Abstract This is a special downhole graded mutli-layer prepacked sand filter for oil and other fluids containing sand. The preferred embodiment for the sand filter includes an inner annular consolidated layer of particles placed about a slotted pipe, an intermediate annular layer of consolidated particles adjacent said inner layer and an outer annular layer of consolidated particles next to the intermediate layer of particles. There is an opening or spacing between the particles to permit flow through the prepacked liner. The spacing between the particles of the outer annular layer is such to retain only the coarser sand particles and the spacings or openings in the inner two annular layers are progressively smaller to retain the less coarse sand particles. The coarser sand particles bridge about the larger openings in the outer annular layer and progressively finer sand materials bridge across the openings or spacings between the particles of the intermediate and inner annular layers.
A graded prepacked sand screen filter having a hollow interior which comprises: an inner annular layer of particles having a first graded mesh size; a second annular layer surrounding said inner layer of particles, said second annular layer having a second graded mesh size which is larger than the graded mesh size of any annular layer of smaller diameter.
Claim 2
Dependent Claim
59 words
A graded prepacked sand screen filter having a hollow interior which comprises: an inner annular layer of particles having a first graded mesh size; a second annular layer surrounding said inner layer of particles, said second annular layer having a second graded mesh size which is larger than the graded mesh size of any annular layer of smaller diameter.
Claim 3
Dependent Claim
14 words
A filter as defined in claim 1 in which said particles are lumnite clinker.
Claim 4
Dependent Claim
38 words
A filter as defined in claim 1 including a third annular layer of particles surrounding said second layer, the mesh size of the particles of said third layer being larger than the mesh size of said second layer.
Claim 5
Dependent Claim
23 words
A screen filter as defined in claim 3 in which said particles are lumnite clinker which have been consolidated by soaking in water.
Claim 6
Dependent Claim
59 words
A graded prepacked sand screen filter having a bore for use in a well to filter sand from a fluid being produced from an underground formation which comprises: consolidated particles having an annular form, the particles near the bore of the annular form having a mesh size smaller than the particles at the outer surface of the annular form.
Claim 7
Dependent Claim
59 words
A graded prepacked sand screen filter having a bore for use in a well to filter sand from a fluid being produced from an underground formation which comprises: consolidated particles having an annular form, the particles near the bore of the annular form having a mesh size smaller than the particles at the outer surface of the annular form.
Claim 8
Dependent Claim
22 words
A sand filter as defined in claim 5 in which said annular form of consolidated particles is mounted on a slotted pipe.