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Running Horizontal Wells with MSS Completion

17 – 19 September 2014

Samara, Russia |Holiday Inn Samara Hotel

Technical Agenda

Workshop technical sessions:

  • Session 1. Design and Modeling of Horizontal Wells with Multistage Hydraulic Fracturing
  • Session 2. Completion
  • Session 3. Hydraulic Fracturing in Horizontal Wells – Challenges
  • Session 4. Well development: studies and monitoring
  • Session 5. Post-HF Well Operation

Session 1: Design and Modeling of Horizontal Wells with Multistage Hydraulic Fracturing

Predicting realistic scenarios of reservoir development using horizontal wells with multistage hydraulic fracturing is fundamental to maximize return on project investments. Integration of information about the formation, including geological and geophysical, petrophysical, geomechanical and, increasingly frequent recently, microseismic data, makes it possible to model expected hydrocarbon production rates, analyze sensitivity of horizontal well production rates to changing parameters, such as horizontal borehole length, distance between HF ports, HF geometry secured by proppant, proppant weight per stage, number of stages and many other parameters. The output of modeling is the economical comparison of completion techniques or field development options, as well as development of more advanced completion techniques.

The best criterion to evaluate a model is how accurate the predicted production is for the selected formation completion and stimulation system. Upon stimulation operations, the measured production rates and pressures can be compared with the model values.  To that end, it is important to choose a model providing the best outline of hydraulic fracture geometry, e.g. 3D model, pseudo-3D or 2.5D model, or to develop new models with unconventional fracture geometry. And here, microseismic measurements made during multistage hydraulic fracturing are becoming vital when choosing the most representative model. Apparently, microseismic studies are also helpful as an additional tool used to evaluate the validity of resulting hydraulic fracture half-length.

Currently, numerical modeling programs predict expected efficiency of hydraulic wells with multistage HF for various drawdown pressures, which allows the target value to be approximated to maximum economic factors.

The list of topics to discuss includes, but is not limited to:

  • Eternal question – hydraulic fractures are to run across or along the horizontal borehole? Selection criteria. Existing practice.
  • What is to be chosen: geometrical approach to HF port distribution (with equal spacing) or optimized distribution technique based on filtration, capacity, and structure evaluation, geology and other data available for analysis and modeling?
  • How wide is data integration (including geological and geophysical, petrophysical, geomechanical, and microseismic data) used for horizontal well multistage HF modeling? Or a simple set of well survey data (logging, self-potential, resistance) would suffice?
  • Want – Can: what dictates the design and modeling of horizontal wells with multistage HF – formation requirements or limitations of well service companies? The discussion shall touch upon how often the models or projects planned are feasible in reality. For example, modeling demonstrates (formation requirement) 2000 m optimal horizontal borehole with 10 HFs, but in reality (capabilities of well service companies), the project may be implemented with a 1500 m borehole and 7 HFs.
  • A caliper tool inside a horizontal borehole: is it that necessary to arrange the elements of multistage HF assemblies?
  • Prediction of well potential with multistage HF – models used for evaluation and calculations.
  • Assessment of operating well effect upon surroundings, assessment of flooding system effects when using production horizontal wells with multistage HF.
  • Methods for calculating productivity of wells with multistage HF after refrac. Are there such methods? Or is the calculation for potential recovery of a single port used as the basis (as an alternative for a vertical well) with further multiplication by the number of ports?

This Session will touch upon the modeling and design process for horizontal wells with multistage HF, basic assumptions used in the process, risk and capabilities evaluation for the emerging multistage HF market, as well as major issues and how these can be resolved.

Session 2: Completion

Over the past three decades, well designs went through an evolution of single treatment vertical completion, multiple treatment vertical completion to a single treatment openhole horizontal to a cased and cemented multiple treatment horizontal completion using +15,000 m3 of water and 3 million kg of proppant for a single well. Most of this evolution has occurred in the past 10 years with the introduction of mechanical sliding sleeve completions and plug and perforation completion techniques and technologies. This evolution has just begun in Russia as operators begin to explore formations with lower permeabilities than their legacy formations. Horizontal completions are resource intensive and logistically challenging. In areas that do not have the infrastructure required to support the transporting of resources, operators experience elevated costs in logistics and time dependent services. This increase in cost, aside from the increase in resources, has hindered the economic incentive for most operators. In North America it took 5 -10 years to get where the industry is today. In the beginning of horizontal completions in North America, the average lateral length was 500m to 1,000m with four to eight treatments. Is the use of completions designs from North America in Russia, dampening the development of horizontal wells in Russia? What options are available to Russian operators? What should the timeline look like for the evolution of horizontal wells in Russia? Will this timeline promote the development of the reservoirs, infrastructure and ultimately the economics?

Within the past 5 years as conventional assets all over the world have entered the tertiary phase of development, the interest in unconventional oil reservoirs has exploded, horizontal completions in unconventional reservoirs demand a great deal of resources, time and capital. Conventional horizontal completions require a fraction of the resources, time and capital that an unconventional horizontal completion does. Being that the investment in an unconventional well is a magnitude greater than a conventional well, the efficiency in the drilling and completion operations, drilling accuracy and the stimulation design is paramount to the economic success of an unconventional asset. Russian operators are currently pursuing both conventional and unconventional reservoirs with horizontal wells. Would focusing on one of them help improve the economics and consequently improve the infrastructure and logistics?

The list of topics to discuss includes, but is not limited to:

  • Is the Oil and Gas industry in Russia trying to grow faster than the economics will allow them to?
  • Based on the current infrastructure in Russia, what would be the most economically options for operators to complete horizontal wells with respect to resource availability, economics and logistics?
  • How can horizontal completions be designed to take advantage of the currently available equipment service companies have in Russia?
  • Currently the horizontal drilling and stimulation efficiency in Russia is a fraction of what is being done in North America. How can operators increase their efficiency to reduce their costs?
  • Being that unconventional completions require an enormousness amount of resources compared to conventional completions, should Russian operators focus on conventional horizontals until the infrastructure here in Russia can support the efficiency needed for the resource intensity of unconventional reservoirs?
  • How should Russian operators approach the designs for conventional and unconventional completions in order to improve the current economics?
  • What can the Russian Federation do to help both the operators and service companies to improve the infrastructure and logistics in Russia?

Session 3: Hydraulic Fracturing in Horizontal Wells – Challenges

In continuation of shale revolution in the North America, Russia is also gaining the momentum: in recent years, one may observe a clear tendency of developing approaches to exploiting fields with hard to recover reserves.

Horizontal drilling is becoming more extensive every year with continuous adaptation of the approaches used, whilst the goals demonstrate the gain in scale and ambition.

However, the HF execution phase may encounter unconventional issues that are faced by the engineers of well service and production companies on a daily basis.

It is commonly admitted that the multistage HF technology itself and process solutions have drastically evolved since the first project in Russia.

The Russia’s clutch for “heavy oil” has formed its own features in terms of "trials and errors", and the statistics demonstrate emerging challenges.

The list of topics to discuss includes, but is not limited to:

  • HF technology – differences from the remaining world when working in horizontal wells.
  • Completion systems – Which HF limitations is the completion technology itself impose?
  • Design errors – Is HF execution the only answer to the question “Was it all planned correctly?”? Can HF correct human errors?
  • Large Numbers Law – Is it worth going for quantity? Do the increased number of stage and increased volume of proppant bring better economic results? What’s the cost of mistake?
  • New technologies and approaches.
  • Way to re-fracturing – what challenges are or may be encountered during re-fracturing of horizontal wells.

This session will discuss the basic challenges faced during HF of horizontal wells, both drilled and completed specially for multistage HF, and wells from the existing pool that have to be brought back to their productivity, as well as the attempts to execute re-fracturing or several HF operations in differently completed horizontal wells.

Eventually, we will try to find answers to the basic acute problems, and to decide together how the future of horizontal well HF operations should look like.

Session 4: Well development: studies and monitoring

Techniques for well development and putting into operation after multistage hydraulic fracturing are a final stage in the production chain aimed at obtaining well fluid, and carry a huge flow of the information that characterizes and determines the efficiency of the whole range of the performed operations, such as designing, selecting a completion system, drilling, determining horizontal length, number of hydraulic fracturing intervals and distance between them, fracture parameters, directional attitude, etc. It is for this reason that development method selection and testing after multistage hydraulic fracturing are critical work phases.

Well development methods greatly depend on the selected completion system of wells with multistage hydraulic fracturing and, obviously, shall include a range of well surveying and testing operations to determine top-priority recommendations on optimizing the aforesaid parameters of multistage hydraulic fracturing treatment design and selecting optimum production conditions of wells after hydraulic fracturing. These issues are covered not only by service companies, but also by producers.

Main topics for discussion include but not limited to the following:

  • Optimum methods for well flushing and clean-out after multistage hydraulic fracturing
  • Well development optimization, creation of pressure drawdown
  • Well testing techniques
  • Sand control after hydraulic fracturing
  • Methods of geophysical studies in long horizontal wells
  • Techniques of preparatory works before repeated hydraulic fractures in multistage hydraulic fracturing layouts
  • Methods for determination of productive and non-productive intervals after hydraulic fracturing
  • Squeeze cementing techniques
  • Manipulations with well equipment.

This session will deal with reviewing a process of well development, surveying and monitoring after multistage hydraulic fracturing, and identifying major problems and ways of their solution.
Based on the results of the session, we will try to answer these questions, and determine together an optimum range of works on multistage hydraulic fracturing study and efficiency evaluation.

Session 5: Post-HF Well Operation

Hydraulic fracturing is not only one of the most difficult jobs in the oil and gas sector, but is the most costly way of production enhancement.

High water cut of mature fields and current trends of developing approaches to exploiting fields with hard to recover reserves whip up towards the development of well drilling and development techniques, as well as production enhancement methods, including hydraulic fracturing.

As it stands in the oil sector, the economic factors come to the fore, and the achievement of target gains in oil production and effect duration becomes a primary objective to attain positive business performance indicators.

To that end, the entire cycle from well drilling planning to its development and operation of electrical submersible pumps (ESP) shall include risk assessment and elimination of adverse factors.

The challenges of well operation after HF have been addressed by oil companies since these had appeared, with specific successes achieved, but there is still an acute problem of acquiring high quality field data to choose optimal well operation modes and submersible tool running operations to ensure wells are efficiently operated after HF.

The list of topics to discuss includes, but is not limited to:

  • Evaluation and achievement of well potential – how may the potential be correctly valuated and at which stage? How may ESP be chosen correctly?
  • Correct well development and bringing on to stable production (BSP) – how do the rate and drawdown pressure affect the development? How may a well be correctly brought on to stable production?
  • Challenges of ESP operation after HF – carryover of suspended solids, fouling of actuating elements with proppant, frequent well servicing, clogging of perforated intervals, etc.
  • Effect duration – which factors affect HF effect duration during operation?
  • Hydraulic fracture productivity recovery – which methods and how efficiently are they used to assess completed HF efficiency (well surveys, dynamic well tests)? Are there re-stimulation methods and approaches to eliminate damages in a proppant secured fracture, and what difficulties would we face when implementing such methods and approaches? 

This session discusses well operation after HF, primary issues resulting in less efficient HF and corrective measures. Eventually, we will try to find answers to the issues, and to decide together how efficient well operation after HF should look like.