipment. Novel well testing equipment such as new generation welltest separators equipped with Coriolis mass flow meters, new generation burners and others, in combination with recently developed well testing techniques, allowed us to overcome these challenges. The paper provides practical recommendations, supported by case studies, highlighting the results and lessons learned from successful operations around the worlds in the following well test areas: –Heavy oil testing–Well test operations in high H2S and CO2 environment–Well test operations in reservoir fluids with high wax or Asphaltene content–Deepwater welltest operations with a high risk of hydrate formation–Well test operations with production of foamy oil–Heat management–Viscous fluid management–Contingency planning Recipes for success are provided to ensure that safe operation can be performed in the challenging environment while keeping the cost in line with the AFEs.

Successful Well Test Operations in Complex Reservoir Fluids: Lessons Learned and Best Practices Over 40 Years of Worldwide Operations

Day 3 Wed, November 14, 2018

Theuveny

2018

Cost Effective and Ecologically Sound Fluid Disposal During Well Clean up and Post Fracturing Flowback Operations

Day 3 Wed, November 11, 2020

Theuveny

2020

An important aspect of the well test and poststimulation flowback operations is the need to produce, responsibly manage, and safely dispose of the substantial amount of hydrocarbons, typically through flaring, which is potentially an environmental concern. This challenge has received significant attention over the past few decades and remains a major concern today. It is especially important in offshore environments, considering requirements for safe disposal of large volumes of crude and gas as well as completion fluids and possibly formation water. A common alternative to offshore flaring is storing the crude on the drilling rig, test barge, or tanker. The methods used for fluid disposal during offshore operations were reviewed as the basis for defining a practical workflow to select the optimal operations design, thus leading to a significant reduction or full elimination of burning. Inaccurately selected fluid disposal strategies can significantly constrain operations, limiting achievable objectives and increasing the risk of HSE incidents. The typical methods employed include fluid storage at the well site, high efficiency burners, and the transfer of produced liquids to oil tankers during extended well tests. Additional considerations from traditional approaches relate to the evolution of regulatory and legal frameworks on environmental concerns. Each method has its benefits and practical limitations. An analysis of possible approaches to avoid burning fluids and minimizing operational limits to well test operations identified that starting from a certain volume, crude storage and the transfer to production facilities can be considered as the best option to avoid burning while adding value to well effluents and turning well tests from a cost-to revenue-generating activity. Focusing on offshore operations with limited deck space and thus potentially limited storage capacity, the solution developed for the North Sea involved transferring the produced crude into a small shuttle tanker via a soft wall surface floating rubber hose. By using a floating transfer hose, the special requirements for hose installation were avoided, saving valuable rig time. It also reduced the need for pipe preheating and enabled the tanker to move, decreasing petrol consumption for maintaining dynamic positioning. The paper will summarize the results and lessons learned from the application of different methods used for fluid disposal in a wide range of well test operations around the globe. These were used to determine that economical and environmentally responsible solutions exist for fluid disposal during well test operations. The paper will also detail an innovative, field-proven, and cost-effective fluid storage solution using a shuttle tanker during well test and flow back operations offshore. This technique was applied in five successfully performed well tests in the North Sea, storing more than 50,000 barrels of reservoir crude in total.

Fast, Environmentally Sound and Efficient Well Clean-Up Operations: Lessons Learned and Best Practices from Operations Around the World

Day 2 Wed, September 08, 2021

Zhandin

2021

Well clean-up is one of the most complex operations performed at the wellsite today. During clean-up, a well is flowing for the first time after initial completion or workover operations through temporary surface facilities to either conduct a welltest or to simply condition the well before connecting it to production facilities. Currently, there are no practical recommendations available that would summarize clean-up experiences and guide operating companies through the process of efficiently planning well clean-up operations. Conventional well clean-up operations are inherently challenging owing to the requirements for accurate data measurements, safe handling and disposal of produced fluids (hydrocarbons, completion brine, water, and solids). Experience has shown that it is nearly impossible to perform well clean up within pre-defined constraints and target criteria without an appropriate design, equipment selection and operations planning to account for the specificities of each situation. Steady-state flow simulators have been the standard tool to model pressure and temperature changes along the wellbore and through temporary production system during well clean-up process. Those assume either final stabilized conditions or a limited number of intermediate ones and formed the basis for equipment selection. But this approach has critical limitations in modelling flowing well behavior and fast-changing flowing conditions, and therefore in assessing operational flow assurance risks and the dynamic capability of the surface plant to handle produced fluids. The paper describes in detail today's challenges during well clean-up operations that combine the need for operational safety, minimal environmental footprint and flow assurance considerations that have to be balanced with costs and production performance optimization. The paper provides practical recommendations and presents multiple case studies highlighting the results and lessons learned from applying a novel, unique workflow based on the application of a transient-multiphase flow simulator. Combined with modern well-testing equipment such as modern test separators, remotely actuated adjustable chokes or environmentally friendly fluid disposal techniques, such advanced design allows performing clean-up operations efficiently while remaining within time, rates, pressure or emissions limits.