Drilling method for maintaining productivity while eliminating perforating and gravel packing

Abstract

A method for well construction and completion is disclosed. First, a productive section of a well is drilled in the presence of a fluid system that controls fluid losses, is substantially non-damaging to the formation and includes particles in a particle size distribution sufficient to form a low permeability filter cake on a formation face and to allow the majority of the filter cake particles to flow back into the borehole after well completion. after drilling, a casing includes at least one and preferably a plurality of extendable permeable elements or member is run in the well so that the elements are positioned and aligned with sites in the producing formation and once extended form production conduits between the formation and an interior of the casing. A completed borehole is also disclosed including a casing having production conduits formed from the extendable members or elements.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] This invention relates to a method of drilling and completing a well. [0003] More particularly, this invention relates to a method for placing a means of communication between a productive formation and a well borehole without perforating and gravel packing the well borehole at sites of production. The method also relates to minimizing formation damage caused by conventional drilling, perforating, and gravel packing. The method combines and integrates elements of well drilling and construction with the well completion in a manner to reduce time, improve safety, and maximize productivity. [0004] 2. Description of the Related Art [0005] The search for oil and gas reserves has taken the industry to remote sites including land, traditional offshore locations, and offshore deepwater. Historically the cost for exploring and developing hydrocarbons has been very high, and as the search for hydrocarbons continues in more re...

AI Technical Summary

Benefits of technology

[0014] The present invention provides a method for drilling and completing a well, where the method achieves improved formation productivity without the need for well perforation and gravel packing.

[0015] The present invention provides a method of well construction and completion including the steps of drilling an interval of a well into or into and through a productive formation in the presence of a fluid system adapted to control fluid loss, to be substantially non-damaging to the productive formation, and to form a filter cake having substantial flow back properties minimizing adverse affects on formation productivity. After the productive interval is drilled, a casing string including at least one and preferably a plurality of laterally extendable members having a sand control medium associated therewith is run into the well so that the members can be deployed to contact sites in the productive interval, i.e., the extendable members are positioned and aligned within the productive formation interval of the well. After the casing has been properly run into the well, the members are extended such that each member comes into contact with the filter cake and / or the productive formation at their associated sites, where the contacting in sufficient to allow productive formation fluids to flow through the member into the casing and out of the well. Once the members are deployed forming production conduits between an interior of the casing and the formation, the casing is cemented in place. After casing cementing, production tubing / equipment is run into the well borehole and the well is placed on production.

[0017] The present invention provides a method of well construction and completion including the steps of drilling a first interval of a well through non-productive formations in the presence of a first fluid system. Prior to drilling into or into and through a productive formation, the first drilling fluid is replaced with a second fluid system adapted to control fluid loss, to be substantially non-damaging to the productive formation, and to form a filter cake having substantial flow back properties minimizing adverse affects on formation productivity. After fluid system replacement, a second interval of the well is drilled into or into and through a productive formation in the presence of the second fluid system. After the productive interval is drilled, a casing string including at least one and preferably a plurality of laterally extendable members having a sand control medium associated therewith is run into the well so that the members can be deployed to contact sites in the productive interval, i.e., the extendable members are positioned and aligned within the productive formation interval of the well. After the casing has been properly run into the well, the members are extended such that each member comes into contact with the filter cake and / or the productive formation at their associated sites, where the contacting in sufficient to allow productive formation fluids to flow through the member into the casing and out of the well. Once the members are deployed forming production conduits between an interior of the casing and the formation, the casing is cemented in place. After casing cementing, production tubing / equipment is run into the well borehole and the well is placed on production.

Problems solved by technology

Historically the cost for exploring and developing hydrocarbons has been very high, and as the search for hydrocarbons continues in more remote areas costs are escalating because of the amount of equipment and personnel required in these areas.

Formation damage can negatively affect productivity of the resulting wells.

These unconsolidated formations may produce sand particles and other debris which can cause well bore and surface facility problems as well as negatively affecting the productivity of the well.

This is a costly, time-consuming process.

There have been instances where leaks have caused perforating guns to low order detonate resulting in no or poor perforating performance and expensive fishing operations to remove the damaged perforating gun bodies.

Also, gravel pack screens have failed during the high-pressure pumping operation causing additional fishing operations or worse the damage isn't discover until the well is placed on production necessitating a workover of the well.

Formation damage is also a problem during conventional well construction and completion.

Another source of formation damage is the shaped charges or explosives used in perforating.

This causes crushing of the formation matrix reducing the permeability and flow potential of the formation.

Additional damage can come from the polymer gels used for controlling fluid losses after formation perforation.

However, most mud weighting materials are solid mineral particles such as barite and bentonite that cannot be readily dissolved.

This may cause unnecessary pressure drops which restrict production.

These operations are costly and time consuming and not always successful resulting in a need to re-drill a portion of, or possibly the entire well.

Formation damage is mitigated by the use of special drilling fluids termed “Drill-In-Fluids.” A common problem with this type of completion is the inability to isolate areas in the completion that produce water.

Isolating and stopping areas of water production is made extremely difficult due to not having cemented casing in-place to help control the flow of water in the annulus between the screen and the formation.

This plugging restricts the production potential of the well and may cause a workover or loss of hydrocarbon recovery from the reservoir.

These devices have not been widely used.

These devices trap drilling mud filter cake between the sand control filter media and formation face which limit productivity due to plugging of the formation and filter media The drilling fluids used in the well construction process generally contain minerals such as barite, bentonite, and / or clays in the form of solid particles.

These filter cakes have a leak off rate which allows filtrate and smaller particles to enter the pore spaces of the formation and can cause considerable damage to a formation's productivity.

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