3D connection of 2D plots

hi, I have written a code which shows a 2D circle with 4 lines:

%2D wellbore shape
R=10.795
rb=12
thetab=50
x=-rb:0.1:rb
y=(R^2-x.^2).^(0.5)
plot(x,y)
hold on
y=-(R^2-x.^2).^(0.5)
plot(x,y)
s=((R^2+rb^2-2*R*rb*sin(thetab))^0.5)
thetax=(asind((R*cosd(thetab)/s)));

jj=isreal(thetax)
if jj==1
    m1=tand(thetax)
b=-m1*rb
A=(((2*(m1^2)*rb+(4*(m1^4)*(rb^2)-4*(m1^2+1)*((m1^2)*(rb^2)-R^2))^0.5)/(2*(m1^2+1))))
ii=isreal(A)
if ii==1
x=A:rb
y=m1*(x-rb)

plot(x,y)
hold on
y=-m1*(x-rb)
plot(x,y)
x=-rb:-A
y=m1*x+m1*rb
plot(x,y)
hold on
y=-m1*x-m1*rb
plot(x,y)
grid on
    end
end
if jj==1
     m1=tand(thetax)
b=-m1*rb
A=(((2*(m1^2)*rb+(4*(m1^4)*(rb^2)-4*(m1^2+1)*((m1^2)*(rb^2)-R^2))^0.5)/(2*(m1^2+1))))
ii=isreal(A)
if ii==0
    clear('A')
    A=0
   x=A:rb
y=m1*(x-rb)

plot(x,y)
hold on
y=-m1*(x-rb)
plot(x,y)
x=-rb:-A
y=m1*x+m1*rb
plot(x,y)
hold on
y=-m1*x-m1*rb
plot(x,y)
grid on 
    end
end
if jj==0
    thetax=0
    m1=tand(thetax)
b=-m1*rb
A=(((2*(m1^2)*rb+(4*(m1^4)*(rb^2)-4*(m1^2+1)*((m1^2)*(rb^2)-R^2))^0.5)/(2*(m1^2+1))))
ii=isreal(A)
    if ii==0
        A=0
        thetax=0
    end
end

but problem is that 'rb' and 'thetab' are (1xn) matrixes and every element of these matrixes shows 'rb' and 'thetab' for a special depth(z). so we should have several circles in different depths(z) in 3D space, and this is not the end! these plots should be connected together to form a 3D surface. like this picture:<<http://www.geoexpro.com/ckfinder/userfiles/images/2008%20-%20Vol%205/No%204/Improving%20Wellbore%20Stability/ultrasonic458.jpeg>>
I should mention that 0<thetab<90 and, R<rb<2*R
who knows how can i do this?
thanks alot,